Dissertations / Theses on the topic 'Poly Ether Imine'

Na montagem de um farol automobilístico são utilizados diversos materiais, tais como insertos metálicos nas fixações, vidros nas lâmpadas, materiais poliméricos nas lentes, carcaças, molduras, vedações e refletores, além de vernizes, tintas, película de metal para reflexão do feixe luminoso. Há cerca de quatro décadas foi iniciada a confecção dos refletores utilizando o BMC (bulk moulding compound), sigla em inglês para composto para moldagem em forma de massa, que é um compósito polimérico termofixo. Este material apresenta inúmeras vantagens sobre o metal, tal como forma e geometria que podem se integrar facilmente ao desenho do carro, elevada produtividade, baixo custo e da elevada resistência térmica. Contudo, apresentam o inconveniente de não poderem ser reciclados. Uma opção ao BMC tem sido o PEI [poli (éter imida)], que é um material polimérico termoplástico de alto desempenho que apresenta propriedades atrativas para essa utilização. Oferece também elevada produtividade, porém com um custo elevado se comparado ao BMC. Tem a vantagem de pode ser reciclado. De modo a analisar o potencial dos dois materiais e extrair deles suas vantagens competitivas, bem como determinar suas possíveis limitações, o presente trabalho apresenta os resultados de caracterização mecânica, análise térmica, ensaios de impacto, ensaios de temperatura de deflexão térmica (HDT) e reaproveitamento de resíduos de BMC, incorporando-o ao PVC [poli (cloreto de vinila)], resultando uma nova blenda polimérica. O estudo conclui que ambos os materiais podem ser utilizados para fabricação de refletores automobilísticos. No entanto, o preço do PEI é maior que o do BMC, o que desestimula sua utilização em produtos de alta escala de produção, como, por exemplo, o produto do presente trabalho. O BMC por sua vez não pode ser reciclado, exigindo um custo adicional para seu reaproveitamento de maneira a evitar seu descarte em aterro sanitário.
For assembly of an automobile headlight a lot of materials are used such as metallic inserts anchors, glass in the lamps, lens of polymeric materials, bezels, frames, fences and reflectors as well as paints, metallic sheet for reflection of the luminous beam. About four decades ago begun the manufacturing of BMC reflectors, which is a thermoset composite material. This material presents countless advantages on the metal, such as shape and geometry that can easily integrate the designing of cars, high productivity, low cost and high heat resistance. However, they have the disadvantage of not being able to be recycled. An option to the BMC has been the PEI [poly (ether imide)], which is a high performance polymeric thermoplastic material which brings attractive properties for the production of reflectors. It also offers high productivity, however with a high cost compared to BMC. It also has the advantage of being recycled. In order to analyze the potential of both materials and extract their competitive advantages, as well as determine their possible limitations, this study presents the results of mechanical characterization, thermal analysis, impact tests, tests on heat deflection temperature (HDT) and the reuse of BMC waste, incorporating it to PVC [poly (vinyl chloride)], resulting in a new polymeric blend. The study concludes that both materials can be used for manufacturing automobile reflectors. However, the price of PEI is higher than the one of BMC, which discourages their use in high-scale production products, as the one of this work. The BMC for your time can not be recycled, demanding an extra cost for their reuse, avoiding its disposal in landfill.

Commercially available 4,4â -dichlorodiphenylsulfone (DCDPS) was successfully disulfonated with fuming sulfuric acid to yield 3,3â -disodiumsulfonyl-4,4â -dichlorodiphenylsulfone (SDCDPS). Subsequently, DCDPS and SDCDPS were systematically reacted with 4,4â -biphenol under nucleophilic step polymerization conditions to generate a series of high molecular weight, film-forming, ductile, ion conducting copolymers. These were converted to the acid form and investigated as proton exchange membranes for fuel cells. Hydrophilicity increased with the level of sulfonation. However, water sorption increased gradually until about 50 mole percent SDCDPS was incorporated, and thereafter showed a large increase to yield water soluble materials for the 100% SDCDPS system. Atomic force microscopy (AFM) confirmed that the morphology of the copolymers displayed continuity of the hydrophilic phase at 60 mole percent SDCDPS. Conductivity measurements in the 40-50 mole percent SDCDPS range, where excellent mechanical strength was maintained, produced values of 0.1 S/cm or higher which were comparable to the control, Nafionâ ¢. These compositions also show a high degree of compatibility with heteropolyacids such as phosphotungstic acid. These inorganic compounds provide a promising mechanism for obtaining conductivity at temperatures well above the boiling point of water and membrane compositions containing them are being actively pursued. The water soluble 100% SDCDPS system was further investigated by successfully functionalizing the endgroups to afford aromatic amines via appropriate endcapping with m-aminophenol. Oligomers and polymers from 5-30 kg/mole number average molecular weight were synthesized and well characterized by NMR spectroscopy, endgroup titrations and size exclusion chromatography. The diamino-telechelic sulfonated segment was reacted with several dianhydrides and diamines to produce multiblock, hydrophobic polyimide-hydrophilic sulfonated polyarylene ether copolymers. Both ester-acid and amic acid synthesis routes were utilized in combination with spin-casting and bulk imidization. A series of tough, film-forming segmented copolymers was prepared and characterized. AFM measurements demonstrated the generation of quite well defined, nanophase-separated morphologies which were dependent upon composition as well as aging in a humid environment. Characterizations of the segmented copolymers for conductivity, and water and methanol sorption were performed and comparisons to state-of-the-art perfluorinated Nafionâ ¢ systems were made. It is concluded that the segmented or block systems have the potential to enhance certain desirable PEM characteristics in fuel cells, particularly those related to swelling, retention of mechanical strength at elevated temperatures, and critical adhesion issues in membrane electrode assemblies.
Ph. D.

End-functional poly(ether amic acid)s and poly(siloxane imide) multiblock copolymers, comprised of 2,2'-Bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) / meta-phenylene diamine (MPDA) and hexafluoroisopropylidene-2-bis(phthalic acid anhydride) (6FDA) / meta-phenylene diamine (MPDA) polyimide segments, have been prepared and characterized to explore possibilities for controlling interface properties. Incorporation of polydimethylsiloxane (PDMS) components into polyimide backbone structures can yield advantageous properties such as low energy surfaces and low stress interfaces. End-functional BPDA/MPDA poly(amic acid) salts and poly(siloxane amic acid) salts were prepared in methanolic or aqueous tripropylamine solutions. The polymeric salts formed stable water solutions (or dispersions) and imidized in less than 10 minutes at 260°C. The water solubility and rapid imidization times are ideal for on-line processing. Thus, these materials can be used as sizing and interface toughening agents for fiber reinforced composite manufacturing. Epoxy-polyimide networks prepared from the amine functionalized polyimide with DER 331 epoxy resin and diamino diphenylsulfone showed microphase separation (100-300 nm inclusions) by transmission electron microscopy. Slight toughening of the cured epoxy with 9 weight % imide was observed with the imide as the included phase. Epoxy bilayer films of polyimide (amine end-functional and commercial Ultem⠢) and poly(siloxane imide) multiblock copolymers were prepared to evaluate the polymer-matrix interphase region. Atomic force microscopy (AFM) analysis of the bilayer films showed diffusion at the interphase for the bilayers prepared with the polyimides and the BPADA/MPDA block copolymers containing polyimide continuous phases. Poly(siloxane imide) multiblock copolymers comprised of 6FDA/MPDA polyimide structures are ideal candidates for controlling interfacial properties between silicon substrates layered with thin films for microelectronic applications. These high Tg materials offer an approach for obtaining reduced moisture absorption and low stress interfaces. Evaluation of the refractive indices of the block copolymer films showed a decrease with increasing siloxane content thus suggesting the possibility of lower dielectric constants. The polymer-metal interfacial properties were investigated for films cast on titanium and tantalum substrates. The results suggested a correlation between the surface hydroxyl concentration of the metal oxide layer with the interfacial properties of the cast poly(siloxane imide) block copolymer films. The surface hydroxyls were thought to hydrogen bond with the PDMS component of the block copolymer. Since the titanium substrate has a higher surface hydroxyl concentration than the tantalum, higher silicon concentrations were observed. The melt imidized end-functional polyimides and poly(siloxane imide) block copolymers produced thermally stable materials with 5% weight loss temperatures well above 400°C. However, the block copolymers showed slightly lower 5% weight loss temperatures as a function of siloxane content with a significant increase in char formation. Correlation of the upper glass transition temperatures with the imide segment length was consistent with findings noted for other phase separated randomly segmented block copolymers. Incorporating PDMS into the polyimide backbone structure has an effect on the bulk and surface properties. The bulk properties of the poly(siloxane imide) block copolymers were characterized using TEM. The morphologies were consistent with classical block copolymers. Surface properties of the block copolymer films as a function of PDMS content were investigated using angular dependent X-ray photoelectron spectroscopy at take-off angles of 15, 30, and 45°. Surface enrichment of PDMS content over that of the bulk was observed at all three sampling depths. Further evidence of this siloxane enrichment in the surface was demonstrated with water contact angle analyses. With as little as 5 weight % PDMS ( = 5000 g/mol) in the block copolymer there was over a 25% increase in the water contact angle over the polyimide control. The surface topography was influenced by the degree of phase separation and was characterized using AFM. The roughness factor was used to represent the data. It was found that the surface roughness increased with increasing PDMS content.
Ph. D.

Dendrimers are hyperbranched macromolecules, with branches-upon-branches architectures, precise constitutions and molecular weights of several kiloDaltons (Figure 1). The dendritic structure remains to be an influential feature in the developments of dendrimer chemistry at large. Organometallic catalysis forms an active area, wherein the dendrimers find a defined importance. A number of dendrimer types have been utilized to study organometallic catalysis that combine the dendritic architectural principles. Chapter 1 of the Thesis summarizes the advances in the dendrimer-mediated catalyses, apart from an overview of the methods adopted to synthesize dendrimers. Chapter 2 describes the synthesis of newer types of larger generation poly(propyl ether imine) (PETIM) dendrimers. The molecular structure of a sixth generation PETIM dendrimer is shown in Figure 2. The PETIM series of dendrimers are synthesized by iterative synthetic cycles of two reductions and two Michael addition reactions. Modifications of the synthetic methods were identified, so as to facilitate the synthesis and purification of the higher generation dendrimers. Formation of the PETIM dendrimers, possessing a tertiary amine as the branch juncture and ether as the linker component, is assessed systematically by routine analytical techniques. The peripheries of these dendrimers possess either alcohols or amines or carboxylic acids or esters or nitriles, thereby opening up possibilities for varied studies. Architecturally-driven effects are searched constantly while integrating dendrimers in wide ranging studies. With knowledge that un-functionalized PAMAM and PPI dendrimers show fluorescence properties, we tested the PETIM dendrimers for their luminescence property. The photophysical properties of PETIM dendrimers presenting esters, alcohols, acid salts, nitriles and amines at their peripheries were studied. The anomalous fluorescence arising from alcohol terminated PETIM dendrimers (Figure 3) was established through a series of experiments. Various experimental parameters including pH, viscosity of the solvents, aging, temperature and concentration were used to assess the photochemical properties of the PETIM dendrimers. It was observed that generations 1 to 5 absorbed in the region of 260-340 nm, in MeOH and in aqueous solutions. Excitation of the OH-terminated dendrimer solutions at 330 nm led to an emission at ~390 nm (Figure 4). Dendrimers presenting esters, acid salts and amines at their peripheries also exhibited a similar excitation and emission wavelengths. An increase in the fluorescence intensity was observed at low pH and with more viscous solvents. Lifetime measurements showed at least two species (~2.5 and ~7.0 ns) were responsible for the emission. The quenching of the fluorescence originating from the PETIM dendrimers by inorganic anions was also established in the present study. The periodate, persulfate, perchlorate and nitrite anions quenched the fluorescence efficiently among several anions tested. An ‘oxygen-interacted moiety’, in addition to altered hydrogen bonding properties of the dendrimers, was presumed contribute to the anomalous fluorescence behavior. Chapter 3 of the Thesis elaborates photophysical studies of several PETIM dendrimers. Incorporation of catalytically active moieties at the peripheries of dendrimers was identified as an important avenue, in order to explore the effect of the dendritic architectures on the catalytic activities of chosen catalytic moieties. In order to assess the effect of the dendritic scaffold, in relation to both numbers and locations of the catalytic units, an effort was undertaken to study the catalytic activities of catalytic units, that are present in varying numbers within one generation. Partial and full phosphine-metal complex substituted three generations of dendritic catalysts were synthesized, by using a selective alkylation as a key step. The number of the primary amine groups led to define the number of phosphine groups at the peripheries. The primary amine groups were, in turn, prepared by a Michael addition of acrylonitrile and hydroxyl groups, followed by a reduction of the nitrile moieties to the corresponding amines. The first and the second generation PETIM dendrimers utilized in this study present up to four and eight hydroxyl groups at their peripheries. A partial etherification was exercised in order to mask few hydroxyl groups, useful to prepare the partially substituted phosphine groups. Subsequent Michael addition of acrylonitrile with remaining hydroxyl groups, to afford the nitrile terminated dendrimers, and a metal-mediated reduction of the nitrile to amine led to the required number of amine functionalized dendrimers. Functionalization of the peripheries with alkyldiphenyl phosphine moieties was conducted through a Mannich reaction of the amines with formaldehyde and diphenyl phosphine. The subsequent metal complexation with Pd(COD)Cl2 afforded a series of phosphine-Pd(II) complexes, for the zero, first and second generation PETIM dendrimers. Figure 5 shows the molecular structures of a partially and a fully substituted second generation dendrimer. Catalytic activities of the dendrimer-Pd(II) complexes were assessed in both Heck and Suzuki coupling reactions. A C-C bond forming reactions were studied, with the series of dendritic-Pd(II) catalysts, using Cs2CO3 as a base and at 40 oC. In an overall observation, it was found that an individual catalytic site showed a considerable increase in the catalytic activity when it was present in multiple numbers than as a single unit within the same generation (Figure 6). Figure 6. Bar diagrams of (a) Heck reaction and (b) Suzuki reaction, employing the dendritic catalysts 1 - 11. The Heck coupling reaction involved tert-butyl acrylate and iodobenzene, and the Suzuki coupling reaction involved phenyl boronic acid and iodobenzene. The observations revealed that: (i) the higher generation dendritic catalysts exhibited higher catalytic activities per catalytic site and (ii) the dendritic scaffold has a role in enhancing the activities of the individual catalytic sites. The catalysis study identified the catalytic activities that occurred when a series of catalysts within a given dendrimer generation was used. Such a study is hitherto unknown and the observations of this study address some of the pertinent queries relating to the efficiencies of multivalent dendritic catalysts. Chapter 4 of the Thesis describes the synthesis and characterization of series of organometallic PETIM dendrimer and studies of their catalytic activities. Studies on solid-supported catalysis present a significant importance in heterogeneous organometallic catalysis. Silica is a prominently utilized heterogeneous metal catalyst support. Functionalization of the solid supports with suitable chelating ligands is emerging as a viable strategy to circumvent not only the pertinent metal catalyst deterioration and leaching limitations, but also to stabilize the metal particles and to adjust their catalytic efficiencies. In exploring heterogeneous organometallic catalysis, functionalization of silica with a first generation phosphinated dendritic amine was undertaken. The synthetic scheme adopted to synthesize dendrimer functionalized silica is shown in Scheme 1. The reaction of the chloropropylated silica 4 with amine 3 was conducted in CHCl3. Complexation of the functionalized silica 5 with Pd(COD)Cl2 led to isolation of Pd(II)- impregnated silica. Scheme 1. Preparation of Pd nanoparticles stabilized by functionalized silica. It was anticipated that the ratio of phosphine to Pd(II) would be 1:0.5, resulting from a bidendate binding of the phosphine ligand to Pd metal. The observed ICP-OES result indicated that all phosphine ligands did not chelate the metal. With the desire to obtain the metal nanoparticles, the metal complex was subjected to a reduction, which was performed by conditioning 5-Pd(II) complex in EtOH. The Pd metal nanoparticle thus formed was characterized by physical methods, and the spherical nanoparticles were found to have >85 % size distribution between 2-4 nm (Figure 7). Analyses of the Pd(0) impregnated in dendrimer functionalized silica were performed using NMR, XPS spectroscopies, elemental analysis and microscopies. Figure 7. Transmission electron micrograph and histogram of 6, obtained after treatment with EtOH. The Pd-nanoparticle stabilized silica was used in the hydrogenation of several α, β-unsaturated olefins. The catalyst recycling experiments were conducted more than 10 times, and no loss in the catalytic activities were observed. Chapter 5 describes the functionalization of the silica support with diphenylphosphinomethyl-derivatized dendritic amine, palladium nanoparticle formation and the catalysis studies. Overall, the Thesis establishes the synthesis of larger generation PETIM dendrimers, studies of their anomalous fluorescence behavior, organometallic catalysis in solution, as well as, in heterogeneous conditions, pertaining to the C-C bond forming reactions and hydrogenation reactions. (For figure, graph and structural formula pl see the pdf file)

Synthesis and Studies of Dendritic Poly(Ether Imine) Boronates and Cholesteryl-Functionalized Mesogens SYNOPSIS Dendrimers are hyperbranched synthetic macromolecules having branches-upon-branches structures, high molecular weights, globular shapes and monodispersities. Dendrimers possess a large number of modifiable functional groups at their peripheries. Initial efforts were largely concerned with the synthesis, design and development of new dendrimers. Exploring the chemical, biological and material applicability of these macromolecules are relevant to current interests, as a result of the unique structural features of dendrimers. Incorporation of transition metals and organic moieties at the peripheries of the dendrimers was studied to determine their efficacies in catalysis. Evolution of dendritic effects was observed in few instances, that were non-linear in nature. On the other hand, dendritic peripheries were also utilized to study mesogenic properties in liquid crystals. Chapter 1 of the Thesis gives an overview of the types of dendrimers, its structural features and their application in catalysis and as liquid crystalline materials. Chapter 2 describes the synthesis of a new type of poly(ethyl ether imine) dendrimer, having nitrogen as a branching unit, ethylene moiety as the spacer and an oxygen as the connecting linker. Synthesis, characterization, and studies of the photophysical properties of these dendrimers are described in this chapter. The molecular structure of second generation dendrimer is shown in Figure 1. Synthesis of this dendrimer was initiated using 2,2'-oxy-bis(ethan-1¬amine) as the core. The reaction sequence of two alternate nucleophilic substitutions and two alternate reductions, involving ethyl bromoacetate and bromoacetonitrile as monomers was employed in the synthesis of the dendrimer. The formation of dendrimers having ether linkage and tertiary amines as branching unit was established by spectroscopies and mass spectrometry. A number of functional groups, such as, acid, alcohol, amine, ester and nitrile are present at the peripheries of each generation the dendrimers that open up the possibilities for further studies. Carboxylic acid terminated poly(ethyl ether imine) dendrimers are substituted iminodiacetic acids, belonging to the class of polyaminocarboxylic acid. Methyl iminodiacetic acid boronates with NB coordination have emerged as an excellent substitute for unstable boronic acids. Upon increasing the steric bulk on the nitrogen moiety, the hydrolytic stability of the boronates to a base-catalyzed hydrolysis is increased. Combining the structure of carboxylic acid terminated dendrimer and the stability of the dendritic boronates, such dendritic iminodiacetic acids were reacted with arylboronic acids to prepare bis-and tetrakis-boronates (Figure 2). Kinetic hydrolytic studies of boronates were conducted to assess the stabilities of the newly synthesized dendritic boronates. From the studies it was observed that the tetrakis-boronate was ~20 times more stable in comparison with dimeric and monomeric boronates (Figure 3). Subsequent to synthesis and hydrolytic stability studies, C-C bond-forming Suzuki-Miyaura cross-coupling reactions were conducted. A comparison of the reactivities among monomeric, dimeric and tetrameric arylboronates in C-C bond-forming reactions showed a higher reactivity of monomeric and dimeric boronates, than the tetrameric aryl boronate to construct ter-and tetra-aryl in one-pot iterative manner (Figure 4). Chapter 3 of this Thesis describes the synthesis and characterization of dendritic boronates and studies of their hydrolytic stability in Suzuki-Miyaura cross¬coupling reactions to construct ter-and tetraaryls. Figure 4. Synthesis of (a) ter-(6) and (b) tetra-aryls (7) by following one-pot iterative cross-coupling reactions. Step-wise iterative synthesis of dendrimer allows a uniform branching throughout the structure. The first and second generation poly(ether imine) dendrimer series, having hydroxyl groups at their peripheries were chosen for further modification. A versatile mesogenic group, namely, cholesterol was covalently attached at the peripheries of the dendrimers with succinic moiety as linker, so as to install 4 and 8 cholesteryl moieties at the peripheries of the dendrimers (Figure 5), that were characterized by H, C NMR spectroscopies and elemental analysis, so as to confirm their structural homogeneities. Figure 5. Molecular structures of the first and second generation dendritic mesogens. Subsequent to synthesis and characterization, liquid crystalline properties of all the dendritic mesogens was assessed through differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) studies. In POM study, broken fan or leaf like texture revealed the lamellar arrangement, whereas homeotropic appearance of texture on surfactant (cetyltrimethylammonium bromide) coated substrate indicated the lamellar nature of G1-Et-(OCS)4, G1-Pr-(OCS)4 and G2-Pr-(OCS)8 (Figure 6). From DSC studies, the change in enthalpy was found to increase with increase in generation and change in enthalpy per mesogenic unit was found to be ~ -1 1-2 kJ mol, which indicated the mesophase arrangement to be lamellar. Decrease in the length of spacer dendritic backbone and increase in the generation increased the isotropization temperature of the dendritic liquid crystals. Variable temperature XRD studies were undertaken to characterize the mesophase property. Two sharp peaks in small angle region and a diffused halo in wide angle region in XRD pattern of the material suggested the smectic A (SmA) liquid crystalline arrangement of G1-Et-(OCS)4, G1-Pr-(OCS)4 and G2-Pr-(OCS)8 (Figure 7). Figure 6. POM textures of (a) G1-Et-(OCS)4 at 136 oC; (b) G2-Et-(OCS)8 at 129 oC; (c) G1-Pr-(OCS)4 at 92 oC; (d) G2-Pr-(OCS)8 at 118 oC and (e) transition temperatures for dendromesogens (DSC second heating cycle, heating-cooling rate = 10 oC min-1). Figure 7. Small angle XRD profiles of: (a) G1-Pr-(OCS)4 and (b) G2-Et-(OCS)8 at 60 o C (black), 150 oC (red) and 180 oC (green), (Insets: Lorentzean fit of wide angle peak). The second generation ethyl-linker dendrimer G2-Et-(OCS)8 exhibited a layered structure with a superimposed in-plane modulation (SmÃ), the length of which corresponded to a rectangular column width. Chapter 4 describes the synthesis, characterization and studies of mesophase property and fluorescence property of cholesterol functionalized homologous pairs of the PETIM dendritic liquid crystals. Peripheral functionalization of the dendrimers provides an easy access to dendritic liquid crystalline materials. The covalent functionalization was extended further with the dendrimers for both the series, so as to have 2, 4, 8 and 16 cholesteryl groups at the peripheries of 0, 1, 2 and 3 generation dendrimers, respectively, having succinic amide and phthalic ester functionalities for 1, 2 and 3 generation dendrimers with 4, 8 and 16 cholesteryl groups. Molecular structures of third generation dendrimers are shown in Figure 8. Figure 8. Molecular structures of third generation G3-Pr-(NHCS)16 and G3-Pr-(OCP)16. Subsequent to synthesis and characterization, mesophase property was studied through POM, DSC and XRD techniques. In POM study, a birefringent texture was observed in heating and cooling cycles. Leaflet, broken fan or bâtonnet like texture suggested the layered arrangement of the molecules (Figure 9). In DSC studiues, it was observed that the amide-linked dendrimers showed higher glass transition and isotropization temperatures than that of ester-linked dendrimers within the same generation irrespective of the back-bone of the dendrimer. Succinic moiety linked dendrimers showed lower glass transition temperature than that of phthalic moiety linked dendrimers and consequently, larger mesophase range. The change in enthalpy for isotropization was found to increase with increase in generation, whereas change in -1 enthalpy per mesogenic unit was 1-2 kJ mol, indicative of a layered arrangement in the mesophase. Figure 9. POM textures (20x) of (a) G3-Pr-(NHCS)16 at 90 oC; (b) G3-Pr-(OCS)16 at 90 ooo C; (c) PG1-(NHCS)4 at 134 C; (d) G3-Pr-(OCP)16 at 98 C and (e) transition temperatures for dendromesogens (second cycle, heating-cooling rate = 10 oC min-1). Appearance of two sharp peaks in small angle region and a wide halo in wide angle region in XRD pattern supported lamellar mesophase property of the material (Figure 10). On decreasing the temperature, increase in the layer thickness also suggested the smectic A arrangement of the molecules except third generation phthalate derivative G3-Pr-(OCP)16, which showed rectangular columnar mesophase. For all the dendromesogens, the layer thickness increased with the increase in generation. Upon protonation, the first generation dendrimer showed a change in mesophase from simple smectic A to modulated smectic A with decrease in layer thickness. The change in liquid crystal property of the dendromesogens from lamellar to columnar mesophase by changing the linker of the mesogen is unknown so far in the dendrimer liquid crystals. Chapter 5 gives details of synthesis, characterization and mesophase property study of ester-and amide-linked dendritic liquid crystals. Overall, the Thesis establishes a synthetic methodology for the synthesis of a new homologous series of poly(ether imine) dendrimers with ethyl spacer; synthesis of dendritic boronates and their studies in cross-coupling reactions through in-situ slow release of boronic acid; hydrolytic stability study showed higher stability of dendritic boronates which was used in one-pot iterative cross-coupling reactions to construct ter-and tetra-aryls. decrease in linker length in dendrimer backbone modified the thermal, as well as, mesophase behavior of the dendritic liquid crystals; change in the linker functionality from ester to amide changed the thermal behavior of dendritic liquid crystals; a switching of mesophase property from lamellar to columnar was observed by changing the rigidity of the linker from succinate to phthalate without changing the linker length. The results of the above chapters are in different stages of publications: 1 Dendritic iminodiacetic acids and their boronates in Suzuki-Miyaura cross¬coupling reactions. Sharma, A.; Kumar, P.; Pal, R.; Jayaraman, N. Revised Manuscript submitted. 2 In-plane modulated smectic à vs smectic A lamellar structures in homologous pairs of dendritic liquid crystals. Kumar, P.; Rao, D. S. S.; Prasad, S. K.; Jayaraman, N. Revised Manuscript submitted. 3 Effect of protonation on dendritic liquid crystals of poly(ether imine) dendrimers: structure property relationship studies. Kumar, P.; Rao, D. S. S.; Prasad, S. K.; Jayaraman, N. Manuscript submitted. 4 Smectic to rectangular columnar switch from succinic to phthalic linker alteration in poly(ether imine) dendritic liquid crystals. Kumar, P.; Rao, D. S. S.; Prasad, S. K.; Jayaraman, N. Manuscript in preparation.

Dendrimers are synthetic macromolecules with branches-upon-branches structures, nanoscale dimensions and a high density of surface groups. Presence of multiple cationic sites in dendrimers permits their efficient nucleic acid complexation and cellular internalization through endocytic pathways. PETIM dendrimers of are characterized by tertiary amine branch points, and ether linkages. A third generation PETIM dendrimer, G3(NH2)24, with nitrogen at the core and twenty four peripheral primary amines was synthesized through alternate Michael addition and reduction reactions. The ability of G3(NH2)24 to interact with DNA was ascertained by spectroscopic and bio-physical techniques. These studies established the formation of dendrimer-DNA, and complex formation was also shown to protect the plasmid DNA from nucleases. Toxicity studies in cell culture, as well as, in female Balb/c mice established the non-toxic properties of the dendrimer. G3(NH2)24 was able to mediate efficient transfection in mammalian cells and in vivo. Targeted delivery of small interfering RNA (siRNA) to hepatocytes, in order to combat hepatitis C virus (HCV) infection was undertaken to expand the scope of PETIM dendrimer based gene delivery. Functionalization of the dendrimer periphery with galactose units ensured preferential delivery to the liver through multivalent interactions with the asialoglycoprotein receptors on the liver cell surface. The delivery of siRNA to the perinuclear region, in close proximity to the HCV RNA replication site resulted in ~75% decrease in viral RNA levels in replicon containing cells, as well as, JFH-1 infectious virus systems. The dendrimer-siRNA complexes were preferentially delivered to mice liver and were active in vivo. Physico-chemical studies of the protonation pattern of PETIM dendrimer indicated that the protonation of the dendrimer amines proceeded in a shell-wise pattern from the periphery to the core. The primary amines of the dendrimer as well as the outer shell tertiary amines with pKa values ~7-10 were protonated at physiological pH and were cationic sites for nucleic acid condensation. The inner shell tertiary amines with a pKa of ~4-6 were protonated at endosomal pH and aided ‘endosomal escape’ due to the high buffering capacity of 3.5. Work described in the Thesis establish a new synthetic dendrimer vector, namely, the series of PETIM dendrimers, as a high value gene delivery vector, making in-roads towards pre-clinical and possible clinical trials in future studies.

碩士
國立交通大學
應用化學系
87
Hyperbranched poly(ether imide)s containing a large number of chain end function groups were synthesized. The physical properties of the polymers such as thermal property and solubility were investigated and depend having on the nature of the chain end. The poly (ether ketone)s with the degree of branching ~0% and 100 % were also synthesized. The effect of the degree of branching on the physical properties of the hyperbranched poly(ether ketone)s was studied.

碩士
國立交通大學
應用化學系
91
Self-condensation of AB2 type monomers, 4-{4-[di(4-aminophenyl)methyl]phenoxy}phthalic acid (3) and the diacid monomer (10) using TPP and pyridine as condensing agents in NMP (1-methyl-2-pyrrolidinone) yielded hyperbranched poly(ether imide), P1 and hyperbranched poly(ether imide amide), P6. After compound (9) was reacted with 1,4-diaminophenylene, TPP and pyridine was added directly yielded Hyperbranched poly(ether imide amide), P6’. The hyperbranched macromolecules contain a large number of chain end functional groups, and the physical properties of the polymers such as thermal properties and solubility depend on the nature of the end groups. The degree of branching of the hyperbranched polymers, P1, P6 and P6’, was determined with the help of model compounds using 1H-NMR and was found to be 56%, 60.4% and 60.9%. The end capping reactions of the hyperbranched polymers, P1 and P6, also ensure that the physical properties of the polymers rely on the nature of the chain ends. In addition, the structure of the PI-POSS was globular and the morphology of PI-POSS was regular, which were determined by the measurement of TEM.

This dissertation reports the studies of the blends of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI). The investigations reported encompass both the thermodynamic and kinetic aspects of this binary blend. The phase behavior of PEEK/PEI blends in the amorphous states was investigated by differential scanning calorimetry (DSC), density measurement, and Fourier-Transform Infrared (FTIR) spectroscopy. Amorphous PEEK/PEI blends were miscible over the whole composition range. The specific volume measurement and the equilibrium melting point depression analysis showed the existence of favorable interaction between PEEK and PEI. The FTIR study suggested that the oxygen lone-pair electrons of the ether groups in PEEK interact favorably with the electron-deficient imide rings in PEI. The coplanarity of the two nearest imide rings in PEI was changed by blending to accommodate the favorable interaction with PEEK. The two-stage crystallization behavior of PEEK and PEEK/PEI blends was studied by thermal mechanical analysis (TMA) and DSC. The two crystallization stages of PEEK were first time distinguished clearly by measuring the thickness change of PEEK films during isothermal crystallization. A crystallization kinetics model considering both primary and secondary crystallization was applied to extract the respective rate constants of the two crystallization stages. The results were discussed in terms of the diffusion mechanisms during PEEK crystallization. The growth of PEEK spherulites from the pure melt and from the blends with PEI was studied by hot stage optical microscopy. The spherulite growth kinetics was analyzed using a modified Lauritzen-Hoffman theory which considers the diluent effect of PEI. The regime III-II transition was observed for PEEK and PEEK/PEI blends. The side surface free energy, fold surface free energy, and the work of chain folding were calculated, and were discussed in terms of the stiffness and bulkiness of PEEK molecules. The semicrystalline morphology and the melting behavior of PEEK/PEI blends were studied by optical microscopy and DSC, respectively. The optical micrographs of PEEK spherulites grown from the blends showed that a significant amount of PEI was rejected to the interfibrillar regions of the PEEK spherulites. The melting study indicated that PEEK crystal reorganization on heating was hindered by blending with PEI, and this was attributed to the incorporation of PEI in the PEEK crystalline interlamellar regions. The amorphous and the crystalline PEEK/PEI blend films were drawn uniaxially by solid-state coextrusion. The glass transition, density, crystallization behavior, and the respective orientations were studied. The T$\sb{\rm g}$s of amorphous PEEK/PEI blends were depressed by drawing. The kinetics of crystallization of drawn PEEK/PEI blends was also reported. The orientation studies by IR dichroism showed that the orientations of both PEEK and PEI were decreased by increasing PEI content in the blends.

碩士
大同大學
化學工程研究所
88
Aromatic poly(ether-amide)s were synthesized by the direct polycondensation from the terephthalic acid (TPA) and isophthalic acid (IPA) with various aromatic diamines in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved CaCl2 using triphenyl phosphite (TPP) and pyridine as condensing agents. Effects of the number of p-oxyphenylene units in the diamine, the catenation of the benzene ring, and the presence of pendant groups on the properties of the poly(ether-amide)s were investigated. Several systematically varied aromatic polyimides having high molecular weights were prepared by the classic two-step procedure from dianhydrides PMDA and BPDA with various structurally different diamines that included (a) ether diamines with different chain length, (b) diamines containing the biphenylene unit, (c) diamines with different catenations on the aromatic ring, and (d) ether diamines having different pendant groups. The "structure-property" relationships of these polyimides were studied. Moreover, novel hydroxy-containing poly(ether-imide)s having ortho-linked benzene rings in the backbone were prepared from 1,2-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 1,2-bis(3,4-dicarboxyphenoxy)-4-tert-butylbenzene dianhydride with bis(o-aminophenol)s in refluxing m-cresol. Some basic properties, such as solubility, film-formability, crystallinity, and thermal properties, of the poly(ether-imide)s were evaluated.

碩士
國立成功大學
化學工程學系碩博士班
91
Miscibility and morphology of poly(pentamethylene terephthalate)/ poly(ether imide) (PPT/PEI), poly(hexamethylene terephthalate) /poly(ether imide) (PHT/PEI), poly(ethylene 2,6-naphthalate)/ poly(pentamethylene terephthalate)/poly(ether imide) (PEN/PPT/PEI), and poly(ethylene 2,6-naphthalate)/poly(trimethylene terephthalate) /poly(ether imide) (PEN/PTT/PEI) blends were investigated by using differential scanning calorimeter (DSC), polarized-light microscopy (POM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), and proton nuclear magnetic resonance (1H-NMR). For PPT/PEI and PHT/PEI blends, POM showed phase heterogeneity, and two glass transition temperatures (Tg) were obtained in DSC. These results demonstrated immiscibility. Polymer-polymer interaction parameter (X12) was calculated and found to be 0.12±0.01 for PPT/PEI blends and 0.17±0.01 for PHT/PEI blends. The relationship between amount of methylene groups of aryl polyester and miscibility was also discussed. For ternary blends, POM and DSC results indicated immiscibility for PEN/PPT/PEI blends and partial miscibility for PEN/PTT/PEI blends, but all components of these two ternary blends were phase homogeneous after heat treatments. 1H-NMR results indicated the generation of PEN/PPT and PEN/PTT copolymers by so-called “transesterification”. The influence of transesterification on the behaviors of glass transition, solubility and crystallization was discussed in detail. Finally, the transesterification products of PEN/PPT and PEN/PTT blends, ENPT and ENTT, were blended with PEI respectively. The results of POM and DSC demonstrated the miscibility of ENPT/PEI and ENTT/PEI blends. In addition, the compatibilizing effect of ENPT on PPT/PEI blends in their ternary mixture was also shown.

碩士
大同大學
化學工程學系(所)
94
Part 1: A series of novel fluorinated poly(ether imide)s (IV) having inherent viscosities of 0.70-1.08 dL/g were prepared from 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride (I) and various trifluoromethyl (CF3)-substituted aromatic bis(ether amine)s II¬¬a-g by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s showed excellent solubility in many organic solvents and could be solution-cast into transparent, flexible, and tough films. These films were essentially colorless, with an ultraviolet-visible absorption edge of 375-380 nm and a very low b* value (a yellowness index) of 5.5 to 7.3. They also showed good thermal stability with glass-transition temperatures of 207-269 oC, 10% weight loss temperatures in excess of 474 oC, and char yields at 800 oC in nitrogen more than 62%. In comparison with analogous V series poly(ether imide)s without the -CF3 substituents, the IV series polymers showed better solubility, lower color intensity, and lower dielectric constants. Part 2: A series of organosoluble and colorless fluorinated poly(ether imide)s (4a-g) were prepared from 3,6-bis(3,4-dicarboxyphenoxy) benzonorbornane dianhydride (1) and various trifluoromethyl (CF3)-substituted aromatic bis(ether amine)s 2a-g by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s had inherent viscosities of 1.19-1.78 dL/g and showed excellent solubility in many organic solvents. They could be solution-cast into transparent, flexible, and tough films with good mechanical properties. These films were virtually colorless, with an ultraviolet-visible absorption edge of 372-379 nm and a very low b* value (a yellowness index) of 10.8 to 14.1. The glass-transition temperatures (Tg) and softening temperatures (Ts) were recorded between 216-292 oC and 209-285oC, respectively. The decomposition temperature for 10% weight loss all occurred above 479 oC in nitrogen and 467 oC in air, and the char yields at 800 oC in nitrogen were more than 51%. They also showed low dielectric constants of 2.84-3.58 (1 MHz) and moisture absorptions in the range of 0.05-0.19%. In comparison with analogous 5 series poly(ether imide)s without the -CF3 substituents, the 4 series ones showed better solubility, lower color intensity, and lower dielectric constants. Part 3: A series of organic-soluble polynaphthalimides (PNI) bearing flexible ether links and phthalide cardo group were synthesized from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with 3,3-bis[4-(4-aminophenoxy)-3-methylphenyl]phthalide (BAMP) and its mixtures with other dietheramines (6b-g) by high-temperature solution polycondensation in m-cresol. The PNIs had moderate to high inherent viscosities in the range of 1.24-2.25 dL/g and could afford flexible and tough films with tensile strengths of 97-138 MPa by casting their m-cresol solutions. These PNIs exhibited high thermal stability, with glass-transition temperature of 291-321 °C, 10% weight-loss temperatures above 542 °C, and char yields at 800 °C in nitrogen higher than 56%. In comparison with PNIs without the BAMP component, these BAMP-modified PNIs revealed an enhanced solubility and film-forming capability.

A diglycidylether of bisphenol A, DGEBA, base epoxy resin has been modified with several different types of poly(ether imide)s with the goal of increasing the toughness of this high Tg epoxy system. Initially, Ultem$\sp\circler $ 1000-1000 from GE was blended into Epon 828/DDS. Phase separated systems resulted with a 2.5-fold increase in the fracture energy over the neat epoxy resin (676 J/m$\sp2$ vs. 265 J/m$\sp2).$ As seen under the SEM, the included phase pulled out of the continuous phase, indicating poor adhesion between the two phases. Next an amine terminated poly(ether imide), ATPEI, of Mn equal to 8600 was reacted into the same epoxy resin system. There was no increase in the fracture energy with the addition of the ATPEI except at the 40 weight percent loading level. At this level, the fracture energy was comparable to that of the 40% Ultem$\sp\circler$/E828/DDS (700 J/m$\sp2).$ Phase separation was not observed in the TEM above 10 weight percent of the ATPEI in the E828/DDS. A mix of the Ultem$\sp\circler$ and the ATPEI were added to the epoxy resin with favorable results. Phase separation was present. Good adhesion between the phases was evident. And at 20 weight percent, the mixed PEI modified E828/DDS had a higher fracture energy than either of the other two systems investigated previously in this study (409 J/m$\sp2$ for the mix vs. 176 J/m$\sp2$ for the ATPEI and 353 J/m$\sp2$ for the Ultem$\sp\circler).$ Finally, an amine terminated poly(ether imide) with Mn equal to 25,500 was reacted into the same epoxy resin. The fracture energy at 20 weight percent was higher than any of the systems studied previously (451 J/m$\sp2$ vs. 409 J/m$\sp2$ for the mixed PEI modified system). Phase separated morphologies occurred at lower loading levels than anticipated-co-continuous at 20% and phase inverted at 30%. In all cases the Tg's remained above 200$\sp\circ$C.

碩士
國立臺北科技大學
化學工程研究所
99
This thesis deals with the synthesis and properties of new triptycene-containing poly(ether-imide)s and poly(ether-amide)s. Their properties such as inherent viscosity, molecular weights, film-forming ability, solubility, crystallinity, thermal and optical properties were investigated and compared with their analogs without triptycene units. The first part deals with the synthesis and characterization of aromatic poly(ether-imide)s based on a triptycene bis(ether anhydride). A series of poly(ether-imide)s containing three-dimensional triptycene moieties were prepared from 1,4-bis(3,4-dicarboxyphenoxy)triptycene dianhydride with various aromatic diamines via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization to the poly(ether-imide)s. The inherent viscosities of the poly(amic acid) precursors were in the range of 0.44-0.91 dL/g. Most of the poly(ether-imide)s showed good solubility in many organic solvents and could be solution-cast into transparent and tough films. They also showed good thermal stability with glass-transition temperatures of 238~302 oC and 10% weight loss temperatures in excess of 572 oC. These triptycene-based poly(ether-imide)s showed enhanced optical transparency, decreased color intensity and lowered dielectric constants as compared to conventional aromatic polyimides. The poly(ether-imide)s derived from trifluoromethyl-containing bis(ether amine)s could afford highly optically transparent and almost colorless films. The second part of this thesis describes the synthesis and properties of novel triptycene-containing poly(ether-amide)s from 1,4-bis(4-carboxyphenoxy)triptycene with various aromatic diamines or from 1,4-bis(4-aminophenoxy)triptycene with various aromatic dicarboxylic acids via the phosphorylation polyamidation reaction. These poly(ether-amide)s were essentially amorphous and showed a significantly increased solubility as compared with their analogs without the triptycene units. All the poly(ether-amide)s could be solution-cast into flexible and tough films. Apart from high Tg values and good thermal stability, these poly(ether-amide) films exhibited high optical transparency with an ultraviolet-visible absorption cutoff wavelength (λ0) down to 338 nm.

碩士
大同大學
化學工程研究所
91
ABSTRACT A hydroxyl-containing poly(ether imide) V was prepared from 1,4-bis(3,4-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in refluxing m-cresol. The poly(ether imide) showed a high optical transparency in the visible region and a good thermal stability. A photoresist system was prepared by mixing the poly(ether imide) V and 2,3,4-tris(1-oxo-2-diazonaphthoquinone- 5-sulfonyloxy)benzophenone (D5SB) as the photoreactive component. The positive-working type polyimide resist containing 35 wt% D5SB showed a sensitivity of 84 mJ/cm2 and a contrast of 2.8 when it was exposed to 365, 405, 436-nm light and developed with a 2 wt% aqueous tetramethylammonium hydroxide (TMAH) solution at 40 ℃. After curing at 260 oC for 1 h, D5SB in the polyimide resist could be removed; and thus, the thermal stability of the residual polyimide film was not deteriorated.

碩士
國立臺北科技大學
化學工程研究所
102
This study has been separated into two parts. In the first part of this thesis, a novel class of the fluorinated poly(ether-imide)s (PEIs) with anthraquinone (AQ) units were prepared from the polycondensation reactions of a newly synthesized AQ-dietheramine monomer, namely 2,6-bis(4-amino-2-trifluoromethylphenoxy)- anthraquinone, with aromatic tetracarboxylic dianhydrides via a conventional two-step technique. The fluorinated poly(ether-imide)s exhibited enhanced solubility and optical transparency because of increased free volume caused by the CF3 substituents. Furthermore, these PEIs showed high thermal stability, with glass-transition temperatures of 263-312 ℃ and decomposition temperatures in excess of 500 ℃. These PEIs were also investigated by cyclic voltammetry and spectroelectrochemistry. Preliminary results reveal that these AQ-based PEIs are potentially useful as cathodically coloring red electrochromes. In the second part of this thesis, two ester derivatives featuring anthraquinone (AQ) as an interior core and terminal electroactive triphenylamine (TPA) or carbazole (Cz) groups were prepared by the esterification of 2,6-dihydroxyanthraquinone with 4-(diphenylamino)benzoyl chloride and 4-(9H-carbazol-9-yl)benzoyl chloride, respectively. The electrochemistry and electropolymerization of these monomers were investigated. The polymeric films were built onto ITO/glass surface by repetitive cyclic voltammetry (CV) scanning of the monomer solutions containing an electrolyte. The electrogenerated poly(amine-ester) films exhibited reversible electrochemical processes and strong color changes upon electro-oxidation or electro-reduction, which can be switched by potential modulation. The remarkable electrochromic behavior of the film was clearly interpreted on the basis of spectroelectrochemical studies, and the electrochromic stability was evaluated by the electrochromic switching studies.

碩士
國立成功大學
化學工程學系碩博士班
90
Abstract This study investigates the morphology and the miscibility of the blends containing poly (ethylene terephthalate) (PET), poly (trimethylene terephthalate) (PTT), poly (butylene terephthalate) (PBT), poly (ether imide) (PEI) and polycarbonate (PC) using differential scanning calorimeter (DSC), polarizing optical microscope (POM), scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FTIR). Both hot-melt blending and solvent blending techiques were performed in preparing the PET/PTT/PBT/PEI mixtures. If the mixture samples were prepared by solvent coprecipitation, a single Tg and the homogeneous morphology indeed exist in the PET/PTT/PBT/PEI mixtures. It was believed that in amorphous state this blending system revealed a completely miscibility, in the other words, a miscible system. In addition, for PTT/PC blends, two individual Tg values and POM results revealed phase separation in the blends which implied immisicibility. When PTT/PC blends were annealed at high temperature, transesterficition between PTT and PC molecules may be generated. Original two Tgs were transferred to one and the crystallizing temperature after cyclic heat treatment also effected by the total annealed times. At last a shoulder shift phenomenon of FTIR absorbed peak implied that there was the interaction in this blending system.

碩士
大同大學
化學工程學系(所)
94
ABSTRACT In part I, a series of novel organosoluble and light-colored fluorinated poly(ether imide)s (IV) having inherent viscosities of 0.43-0.59 dL/g were prepared from 4,4’-[1,4-phenylenbis(isopropylidene-1,4-phenyleneoxy)]diphthalic anhydride (I) and various trifluoromethyl-substituted aromatic bis(ether amine)s by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s showed excellent solubility in many organic solvents and could be solution-cast into transparent, flexible, and tough films. These films were essentially colorless, with an UV-visible absorption edge of 361-375 nm and a very low b* value (a yellowness index) of 15.3 to 17.0. They series also showed good thermal stability with glass-transition temperature of 191-248oC, 10% weight loss temperature in excess of 494oC, and char yields at 800oC in nitrogen more than 39%. The thermally cured poly(ether imide) films showed good mechanical properties with tensile strengths of 83-96 MPa, elongations at break of 8-11%, initial moduli of 1.7-2.0 GPa. They possessed lower dielectric constants of 3.25-3.72 (1MHz). In comparison with the V series nonfluorinated poly(ether imide)s, the IV series showed better solubility, lower color intensity and lower dielectric constants. In part II, hybrid organic-inorganic materials based on polyimide-silica system have been produced by the sol-gel route from solution mixture of hydrolysed tetramethoxysilane (TMOS) and an aromatic poly(amic acid) prepared from 4,4’-oxydiphthalic dianhydride (ODPA) and 4,4’-bis(4-aminophenoxy)biphenyl (I”) with or without the use of 3-aminopropyltrimethoxysilane (APrTMOS) as a chain-end capper. The APrTMOS-modified hybrid films (V series) containing up to 40 wt% silica were mechanically robust and optically transparent. The V series hybrid films showed a higher optical transparency than the VI series analogs (without APrTMOS as the coupling agent). All the hybrid films showed excellent thermal stability, including moderately high Tgs of 243-254℃, 10% weight loss temperatures higher than 560 oC, and high char yields at 800oC in nitrogen (＞60%). In part III, an alkoxysilane terminated amide acid prepolymer was prepared from 4,4’-bis(4-aminophenoxy)biphenyl (I”) or 4,4’-bis(4-amino-2-trifluoromethylphenoxy)- biphenyl (I’) with 4,4’-oxydiphthalic dianhydride (ODPA) using 3-aminopropyltrimethoxysilane (APrTMOS) as an end capper. Two series of polyimide/silica (PI/SiO2) hybrid films with chemical bonding between the polyimide backbone and silica network have been prepared from the mixture of APrTMOS-terminated prepolymer, tetramethoxysilane (TMOS), and water via a sol-gel reaction, followed by solution casting and multistep heating. The hybrid films containing up to 40 wt% silica were mechanically robust, transparent, and light-colored. The fluorine-containing PI/SiO2 hybrid films (IX series) showed a higher optical transparency and less color intensity than the non-fluorinated (VIII series). All the hybrid films showed excellent thermal stability, including moduately high Tgs of 242-266 ℃, 10% weight loss temperatures higher then 535 ℃, and high char yield at 800 ℃ in nitrogen (＞ 54%).

碩士
國立臺灣科技大學
化學工程系
90
Abstract A series of polyimides containing pendent benzothiazole groups were synthesized from two new diamines. The diamines(3a,3b) were derived by a nucleophilic substitution of the bisphenol (hydroquinone and 2-tert-butyl hydroquinone ) with 3-(2-benzothiazole)-4- chloronitrobenzene in presence of K2CO3 and then were reduced. The diamines 3a and 3b were polymerized with aromatic dianhydrides in refluxing m-cresol containing isoquinoline to afford two new series of poly(ether-imide)s(7,8) with benzothiazole pendent groups. The poly(amic-acid)s had inherent viscosities of 0.7~0.88 dL/g. The soluble polyimides had inherent viscosities of 0.62~1.2 dL/g。The polyimide 8 containing pendent groups( tert-butyl and benzothiazole) showed good solubilities in common solvents such as 1-methy-2-pyrrolidinone(NMP), N,N-dimethylacetamide, chloroform, THF ,and Cyclehexanone. The polyimide 8a derived from pyromellitic dianhydride(PMDA) was even soluble in NMP. They can form tough and transparent films. The films have tensile strength of 82~133 Mpa, and elongaton to break of 4~34 %. Differential scanning calorimetry(DSC) and dynamic mechanical analysis(DMA) reveal their glass transition temperatures were found to be 279~343℃ and 294~352℃, respectively. Thermogravimetric analyses demonstrated that all polymers were stable up to 450℃, and the 10% mass loss temperatures were recorded in the range of 510~582℃ in nitrogen atmosphere.

碩士
國立臺灣科技大學
化學工程系
90
Polyimides with enhanced solubility have been synthesized from aromatic tetracarbozoylic dianhydrides and the fluorene cardo diamines with bulky side groups. Two new bisphenols(1a and 1b) were synthesized from fluorenone and 2-tert-butylphenol or 2-phenylphenol. New four kinds of diamines(4a, 4b, 5a, 5b) were derived by a nucleophilic substitution of the bisphenols(1a and 1b) with p-fluoronitrobenzene or 2-chloro-5-nitrobenzotrifluoride in the presence of K2CO3 and then were reduced. The polyimides with high inherent viscosities ranging from 0.49 to 1.87 dL/g showed excellent solubilities in common solvents such as 1-methyl-2-pyrrolidinone(NMP), N,N-dimethylacetamide, chloroform, tetrahydrofuran, and cyclohexanone. Most of polyimides derived from 9,9-bis[(4-(4-aminophenoxy)-3-tert-butyl)phenyl]fluorene were even soluble in acetone. Since active electronic devices can be sensitive to high temperatures, a polyimide such as this which does not require high temperature processing may be beneficial. Four kinds of fluorine-based polyimide can form a tough and transparent film. The films have tensile strengths of 79~144 MPa, and elongation to break of 3~15%. Differential scanning calorimetry(DSC) and dynamic mechanical analysis(DMA) reveal their glass transition temperatures were found to be 259~316 and 272~335℃, respectively. Thermogravimetric analyses demonstrated that almost all polymers were stable up to 450℃, and the 10% mass loss temperatures were recorded in the range of 481~590℃ in nitrogen atmosphere.

碩士
大同大學
化學工程學系(所)
93
First, a series of novel poly(ether imide)s 6 series characterized by colorless, high transparency and highly solubility were synthesized from 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride (3) and various fluorinated diamines (4a-i) via ring-opening polyaddition at room temperature to poly(amic acid) (PAA), followed by thermal (H) or chemical (C) imidization to obtain polymers. The GPC data of 6a-i(C) indicated that the and values were available in the range of 1.6×104-2.5×104 and 2.8×104-4.4×104, and the polydispersity index (PDI) values were 1.6-1.8. In solubility, 6 series showed excellent solubility in a variety of organic solvents and they were soluble in a concentration more than 10% in the amide polar solvent such as N-methyl-2-pyrrolidone, N,N -dimethylformamide and N,N-dimethylacetamide (DMAc), ether-type solvents such as dioxane and tetrahydofuran, and chlorinated solvents such as dichloromethane and chloroform. Moreover, the 6 series polymers showed a high optical transparency and were essentially colorless, with an ultraviolet-visible absorption edge 366.0 to 375.0 nm and low b* values (a yellowness index) of 5.0-9.0. These films showed strength tensiles of 79-104 MPa, elongations at break of 5.8-15.8%, initial moduli of 1.8-2.3 GPa, and most of them had strength at yield of 84-109 MPa. The thermal properties of glass transition (Tg) and softening temperature (Ts) were recorded by DSC and TMA at 186-266 ℃ and 163-244 ℃, and the decomposition temperatures at 10% weight loss are all above 485 ℃ in air or nitrogen atmosphere, respectively, and they left within a range of 47.5-64.5% char yield at 800 ℃ in nitrogen. The 6 series showed low-dielectric constants of 3.05-3.46 (at 1MHz), with moisture absorption in the range of 0.18-0.65wt % than the analogous nonfluorinated polyimides 7 series. Second, a series of fluorine-containing, light-colored and thermal stability PEI 6’ series were synthesized from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (3’) and various fluorinated diamines via ring-opening polyaddition to form PAA, followed by thermal or chemical imidization to obtain polymers. In this study, the GPC data of and values of 6’(C) series were available in the range of 1.5×104-2.1×104 and 2.2×104-3.3×104, and the polydispersity index ( / ) values were 1.5-1.7. The 6’ series showed excellent solubility in a variety of organic solvents and they were soluble in a concentration more than 10% w/v in the amide polar solvent and chlorinated solvent. Moreover, 6’ series showed a high optical transparency and less color intensity than the analogous nonfluorinated polyimides 7’ series, with an ultraviolet-visible absorption cutoff wavelengths between 373.0 to 384.5 nm, and low b* values (a yellowness index) ranging from 6.2 to 9.4. These films showed strength tensiles of 83-100 MPa, elongations at break of 7.8-17.1%, initial moduli of 1.8-2.3 GPa, and a part of them had strength at yield of 96-101 MPa. The thermal properties of glass transition (Tg) was recorded by DSC at 174-288 ℃, and the decomposition temperatures at 10% weight loss were analyzed by TGA in nitrogen and air atmosphere ranging of 487-559 ℃ and 492-545 ℃, respectively. They left 47.0-59.1% char yield at 800 ℃ in nitrogen, and 6’ series showed low-dielectric constants of 2.79-3.49 (at 1MHz), with moisture absorption in the range of 0.19-0.33 wt %. Third, Four series (IV, V, VI, and VI’) of polyimide-silica hybrid (PI/SiO2) were prepared by the sol-gel reaction and characterized in this study. The viscous poly(amic acid)s were synthesized from biphenyltetracarboximide (BPDA) and oxydiphenyldiamine (ODA), then the hybrid composite films were obtained by the hydrolysis and polycondensation of tetramethylorthosilicate (TMOS) and H2O in PAA solution following by spin coating and multistep heating. The former three series were prepared through 3-aminopropyltrimethoxysilane (APrTMOS) as coupling agent. The IV series was changes in chain length of PI segment; the V series was changes in the contents of silica. The optical, thermal and mechanical properties of the PI/SiO2 hybrids were investigated. The results showed that PI/SiO2 hybrids (IV, V and VI) with APrTMOS as coupling agent showed a high transparence and nanocomposite of PI/SiO2 hybrids even at high silica content of about 50wt%. However, the VI’ series without coupling agent revealed opaque thin films. As the content of SiO2 was 20wt%, we changed the PI segment length (the IV series), the tensile strength, initial moduli, and the elongation at break increased with the PI segment length increased. When chain length (m) was larger than 10, the tensile strength increased unobvious, but the elongation at break was the largest as m=10. The V series were fixed PI segment and changed the contents of SiO2. As the contents of SiO2 changed from 0 to 50%, the moduli of the V series increased from 1.9 to 4.3 GPa, though the tensile strength and the elongation at break had the largest value at the content of SiO2 20wt%. Moreover, the VI series synthesized from high molecular weight of PAA was found that the tensile strength and initial modulus also increased more obvious than V series as the content of SiO2 increased. Concerned for the VI’ series without coupling agent, the Tg values were also lower than VI series but their mechanical properties was similar to the V and VI series. In addition, all T10 and Tg values of PI/SiO2 hybrids could be raised causing the content of silica, though the relation between the values of T10 and Tg and the various SiO2-contentind is not clear.

Membrane technology plays a crucial role in different separation processes such as biotechnology, pharmaceutical, and food industries, drinking water supply, and wastewater treatment. However, there is a growing concern that solvents commonly used for membrane fabrication, such as dimethylformamide (DMF), dimethylacetamide (DMAc), and 1-methyl-2-pyrrolidone (NMP), are toxic to the environment and human health. To explore the possibility of substituting these toxic solvents by less toxic or safer solvents, polymers commonly used for membrane fabrication, such as polyacrylonitrile (PAN), cellulose acetate (CA), polyethersulfone (PES), and poly(ether imide sulfone) (EXTEMTM), were dissolved in ionic liquids. Flat sheet and hollow fiber membranes were then fabricated. The thermodynamics of the polymer solutions, the kinetics of phase inversion and other factors, which resulted in significant differences in the membrane structure, compared to those of membranes fabricated from more toxic solvents, were investigated. Higher water permeance with smaller pores, unique and uniform morphologies, and narrower pore size distribution, were observed in the ionic liquid-based membranes. Furthermore, comparable performance on separation of peptides and proteins with various molecular weights was achieved with the membranes fabricated from ionic liquid solutions. In summary, we propose less hazardous polymer solutions to the environment, which can be used for the membrane fabrication with better performance and more regular morphology.

碩士
大同工學院
化學工程研究所
86
Aromatic polyimides have found wide usage as films; coating, complex materials due to their outstanding thermal behaviors combined their excellent mechanical and electrical properties. However, the combination of these properties made the rigid aromatic polyimides essentially difficult to fabricate in the melt or with the solvent. Therefore, there has been considerable research carried out and aimed at developing aromatic polyimides that are processed in the imide form. The current study focuses on the syntheses and characterizations of a series of polyimides and poly(amide-imide)s containing ether and bulk group. The dianhydride and the diamine were prepared from bisphenol and 4-nitrophthalonitrile and p-chloronitrobenzene, respectively. Polyimides were prepared by high-temperature solution condensation or two-stage process, and poly(amide-imide)s was prepared by solution condensation. The polymers had afforded flexible and tough films by solution coating with their good solubilities in organic solvents. Most typical films of polymers showed yield points, and good mechanical properties. The glass transition temperatures of these polymers were recorded above 200℃ by the differential scanning calorimetry. Decomposition temperatures for 10% weight loss all occurred above 500℃, and their residues were more than 42% at 800℃ in nitrogen atmosphere. In general, the cyclohexane cardo-based polymers exhibited relatively better solubilities in organic solvents and tensile properties as compared to the corresponding isopropane-based polymers.

碩士
國立雲林科技大學
化學工程與材料工程系
102
In this study , we have prepared fluorine-containing sulfonated polyimide –siloxane (FSPIS) from 2,2'-Bis(trifluoromethyl)benzidine (TFMB), 4,4-bis (4-aminophenoxy)-3,3-bis(4-sulfophenyl)biphenyl acid (BAPBDS), dimethylsiloxane (PDMS) and1,4,5,8-naphthalenetetracarboxylic dianhydride (NDTA) through thermal imidization. The crosslinked structure FSPIS (CFSPIS) was prepared from the siloxane segments whose methyl substitute was attacked by the diperoxide (BPO) to initiator the crosslinking reaction, then mixed solvents of ethanol, ethane-1,2-diol, 1,4-butanediol, glycerol with different proportions of ethanol, ethane-1,2-diol were used to prepare MEA(Membrane Electrode Assembly). First, the FSPIS was synthesized, and then different proportions of BPO initiator was used to prepare proton exchange membranes with different degrees of crosslinking. The chemical structures of FSPIS and CFSPIS were characterized by 1H-NMR and FT-IR. The water uptake, swelling ratio, thermal properties, morphology, hydrolytic and oxidation stability, proton conductivity as well as fuel cell power performances were investigated to check the viability of the proton exchange membrane prepared by fluorinated sulfonated polyimide siloxane crosslinking structure. The properties of the fuel cell proton exchange membrane were also compared with those of Nafion®212. The results showed that the dimensional stability, hydrolytic and oxidation stability increase as the degrees of crosslikage. The CFSPIS has good physical properties and owns a current density of 781 mW/cm2 using ethanol:ethane-1,2-diol=1:2 as mixed solvent.

碩士
國立臺灣科技大學
化學工程系
90
A novel bis(ether anhydride) monomer, 9,9-bis[(4-(3,4- dicarboxyphenoxy)-3-phenyl)phenyl]fluorene dianhydride(3), was synthesized from the nitrodisplacement of 4-nitrophthalonitrile by the bisphenoxide ion of 9,9-bis[(4- hydroxy-3-phenyl)phenyl]fluorene, followed by alkaline hydrolysis of the intermediate tetranitrile and dehydration of the resulting tetracarboxylic acid. A series of poly(ether imide)s bearing the fluorenylidene group and the phenyl side groups were successfully synthesized from the bis(ether anhydride) 3 with various aromatic diamines via the one-step method that included ring-opening polyaddition to form the poly(amic acid)s followed by chemical imidization to the polyimides 5. The polyimides with inherent viscosities ranging from 0.42 to 0.63 dL/g showed excellent solubilities in common solvents such as 1-methyl-2-pyrrolidinone(NMP), N,N-dimethylacetamide, chloroform, tetrahydrofuran, and cyclohexanone. This kind of fluorene-based polyimide can form a tough and transparent film. The films have tensile strengths of 50~111 MPa, and elongation to break of 2~6%. Differential scanning calorimetry(DSC) and dynamic mechanical analysis(DMA) reveal their glass transition temperatures were found to be 249~268℃ and 270~295℃,respectively. Thermogravimetric analyses demonstrated that almost all polymers were stable up to 450℃, and the 10% mass loss temperatures were recorded in the range of 488~554℃ in nitrogen atmosphere.

碩士
大同大學
化學工程學系(所)
93
Part 1: A series of colorless and organsoluble poly(ether imide)s (PEIs) 8a-h were prepared from 2,3-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride (3) with various fluorinated diamines via a conventional two-stage process including ring-opening polyaddition to form the PEI films. The inherent viscosities of 8 were in the range of 0.43-0.86 dL/g. The GPC data revealed that the polymers had and of 2.3-5.1×104 and 3.6-7.4×104, respectively, and the polydispersity index (PDI) values were 1.5. The 8(C) series except 8a,c(C) were highly soluble in all the tested solvents. These films 8 had cut-off wavelengths between 367.5 and 377.0 nm, as well as b* value (a yellowness index) ranging from 4.1 to 5.5. The 8 series had a tensile strength in the range from 75-104M Pa, an elongation at break within a range of 5-9%, and initial modulus in the range from 1.7-2.2G Pa. The glass transition temperature (Tg) of these PEIs were recorded between 208-281° C and the decomposition temperatures at 10% weight loss are all above 492° C in air or nitrogen atmosphere, respectively, and they left more than 51% char yield at 800° C in nitrogen. These films showed dielectric constants of 3.02-3.58(1 MHz), and moisture absorptions of 0.24-0.50 wt%. In comparison of 8 series with the analogous non-fluorinated PEI 9 series, the 8 series revealed better solubility, lower color intensity, dielectric constant, and moisture absorption. Part 2: A novel fluorinated diimide-dicarboxylic acid (DIDA), 1,4-bis(4-trimellitimido-2- trifluoromethylphenoxy)-2,5-di-tert-butylbenzene (3’), synthesized by reacting 1,4-bis(4-amino-2-trifluoromethylphenoxy)-2,5-di-tert-butyl benzene (2’) with trimellitic anhydride in polar solvents (PSv), was found to crystallize easily in amide-type solvents, such as 1-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylforamide (DMF), 1,3-dimethyl-2-imidazolidinone (DMI), or dimethyl sulfoxide (DMSO) media, to form a series of stable crystalline solvates (3’•NMP, 3’•DMAc, 3’•DMF, 3’•DMI and 3’•DMSO) containing a certain quantity of crystalline solvent. The solvates 3’•PSv were characterized and proven by DSC, TGA, X-ray analysis, and elemental analysis. The decomposition temperature (Td) was different with the type of polar solvents in 3’•PSv. Most of the 3’•PSv were formed from 3 and polar solvents in the ratio of 1:2, and the solvation processes were found to be reversible. A series of soluble fluorinated poly(amide-imide)s 6’a-i were prepared from reacting either the solvate 3’•NMP or dry/non-solvents 3’ with an equivalent amount of diamines by phosphorylation reaction using triphenyl phosphite and pyridine as condensing agents. All the 6’ series polymers afforded tough, transparent, and flexible films. The glass-transition temperature of these polymers ranged from 259 to 305° C. All of them did not show significant decomposition below 450° C in both nitrogen and air atmospheres. For a comparative purpose, another series of poly(amide-imide)s 7’a-i derived from non-fluorinated DIDA, 1,4-bis(4-trimellitimidophenoxy)-2,5-di- tert-butylbenzene, and aromatic diamines were also prepared and characterized. Part 3: Two series of polynaphthalimides (PNI) 2” and 3” were prepared from 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA) with usual aromatic diamines (1”a-h) or 1”a, which was used as the soluble modifying agent, and usual diamines (1”b-h) via a one-stage process at high-temperature condensation. The 2” and 3” series had inherent viscosities of 0.57-1.34 and 0.82-1.63 dL/g. Besides, 2”a and 3” series except 3”c were soluble in NMP and m-cresol and even in less polar solvents. The PNI films had a tensile strength in the range of 75-99 MPa, an elongation at break within the range of 5-21%, and an initial modulus in the range of 1.8-2.2G Pa. The glass-transition temperature (Tg) and softening temperature (Ts) of these PNIs were in the range of 360-404° C and 188-241° C, and the 10% weight-loss temperatures were above 495° C, with more than a 44% char yield at 800° C in nitrogen. These PI films had dielectric constants of 4.14-6.46 (1M Hz), with moisture absorption in the range of 0.87-1.91 wt%.

碩士
國立臺灣科技大學
化學工程系
90
Abstract A series of polyimides containing benzothiazole pendent groups were synthesized from two new diamines. The diamines(3a and 3b) were derived by a nuclephilic substitution of the bisphenols (4,4´-isopropylidendiphenol and 4,4´-(hexafluoroisopropylidene)di- phenol) with 3-(2-benzothiazole)-4-chloronitrobenzene in the presence of K2CO3 and then were reduced. A series of poly(ether imide)s bearing benzothiazole pendent groups were prepared from the diamines 3 with various aromatic dianhydride via the one-step method that included ring-opening polyaddition to form the poly(amic acid)s followed by chemical imidization to the polyimides(5 and 6). The polyimides with inherent viscosities ranging from 0.31 to 0.71 dl/g showed good solubilities in common solvents such as 1-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide(DMAc), chloroform, and tetrahydro- furan. The polyimide derived from pyromellitic dianhydride(PMDA) was even soluble in NMP and DMAc. Tough, transparent films of the soluble polyimides were cast from solution. These films have tensile strengths of 64-120 Mpa, and elongations to break of 3-8 ﹪. Glass transition temperatures ranged from 264 to 318°C and above with the polymers showing little or no weight loss by TGA up to 400°C in both air and nitrogen. The glass transition temperatures of the polyimides increased 16 to 53°C (compared to the polyimide analogs without benzothiazole pendent groups).