Artículos de revistas: "PAEK Polymers"

1

Liu, Bei, Zheng Chen, Liming Lin, Yuntao Han, Jinhui Pang y Zhenhua Jiang. "Synthesis and characterization of poly(arylene ether ketone)s with 3,6-diphenyl-9H-carbazole pendants using C–N coupling reaction". High Performance Polymers 29, n.º 5 (29 de junio de 2016): 575–84. http://dx.doi.org/10.1177/0954008316655592.

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3,6-Diphenyl-9 H-carbazole pendants are grafted herein to poly(arylene ether ketone)s (PAEKs) via the Ullmann C–N coupling reaction. To the best of our knowledge, this is the first time that PAEKs containing a carbazole pendant (Cz) have been synthesized through the Ullmann C–N coupling reaction. The high molecular weights of PAEK-Cz (PAEKs with 3,6-diphenyl-9 H-carbazole pendants) are inherited from their precursors, owing to the high reactivity of their monomers. The obtained PAEK-Cz- x polymers exhibit good solubility in most common organic solvents and excellent thermal stabilities, with the 5% weight loss temperatures for all products being above 598°C under a nitrogen atmosphere. The glass transition temperatures are all above 199°C and can be controlled by adjusting the feed ratio of monomers. The polymer membranes obtained by the casting method are tough and thus have strong potential for practical applications.

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2

Alentiev, Alexandre, Sergey Chirkov, Roman Nikiforov, Mikhail Buzin, Oleg Miloserdov, Victoria Ryzhikh, Nikolay Belov, Vera Shaposhnikova y Sergey Salazkin. "Structure-Property Relationship on the Example of Gas Separation Characteristics of Poly(Arylene Ether Ketone)s and Poly(Diphenylene Phtalide)". Membranes 11, n.º 9 (31 de agosto de 2021): 677. http://dx.doi.org/10.3390/membranes11090677.

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Three poly(arylene ether ketone)s (PAEKs) with propylidene (C1, C2) and phtalide (C3) fragments, and one phtalide-containing polyarylene (C4), were synthesized. Their chemical structures were confirmed via 1H NMR, 13C NMR and 19F NMR spectroscopy. The polymers have shown a high glass transition temperature (>155 °C), excellent film-forming properties, and a high free volume for this polymer type. The influence of various functional groups in the structure of PAEKs on gas transport parameters was evaluated. Expectedly, due to the higher free volume, the introduction of the hexafluoropropylidene group to PAEK resulted in a higher increase of gas permeability in comparison with the propylidene group. The substitution of the fluorine-containing group on a rigid phtalide moiety (C3) significantly increases the glass transition temperature of the polymer, while the gas permeation slightly decreases. Finally, the removal of two ether groups from the PAEK structure (C4) leads to a rigid polymer chain that is characterized by the highest free volume, gas permeability, and diffusion coefficients among the PAEKs under investigation. Also, theoretically predicted transport parameters were investigated, to further study the structure–properties relationship for the PAEKs. Methods of modified atomic (MAC) and bond (BC) contributions were applied for this purpose (estimation of gas permeation and diffusion). Gas solubility coefficients for PAEKs were forecasted by the “Short polymer chain surface based prediction” (SPCSBP) method. Both the MAC and BC techniques showed reasonable predicted parameters for three polymers, while a significant underestimation of gas transport parameters was observed for C4. The results for all three prediction methods were compared with the experimental data obtained in this work. The predicted parameters were in good agreement with the experimental data for phtalide-containing polymers (C3 and C4), while for propylidene-containing poly(arylene ether ketone)s they were overestimated, due to a possible influence of the propylidene fragment on the indices of the oligomeric chains. MAC and BC methods demonstrated a better prediction power than the SPCSBP method.

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3

Jiang, Junqiao, Erli Qu, Min Xiao, Dongmei Han, Shuanjin Wang y Yuezhong Meng. "3D Network Structural Poly (Aryl Ether Ketone)-Polybenzimidazole Polymer for High-Temperature Proton Exchange Membrane Fuel Cells". Advances in Polymer Technology 2020 (14 de agosto de 2020): 1–13. http://dx.doi.org/10.1155/2020/4563860.

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Poor mechanical property is a critical problem for phosphoric acid-doped high-temperature proton exchange membranes (HT-PEMs). In order to address this concern, in this work, a 3D network structural poly (aryl ether ketone)-polybenzimidazole (PAEK-cr-PBI) polymer electrolyte membrane was successfully synthesized through crosslinking reaction between poly (aryl ether ketone) with the pendant carboxyl group (PAEK-COOH) and amino-terminated polybenzimidazole (PBI-4NH2). PAEK-COOH with a poly (aryl ether ketone) backbone endows superior thermal, mechanical, and chemical stability, while PBI-4NH2 serves as both a proton conductor and a crosslinker with basic imidazole groups to absorb phosphoric acid. Moreover, the composite membrane of PAEK-cr-PBI blended with linear PBI (PAEK-cr-PBI@PBI) was also prepared. Both membranes with a proper phosphoric acid (PA) uptake exhibit an excellent proton conductivity of around 50 mS cm-1 at 170°C, which is comparable to that of the well-documented PA-doped PBI membrane. Furthermore, the PA-doped PAEK-cr-PBI membrane shows superior mechanical properties of 17 MPa compared with common PA-doped PBI. Based upon these encouraging results, the as-synthesized PAEK-cr-PBI gives a highly practical promise for its application in high-temperature proton exchange membrane fuel cells (HT-PEMFCs).

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Sorokin, Anton E., Alexander P. Krasnov, Vera V. Shaposhnikova, Sergey N. Salazkin, Mikhail V. Gorshkov y Alexander V. Naumkin. "INTERACTION IN POLYARYLATE – POLY(ARYLENE ETHER KETONE) MIXTURE AT HIGH-TEMPERATURE PROCESSING". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, n.º 8 (20 de agosto de 2019): 147–54. http://dx.doi.org/10.6060/ivkkt.20196208.5890.

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Methods of modifying polyarylate based on bisphenol A and mixture of iso- and terephthalic acids by a representative of a promising class of polymers — polyarylene ether ketone have been discussed in this article. Comparative thermomechanical and thermofriction tests of two grades of poly(arylene ether ketone)based on bisphenol A and 4,4'-difluorobenzophenone (PAEK-32 and PAEK-34) have been carried out. It has been established that PAEK-34 is the most suitable for modifying polyarylate, which is confirmed by its higher softening temperature and stable friction coefficient at elevated temperatures. The thermomechanical properties and molecular mass distribution of amorphous polyarylene ether ketone before and after pressing have been studied. It has been established that during processing of poly(arylene ether ketone) PAEK-34 it’s molecular weight increases from 123 to 178 thousand a.m.u. with simultaneous change in the character of the molecular mass distribution from bimodal to unimodal. At the same time, there is a sharp decrease in the content of the low molecular weight fraction from 23.32 to 7.2%. Theoretical compatibility of polyarethylene ether ketone PAEK-34 and polyarylate DV based on the theory of solubility of substances has been studied. It was established that mixtures of these polymers are compatible for any components’ ratio according to the calculation results. The thermomechanical characteristics of the mixtures obtained on the basis of polyarylate and polyarylene ether ketone have been evaluated. It has been established that the growth of heat resistance of the mixture during processing is caused by intermolecular interaction of components with the formation of new chemical compounds having a block-type copolymer structure. This was confirmed by the change in the nature of the molecular-mass distribution of the polymer mixture upon the transition of the pressing temperature from 260 °C to 300 °C. It was established that the optimal conditions for the realization of block-copolymer formation reaction are created at 300 °C.

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5

Salamov, Ali Kh, Abdulakh K. Mikitaev, Aues A. Beev, Julietti A. Beeva, Mukhamed Kh Ligidov y Sergey I. Pakhomov. "POLYARYLENEETHERKETONES OBTAINING WITH REACTION OF NUCLEOPHILIC SUBSTITUTION". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 59, n.º 7 (17 de julio de 2018): 4. http://dx.doi.org/10.6060/tcct.20165907.5389.

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The article deals with the study of influence of the synthesis conditions on the molecular weight of polyaryleneetherketones (PAEK), received with nucleophilic substitution reaction of activated aryl halide. The synthesis of PAEK with the nucleophilic substitution reaction carried out as partially hydrolyzed homopolycondensation of phenolates and aromatic dihalides containing a carbonyl group in the molecule and derivatives of polycondensation of aromatic bisphenols with activated aromatic dihalides, and aromatic nitro compounds. The nucleophilic substitution of halogen in aryldihalogens proceeds through formation of Meisenheimer complex, where the negative charge of the electron-electron ring stabilizes the group. The high efficiency of the synthesis of PAEK with nucleophilic substitution reaction is mainly determined with several factors, the main of which are: 1) the structure of the starting monomers; 2) the nature of the solvent; 3) the nature of phenolate; 4) side reactions. For these materials it was revealed that the ratio of nucleophilic and electrophilic reagents has pronounced effect on the molecular weight of the obtained polymer, without affecting the poly dispersion. PAEK synthesis processes are optimized by controlling the replacement of some of the monomers, the temperature and concentration of reactants change. It was shown that the polyarylene ether ketones and copolymers have a high thermal heat resistance, mechanical properties. They show considerable heat resistance in air, capable of forming a transparent film and melts. Thus, data of literature review show that the nucleophilic substitution reaction is promising for PAEK synthesis of various chemical structures and produces polymers having valuable properties.

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6

Remanan, Manu, Rebbapragada Subba Rao, Shantanu Bhowmik, Lalit Varshney, Mathew Abraham y Karingamanna Jayanarayanan. "Hybrid nanocomposites based on poly aryl ether ketone, boron carbide and multi walled carbon nanotubes: evaluation of tensile, dynamic mechanical and thermal degradation properties". e-Polymers 16, n.º 6 (1 de noviembre de 2016): 493–503. http://dx.doi.org/10.1515/epoly-2016-0162.

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AbstractIn this study an attempt has been made to incorporate a radiation resistant filler like boron carbide (B4C) nanopowder along with multi walled carbon nanotubes (MWCNT) in a high performance polymer namely poly aryl ether ketone (PAEK) for potential applications in the nuclear industry. The dispersion of nanofillers in PAEK was established by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Infra red (IR) spectroscopy indicated the interaction between functionalized MWCNT (F-MWCNT) and PAEK. The optimum combination of B4C and F-MWCNT was obtained from the tensile property analysis. It was found from the dynamic mechanical analysis that the storage modulus of the composite at elevated temperature was enhanced by B4C inclusions. Mechanical damping factor spectra showed the shift of PAEK glass transition temperature to higher values due to the presence of B4C and F-MWCNT. Thermogravimetric analysis (TGA) presented the resistance offered by B4C to the degradation of PAEK especially at elevated temperatures.

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7

Zhang, Xingdi, Gang Liu, Guodong Dang, Weidong Li, Jindong Zhang, Hongwei Zhou, Chunhai Chen y Jianwen Bao. "Properties of carbon fibre/bismaleimide composites ex situ toughened with phosphorous-containing poly(arylene ether ketone) film". High Performance Polymers 29, n.º 5 (10 de junio de 2016): 533–43. http://dx.doi.org/10.1177/0954008316652464.

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To control the dissolution process of a phosphorous-containing poly(arylene ether ketone) (P-PAEK)/bismaleimide (BMI) resin diphase system, a series of P-PAEKs were synthesized by changing the molar ratio of the reactants through nucleophilic substitution. The U3160/BMI composites toughened with P-PAEK film were manufactured by resin transfer moulding based on the concept of ex situ toughening. In addition, the interlaminar properties of the composites were characterized by applying modes I and II fracture toughness tests. The mode I fracture toughness of the composite was shown to be less improved, whereas the mode II fracture toughness was increased by about 74%. Furthermore, the interlaminar microstructure, which was observed by using a scanning electron microscope (SEM), revealed that reaction-induced phase decomposition and inversion occurred in the interlaminar region. The improvement in fracture toughness was attributed to plastic rupture of the continuous P-PAEK phase and debonding or cavitations of the BMI particle phases. Through the application of ex situ toughening, the compression-after-impact properties of the composite were significantly improved, whereas the thermodynamic properties were well maintained. Besides, optical microscopy images showed more space in the interlayer of the toughened specimens, which contributed to the improvement of damage tolerance.

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8

Wang, Yongpeng, Mengzhu Liu, Dayong Lu y Haibo Zhang. "Electrospun porous hybrid CuO/CdO nanofibers using carboxylic-functionalized poly(arylene ether ketone)s as a template for glucose determination". High Performance Polymers 31, n.º 5 (12 de noviembre de 2018): 570–79. http://dx.doi.org/10.1177/0954008318811471.

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As a high performance polymer, PCA-poly(arylene ether ketone) (PAEK) was first used as a template to fabricate hybrid copper oxide (CuO)/cadmium oxide (CdO) nanofibers (NFs) via electrospinning and subsequent calcination. Porous NFs with a mean diameter of 463 nm were obtained. The formation of morphology was decided by the ion exchange reaction between the functional groups on polymer template and metal ions, which was proved by Fourier transform infrared spectra. Energy-dispersive X-ray spectrometer and X-ray powder diffractometry spectra demonstrated the obtained substance was CuO/CdO compound. The products were then investigated in detail for direct electrocatalytic oxidation of glucose, which was evaluated by cyclic voltammetry and chronoamperometry. Results revealed a similar anti-interference, higher sensitive, and faster response of glucose than the fibers produced from traditional template at +0.40 V. The improved performances were ascribed to the porous morphology which increased the surface-to-volume ratio. The porous morphology was found to be decided by the immobilization of metal ions onto PCA-PAEK. In conclusion, the functional group on PCA-PAEK side chain was the decisive factor to prepare CuO/CdO NFs with special morphology and good electrooxidation performances.

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9

Wang, Yongpeng, Pengtao Yan, Xintong Huo, Mengzhu Liu, Haibo Zhang y Zhenhua Jiang. "3D network super-hydrophobic hexafluorbisphenol A poly(aryl ether ketone) membrane prepared by one-step electrospraying". High Performance Polymers 32, n.º 10 (22 de junio de 2020): 1094–101. http://dx.doi.org/10.1177/0954008320930064.

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Novel super-hydrophobic poly(aryl ether ketone) (PAEK) membranes have been firstly prepared by modifying ordinary PAEK into hexafluorbisphenol A-PAEK through traditional nucleophilic condensation polymerization and subsequently simple electrospraying technique. With the solution concentration increased, the micromorphology exhibited nanofibers, nanofiber with spindles, 3D network with microspheres embedded, microspheres and dense films, successively. The static water contact angle increased from 99° to 155°, while the sliding angle from 1.3° to 6.8° (±1°), in which the 3D network presented the strongest super-hydrophobicity. After 200 h of water flushing, the rough surface structure and super-hydrophobicity of the membranes were well retained. Moreover, the membrane exhibited wonderful self-cleaning property, oil/water separation property, and stability due to the hierarchical micro/nanostructures. This work provides a new route for the creation of super-hydrophobic high performance engineering plastic fabrics with the potential values in large-scale application of filtration, oil/water separation, and antifouling.

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10

Dong, Bo, Shiyang Zhu, Ying Song, Shaowei Guan, Jinhui Pang y Zhenghua Jiang. "Synthesis of poly(arylene ether ketone) containing phenylsulfonic acid pendant for proton exchange membrane". High Performance Polymers 29, n.º 10 (26 de octubre de 2016): 1232–40. http://dx.doi.org/10.1177/0954008316674343.

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A series of phenylsulfonic acid–containing poly(arylene ether ketone) (psa-PAEK) were synthesized via polycondensation from 2-(4-methoxy)phenylhydroquinone and other commercial monomers, followed by postsulfonation approach under mild reaction conditions. Controlled substituted sites and the degree of sulfonation were realized using quantities of 2-(4-methoxy)phenylhydroquinone. Giving the psa-PAEK can be soluble in common organic solvents such as Dimethylsulfoxide, purity ≥99.5% (DMSO, Sinopharm Chemical Reagent Co., Ltd, Shanghai, China), NMP, 1-Methyl-2-pyrrolidinone purity ≥99.0% (NMP, Sinopharm Chemical Reagent Co., Lted, Shanghai, China), and N,N-dimethylacetamide, purity ≥99.0% (DMAc, Sinopharm Chemical Reagent Co., Lted, Shanghai, China). The tough and transparent polymer membrane was prepared by the solution casting method, which exhibited excellent mechanical properties and high proton conductivities. The tensile stress at maximum load and elongation at break of these membranes are 28.3–34.1 MPa and 101–126% in dry state, respectively. The proton conductivities of these membranes were higher than 10−2 S cm−1 at room temperature in water. Especially, the psa-PAEK-90 with ion exchange capacity of 1.62 mequiv. g−1 exhibited the proton conductivity of 176 mS cm−1 at 80°C in water. The clear microphase separation morphology was observed by small-angle X-ray scattering, which is a powerful evidence to explain their high conductive behaviors. These results suggest that the psa-PAEK membranes have great potential as a candidate membrane for proton exchange membrane fuel cell applications.

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11

Sudheendra, K., Jennifer Vinodhini, M. Govindaraju y Shantanu Bhowmik. "Comparative studies of nitrogen plasma and argon plasma treatment on the strength of PBO fibre reinforced high-temperature resistant thermoplastic composite". High Performance Polymers 33, n.º 7 (4 de febrero de 2021): 729–40. http://dx.doi.org/10.1177/0954008320987296.

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The study involves the processing of a novel poly [1, 4-phenylene-cis-benzobisoxazole] (PBO) fibre reinforced high-temperature thermoplastic composite with polyaryletherketone (PAEK) as the matrix. The PBO fibre and the PAEK film surface was modified using the method of argon and nitrogen plasma treatment. The investigation primarily focuses on evaluating the tensile properties of the fabricated laminates and correlating it with the effect of plasma treatment, surface characteristics, and its fracture surface. A 5% decrease in tensile strength was observed post argon plasma treatment while a 27% increase in strength was observed post nitrogen plasma treatment. The morphology of the failure surface was investigated by scanning electron microscopy and an interfacial failure was observed. Furthermore, the effect of plasma on the wettability of PBO fibres and PAEK film surface was confirmed by the Dynamic Contact Angle analysis and sessile drop method respectively. FTIR spectral analysis was done to investigate the effect of plasma treatment on the chemical structure on the surface. The results of the wettability study showed that the argon plasma treatment of the fibre surface increased its hydrophobicity while nitrogen plasma treatment resulted in the reduction of contact angle.

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12

Wang, Yongpeng, Qingwen Zhang, Mengzhu Liu, Qizhong Zhang, Haibo Zhang y Zhenhua Jiang. "The performances of modified single-walled carbon nanotubes/poly(ether ether ketone) composites prepared by solution blending and melt blending". High Performance Polymers 32, n.º 3 (4 de julio de 2019): 276–85. http://dx.doi.org/10.1177/0954008319860887.

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The modified single-walled carbon nanotubes (m-SWCNTs)/poly(ether ether ketone) (PEEK) composites were prepared by solution blending and melt blending, respectively. The mechanical, dielectric, and frictional performances of the m-SWCNTs/PEEK composites obtained by different processing technic were investigated. The poly(aryl ether ketone)s with pyrene (PAEK-Pys) were synthesized through iridium-catalyzed C−H borylation followed by Suzuki coupling. PAEK-Pys were characterized using ultraviolet–visible spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The polymers were then used for surface modification of pristine SWCNTs. Finally, the m-SWCNTs were used to prepare m-SWCNTs/PEEK composites via co-blending in solution or melt. The mechanical, frictional, and dielectric performance of the m-SWCNTs/PEEK composite by solution blending were better than these in m-SWCNTs/PEEK composite by melt blending. These results suggest that the method of solution blending is more favorable for the dispersion of the SWCNTs in PEEK.

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13

Harris, J. E., P. A. Winslow, J. H. Botkin, L. M. Maresca, R. A. Clendinning, R. J. Cotter, M. Matzner y G. T. Kwiatkowski. "Poly(aryl ether ketone) (PAEK) block and chain-extended copolymers. 2. Preparation and characterization of chain-extended PAEK copolymers and poly(ether ketone ketone)/poly(ether ether ketone) block copolymers". Macromolecules 26, n.º 9 (abril de 1993): 2366–71. http://dx.doi.org/10.1021/ma00061a032.

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14

Gan, Daoji, Shiqiang Lu y Zhijian Wang. "Synthesis and characterization of poly(ether ketone ketone) (PEKK)/sodium sulfonated poly(arylene ether ketone) (S-PAEK) block copolymers". Polymer International 50, n.º 7 (2001): 812–16. http://dx.doi.org/10.1002/pi.700.

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15

Hsiung, C. M. y M. Cakmak. "Effect of melt spinning and cold drawing on structure and properties of poly (aryl ether ketone) (PAEK) fibers". Polymer Engineering and Science 31, n.º 3 (febrero de 1991): 172–90. http://dx.doi.org/10.1002/pen.760310305.

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16

Hsiung, C. M. y M. Cakmak. "Effect of processing conditions on the structural gradients developed in injection-molded poly(aryl ether ketone) (PAEK) parts. I. Characterization by microbeam X-ray diffraction technique". Journal of Applied Polymer Science 47, n.º 1 (5 de enero de 1993): 125–47. http://dx.doi.org/10.1002/app.1993.070470116.

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17

Jin, Lei, Md Mahabubur Rahman, Faiz Ahmed, Taewook Ryu, Sujin Yoon, Wei Zhang, Daeho Kim y Hohyoun Jang. "Highly Proton Conductive Sulfonyl Imide Based Polymer Blended from Poly(arylene ether sulfone) and Parmax-1200 for Fuel Cells". Journal of Nanoscience and Nanotechnology 21, n.º 3 (1 de marzo de 2021): 1845–53. http://dx.doi.org/10.1166/jnn.2021.18932.

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Thermally and chemically stable, sulfonyl imide-based polymer blends have been prepared from sulfonimide poly(arylene ether sulfone) (SI-PAES) and sulfonimide Parmax-1200 (SI-Parmax-1200) using the solvent casting method. Initially, sulfonimide poly(arylene ether sulfone) (SI-PAES) polymers have typically been synthesized via direct polymerization of bis(4-chlorophenyl) sulfonyl imide (SI-DCDPS) and bis(4-fluorophenyl) sulfone (DFDPS) with bisphenol A (BPA). Subsequently, SI-Parmax-1200 has been synthesized via post-modification of the existing Parmax-1200 polymer followed by sulfonation and imidization. The SI-PAES/SI-Parmax-1200 blend membranes show high ion exchange capacity ranging from 1.65 to 1.97 meq/g, water uptake ranging from 22.8 to 65.4% and proton conductivity from 25.9 to 78.5 mS/cm. Markedly, the SI-PAES-40/SI-Parmax-1200 membrane (blended-40) exhibits the highest proton conductivity (78.5 mS/cm), which is almost similar to Nafion 117® (84.73 mS/cm). The thermogravimetric analysis (TGA) and Fenton's test confirm the excellent thermal and chemical stability of the synthetic polymer blends. Furthermore, the scanning electron microscopy (SEM) study shows a distinct phase separation at the hydrophobic/hydrophilic segments, which facilitate proton conduction throughout the ionic channel of the blend polymers. Therefore, the synthetic polymer blends represent an alternative to Nafion 117® as proton exchangers for fuel cells.

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Korolev, Alexander, Maxim Mishnev, Dmitry Zherebtsov, Nikolai Ivanovich Vatin y Maria Karelina. "Polymers under Load and Heating Deformability: Modelling and Predicting". Polymers 13, n.º 3 (29 de enero de 2021): 428. http://dx.doi.org/10.3390/polym13030428.

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The polymer deformability under load and heating is the determining factor in calculating reinforced polymer structures used under heating. Deformability–load/temperature relations make it possible to calculate temperature stresses and deformations in bearing cross-sections of polymer structures such as chimneys, smokestacks, etc. The present study suggests a method of calculating deformability of polymers subjected to the temperature loads. The method is based on the structure model of pack or layer bonded polymer domains where the elasticity of rigid bonds decreases with heating according to entropy principles. The method has been successfully tested on various polymers and compounds with due account for the effect of mineral additives on the deformation modulus increase.

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Almubarak, Tariq, Jun Hong C. Ng, Mohammed AlKhaldi, Saroj Panda y Hisham A. Nasr-El-Din. "Insights on Potential Formation Damage Mechanisms Associated with the Use of Gel Breakers in Hydraulic Fracturing". Polymers 12, n.º 11 (17 de noviembre de 2020): 2722. http://dx.doi.org/10.3390/polym12112722.

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Hydraulic fracturing using water-soluble polymers has been extensively used to enhance the productivity of oil and gas wells. However, the production enhancement can be significantly impaired due to polymer residue generated within the proppant pack in the created fractures. This work describes an approach to establish a suitable fracturing fluid cleanup process by characterizing broken polymer residues generated from the use of different gel breaker types. Commonly used gel breakers such as inorganic oxidizers (bromate and persulfate salts), specific enzymes, and acids were evaluated in this work. The influence of each gel breaker was examined using High-Pressure/High-Temperature (HP/HT) rheometer, aging cells, zeta potential, Gel Permeation Chromatography (GPC), and Environmental Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy (ESEM/EDS). Experiments were performed on a carboxymethylhydroxypropyl guar (CMHPG) fracturing fluid at temperatures up to 300 °F. The developed GPC methodology showed that the size of the broken polymer chains was mainly dependent on the type of gel breakers used. Moreover, laboratory tests have revealed that some gel breakers may negatively influence the performance of polymeric clay stabilizers. Additionally, this work showed damaging precipitations that can be generated due to the interactions of gel breakers with H2S.

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Wang, Kun Li, Jian Wei Lee, I. Hao Shih, Yi Liang Liu y En Tang Kang. "Resistive Polymer Memory Materials Containing Electron Donor and Acceptor Moieties". Advanced Materials Research 488-489 (marzo de 2012): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.3.

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Two series of polymers including polyimides and poly(aryl ether)s were prepared and used as active layers of polymer memories. The poly(aryl ether)-based polymers showed flash behaviors and polyimide-based polymers showed WORM behaviors. The poly(aryl ether)s flash memories can be negatively switched on and positively switched off, and the switching voltages are relative to the chemical structure of bisphenol moiety. On the other hand, the polyimide-based polymer devices can be bidirectionally switched on with comparable positive and negative switching threshold voltages, but cannot be switched off. The polyimides showed write-once-and-read- many-times (WORM) memory behavior. The poly(aryl ether) (AZTA-PAEb) showed very different memory behavior from polyimides (AZTA-PI and AZTA-PEI) although they contain the similar chemical structure (electron-donor triphenylamine and electron-acceptor triazine moieties). The imide structure in the polyimides plays a great role in the memory effects.

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Arlin, Jean-Baptiste, Alan R. Kennedy y Kenneth Shankland. "Magnesium, calcium and strontium salts of phenylacetic acid". Acta Crystallographica Section C Crystal Structure Communications 68, n.º 2 (6 de enero de 2012): m29—m33. http://dx.doi.org/10.1107/s0108270111055284.

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Three alkaline earth metal salts of phenylacetic acid were examined and all were found to have similar structural types to analogous salts of benzoic and halobenzoic acids. Thus, a synchrotron study shows that the cations incatena-poly[[[tetraaquamagnesium(II)]-μ-phenylacetato-κ2O:O′] phenylacetate], {[Mg(C8H7O2)(H2O)4](C8H7O2)}n, form a one-dimensional coordination polymer that propagates through Mg—O—C—O—Mg interactions involving both crystallographically independent Mg centres (Z′ = 2) and through translation along theaaxis. The polymeric chains pack to give alternate inorganic layers and organic bilayers. The Ca and Sr speciescatena-poly[[[diaqua(phenylacetato-κ2O,O′)calcium(II)]-μ3-phenylacetato-1′:1:1′′κ4O:O,O′:O′] monohydrate], {[Ca(C8H7O2)2(H2O)2]·H2O}n, andcatena-poly[[[diaqua(phenylacetato-κ2O,O′)strontium(II)]-μ3-phenylacetato-1′:1:1′′κ4O:O,O′:O′] monohydrate], {[Sr(C8H7O2)2(H2O)2]·H2O}n, are essentially isostructural. Both form one-dimensional coordination polymers through a carboxylate group that forms fourM—O bonds. The polymeric chains propagatevia21screw axes parallel to thebaxis and are further linked in thebcplane by hydrogen bonding involving the non-metal-bound water molecule. Similarly to the Mg salt, both have inorganic layers that alternate with organic bilayers.

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22

Yang, Jung-Eun, Young Taik Hong y Jae-Suk Lee. "Synthesis and Characterization of Polystyrene-Poly(arylene ether sulfone)-Polystyrene Triblock Copolymer for Proton Exchange Membrane Applications". Journal of Nanoscience and Nanotechnology 6, n.º 11 (1 de noviembre de 2006): 3594–98. http://dx.doi.org/10.1166/jnn.2006.17989.

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The polystyrene-poly(arylene ether sulfone)-polystyrene (PS-PAES-PS) coil-semirod-coil triblock copolymer was synthesized by the condensation reaction of PS-COCl and H2N-PAES-NH2 telechelic polymers. The reaction was facile characterized by high yields with a perfect control over the block lengths. Following a known reaction protocol it was possible to selectively sulfonate the PS block of the triblock copolymer that led to the sulfonated copolymer sPS-PAES-sPS. Studies on its proton conductivity and methanol permeability were carried out to evaluate its use as the proton exchange membrane in direct methanol fuel cells. Proton conductivity of the membranes was increased depending on the sulfonic acid group content in the sulfonated polymer. The membranes exhibited good dimensional and thermal stability, and low methanol permeability compared to Nafion 117.

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23

Sun, Hejing, Haibo Zhang, Jinhui Pang, Zheng Chen, Yuntao Han, Su Li, Xiaocui Han y Zhenhua Jiang. "Resistive memory devices based on novel functionalized poly(aryl ether)s with pendant azobenzene". High Performance Polymers 31, n.º 3 (12 de marzo de 2018): 273–81. http://dx.doi.org/10.1177/0954008318763739.

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We designed and synthesized two novel azobenzene functionalized poly(aryl ether)s (PAEs), PAE-azo-1 and PAE-azo-2, from a new azobenzene monomer via nucleophilic aromatic substitution polycondensation. This direct polymerization approach via azobenzene monomer has the advantages of controlling the distribution and amount of the azobenzene chromophores in the polymer. Both of the polymers showed very good thermal stability and excellent solubility for future application in the electronics industry. These polymers were fabricated as films by simple spin-coating and both of them were then prepared as sandwich memory devices. PAE-azo-1 and PAE-azo-2 exhibit write-once-read-many-times-type memory behavior, which can be encoded as “0” and “1,” and possess the low operation voltage below −3.0 V. The memory mechanism was investigated through ultraviolet–visible optical absorption spectrum and the cyclic voltammetry. These obtained results indicate that the novel azobenzene functionalized PAEs are a promising candidate for low power consumption and high-performance materials for data storage.

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24

Shang, Chengyuan, Xiaojuan Zhao, Junwei Li, Jingang Liu y Wei Huang. "Poly(aryl ether ketone/sulfone)s containing ortho-methyl and pendant trifluoromethyl-substituted phenyl groups: Synthesis and properties". High Performance Polymers 24, n.º 8 (13 de julio de 2012): 692–701. http://dx.doi.org/10.1177/0954008312449845.

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Two novel bisphenols, 1,1-bis(4′-hydroxy-3′,5′-dimethylphenyl)-1-(3′′-trifluoromethylphenyl)-2,2,2-trifluoroethane (4M6FDO) and 1,1-bis(4′-hydroxy-3′,5′-dimethylphenyl)-1-[3′′,5′′-bis(trifluoromethyl)phenyl]-2,2,2-trifluoroethane (4M9FDO), with methyl groups ortho-substituted to the phenol groups, bulky trifluoromethyl-substituted phenyl groups and trifluoromethyl groups in the structure, were synthesized and characterized. The bisphenols were polymerized with 4,4′-difluorobenzophenone and bis(4-fluorophenyl) sulfone, respectively, via a aromatic nucleophilic substitution polycondensation to afford four poly(aryl ether ketone/sulfone)s (PAEKs/PAESs) with the inherent viscosities of 0.32–0.52 dL g−1. The ortho-methyl and pendant trifluoromethyl-substituted phenyl groups endow the polymers with good solubility, the rigidity of the polymer chains increase the glass transition ( Tg) of the polymers to 197–235 °C. Flexible and tough films cast from N,N-dimethylacetamide showed good thermal stability, low dielectric constants of 2.67–2.73 and low water uptakes of 0.21–0.40%. Moreover, the polymers showed good transparency with light transmittance at 450 nm as high as 96% and cutoff wavelength as low as 285 nm. The PAEKs also exhibited low light-absorption at the optocommunication wavelengths of 1310 and 1550 nm.

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25

Timofiychuk, O. A., T. I. Prudnicova, D. O. Mishurov, V. L. Avramenko y R. G. Shevcova. "Decomposition of biodegradable films developed on the basis of polyvinyl alcohol in the natural environment". Facta universitatis - series: Physics, Chemistry and Technology 7, n.º 1 (2009): 61–67. http://dx.doi.org/10.2298/fupct0901061t.

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The use of polymeric pack has made for many important problems. Biodegradable plastics may provide solutions to global environmental problems. The aim of this study is to examine the utilization possibilities in natural environment of biodegradable films, which was developed with polyvinyl alcohol and organic filler materials (amylum and cellulose). The films stability against the filamentous fungus was analyzed, the soil type with optimal conditions to the biodegradation of polymers was determined; the mold fungi were separated from biodegradable films and were identified to a genus.

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26

Liang, Feng, Ghaithan Al-Muntasheri, Hooisweng Ow y Jason Cox. "Reduced-Polymer-Loading, High-Temperature Fracturing Fluids by Use of Nanocrosslinkers". SPE Journal 22, n.º 02 (5 de octubre de 2016): 622–31. http://dx.doi.org/10.2118/177469-pa.

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Summary In the quest to discover more natural-gas resources, considerable attention has been devoted to finding and extracting gas locked within tight formations with permeability in the nano- to microdarcy range. The main challenges associated with working in such formations are the intrinsically high-temperature and high-pressure bottom conditions. For formations with bottomhole temperatures at approximately 350–400°F, traditional hydraulic-fracturing fluids that use crosslinked polysaccharide gels, such as guar and its derivatives, are not suitable because of significant polymer breakdown in this temperature range. Fracturing fluids that can work at these temperatures require thermally stable synthetic polymers such as acrylamide-based polymers. However, such polymers have to be used at very-high concentrations to suspend proppants. The high-polymer concentrations make it very difficult to completely degrade at the end of a fracturing operation. As a consequence, formation damage by polymer residue can reduce formation conductivity to gas flow. This paper addresses the shortcomings of the current state-of-the-art high-temperature fracturing fluids and focuses on developing a less-damaging, high-temperature-stable fluid that can be used at temperatures up to 400°F. A laboratory study was conducted with this novel system, which comprises a synthetic acrylamide-based copolymer gelling agent and is capable of being crosslinked with an amine-containing polymer-coated nanosized particulate crosslinker (nanocrosslinker). The laboratory data have demonstrated that the temperature stability of the crosslinked fluid is much better than that of a similar fluid lacking the nanocrosslinker. The nanocrosslinker allows the novel fluid system to operate at significantly lower polymer concentrations (25–45 lbm/1,000 gal) compared with current commercial fluid systems (50–87 lbm/1,000 gal) designed for temperatures from 350 to 400°F. This paper presents results from rheological studies that demonstrate superior crosslinking performance and thermal stability in this temperature range. This fracturing-fluid system has sufficient proppant-carrying viscosity, and allows for efficient cleanup by use of an oxidizer-type breaker. Low polymer loading and little or no polymer residue are anticipated to facilitate efficient cleanup, reduced formation damage, better fluid conductivity, and enhanced production rates. Laboratory results from proppant-pack regained-conductivity tests are also presented.

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27

Li, Xi, Zheng Shu, Pingya Luo y Zhongbin Ye. "Associating Polymer Networks Based on Cyclodextrin Inclusion Compounds for Heavy Oil Recovery". Journal of Chemistry 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/7218901.

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This work evaluates an approach to improve the enhanced heavy oil recovery performance of hydrophobic associating polymer. A polymeric system based on water-soluble hydrophobic associating polymer (WSHAP) and cyclodextrin (CD) polymer was proposed in this work. Addition of CD polymer to WSHAP forms interpolymer bridges by inclusion of CD groups with hydrophobic tails, and thereby the network structure is strengthened. The proposed system offers good viscoelasticity, pronounced shear thinning, and interesting viscosity-temperature relations. Sand pack tests indicated that the proposed system can build high resistance factor during the propagation in porous media, and its moderate adsorption phenomenon was represented by the thickness of the adsorbed layer. The relationship between effective viscosity and oil recovery increment indicated that the proposed system can significantly reduce the residual oil saturation due to the “piston-like” propagation. The overall oil recovery was raised by 5.7 and 24.5% of the original oil in place compared with WSHAP and partially hydrolyzed polyacrylamide (HPAM), respectively.

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28

Na, Ruiqi, Pengfei Huo, Xingrui Zhang, Shuling Zhang, Yinlong Du, Kai Zhu, Yaning Lu, Menghan Zhang, Jiashuang Luan y Guibin Wang. "A flexible solid-state supercapacitor based on a poly(aryl ether ketone)–poly(ethylene glycol) copolymer solid polymer electrolyte for high temperature applications". RSC Advances 6, n.º 69 (2016): 65186–95. http://dx.doi.org/10.1039/c6ra11202a.

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Here in we fabricated a high temperature flexible solid-state supercapacitor based on PAEK–PEG copolymers solid polymer electrolyte. As fabricated supercapacitor has excellent electrochemical performance at various operating temperature especially high temperature (120 °C).

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29

Jones, Austin L., Carr Hoi Yi Ho, Parand R. Riley, Indunil Angunawela, Harald Ade, Franky So y John R. Reynolds. "Investigating the active layer thickness dependence of non-fullerene organic solar cells based on PM7 derivatives". Journal of Materials Chemistry C 8, n.º 43 (2020): 15459–69. http://dx.doi.org/10.1039/d0tc03096a.

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This work exposes the importance of testing a polymers active layer thickness tolerance as small modifications to a polymers structure can radically change its ability to stack/pack in the BHJ which is reflected in thick active layer OSCs.

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30

Lavine, M. S. "Cylindrical polymer micelles pack in 3D". Science 347, n.º 6228 (19 de marzo de 2015): 1325. http://dx.doi.org/10.1126/science.347.6228.1325-b.

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31

Liu, Yiqun, Y. Gene Liao y Ming-Chia Lai. "Transient Temperature Distributions on Lithium-Ion Polymer SLI Battery". Vehicles 1, n.º 1 (25 de julio de 2019): 127–37. http://dx.doi.org/10.3390/vehicles1010008.

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Lithium-ion polymer batteries currently are the most popular vehicle onboard electric energy storage systems ranging from the 12 V/24 V starting, lighting, and ignition (SLI) battery to the high-voltage traction battery pack in hybrid and electric vehicles. The operating temperature has a significant impact on the performance, safety, and cycle lifetime of lithium-ion batteries. It is essential to quantify the heat generation and temperature distribution of a battery cell, module, and pack during different operating conditions. In this paper, the transient temperature distributions across a battery module consisting of four series-connected lithium-ion polymer battery cells are measured under various charging and discharging currents. A battery thermal model, correlated with the experimental data, is built in the module-level in the ANSYS/Fluent platform. This validated module thermal model is then extended to a pack thermal model which contains four parallel-connected modules. The temperature distributions on the battery pack model are simulated under 40 A, 60 A, and 80 A constant discharge currents. An air-cool thermal management system is integrated with the battery pack model to ensure the operating temperature and temperature gradient within the optimal range. This paper could provide thermal management design guideline for the lithium-ion polymer battery pack.

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32

Gaikwad, S. D. y R. K. Goyal. "Study on the Effect of Ball Milling on Dielectric and Thermal Behaviour of High Performance Polymer Composites". Nano Hybrids and Composites 17 (agosto de 2017): 72–78. http://dx.doi.org/10.4028/www.scientific.net/nhc.17.72.

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The synthesis of electrolytic grade iron (Fe) nanopowder was done by using planetary ball milling. It was found that the average crystallite size of the iron powder after 20 h milling was 32 nm. The high performance polymeric composites based on poly (aryletherketone) (PAEK) as a matrix and Fe as filler were prepared by planetary ball milling followed by hot pressing. Composites containing 50 wt.% Fe particles with varying milling time (0 to 20 h) were prepared. Scanning electron microscopy showed that the Fe particles are well dispersed in the PAEK matrix. The dielectric constant of the PAEK/Fe (50 wt.%) composite increased with ball milling time up to 5 h thereafter it decreased on further increasing the milling time. It was also found that the 10 % weight loss (T10) degradation temperature and the maximum degradation temperatures of the composites were above 530 °C. However, for a given composite, these temperatures were found to decrease with increasing ball milling time.

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33

Na, Ruiqi, Guanze Huo, Shuling Zhang, Pengfei Huo, Yinlong Du, Jiashuang Luan, Kai Zhu y Guibin Wang. "A novel poly(ethylene glycol)–grafted poly(arylene ether ketone) blend micro-porous polymer electrolyte for solid-state electric double layer capacitors formed by incorporating a chitosan-based LiClO4 gel electrolyte". Journal of Materials Chemistry A 4, n.º 46 (2016): 18116–27. http://dx.doi.org/10.1039/c6ta07846j.

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34

SMITH, F. "Pack Dyeing Machines". Journal of the Society of Dyers and Colourists 32, n.º 5 (22 de octubre de 2008): 128–35. http://dx.doi.org/10.1111/j.1478-4408.1916.tb00921.x.

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35

WHITTAKER, C. M. "Pack Dyeing Machines". Journal of the Society of Dyers and Colourists 32, n.º 7 (22 de octubre de 2008): 187. http://dx.doi.org/10.1111/j.1478-4408.1916.tb00931.x.

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36

Yeh, Wu, Huang, Lee y Jeng. "In Search of a Green Process: Polymeric Films with Ordered Arrays via a Water Droplet Technique". Polymers 11, n.º 9 (9 de septiembre de 2019): 1473. http://dx.doi.org/10.3390/polym11091473.

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As an efficient technique for the preparation of polymeric hexagonal orderly arrays, the breath figure (BF) process has opened a modern avenue for a bottom-up fabrication method for more than two decades. Through the use of the water vapor condensation on the solution surface, the water droplets will hexagonally pack into ordered arrays, acting as a template for controlling the regular micro patterns of polymeric films. Comparing to the top-down techniques, such as lithography or chemical etching, the use of water vapor as the template provides a simple fabrication process with sustainability. However, using highly hazardous solvents such as chloroform, carbon disulfide (CS2), benzene, dichloromethane, etc., to dissolve polymers might hinder the development toward green processes based on this technique. In this review, we will touch upon the contemporary techniques of the BF process, including its up-to-date applications first. More importantly, the search of greener processes along with less hazardous solvents for the possibility of a more sustainable BF process is the focal point of this review.

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37

Mirsafaei, Razieh y Majid Kolahdoozan. "Preparation and characterization of poly (amide-ester-imide)/Na+-MMT nanocomposite via ultrasonic method". Journal of Polymer Engineering 37, n.º 5 (24 de mayo de 2017): 443–48. http://dx.doi.org/10.1515/polyeng-2016-0178.

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Abstract The novel poly (amide-ester-imide) (PAEI)/Na+-MMT (montmorillonite) nanocomposites were synthesized by ultrasound-assisted technique successfully. PAEI/Na+-MMT nanocomposites with various content of Na+-MMT were applied to enhance the dispersion of the clay layers with polymer matrix. Water-soluble PAEI containing poly (ethylene glycol) (PEG-6000) was prepared, and nanocomposites with various content of Na+-MMT (5, 10, 15, and 20 mass %) were fabricated by ultrasonic method to produce nano-scale composites. The effects of Na+-MMT on the nanocomposites were investigated by Fourier transform infrared, X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) and for thermal properties. XRD approved the structure information of the synthesized nanomaterials, and it was shown that the interlayer spacing increased with clay loading. The magnitude of dispersion of the clay in the nanocomposite matrix was investigated by TEM and SEM images. The results indicated that the lateral dimension of Na+-MMT particles in composites was approximately 100 nm, and the nanomaterials are well dispersed in the polymer matrix to produce exfoliated structure in polymer/nanocomposite. Thermogravimetric analysis confirms that PAEI/Na+-MMT nanocomposites show superior thermal stability with respect to the pure PAEIs.

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38

Otero, Toribio F. y Jose G. Martinez. "Chemo-ionic-conformational memory from reactive dense gels: a way to explore new multivalent memories and brain memory". MRS Proceedings 1729 (2015): 137–42. http://dx.doi.org/10.1557/opl.2015.156.

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ABSTRACTSo far we ignore how brain stores memory. Neurons communicate by pulses where the charges are carried between them by ions flowing through channels. Those pulses present a characteristic maximum related to the conformational movements of the channel protein opening and closing. Electrochemical responses from dense gel electrodes of conducting polymers mimic those pulses. Here we proved that the biomimetic pulse includes simultaneously electrical, chemical and conformational information related to the energy stored by the initial conformational packed state of the polymer. This energetic memory increases linearly with the potential used to reduce and pack (write) the initial state: hundreds of different values can be written (stored) in a full reproducible way (multivalent memory). Every state constitutes a chemo-ionic-conformational (CHEMICONF) memory. Each multivalent memory is read and erased by the reverse electrochemical reaction. Crosslinking states produce permanent memories not erased while reading. Developing CHEMICONF memories can provide new hypothesis to reveal brain memory mechanisms.

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39

Farinola, Gianluca M., Francesco Babudri, Antonio Cardone, Omar Hassan Omar y Francesco Naso. "Synthesis of substituted conjugated polymers: Tuning properties by functionalization". Pure and Applied Chemistry 80, n.º 8 (1 de enero de 2008): 1735–46. http://dx.doi.org/10.1351/pac200880081735.

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The review addresses features of special interest concerning two classes of functionalized semiconducting polymers: poly(aryleneethynylene)s (PAEs) bearing biomolecules as chiral nonracemic pendant groups and poly(phenylenevinylene)s (PPVs), which are fluorinated in various positions of the repeating units. Molecular design and choice of specific substituents, synthetic protocols, and the effect of functionalization on properties of the polymers both in solution and in the solid state are discussed.

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40

Jung, Andre, Manuel B. Endres y Oliver Weichold. "Influence of Environmental Factors on the Swelling Capacities of Superabsorbent Polymers Used in Concrete". Polymers 12, n.º 10 (24 de septiembre de 2020): 2185. http://dx.doi.org/10.3390/polym12102185.

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Superabsorbent polymers (SAP) are of major interest as materials to control the cement hydration process. The swelling behavior of the SAPs significantly influences the performance of the resulting concrete by slowly releasing polymer-bound water in order to maintain a consistent w/c value. A round-robin test conducted by the RILEM Technical Committee 260-RSC showed that the same batch of polymer can lead to large deviations in concrete performance and this was assumed to originate in different storage conditions of the SAP. In this contribution the change in the performance of two SAPs, a crosslinked poly(acrylate) and a crosslinked poly(acrylate-co-acrylamide), was assessed after ageing in standard climate, at 50 °C, and under UV irradiation. During storage in standard climate or 50 °C, ageing led to dehydration of the SAP, and this subsequently led to a higher water uptake during swelling. By contrast, UV irradiation reduced the water uptake, most likely as a result of photo-crosslinking. Dynamic water vapor sorption experiments indicated a strong dependence of the water uptake on both the ambient humidity and the temperature. As a result, cement mixtures containing SAP must be calculated on the dry mass of the SAP rather than the actual weight on site. A standard procedure of how to pack and handle SAP to be used in concrete is also provided.

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41

Kim, Sang Hee, Kyu Ha Lee, Ji Young Chu, Ae Rhan Kim y Dong Jin Yoo. "Enhanced Hydroxide Conductivity and Dimensional Stability with Blended Membranes Containing Hyperbranched PAES/Linear PPO as Anion Exchange Membranes". Polymers 12, n.º 12 (16 de diciembre de 2020): 3011. http://dx.doi.org/10.3390/polym12123011.

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A series of novel blended anion exchange membranes (AEMs) were prepared with hyperbranched brominated poly(arylene ether sulfone) (Br-HB-PAES) and linear chloromethylated poly(phenylene oxide) (CM-PPO). The as-prepared blended membranes were fabricated with different weight ratios of Br-HB-PAES to CM-PPO, and the quaternization reaction for introducing the ionic functional group was performed by triethylamine. The Q-PAES/PPO-XY (quaternized-PAES/PPO-XY) blended membranes promoted the ion channel formation as the strong hydrogen bonds interconnecting the two polymers were maintained, and showed an improved hydroxide conductivity with excellent thermal behavior. In particular, the Q-PAES/PPO-55 membrane showed a very high hydroxide ion conductivity (90.9 mS cm−1) compared to the pristine Q-HB-PAES membrane (32.8 mS cm−1), a result supported by the morphology of the membrane as determined by the AFM analysis. In addition, the rigid hyperbranched structure showed a suppressed swelling ratio of 17.9–24.9% despite an excessive water uptake of 33.2–50.3% at 90 °C, and demonstrated a remarkable alkaline stability under 2.0 M KOH conditions over 1000 h.

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42

Zhang, Qian, Xue Chen, Heng Wu, Wandong Luo, Xiangyang Liu, Li Feng y Tiantao Zhao. "Comparison of Clay Ceramsite and Biodegradable Polymers as Carriers in Pack-bed Biofilm Reactor for Nitrate Removal". International Journal of Environmental Research and Public Health 16, n.º 21 (29 de octubre de 2019): 4184. http://dx.doi.org/10.3390/ijerph16214184.

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In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.

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43

Zhang, Hong-Tao y Xiao-Long Wang. "A new twofold interpenetrated two-dimensional cadmium(II) coordination polymer constructed from 2,2′-(benzene-1,4-dicarboxamido)dipropionate". Acta Crystallographica Section C Structural Chemistry 74, n.º 11 (22 de octubre de 2018): 1434–39. http://dx.doi.org/10.1107/s2053229618013967.

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In recent years, much initial interest and enthusiasm has focused on the self-assembly of coordination polymers due to the aesthetics of their crystalline architectures and their potential applications as new functional materials. As part of an exploration of chiral coordination polymers, a new twofold interpenetrated two-dimensional (2D) coordination polymer, namely, poly[[tetraaquabis[μ3-(2R,2′R)-2,2′-(benzene-1,4-dicarboxamido)dipropionato-κ5 O,O′:O′′,O′′′:O′′]dicadmium(II)] trihydrate], {[Cd2(C14H14N2O6)2(H2O)4]·3H2O} n , has been synthesized by the reaction of Cd(CH3COO)2·2H2O with the designed ligand (2R,2′R)-2,2′-(benzene-1,4-dicarboxamido)dipropionic acid (H2 L). The compound has been structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction analysis. In the crystal structure, each CdII cation binds to three carboxylate groups from two crystallographically independent L 2− dianions. Four carboxylate groups link two crystallographically independent cadmium cations into a 4,4-connected secondary building unit (SBU). The resulting SBUs are extended into a two-dimensional folding sheet via the terephthalamide moiety of the ligand as a spacer, which can be simplified as a (4,4)-connected 4,4L15 net with the point symbol (3.53.62)(32.52.62). In the lattice, two independent folding sheets interpenetrate each other to yield a double-sheet layer. The resulting 2D layers pack in parallel arrays through intermolecular hydrogen bonds and interlayer π–π interactions. The thermal stability and photoluminescence properties of the title compound have been investigated and it exhibits an enhanced fluorescence emission and a longer lifetime compared with free H2 L.

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Almubarak, Tariq, Jun Hong Ng, Hisham A. Nasr–El–Din, Khatere Sokhanvarian y Mohammed AlKhaldi. "Dual-Polymer Hydraulic-Fracturing Fluids: A Synergy Between Polysaccharides and Polyacrylamides". SPE Journal 24, n.º 06 (19 de julio de 2019): 2635–52. http://dx.doi.org/10.2118/191580-pa.

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Summary As exploration for oil and gas continues, it becomes necessary to produce from deeper formations, and to meet the challenge of low permeability and higher temperatures. Unconventional shale formations are addressed with slickwater fracturing fluids, owing to the shale's unique geomechanical properties. On the other hand, conventional formations require crosslinked fracturing fluids to properly enhance productivity. Guar and its derivatives have a history of success in crosslinked hydraulic–fracturing fluids. However, they require higher polymer loading to withstand higher–temperature environments. This leads to an increase in mixing time and additive requirements. Most importantly, as a result of high polymer loading, they do not break completely and thus generate residual–polymer fragments that can plug the formation and significantly reduce fracture conductivity. In this work, a new hybrid dual–polymer hydraulic–fracturing fluid was developed. The fluid consists of a guar derivative and a polyacrylamide–based synthetic polymer. Compared with conventional fracturing fluids, this new system is easily hydrated, requires fewer additives, can be mixed “on the fly,” and is capable of maintaining excellent rheological performance at low polymer loadings. The polymer mixture solutions were prepared at a total polymer concentration of 20 to 40 lbm/1,000 gal at volume ratios of 2:1, 1:1, and 1:2. The fluids were crosslinked with a metallic crosslinker and broken with an oxidizer at 300°F. Testing focused on crosslinker/polymer–ratio analysis to effectively lower loading while maintaining sufficient performance to carry proppant at this temperature. A high–pressure/high–temperature (HP/HT) rheometer was used to measure viscosity, storage modulus, and fluid–breaking performance. An HP/HT aging cell and HP/HT see–through cell were used for proppant settling. Fourier–transform infrared (FTIR) spectroscopy, Cryo scanning electron microscopy (Cryo–SEM), and an HP/HT rheometer were also used to understand the interaction. Results indicated that the dual–polymer fracturing fluid was able to generate stable viscosity at 300°F and 100 s−1 as well as generate a higher viscosity compared with the individual–polymer fracturing fluid. Also, properly understanding and tuning the crosslinker to the polymer ratio generated excellent performance at 20 lbm/1,000 gal. The two polymers formed an improved crosslinking network that enhanced proppant–carrying properties. This fluid also demonstrated a clean and controlled breaking performance with an oxidizer. Extensive experiments were pursued to evaluate the new dual–polymer system for the first time. This system exhibited a positive interaction between the polysaccharide and polyacrylamide families and generated excellent rheological properties. The major benefit of using a mixed–polymer system is reduced polymer loading. Lower loading is highly desirable because it reduces material cost, eases field operation, and potentially lowers damage to the fracture face, proppant pack, and formation.

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45

Kim, Jin-Soo y Byoung-Uk Cho. "Effects of PAE-PVA and PAE-MP Dual Polymer Systems on Strength Properties of Paper". Journal of Korea Technical Association of the Pulp and Paper Industry 52, n.º 6 (31 de diciembre de 2020): 82–93. http://dx.doi.org/10.7584/jktappi.2020.12.52.6.82.

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46

Park, Chan, Dae-Jeon Jun, Sang-Won Park y Hyun-Pil Lim. "Use of polyaryletherketone (PAEK) based polymer for implant-supported telescopic overdenture: A case report". Journal of Advanced Prosthodontics 9, n.º 1 (2017): 74. http://dx.doi.org/10.4047/jap.2017.9.1.74.

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47

Kang, Hyo, Kihyun Kim, Daeseung Kang y Jong-Chan Lee. "Liquid crystal alignment behavior on sulfonated poly(arylene ether sulfone) films". RSC Advances 5, n.º 79 (2015): 64031–36. http://dx.doi.org/10.1039/c5ra12523e.

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A series of sulfonated poly(arylene ether sulfone) (PAES#, # is the feed monomer ratio of 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone) derivatives were synthesized to investigate the liquid crystal (LC) alignment property of these polymer films.

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48

Corredor, Laura, Maen Husein y Brij Maini. "Effect of Hydrophobic and Hydrophilic Metal Oxide Nanoparticles on the Performance of Xanthan Gum Solutions for Heavy Oil Recovery". Nanomaterials 9, n.º 1 (12 de enero de 2019): 94. http://dx.doi.org/10.3390/nano9010094.

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Recent studies revealed higher polymer flooding performance upon adding metal oxide nanoparticles (NPs) to acrylamide-based polymers during heavy oil recovery. The current study considers the effect of TiO2, Al2O3, in-situ prepared Fe(OH)3 and surface-modified SiO2 NPs on the performance of xanthan gum (XG) solutions to enhance heavy oil recovery. Surface modification of the SiO2 NPs was achieved by chemical grafting with 3-(methacryloyloxy)propyl]trimethoxysilane (MPS) and octyltriethoxysilane (OTES). The nanopolymer sols were characterized by their rheological properties and ζ-potential measurements. The efficiency of the nanopolymer sols in displacing oil was assessed using a linear sand-pack at 25 °C and two salinities (0.3 wt % and 1.0 wt % NaCl). The ζ-potential measurements showed that the NP dispersions in deionized (DI) water are unstable, but their colloidal stability improved in presence of XG. The addition of unmodified and modified SiO2 NPs increased the viscosity of the XG solution at all salinities. However, the high XG adsorption onto the surface of Fe(OH)3, Al2O3, and TiO2 NPs reduced the viscosity of the XG solution. Also, the NPs increased the cumulative oil recovery between 3% and 9%, and between 1% and 5% at 0 wt % and 0.3 wt % NaCl, respectively. At 1.0 wt % NaCl, the NPs reduced oil recovery by XG solution between 5% and 12%, except for Fe(OH)3 and TiO2 NPs. These NPs increased the oil recovery between 2% and 3% by virtue of reduced polymer adsorption caused by the alkalinity of the Fe(OH)3 and TiO2 nanopolymer sols.

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49

Venkatramaiah, Nutalapati, Ricardo F. Mendes, Artur M. S. Silva, João P. C. Tomé y Filipe A. Almeida Paz. "A ladder coordination polymer based on Ca2+and (4,5-dicyano-1,2-phenylene)bis(phosphonic acid): crystal structure and solution-state NMR study". Acta Crystallographica Section C Structural Chemistry 72, n.º 9 (25 de agosto de 2016): 685–91. http://dx.doi.org/10.1107/s2053229616012328.

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The preparation of coordination polymers (CPs) based on either transition metal centres or rare-earth cations has grown considerably in recent decades. The different coordination chemistry of these metals allied to the use of a large variety of organic linkers has led to an amazing structural diversity. Most of these compounds are based on carboxylic acids or nitrogen-containing ligands. More recently, a wide range of molecules containing phosphonic acid groups have been reported. For the particular case of Ca2+-based CPs, some interesting functional materials have been reported. A novel one-dimensional Ca2+-based coordination polymer with a new organic linker, namely poly[[diaqua[μ4-(4,5-dicyano-1,2-phenylene)bis(phosphonato)][μ3-(4,5-dicyano-1,2-phenylene)bis(phosphonato)]dicalcium(II)] tetrahydrate], {[Ca2(C8H4N2O6P2)2(H2O)2]·4H2O}n, has been prepared at ambient temperature. The crystal structure features one-dimensional ladder-like∞1[Ca2(H2cpp)2(H2O)2] polymers [H2cpp is (4,5-dicyano-1,2-phenylene)bis(phosphonate)], which are created by two distinct coordination modes of the anionic H2cpp2−cyanophosphonate organic linkers: while one molecule is only bound to Ca2+cationsviathe phosphonate groups, the other establishes an extra single connectionviaa cyano group. Ladders close pack with water molecules through an extensive network of strong and highly directional O—H...O and O—H...N hydrogen bonds; the observed donor–acceptor distances range from 2.499 (5) to 3.004 (6) Å and the interaction angles were found in the range 135–178°. One water molecule was found to be disordered over three distinct crystallographic positions. A detailed solution-state NMR study of the organic linker is also provided.

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50

He, Hong, Jingyu Fu, Baofeng Hou, Fuqing Yuan, Lanlei Guo, Zongyang Li y Qing You. "Investigation of Injection Strategy of Branched-Preformed Particle Gel/Polymer/Surfactant for Enhanced Oil Recovery after Polymer Flooding in Heterogeneous Reservoirs". Energies 11, n.º 8 (27 de julio de 2018): 1950. http://dx.doi.org/10.3390/en11081950.

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The heterogeneous phase combination flooding (HPCF) system which is composed of a branched-preformed particle gel (B-PPG), polymer, and surfactant has been proposed to enhance oil recovery after polymer flooding in heterogeneous reservoirs by mobility control and reducing oil–water interfacial tension. However, the high cost of chemicals can make this process economically challenging in an era of low oil prices. Thus, in an era of low oil prices, it is becoming even more essential to optimize the heterogeneous phase combination flooding design. In order to optimize the HPCF process, the injection strategy has been designed such that the incremental oil recovery can be maximized using the corresponding combination of the B-PPG, polymer, and surfactant, thereby ensuring a more economically-viable recovery process. Different HPCF injection strategies including simultaneous injection and alternation injection were investigated by conducting parallel sand pack flooding experiments and large-scale plate sand pack flooding experiments. Results show that based on the flow rate ratio, the pressure rising area and the incremental oil recovery, no matter whether the injection strategy is simultaneous injection or alternation injection of HPCF, the HPCF can significantly block high permeability zone, increase the sweep efficiency and oil displacement efficiency, and effectively improve oil recovery. Compared with the simultaneous injection mode, the alternation injection of HPCF can show better sweep efficiency and oil displacement efficiency. Moreover, when the slug of HPCF and polymer/surfactant with the equivalent economical cost is injected by alternation injection mode, as the alternating cycle increases, the incremental oil recovery increases. The remaining oil distribution at different flooding stages investigated by conducting large-scale plate sand pack flooding experiments shows that alternation injection of HPCF can recover more remaining oil in the low permeability zone than simultaneous injection. Hence, these findings could provide the guidance for developing the injection strategy of HPCF to further enhance oil recovery after polymer flooding in heterogeneous reservoirs in the era of low oil prices.

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