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Journal articles on the topic 'Polyester'

Author: Grafiati
Published: 4 June 2021
Last updated: 25 May 2024

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1

REHM, Bernd H. A. "Polyester synthases: natural catalysts for plastics." Biochemical Journal 376, no. 1 (November 15, 2003): 15–33. http://dx.doi.org/10.1042/bj20031254.

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Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester synthases are the key enzymes of polyester biosynthesis and catalyse the conversion of (R)-hydroxyacyl-CoA thioesters to polyesters with the concomitant release of CoA. These soluble enzymes turn into amphipathic enzymes upon covalent catalysis of polyester-chain formation. A self-assembly process is initiated resulting in the formation of insoluble cytoplasmic inclusions with a phospholipid monolayer and covalently attached polyester synthases at the surface. Surface-attached polyester synthases show a marked increase in enzyme activity. These polyester synthases have only recently been biochemically characterized. An overview of these recent findings is provided. At present, 59 polyester synthase structural genes from 45 different bacteria have been cloned and the nucleotide sequences have been obtained. The multiple alignment of the primary structures of these polyester synthases show an overall identity of 8–96% with only eight strictly conserved amino acid residues. Polyester synthases can been assigned to four classes based on their substrate specificity and subunit composition. The current knowledge on the organization of the polyester synthase genes, and other genes encoding proteins related to PHA metabolism, is compiled. In addition, the primary structures of the 59 PHA synthases are aligned and analysed with respect to highly conserved amino acids, and biochemical features of polyester synthases are described. The proposed catalytic mechanism based on similarities to α/β-hydrolases and mutational analysis is discussed. Different threading algorithms suggest that polyester synthases belong to the α/β-hydrolase superfamily, with a conserved cysteine residue as catalytic nucleophile. This review provides a survey of the known biochemical features of these unique enzymes and their proposed catalytic mechanism.
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2

Motlatle, Abesach M., Suprakas Sinha Ray, Vincent Ojijo, and Manfred R. Scriba. "Polyester-Based Coatings for Corrosion Protection." Polymers 14, no. 16 (August 21, 2022): 3413. http://dx.doi.org/10.3390/polym14163413.

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The article is the first review encompassing the study and the applications of polyester-based coatings for the corrosion protection of steel. The impact of corrosion and the challenges encountered thus far and the solutions encountered in industry are addressed. Then, the use of polyesters as a promising alternative to current methods, such as phosphating, chromating, galvanization, and inhibitors, are highlighted. The classifications of polyesters and the network structure determine the overall applications and performance of the polymer. The review provides new trends in green chemistry and smart and bio-based polyester-based coatings. Finally, the different applications of polyesters are covered; specifically, the use of polyesters in surface coatings and for other industrial uses is discussed.
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3

Lee, Hee Young, Heidy Cruz, and Younggon Son. "Effects of incorporation of polyester on the electrical resistivity of polycarbonate/multi-walled carbon nanotube nanocomposite." Journal of Composite Materials 53, no. 10 (September 24, 2018): 1291–98. http://dx.doi.org/10.1177/0021998318801932.

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In this work, we present the effect of incorporation of polyester on the electrical properties of injection-molded polycarbonate/multi-walled carbon nanotube nanocomposites. The study was conducted by melt-mixing polycarbonate, multi-walled carbon nanotube, and three types of polyesters: polybutylene terephthalate, polyethylene terephthalate, and liquid crystal polymer. It was found that the volume resistivities of injection-molded composites containing 2 phr polyester significantly decreased because of the transesterification reaction between the polycarbonate and polyester. The resulting polycarbonate-polyester random block copolymer kept the conductive networks intact because of the preferential affinity of multi-walled carbon nanotubes with polyester. This study showed that incorporating polyester with polycarbonate–multi-walled carbon nanotube increases the electrical conductivity of injection-molded polycarbonate/multi-walled carbon nanotube nanocomposites to a great extent.
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4

Zhao, Yawei, and Wen Zhong. "Recent Progress in Advanced Polyester Elastomers for Tissue Engineering and Bioelectronics." Molecules 28, no. 24 (December 9, 2023): 8025. http://dx.doi.org/10.3390/molecules28248025.

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Polyester elastomers are highly flexible and elastic materials that have demonstrated considerable potential in various biomedical applications including cardiac, vascular, neural, and bone tissue engineering and bioelectronics. Polyesters are desirable candidates for future commercial implants due to their biocompatibility, biodegradability, tunable mechanical properties, and facile synthesis and fabrication methods. The incorporation of bioactive components further improves the therapeutic effects of polyester elastomers in biomedical applications. In this review, novel structural modification methods that contribute to outstanding mechanical behaviors of polyester elastomers are discussed. Recent advances in the application of polyester elastomers in tissue engineering and bioelectronics are outlined and analyzed. A prospective of the future research and development on polyester elastomers is also provided.
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5

Liao, Chengzhu, Yuchao Li, and Sie Chin Tjong. "Antibacterial Activities of Aliphatic Polyester Nanocomposites with Silver Nanoparticles and/or Graphene Oxide Sheets." Nanomaterials 9, no. 8 (August 1, 2019): 1102. http://dx.doi.org/10.3390/nano9081102.

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Aliphatic polyesters such as poly(lactic acid) (PLA), polycaprolactone (PCL) and poly(lactic-co-glycolic) acid (PLGA) copolymers have been widely used as biomaterials for tissue engineering applications including: bone fixation devices, bone scaffolds, and wound dressings in orthopedics. However, biodegradable aliphatic polyesters are prone to bacterial infections due to the lack of antibacterial moieties in their macromolecular chains. In this respect, silver nanoparticles (AgNPs), graphene oxide (GO) sheets and AgNPs-GO hybrids can be used as reinforcing nanofillers for aliphatic polyesters in forming antimicrobial nanocomposites. However, polymeric matrix materials immobilize nanofillers to a large extent so that they cannot penetrate bacterial membrane into cytoplasm as in the case of colloidal nanoparticles or nanosheets. Accordingly, loaded GO sheets of aliphatic polyester nanocomposites have lost their antibacterial functions such as nanoknife cutting, blanket wrapping and membrane phospholipid extraction. In contrast, AgNPs fillers of polyester nanocomposites can release silver ions for destroying bacterial cells. Thus, AgNPs fillers are more effective than loaded GO sheets of polyester nanocomposiites in inhibiting bacterial infections. Aliphatic polyester nanocomposites with AgNPs and AgNPs-GO fillers are effective to kill multi-drug resistant bacteria that cause medical device-related infections.
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6

Kausar, Ayesha. "Review of fundamentals and applications of polyester nanocomposites filled with carbonaceous nanofillers." Journal of Plastic Film & Sheeting 35, no. 1 (June 20, 2018): 22–44. http://dx.doi.org/10.1177/8756087918783827.

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Polyester is a versatile commercially significant polymer (thermoplastic/thermoset) well-known for its biodegradability and excellent thermal, mechanical, and chemical properties. Synthetic aromatic polyester resins usually have better moisture resistance, nonflammability, liquid crystal, strength, thermal, and environmental features compared with natural/aliphatic polyesters. Nanofillers can reinforce these important polymers to further enhance the final nanocomposite structural and physical characteristics. This review presents research devoted to polyester nanocomposites with essential nanofillers such as; nanodiamond, fullerene, carbon nanotube, graphene, and graphene oxide. High-performance polyester/nanocomposites have been developed based on modified polyester design, nanofiller functionality, and optimized interaction between matrix and nanofiller. This article also presents state-of-the-art technological development in the field of polyester/nanocomposites predominantly in supercapacitors, fuel cells, shape memory materials, electromagnetic shielding materials, textiles, and biomedical appliances. Furthermore, future scenarios in scientific development of these nanocomposites are discussed.
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7

Morrow, Cary J. "Biocatalytic Synthesis of Polyesters Using Enzymes." MRS Bulletin 17, no. 11 (November 1992): 43–47. http://dx.doi.org/10.1557/s0883769400046650.

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Plants and animals have been exploited as sources of materials for centuries but, as our ability to analyze and fractionate them has progressed, the extraordinary range of properties available from materials produced by living systems has continued to grow. Doi, in another article in this issue of the MRS Bulletin, presents a discussion of a group of naturally occurring polyesters related to poly(beta-hydroxybutyrate). These polyesters are formed in vivo by several microorganisms as part of an energy storage scheme. Research on these systems has allowed growth conditions to be found that can lead, in a controlled fashion, to a number of copolymers. Useful materials based on these bacterial polyesters appear to be at hand.The in-vivo formation of polyesters in microorganisms also illustrates several of the important reasons for examining biocatalytic polymer synthesis. First, unlike most industrial syntheses of polyesters, the poly(beta-hydroxybutyrate) biosynthesis occurs at a near-ambient temperature using a carbohydrate feedstock. Second, and perhaps most importantly, the stored polyesters are readily biodegraded by the bacteria that manufacture them, so materials based on these polyesters should also be biodegradable. Third, although there are side chains along the polymer backbone, they are introduced in a highly stereo-specific fashion during in-vivo synthesis, leading to an entirely stereoregular polyester. However, along with these advantages, there are also significant limitations to bacterial polyester synthesis. First, there are some substrates that are not incorporated into the polyester by the bacteria. Second, normal metabolism leads to the polyester, always incorporating a fraction of hydroxybutyrate monomers. Third, the backbone is always comprised of four-atom, A-B type 3-hydroxy acid repeat units with variations appearing in the side chain at carbon-3.
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8

Yang, Seung-Cheol, and Jae Pil Kim. "Flame-retardant polyesters. II. Polyester polymers." Journal of Applied Polymer Science 106, no. 2 (2007): 1274–80. http://dx.doi.org/10.1002/app.26544.

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9

Ma, Meng Meng, Lian Yuan Wang, and Hai Yan Zhu. "Enzymatic Degradation of Polyester-Nanoparticles by Lipases and Adsorption of Lipases on the Polyester-Nanoparticles." Advanced Materials Research 418-420 (December 2011): 2302–7. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.2302.

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Enzymatic degradation tests of polymer in form of nanoparticle (NP) were used to study the biodegradation of two different types of polymers polytetramethylene adipitate (SP4/6) and polybutylene isophthalate (PBI) by two commercially available lipases. The two lipases, which are from the yeast Candida cylindracea (CcL) and Pseudomonas species (PsL) respectively, exhibited sufficient degradation activities both for the aliphatic model polyester SP4/6 and the aromatic model polyester PBI and the use of polyester NPs has dramatically shortened the duration of enzymatic degradation tests. It has also been noticed that the degradation percentage of the polyesters was in the range of 35-50%, probably due to the formation of low molecular weight intermediates that are not accessible to the enzymes. Since biodegradation of polymers is a surface process, the adsorption of lipases on the surface of polyester NPs may play an important role. In order to gain some insights into the adsorption process of enzymes on polymer NPs, the adsorption of CcL and PsL lipases on two hardly degradable polyesters polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) was investigated in this work. The adsorption of lipases on these polyester NPs showed a fast kinetic. Langmuir isotherms were found to be generally suitable to describe the adsorption of lipases on polyester NPs, especially at low lipase concentration under the experimental conditions. However, significant derivations from Langmuir isotherms were observed at high lipase concentrations.
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10

Musshoff, H. "Dyeing and Printing Polyester and Polyester-Cellulosic Fabrics with Polyestren Dyes." Journal of the Society of Dyers and Colourists 77, no. 3 (October 22, 2008): 89–96. http://dx.doi.org/10.1111/j.1478-4408.1961.tb02427.x.

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11

Zhao, Guangkuo, Tongtong Ge, Yunfeng Yan, Qi Shuai, and Wei-Ke Su. "Highly Efficient Modular Construction of Functional Drug Delivery Platform Based on Amphiphilic Biodegradable Polymers via Click Chemistry." International Journal of Molecular Sciences 22, no. 19 (September 27, 2021): 10407. http://dx.doi.org/10.3390/ijms221910407.

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Amphiphilic copolymers with pendant functional groups in polyester segments are widely used in nanomedicine. These enriched functionalities are designed to form covalent conjugates with payloads or provide additional stabilization effects for encapsulated drugs. A general method is successfully developed for the efficient preparation of functional biodegradable PEG-polyester copolymers via click chemistry. Firstly, in the presence of mPEG as initiator, Sn(Oct)2-catalyzed ring-opening polymerization of the α-alkynyl functionalized lactone with D,L-lactide or ε-caprolactone afforded linear mPEG-polyesters bearing multiple pendant alkynyl groups. Kinetic studies indicated the formation of random copolymers. Through copper-catalyzed azide-alkyne cycloaddition reaction, various small azido molecules with different functionalities to polyester segments are efficiently grafted. The molecular weights, polydispersities and grafting efficiencies of azido molecules of these copolymers were investigated by NMR and GPC. Secondly, it is demonstrated that the resulting amphiphilic functional copolymers with low CMC values could self-assemble to form nanoparticles in aqueous media. In addition, the in vitro degradation study and cytotoxicity assays indicated the excellent biodegradability and low cytotoxicity of these copolymers. This work provides a general approach toward the preparation of functional PEG-polyester copolymers in a quite efficient way, which may further facilitate the application of functional PEG-polyesters as drug delivery materials.
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12

Jopen, Max, Michael Paulus, Christian Sternemann, Patrick Degen, and Ralf Weberskirch. "Comparative Studies on the Organogel Formation of a Polyester in Three Different Base Oils by X-ray Analysis, Rheology and Infrared Spectroscopy." Gels 9, no. 9 (August 29, 2023): 696. http://dx.doi.org/10.3390/gels9090696.

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High-performance greases typically consist of a base oil and polyurea as a thickener material. To date, few alternatives to polyureas have been investigated. Polyesters could be one such alternative; however, little is known about the gelation of such polyesters because, unlike polyureas, they cannot form hydrogen bonds between the polymer chains. Here, we present studies on the gel formation of a polyester based thickener poly(hexane dodecanoate) with 1-octanol endgroups in three different base oils, i.e., a mineral oil (Brightstock 150), a synthetic Polyalphaolefin (Spectrasyn 40) and castor oil (85 to 90 wt.% ricinoleic acid triglyceride). Small- and wide-angle X-ray scattering measurements indicate a strong interaction of the polyester with castor oil and an increase in the crystalline fraction, with an increasing polymer amount from 5 to 40 wt.%. Moreover, infrared analysis of the polyester in castor oil showed gel formation at a minimum concentration of 20 wt.%. The strong interaction of the polyester with castor oil compared to the other two base oils led to an increase in the yield point γF as a measure of the mechanical stability of the gel, which was determined to be 5.9% compared to 0.8% and 1.0% in Brightstock and Spectrasyn, respectively.
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13

Zeng, Xian Ping, and Jin Fa Liu. "Project for Improving Dark Color Fastness of Polyester or Spandex." Advanced Materials Research 919-921 (April 2014): 2088–91. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.2088.

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In this paper, an analysis of dark color fastness technology of polyesters or spandexs dark color fabric was done. Through the analysis, corresponding solutions were providing to enhancing the washing dark color fastness of polyesters or spandexs synthetic elastic fabric, how to surmount the dark color fastness difference in polyester or spandex, and result is poor in white dyes combination of polyesters or spandexs fine white finished fabric
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14

Wang, Guo He, Dong Juan Gu, and Li Ning Fan. "Research on the Mechanism of Silk-Like Fabrics Based on DPF." Advanced Materials Research 332-334 (September 2011): 591–94. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.591.

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Silk-like fabrics mainly refer to polyester filament fabrics, the appearance and feeling of which is close to silk fabrics. In this paper, FDY polyesters with different dpf were used as wefts to make fabrics interwoven with silk and polyester. Through KES, drapability, luster, gas permeability and flexible test, this paper intends to discuss the influence of dpf to fabric property and style and the simulation mechanism of silk-like fabric comparing with the same kind of silk fabric.
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15

Darie-Niță, Raluca Nicoleta, Maria Râpă, and Stanisław Frąckowiak. "Special Features of Polyester-Based Materials for Medical Applications." Polymers 14, no. 5 (February 27, 2022): 951. http://dx.doi.org/10.3390/polym14050951.

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This article presents current possibilities of using polyester-based materials in hard and soft tissue engineering, wound dressings, surgical implants, vascular reconstructive surgery, ophthalmology, and other medical applications. The review summarizes the recent literature on the key features of processing methods and potential suitable combinations of polyester-based materials with improved physicochemical and biological properties that meet the specific requirements for selected medical fields. The polyester materials used in multiresistant infection prevention, including during the COVID-19 pandemic, as well as aspects covering environmental concerns, current risks and limitations, and potential future directions are also addressed. Depending on the different features of polyester types, as well as their specific medical applications, it can be generally estimated that 25–50% polyesters are used in the medical field, while an increase of at least 20% has been achieved since the COVID-19 pandemic started. The remaining percentage is provided by other types of natural or synthetic polymers; i.e., 25% polyolefins in personal protection equipment (PPE).
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16

Stojanović, Sandra, Jelka Geršak, and Dušan Trajković. "Compression properties of knitted fabrics printed by sublimation transfer printing technique." Advanced Technologies 10, no. 1 (2021): 46–53. http://dx.doi.org/10.5937/savteh2101046s.

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Compression properties of textile materials are useful for determining fullness, softness, smoothness, and stiffness. In addition, compression parameters have significant influence on fabric hand value and quality of textile materials. The present paper reports a study of the sublimation printing process influence on the change in compression properties of knitted fabrics (polyester, cotton, and cotton/ polyester) intended for sportswear manufacturing. For that purpose, the KES-FB3-A Compression Tester was used for measuring compression parameters of knitted fabrics. The parameters, which contributed to the smallest reduction percentage in compression properties of polyester knitted fabrics were yarn linear density and weight. For cotton-rich knitted fabrics sublimation coating powder was used for paper modification to bond disperse dyes to cotton fibres. The analysis of the results showed that the printing process had a smaller influence on the change of compression parameters of polyesters in relation to cotton and cotton/polyester knitted fabrics. It was noted that the printing process had the effect of thickness reduction for all knitted fabrics to varying degrees. Printing process contributed to small decrease in compressibility and specific volume values for polyester knitted fabrics. The modification process contributed to the significant reduction of the compressibility for cotton (from 34.46% to 47.89%) and cotton/polyester (from 38.81% to 50.75%) knitted fabrics. In addition, reduction in specific volume values range from 41.86% to 44.19% for cotton and from 42.37% to 45.75% for cotton/ polyester knitted fabrics was notted.
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17

Kumagai, Shogo, Yuto Morohoshi, Guido Grause, Tomohito Kameda, and Toshiaki Yoshioka. "Pyrolysis versus hydrolysis behavior during steam decomposition of polyesters using 18O-labeled steam." RSC Advances 5, no. 76 (2015): 61828–37. http://dx.doi.org/10.1039/c5ra08577b.

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A method was developed to distinguish between hydrolysis and pyrolysis pathways in the steam degradation of various polyesters. Selectivity was shown to be strongly influenced by the polyester structure.
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18

Leitão, Ana Lúcia, and Francisco J. Enguita. "Structural Insights into Carboxylic Polyester-Degrading Enzymes and Their Functional Depolymerizing Neighbors." International Journal of Molecular Sciences 22, no. 5 (February 26, 2021): 2332. http://dx.doi.org/10.3390/ijms22052332.

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Esters are organic compounds widely represented in cellular structures and metabolism, originated by the condensation of organic acids and alcohols. Esterification reactions are also used by chemical industries for the production of synthetic plastic polymers. Polyester plastics are an increasing source of environmental pollution due to their intrinsic stability and limited recycling efforts. Bioremediation of polyesters based on the use of specific microbial enzymes is an interesting alternative to the current methods for the valorization of used plastics. Microbial esterases are promising catalysts for the biodegradation of polyesters that can be engineered to improve their biochemical properties. In this work, we analyzed the structure-activity relationships in microbial esterases, with special focus on the recently described plastic-degrading enzymes isolated from marine microorganisms and their structural homologs. Our analysis, based on structure-alignment, molecular docking, coevolution of amino acids and surface electrostatics determined the specific characteristics of some polyester hydrolases that could be related with their efficiency in the degradation of aromatic polyesters, such as phthalates.
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19

Li, Jian, Kai Zhang, and Xun Zhang Yu. "Thickening Mechanism of Crystalline Polyester Involved in Low Pressure Sheet Molding Compounds." Advanced Materials Research 152-153 (October 2010): 619–22. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.619.

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In this article, for a better understanding of the viscosity changes in LPMC (low pressure sheet molding compounds), the thickening mechanism of crystalline polyesters was studied. And by means of varying the content of crystalline polyester resin, the thickening effect on resin paste was investigated, too. Results gained during experiments showed that there existed three kinds of functions acting in the process of thickening: swelling, hydrogen bonds and induction crystallization. The thickening effect was excellent when the amount of crystalline polyester resin was 3%. This research supports the producing process for LPMC with theory basement.
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20

Sirrine, Justin M., Allison M. Pekkanen, Ashley M. Nelson, Nicholas A. Chartrain, Christopher B. Williams, and Timothy E. Long. "3D-Printable Biodegradable Polyester Tissue Scaffolds for Cell Adhesion." Australian Journal of Chemistry 68, no. 9 (2015): 1409. http://dx.doi.org/10.1071/ch15327.

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Additive manufacturing, or three-dimensional (3D) printing, has emerged as a viable technique for the production of vascularized tissue engineering scaffolds. In this report, a biocompatible and biodegradable poly(tri(ethylene glycol) adipate) dimethacrylate was synthesized and characterized for suitability in soft-tissue scaffolding applications. The polyester dimethacrylate exhibited highly efficient photocuring, hydrolyzability, and 3D printability in a custom microstereolithography system. The photocured polyester film demonstrated significantly improved cell attachment and viability as compared with controls. These results indicate promise of novel, printable polyesters for 3D patterned, vascularized soft-tissue engineering scaffolds.
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21

McDonnell, Liam A., Peter J. Derrick, Brian B. Powell, and Philip Double. "Sustained Off-Resonance Irradiation Collision-Induced Dissociation of Linear, Substituted and Cyclic Polyesters Using a 9.4 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer." European Journal of Mass Spectrometry 9, no. 2 (April 2003): 117–28. http://dx.doi.org/10.1255/ejms.530.

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The fragment ions obtained from sustained off-resonance irradiation collision-induced dissociation of linear polyesters, substituted polyesters and cyclic polyesters have been characterized using a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. Charge-induced and charge-remote fragmentation channels, together with the participation of other nucleophilic groups, are proposed for the substituted polyesters. The linear polyesters were found to fragment at equivalent positions along the polymer chain whereas, under the experimental conditions employed, the cyclic polyester produced a single fragment.
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22

Huang, Chih-Feng, Shiao-Wei Kuo, Daniela Moravčíková, Jyun-Ci Liao, Yu-Min Han, Ting-Han Lee, Po-Hung Wang, Rong-Ho Lee, Raymond Chien-Chao Tsiang, and Jaroslav Mosnáček. "Effect of variations of CuIIX2/L, surface area of Cu0, solvent, and temperature on atom transfer radical polyaddition of 4-vinylbenzyl 2-bromo-2-isobutyrate inimers." RSC Advances 6, no. 57 (2016): 51816–22. http://dx.doi.org/10.1039/c6ra06186a.

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Optimization of atom transfer radical polyadditions using commercially available catalytic systems allowed obtaining control over the polyester architecture and functionality and functional linear polyesters with high molecular weight (Mw = 16 200).
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23

Okabayashi, Ryouichi, Yoshihiro Ohta, and Tsutomu Yokozawa. "Synthesis of telechelic polyesters by means of transesterification of an A2 + B2 polycondensation-derived cyclic polyester with a functionalized diester." Polymer Chemistry 10, no. 36 (2019): 4973–79. http://dx.doi.org/10.1039/c9py00960d.

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End-functionalized linear polyesters were synthesized by means of base-catalyzed transesterification of a cyclic polyester, obtained by A2 + B2 polycondensation, with a symmetric functional diester as an exchange reagent.
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24

Duarte, Martín E., Birgit Huber, Patrick Theato, and Hatice Mutlu. "The unrevealed potential of elemental sulfur for the synthesis of high sulfur content bio-based aliphatic polyesters." Polymer Chemistry 11, no. 2 (2020): 241–48. http://dx.doi.org/10.1039/c9py01152h.

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We introduce a novel sulfur-containing polyester derivative based on a renewable monomer bearing secondary disulfide groups. Base-mediated sulfur exchange reaction of disulfide bonds using S8 delivers polyesters with tailored functional properties.
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25

Zhang, Rui Xin, Tie Ling Xing, and Guo Qiang Chen. "Preparation and Properties of Kaolin Modified Polyester Fibers." Advanced Materials Research 332-334 (September 2011): 227–30. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.227.

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Abstract:Kaolin masterbatch was prepared first, and then three kinds of kaolin modified polyester fibers (100 dtex) which respectively contained kaolin masterbatch 2%(PK2), 4%(PK4), 6%(PK6) were successfully spun. Properties of kaolin modified fibers were discussed. The results showed that kaolin particles were evenly dispersed in polyesters. Breaking strength and Young’s modulus of the kaolin modified fibers were decreased with the increase of the kaolin content; moisture absorption was increased with the increase of the kaolin content; boiling water shrinkage was decreased with the increase of the kaolin content; and kaolin modified polyester fibers have good performance of ultraviolet resistance.
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26

Loza, Sergey A., Victor V. Dotsenko, and Victor I. Zabolotskiy. "Synthesis of New Hyperbranched Phosphorus-Containing Polyesters Starting from Boltorn H20." Proceedings 9, no. 1 (November 16, 2018): 7. http://dx.doi.org/10.3390/ecsoc-22-05862.

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Upon gentle treatment with SOCl2, hyperbranched polyester Boltorn H20 afforded a mixture of terminal polychlorides. The latter react with an excess of triphenylphosphine in boiling toluene or with pyridine to give a mixture of polyesters with terminal triphenylphosphonium and pyridinium fragments, respectively.
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27

Fu, Hao, Linbo Gong, and Shuling Gong. "A New Approach Utilizing Aza-Michael Addition for Hydrolysis-Resistance Non-Ionic Waterborne Polyester." Polymers 14, no. 13 (June 29, 2022): 2655. http://dx.doi.org/10.3390/polym14132655.

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This work first synthesized a series of linear polyesters by step-growth polycondensation, then an amino-terminated hydrophilic polyether was grafted to the polyester as side-chains through aza-Michael addition to prepare a self-dispersible, non-ionic waterborne comb-like polyester (NWCPE). In contrast to traditional functionalization methods that usually require harsh reaction conditions and complex catalysts, the aza-Michael addition proceeds efficiently at room temperature without a catalyst. In this facile and mild way, the NWCPE samples with number-average molecular weight (Mn) of about 8000 g mol−1 were obtained. All dispersions showed excellent storage stability, reflected by no delamination observed after 6 months of storage. The NWCPE dispersion displayed better hydrolysis resistance than an ionic waterborne polyester, as was indicated by a more slight change in pH value and Mn after a period of storage. In addition, the film obtained after the NWCPE dispersion was cross-linked with the curing agent, it exhibited good water resistance, adhesion, and mechanical properties.
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28

Mustafayev, A. M., Y. N. Gahramanli, B. N. Babanly, and R. I. Ismailova. "SYNTHESIS AND PROPERTIES OF BROMINE-CONTAINING BICYCLIC UNSATURATED POLYESTERS." Azerbaijan Chemical Journal, no. 4 (November 14, 2023): 63–70. http://dx.doi.org/10.32737/0005-2531-2023-4-63-70.

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A method for obtaining bromine-containing bicyclic unsaturated polyesters by the interaction of 1,4,5,6,7,7-hexabromobicyclo-[2,2,1]-hept-5-ene-2,3-dicarboxylic acid anhydride, propanetriol and maleic anhydride was developed. It was found that unsaturated polyethers synthesized by a two-step method have a higher molecular weight (3130), density (1.461 g/cm3), viscosity (105 St) and ether number (400 ml KOH/g). It was found that the compositions of epoxy resin ED-20 with unsaturated polyether obtained by method III possess higher tensile strength (90 MPa), higher relative elongation (9%), higher Vicat resistance (2500C) than unmodified epoxy resin. It was shown that in comparison with pure epoxy resin ED-20, its composition with unsaturated polyester synthesized by method I and cured in the presence of polyethylene polyamine (ED-20: unsaturated polyester: polyethylene polyamine), has flame retardant properties, high tensile strength, higher relative elongation and thermal resistance by Vicat. The best results are achieved when the content of unsaturated polyester in the composition is 20%
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Pesetskii, SS, VV Shevchenko, and VN Koval. "Effect of isocyanate chain extender on the structure and properties of the blends of poly(butylene terephthalate) and thermoplastic polyester elastomer." Journal of Thermoplastic Composite Materials 30, no. 12 (May 13, 2016): 1581–602. http://dx.doi.org/10.1177/0892705716646419.

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The effect of diisocyanate chain extender (CE) additives on the change of molecular structural characteristics, rheological, and mechanical properties of the blends comprising of poly(butylene terephthalate) (PBT) and thermoplastic polyester elastomer (TPEE) obtained by reactive compounding in the melt and having different phase structure is studied. It is shown that addition of CE in the amount of 0.2 wt% to 1.25 wt% causes an increase in viscosity of polyester melts and solutions owing to the chain extension reactions and intermolecular cross-linking of macro-chains which occur in the melt. CE has a strong effect on the character of deformation curves at straining of both polyesters in primary form and their blends irrespective of the ratio of components in them (phase structure of materials). At the increase of its concentration, values of high and low flow limits increase and the difference in values of these parameters decreases, that is, a sharp yield point is gradually degenerating. At the same time, increase in Charpy impact strength on notched specimens is observed, including the subzero temperatures range (−40°C). Besides, CE has an effect on crystallizability of both individual polyester components and their blends. The general trend (irrespective of the polyester type and phase structure of the blend) is the decrease in crystallization temperature. This fact is explained by limitation of molecular mobility due to an increase in the molecular weight of polyester and intensification of interchain interactions.
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Schwab, J., G. C. Bagaglio, J. M. Bentley, and A. Christfreund. "Tailor Made Polyester Polyurethane Elastomers for Shoe Soling." Cellular Polymers 7, no. 2 (March 1988): 134–50. http://dx.doi.org/10.1177/026248938800700202.

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The production of shoe soles using cellular polyurethane elastomers on an industrial scale has been in progress for almost 20 years. Now, polyurethane shoe-soling systems are used not only for house and town shoes but also for work and safety boots as well as sport and leisure shoes. With the development of dual-density technology a large number of polyurethane soling systems are offered today. Further progress depends on improvements to processability and certain properties. This publication gives details of those in polyester-based systems. Developments reported in this paper include: • a new prepolymer, PBA 2224, with improved resistance to freezing • a new range of polyester polyols with improved storage stability that remain processable for more than 6 days under machine recirculation conditions at 45°C • a new range of polyesters that allows greater mixing ratio latitude • special, tailor-made polyesters and prepolymers optimised for special applications such as systems with improved – humid-ageing resistance – flexlife at low temperatures – light stability – particularly of white-coloured shoe-soling systems Such developments have led to an improved robustness in processing which, the authors postulate, should lead to an increase in market demand for polyurethanes as shoe-soling materials.
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Hadavand, Behzad Shirkavand, Farhood Najafi, Mohammad Reza Saeb, and Alireza Malekian. "Hyperbranched polyesters urethane acrylate resin." High Performance Polymers 29, no. 6 (March 17, 2017): 651–62. http://dx.doi.org/10.1177/0954008317696566.

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In the present study, response surface methodology is used to synthesize hyperbranched polyesters based on variables reaction time, ratio of monomer to core, and type of catalyst. Then, the synthesized polyesters were used for preparing hyperbranched urethane acrylates in two steps. In order to characterize these polymers, infrared spectroscopy and proton nuclear magnetic resonance is used. Hyperbranched urethane acrylates were formulated and cured by ultraviolet irradiation. Finally, dynamic mechanical thermal analysis (DMTA) test is used to investigate the viscoelastic properties of the coatings. The results of DMTA test were shown that the higher molar mass distribution of hyperbranched polyester is associated with less uniformity of cross-link network of cured samples. Also by increasing the molar mass of hyperbranched polyester, glass transition temperature of cured urethane acrylate resins was increased. The samples produced by using methane sulfonic acid catalyst show higher strength and more uniform cross-link network than the those made by sulfuric acid catalyst.
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Vancso, G. Julius, and Zhanjie Tan. "Solvent clustering, polar network density, and thermodynamic interactions in coordination polymers: an inverse gas chromatography study of metal-ion-containing polyesters of poly(diethylene glycol-co-succinic acid)." Canadian Journal of Chemistry 73, no. 11 (November 1, 1995): 1855–61. http://dx.doi.org/10.1139/v95-229.

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The spatial distribution of toluene and THF in the polyester poly(diethylene glycol-co-succinic acid) and its Mg2+-containing "telechelic" derivative was described by Kirkwood–Buff–Zimm (KBZ) cluster integrals. The values of KBZ integrals as a function of the volume fraction of solvent in the polymer–solvent systems were obtained from finite concentration inverse gas chromatography measurements utilizing the elution-on-a-plateau technique. The results show that toluene has a higher self-affinity to form clusters in the pure polyester than THF, which is more homogeneously distributed in the polymer. Data for preferential solvation indicate that a segregation of parts of the polymer chains is present in the toluene–polyester system. When metal ions are introduced, the self-affinity of the solvent molecules to gather increases, whereas solvent clusters of toluene form in the free volume, and the gathering of the THF is likely to take place close to the metal ions. Based on the electron donacity values of the various donor groups present in the metal-ion-containing polymer it was assumed that THF in the Mg2+-containing polyester will be bound to the central metal ion while the apolar toluene will participate in the solvation of the apolar parts of the polymer and will be "repelled" from the ion-containing regions. The concentration of these ionic centres, which act as effective cross-links in the coordination polymer, was determined from measurements of thermodynamic activity. A comparison of the experimental and estimated effective cross-link density values indicates a nearly atomic dispersion of Mg2+ in the metal-ion-containing polyesters. Keywords: inverse gas chromatography, cluster integrals, solvent partition in polymers, metal-ion-containing polyesters, Flory–Huggins interaction parameter.
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Latos-Brozio, Malgorzata, and Anna Masek. "Biodegradable Polyester Materials Containing Gallates." Polymers 12, no. 3 (March 18, 2020): 677. http://dx.doi.org/10.3390/polym12030677.

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Gallates are widely used as antioxidants in the food and cosmetics industries. The purpose of the study was to obtain pro-ecological materials based on biodegradable polyesters, such as polylactide (PLA) and polyhydroxyalkanoate (PHA), and gallates. Gallates (ethyl, propyl, octyl, and lauryl) have not been used so far in biodegradable polymers as stabilizers and indicators of aging. This manuscript examines the properties of gallates such as antioxidant capacity and thermal stability. This paper also presents the following analyses of polymer materials: specific migration of gallates from polymers, SEM microscopy, differential scanning calorimetry (DSC), wide-angle X-ray diffraction, mechanical properties, surface free energy, and determination of change of color after controlled UV exposure, thermooxidation, and weathering. All gallates showed strong antioxidant properties and good thermal stability. Due to these properties, in particular their high oxidation temperature, gallates can be successfully used as polyester stabilizers. Biodegradable polyesters containing gallates can be an environmentally friendly alternative to petrochemical packaging materials.
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Morikawa, Takeshi. "Polyester." Kobunshi 37, no. 11 (1988): 818–19. http://dx.doi.org/10.1295/kobunshi.37.818.

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Li, Dongfang, Tommy Iversen, and Monica Ek. "Hydrophobic materials based on cotton linter cellulose and an epoxy-activated polyester derived from a suberin monomer." Holzforschung 69, no. 6 (August 1, 2015): 721–30. http://dx.doi.org/10.1515/hf-2014-0261.

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Abstract Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting epoxy-activated polyester was characterized by nuclear magnetic resonance (NMR) imaging, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, and size exclusion chromatography. Then the polyester was cured with tartaric or oxalic acid, and the crosslinked polyesters were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry. Hydrophobic materials were prepared by compression molding of polyester-impregnated cellulose sheets, and the final products were characterized by FTIR, cross-polarization magic angle spinning 13C NMR, and field-emission scanning electron microscopy. The water contact angle was significantly increased from 0° for the original cellulose sheets to over 100° for the produced hydrophobic materials.
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36

Kuru, Zehra, and Mehmet Arif Kaya. "Poly(Lactic Acid) / Polyester Blends: Review of Current and Future Applications." European Journal of Research and Development 3, no. 1 (March 28, 2023): 175–99. http://dx.doi.org/10.56038/ejrnd.v3i1.259.

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Poly (lactic acid) (PLA) is a promising polymer with its value and potential due to its sustainability, low carbon footprint, and being a superior bio-based polymer compared to other bioplastics. Since it is also a compostable aliphatic polyester, has been frequently subjected to research. Researchers have conducted studies on the compatibility of PLA, which is a bio-based, biodegradable, and compostable, renewable polymer, with traditional petrochemical-based polymers, especially polyesters such as polybutylene terephthalate (PBT), and polyethylene terephthalate (PET). It is highly important that applications of PLA/polyester blends will ensure that the materials developed are not only economically and sustainable but also can meet current and future appropriate needs. PLA-based materials have some disadvantages such as slow biodegradation rate, high cost, and low toughness, and to eliminate mentioned drawbacks generally blends are prepared with petroleum-based polymers. In this review, information about the perspectives with studies for PLA/polyester blends; approaches to the subject, potential application areas, and contributions for the future were given.
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Mountaki, Stella Afroditi, Maria Kaliva, Konstantinos Loukelis, Maria Chatzinikolaidou, and Maria Vamvakaki. "Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications." Polymers 13, no. 10 (May 18, 2021): 1636. http://dx.doi.org/10.3390/polym13101636.

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Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.
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Shao, Fen Juan, Qun Yang, Lan Ying Li, and Da Nian Lu. "Study on Synthesis and Characterization of Unsaturated Polyester by Enzyme-Catalyzed." Key Engineering Materials 575-576 (September 2013): 67–70. http://dx.doi.org/10.4028/www.scientific.net/kem.575-576.67.

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Unsaturated polyester was prepared with adipic acid (AA), fumaric acid (FA), itaconic acid (IA) and 1, 6-hexanediol (HD) by enzyme-catalyzed polmerization. The insoluble gel fraction (Qs), as the cross-linking degree of cured unsaturated polyesters which could be self-cross-linked at high temperature through C=C in it, was got by Soxhlet Extraction. The properties were investigated by FT-IR, 1H NMR, DSC, XRD and so on. The results indicated that the C=C in unsaturated diacids reduced the acitvity of N435, which affected the polmerization. With the introduction of C=C of IA or FA, the Mn of polyester reduced. The C=C could self-cross-link under high temperature for lengthy time. The higher the temperature and the longer the time, the Qs increased. As the C=C of IA was in the side chain, it could move easily. Then Qs of poly (AA-co-IA-co-HD) was higher than ploy (AA-co-FA-co-HD). With the increased content of unsaturated diacid, Qs increased. And the biodegradation of cross-linked polyesters became worse.
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39

Sumera, Florentino C., Shienna Marie A. Pontillas, Josanelle Angela V. Bilo, and John Marty Mateo. "New Poly(Hydroxylauric-co-Lactic Acid) Liquid Polymer for Dissolving Lipophilic Drugs." KIMIKA 28, no. 1 (July 7, 2017): 20–25. http://dx.doi.org/10.26534/kimika.v28i1.20-25.

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A liquid, biocompatible polyester based polymer, which could facilitate injectable formulations by simple mixing with the active substance (drug) is much needed by the pharmaceutical companies. A favourite candidate is polylactic acid (PLA) which is biocompatible and biodegradable. However PLA is solid with high crystallinity. Thus, in this research, hydroxylauric acid (HOLA) was copolymerized with lactic acid (LA) in different ratios by polycondensation technique at 180 °C, without a metal catalyst and avoiding the formation of interfering lactides, to provide a liquid polyester. The copolymers molecular weights were determined by Gel Permeation Chromatography (GPC) and their physical states indicated as solid or liquid were noted. The structures as polyesters were confirmed by FT-IR and 1H NMR spectroscopy. Poly(HOLA:LA) products from reactant ratios 0:100 is solid, while ratios of 20:80, 40:60 are mixed (paste) and 60:40, 80:20 and 100:0 are liquids. Thus, the liquid polyesters from the polycondensation of HOLA and LA without catalyst were picked as potential candidates for dissolving hydrophobic drugs that could be used as injectables in controlled drug delivery experiments.
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Nikolic, Marija, Dejan Poleti, and Jasna Djonlagic. "Biodegradable polyesters based on succinic acid." Chemical Industry 57, no. 11 (2003): 526–35. http://dx.doi.org/10.2298/hemind0311526n.

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Two series of aliphatic polyesters based on succinic acid were synthesized by copolymerization with adipic acid for the first series of saturated polyesters, and with fumaric acid for the second series. Polyesters were prepared starting from the corresponding dimethyl esters and 1,4-butanediol by melt transesterification in the presence of a highly effective catalyst tetra-n-butyl-titanate, Ti(0Bu)4. The molecular structure and composition of the copolyesters was determined by 1H NMR spectroscopy. The effect of copolymer composition on the physical and thermal properties of these random polyesters were investigated using differential scanning calorimetry. The degree of crystallinity was determined by DSC and wide angle X-ray. The degrees of crystallinity of the saturated and unsaturated copolyesters were generally reduced with respect to poly(butylene succinate), PBS. The melting temperatures of the saturated polyesters were lower, while the melting temperatures of the unsaturated copolyesters were higher than the melting temperature of PBS. The biodegradability of the polyesters was investigated by enzymatic degradation tests. The enzymatic degradation tests were performed in a buffer solution with Candida cylindracea lipase and for the unsaturated polyesters with Rhizopus arrhizus lipase. The extent of biodegradation was quantified as the weight loss of polyester films. Also the surface of the polyester films after degradation was observed using optical microscopy. It could be concluded that the biodegradability depended strongly on the degree of crystallinity, but also on the flexibility of the chain backbone. The highest biodegradation was observed for copolyesters containing 50 mol.% of adipic acid units, and in the series of unsaturated polyesters for copolyesters containing 5 and 10 mol.% of fumarate units. Although the degree of crystallinity of the unsaturated polyesters decreased slightly with increasing unsaturation, the biodegradation was not enhanced suggesting that not only the chemical structure and molecular stiffness but also the morphology of the spherulites influenced the biodegradation properties.
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Urbánek, Tomáš, Eliézer Jäger, Alessandro Jäger, and Martin Hrubý. "Selectively Biodegradable Polyesters: Nature-Inspired Construction Materials for Future Biomedical Applications." Polymers 11, no. 6 (June 19, 2019): 1061. http://dx.doi.org/10.3390/polym11061061.

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In the last half-century, the development of biodegradable polyesters for biomedical applications has advanced significantly. Biodegradable polyester materials containing external stimuli-sensitive linkages are favored in the development of therapeutic devices for pharmacological applications such as delivery vehicles for controlled/sustained drug release. These selectively biodegradable polyesters degrade after particular external stimulus (e.g., pH or redox potential change or the presence of certain enzymes). This review outlines the current development of biodegradable synthetic polyesters materials able to undergo hydrolytic or enzymatic degradation for various biomedical applications, including tissue engineering, temporary implants, wound healing and drug delivery.
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42

KOBAYASHI, Takuma, Katsuaki KUZE, and Atsushi KAJI. "Studies on Polyester Elastomer II. Thermal Stability of Polyester-Polyester Block Polymer." KOBUNSHI RONBUNSHU 49, no. 7 (1992): 569–76. http://dx.doi.org/10.1295/koron.49.569.

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43

Nifant’ev, Ilya, Alexander Tavtorkin, Pavel Komarov, Egor Kretov, Sofia Korchagina, Maria Chinova, Dmitry Gavrilov, and Pavel Ivchenko. "Dispersant and Protective Roles of Amphiphilic Poly(ethylene phosphate) Block Copolymers in Polyester/Bone Mineral Composites." International Journal of Molecular Sciences 24, no. 13 (July 6, 2023): 11175. http://dx.doi.org/10.3390/ijms241311175.

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Composites of synthetic bone mineral substitutes (BMS) and biodegradable polyesters are of particular interest for bone surgery and orthopedics. Manufacturing of composite scaffolds commonly uses mixing of the BMS with polymer melts. Melt processing requires a high homogeneity of the mixing, and is complicated by BMS-promoted thermal degradation of polymers. In our work, poly(L-lactide) (PLLA) and poly(ε-caprolactone) (PCL) composites reinforced by commercial β-tricalcium phosphate (βTCP) or synthesized carbonated hydroxyapatite with hexagonal and plate-like crystallite shapes (hCAp and pCAp, respectively) were fabricated using injection molding. pCAp-based composites showed advanced mechanical and thermal characteristics, and the best set of mechanical characteristics was observed for the PLLA-based composite containing 25 wt% of pCAp. To achieve compatibility of polyesters and pCAp, reactive block copolymers of PLLA or PCL with poly(tert-butyl ethylene phosphate) (C1 and C2, respectively) were introduced to the composite. The formation of a polyester-b-poly(ethylene phosphoric acid) (PEPA) compatibilizer during composite preparation, followed by chemical binding of PEPA with pCAp, have been proved experimentally. The presence of 5 wt% of the compatibilizer provided deeper homogenization of the composite, resulting in a marked increase in strength and moduli as well as a more pronounced nucleation effect during isothermal crystallization. The use of C1 increased the thermal stability of the PLLA-based composite, containing 25 wt% of pCAp. In view of positive impacts of polyester-b-PEPA on composite homogeneity, mechanical characteristics, and thermal stability, polyester-b-PEPA will find application in the further development of composite materials for bone surgery and orthopedics.
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44

Ling, Yvonne Tze Qzian, Yiing Jye Yap, Yi Xin Heng, Siang Yin Lee, Rhun Yian Koh, Desmond Teck Chye Ang, Chin Hua Chia, and Seng Neon Gan. "Physiochemical and in-vitro Cytotoxicity Properties of Biocompatible Palm Fatty Acid-Based Polyesters." Sains Malaysiana 50, no. 2 (February 28, 2021): 395–407. http://dx.doi.org/10.17576/jsm-2021-5002-11.

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With the sharp rise in global interest in sustainability and environmental concerns, there is a growing demand in replacing petroleum-derived raw materials with renewable plant-based raw materials in the production of polymers. In this study, two palm fatty acid polyesters were synthesized from palmitic and stearic acids. Their chemical structures were identified by FTIR and 1H-NMR analysis. Both polyesters showed a moderately high conversion rate from the acid value determination. DSC analysis showed that the palmitic acid polyester (PAP) had a lower Tg than that of stearic acid polyester (SAP), where PA P had a Tg of 1.8 °C, while SAP had a Tg of 31.9 °C. TGA demonstrated that thermal decomposition of both polyesters took place via two-stage processes, which occurred above 200 °C. GPC analysis showed that PAP (1031 g/mol) had a higher Mn value than SAP (972 g/mol). MTT assays were performed to determine the cytotoxicity of these polyesters against human keratinocytes (HaCaT), mouse fibroblasts (3T3), mouse hepatocytes (H2.35), and canine kidney cells (MDCK) in both dose- and time-dependent manners, with SDS serving as the experimental benchmark. Comparative cytotoxicity test showed that both PA P and SAP were biocompatibility and non-cytotoxic with the cell viability well above 80%, except SAP demonstrated a moderately low cytotoxicity on fibroblasts with cell viability remaining as 50.4% following 72 h exposure at 100 μg/mL of concentration. These findings suggest that the natural-sourced palm fatty acid polyesters have high potential to be used in pharmaceutical and nutraceutical applications.
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45

Youssef Tawfik, Soheir, Magdy Wadid Sabaa, and Ramzy Takawy Botros. "Preparation and characterisation of water soluble polyester coatings based on waste materials." Pigment & Resin Technology 46, no. 5 (September 4, 2017): 408–22. http://dx.doi.org/10.1108/prt-07-2016-0072.

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Purpose The purpose of this paper is to prepare cheap and environmentally friendly water soluble polyester coatings through the glycolysis of poly(ethylene terephthalate) (PET) waste. Design/methodology/approach A secondary value-added polyester coatings were prepared from PET waste. The first step was the de-polymerisation of PET waste by 2,2-dimethyl-1,3-propanediol with different molar ratios in the presence of different concentrations of zinc acetate as trans-esterification catalyst. The de-polymerised product was characterised by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1HNMR), differential scanning calorimetry and hydroxyl values. The polyesters were successfully synthesised by esterification of the glycolysed product with adipic acid, isophthalic acid, 2,2-dimethyl-1,3-propanediol and trimellitic anhydride in different ratios. FTIR and 1HNMR were used qualitatively and quantitatively to elucidate the structure of the prepared polyesters. Hydroxyl value and the physical properties of the prepared polyesters were also investigated. Two different curing agents were used to prepare the coatings based on the prepared polyesters. Findings Useful coating products were obtained by chemical (glycolysis) of post consumed PET wastes. The 2,2-dimethyl-1,3-propanediol was found to be good glycol in the glycolysis of PET. It was noticed that the rate of glycolysis increases with increasing the amount of catalyst, time of glycolysis and amount of 2,2-dimethyl-1,3-propanediol. N,N-Dimethylethanol amine was a good neutralising agent used for the preparation of water soluble coatings based on glycolysed product of PET. Practical implications The use of waste products like PET waste in water soluble coating systems will bring down the costs of the coatings and will also open a new market of recycled plastic materials and, hence, may provide a potential solution to the problems of solid waste management. It is an attractive option for environmentally friendly and efficient disposal of plastic waste. Originality/value The paper provides a potential way to use undesirable PET waste as industrial raw material. The coatings prepared are eco-friendly, soluble in water that can replace other expensive polyester coatings that are soluble in organic solvents and not environmentally coatings.
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46

Feng, Lifei, Ran Li, Han Yang, Shanwei Chen, and Wenbin Yang. "The Hyperbranched Polyester Reinforced Unsaturated Polyester Resin." Polymers 14, no. 6 (March 11, 2022): 1127. http://dx.doi.org/10.3390/polym14061127.

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We report a method of reinforcing and toughening unsaturated polyester resin (UPR) with a kind of hyperbranched polyester (HBP-1). Polyethylene glycol with different molecular weight was used as the core molecule of the preparation reaction, and the reaction product of phthalic anhydride and glycerol was used as the branching unit. The esterification reaction of polycondensation occurred, and then the hydroxyl-terminated hyperbranched polyester was prepared. The reaction product of maleic anhydride and isooctanol was added to the prepared hydroxyl-terminated hyperbranched polyester for esterification reaction. Both ends of the hyperbranched polyester had unsaturated double bond to obtain the hyperbranched polyester (HBP-1). The effects of this treatment on the morphology, mechanical properties and thermal properties of the composites were studied in detail. The HBP-1 was investigated by Fourier Transform Infrared Spectroscopy (FT-IR). The HBP-1/UPR composites were investigated by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), mechanical properties analysis and Scanning Electron Microscope (SEM). The results showed that HBP-1 enhanced the thermostability and mechanical properties of UPR. However, DMA indicated that the addition of HBP-1 cannot effectively improve the thermodynamic properties of UPR due to the flexible chain in HBP-1 structure. The HBP-1 improves tensile strength, bending strength and impact strength compared to neat UPR.
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47

KOBAYASHI, Takuma, and Touru MIZUGAMI. "Heat Durability of Polyester-Polyester Block Copolymer." KOBUNSHI RONBUNSHU 50, no. 7 (1993): 543–49. http://dx.doi.org/10.1295/koron.50.543.

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48

Todea, Anamaria, Emese Biro, Valentin Badea, Cristina Paul, Adinela Cimporescu, Lajos Nagy, Sándor Kéki, Geza Bandur, Carmen Boeriu, and Francisc Péter. "Optimization of enzymatic ring-opening copolymerizations involving δ-gluconolactone as monomer by experimental design." Pure and Applied Chemistry 86, no. 11 (November 1, 2014): 1781–92. http://dx.doi.org/10.1515/pac-2014-0717.

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Abstract Enzymatic incorporation of carbohydrate-derived monomer units into hydrophobic polyester backbones represents a promising alternative to obtain new biodegradable oligomers and polymers. Immobilized lipases are efficient biocatalysts for copolymerization of β-butyrolactone and δ-gluconolactone, but only a systematic optimization study was able to highlight the influence of the main reaction parameters on the polymerization degree and on the relative copolymer content of the product. Therefore, experimental design was employed for determination of the optimal ring-opening copolymerization conditions in solventless reaction systems, at temperatures up to 80 °C. The obtained products, cyclic and linear polyesters, have been characterized by FT-IR, MALDI-TOF MS, NMR, and TG analysis, demonstrating the incorporation of gluconolactone unit(s) into the hydrophobic backbone of the polyester and the formation of new bio-based products.
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49

Huskić, Miroslav, and Majda Žigon. "Side-chain polyesters and polyester hydrochlorides based on terephthalic acid." Polymer 44, no. 20 (September 2003): 6187–93. http://dx.doi.org/10.1016/s0032-3861(03)00670-0.

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50

Larez, V., J. Cristobal, and Gilberto A. Perdomo Mendoza. "Unsaturated polyesters. V. Polyester from maleic anhydride and 1,6-hexanediol." Journal of Applied Polymer Science 47, no. 1 (January 5, 1993): 121–24. http://dx.doi.org/10.1002/app.1993.070470115.

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