可生物降解脂肪-芳香族共聚聚酯的研究进展

综述了脂肪-芳香族共聚聚酯(CPEs)在生物医用材料和环境友好材料领域的研究进展，介绍了CPEs的合成及力学性能、热性能、生物降解性、生物相容性和环境安全性，展望了CPEs的发展方向。     

PBS及其共聚酯生物降解性能的研究进展

综述了PBS(聚丁二酸丁二醇酯)、PBS基脂肪族共聚酯,PBS基芳香族共聚酯的结构和生物降解性能,并分别总结了它们的结构和生物降解性能之间的关系.PBS基脂肪族共聚酯分为线型PBS基脂肪族共聚酯和枝状PBS基脂肪族共聚酯,分别对它们进行了介绍.得出了PBS及其共聚酯的结构、分子量、聚酯形态、熔点、结晶度等与共聚酯的生物降解性之间的关系.     

PBS基共聚酯降解性能的研究概述

简要分析了结晶能力、链段柔顺性和化学组成等对聚丁二酸丁二醇酯(PBS)基共聚酯降解性能的影响。结果表明,柔软的链结构易于被生物降解,有规晶态结构阻碍生物降解,脂肪族聚酯比芳香族聚酯易于生物降解,并指出提高PBS基共聚酯的降解性能仍然是一项具有挑战性的工作。     

产品开发

生物降解材料新秀——共聚酯前途光明 目前已开发成功的生物降解材料聚乳酸、聚羟基烷酸酯、聚已内酯、聚碳酸亚丙酯、聚碳酸亚乙酯、聚丁二醇丁二酸酯、聚乙烯醇等,由于产品性能和成本等因素,在大范围推广受限,而脂肪-芳香族共聚聚酯作为生物降解材料新秀,兼具脂肪族聚酯良好的生物降解性、生物相容性和芳香族聚酯优异的力学性能及热稳定性,而且生产成本低,开发和市场前景非常广阔。     

以反丁烯二酸合成的不饱和脂肪族聚酯的生物降解性研究

以反丁烯二酸、一缩二乙二醇和1,4-丁二醇为原料,采用熔融缩聚法合成了不饱和脂肪族聚酯和共聚酯,在37℃下,用含有脂肪酶的磷酸缓冲溶液对聚酯的生物降解性进行了研究,讨论了聚酯结构、组成及C=C双键的交联度对生物降解性的影响。结果表明,对于粘稠液体状的聚酯,C=C双键的引入,没有明显的改变其生物降解性;对于固体状的聚酯,C=C双键引入后,熔点(Tm)和结晶度增加;聚酯部分降解后,其热力学性能(Tm、-ΔHm)和结晶度都升高;对于交联后的聚酯,交联度越高,生物降解性越差。     

熔融共混工艺制备的聚(乳酸)弹性体共混体及其表征

<正>研究可生物降解聚合物的理由很多。上涨的油价和环境问题迫使很多研究人员用生物基聚合物开发容易降解的材料。近十年来,潜在自然资源的探索与合成一直是令人感兴趣的课题。有2类可生物降解聚合物:(1)农业聚合物(多糖、蛋白质等);(2)聚酯(芳香族和脂肪族聚酯)。脂肪族聚酯由于其性能,所以无论是均聚物还是共聚物都具有用作可生物降解聚合物的潜力。     

生物降解性脂肪族聚酯改性的研究进展

综述了脂肪族聚酯改性制备生物降解性聚酯的研究进展.在聚酯中引入刚性链段(即将脂肪族聚酯与芳香族、液晶基元共聚合)可改善聚酯的加工性能;在聚酯中引入亲水基大分子(即将脂肪族聚酯淀粉共混或与聚乙二醇共聚合)可改善聚酯的亲水性能.今后脂肪族聚酯改性研究的重点将解决功能化基团的引入、合成路线的简化、成本的降低及改性的效果等方面的问题.     

低熔点聚酯的合成与性能的研究

本文通过在PET链中引入芳香族间位酸和脂肪族二元醇(柔性链节)合成了共聚酯,并对其转变温度、结晶度以及热失重进行了研究。结果表明,芳香族间苯二甲酸和脂肪族二元醇的引入破坏了PET完善的结晶结构,从而导致共聚酯的熔点降低。而且熔点下降程度与改性组分添加量呈良好的线性关系。     

一种可降解共聚酯的合成及表征

采用对苯二甲酸、1,4-丁二醇和脂肪酸为原料,以直接酯化法缩聚合成了生物可降解的高分子质量脂肪-芳香族共聚酯,并分析表征了此共聚酯的结构、分子质量、力学性能、流变性能及降解性能等。     

生物降解树脂PBAT的共混改性研究进展

聚己二酸对苯二甲酸丁二酯(PBAT)是一种新型的完全生物降解脂肪-芳香族共聚酯。与其它聚合物进行共混改性是改善PBAT基材综合性能的有效手段。本报告从PBAT的性能特点和应用出发,综述了近年来PBAT与可降解聚合物、天然高分子、非降解聚合物、无机粒子等进行熔融共混改性的研究进展;并对PBAT将来的发展作了展望。     

Aliphatic-aromatic copolyesters: synthesis and crystallization studies

A melt condensation technique has been employed for the synthesis of aliphatic-aromatic copolyesters using bisphenol-A, resorcinol, hydroquinone and 4,4′-dihydroxydiphenyl sulphone. The incorporation of bisphenols was ascertained by chemical composition using infra-red and nuclear magnetic resonance spectra. The effect of the catalyst and stirring during condensation has been studied. The dependence of thermal properties and crystallization behaviour on copolyester composition has been considered. The results are compared with those obtained by wide-angle X-ray diffraction and density studies.     

Influence of Specific Processing Conditions and Aliphatic-Aromatic Copolyester on Polylactide Properties

This study reports the influence of aliphatic-aromatic copolyesters (AAC) on selected polylactide (PLA) properties. Processing, mechanical, and thermal properties were determined. In addition, we examined changes occurring in the surface geometrical structure of sample fractures. It was found that PLA as modified with AAC exhibited enhanced impact strength and melt flow rate, unaffected elongation at break, and reduced tensile strength and elasticity modulus. The results also demonstrate the plasticizing properties of AAC, which improved PLA processing and its thermal stability. We also observed insufficient adhesion at the interface between the two components, as well as heterogeneity of the obtained material.     

Synthesis and characterization of poly(ethylene‐co‐trimethylene terephthalate)s

Taking advantage of a melt polycondensation process, a series of copolyesters composed of pure terephthalate acid (PTA), ethylene glycol (EG), and 1,3‐propanediol (1,3‐PDO) were synthesized. The component, molecular weight, molecular weight distribution, and thermal properties of the copolymers were characterized. The results show that the contents of trimethylene terephthalate (TT) units in the resulting copolyesters are higher than PDO compositions in original diol. Oligomer content in the copolyesters varies with the compositions and attains a minimum value when the TT ingredient is 49.52 mol %. The glass transition temperature (T_g) of the copolyesters varies from 78.5°C for PET (polyethylene terephthalate) to 43.5°C for PTT (polytrimethylene terephthalate) and decreases monotonically with the components. The copolyesters are amorphous copolymers when TT content is in the range of 32.4–40.8 mol %, as calculated from the melting enthalpy (ΔH_m) measured via differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1511–1521 2006     

螺环二醇改性PET共聚酯的合成及性能

为了扩大聚对苯二甲酸乙二醇酯（PET）的应用范围,常通过引入第三单体来改变其性能。本研究以螺环二醇（SPG）为原料,采用酯交换法熔融缩聚合成了一系列不同单体含量的共聚酯。采用超高效聚合物色谱-多角度激光光散射仪（APC-MALLS）联用分析了共聚酯的分子量与分子量分布,利用核磁氢谱（¹H NMR）、傅里叶红外光谱（FTIR）研究了共聚酯的化学结构,同时采用差示扫描量热仪（DSC）、热重分析仪（TGA）和X射线衍射仪（XRD）研究了共聚酯的热性能以及结晶性能,测试了共聚酯的拉伸性能。结果表明,成功合成了符合纤维级聚酯数均分子量（M_n）和重均分子量（M_w）要求的共聚酯,分子量分布较窄,随着第三单体含量的增加,玻璃化转变温度从77℃提升至85℃,而熔融温度从255℃降低至222℃,热分解温度无明显变化,结晶性能下降。     

Molecular structure of liquid-crystalline copolyesters of vanillic acid, 4-hydroxybenzoic acid and poly(ethylene terephthalate)

Thermotropic liquid-crystalline copolyesters made from vanillic acid (V), 4-hydroxybenzoic acid (B) and poly(ethylene terephthalate) (E) were examined by ¹H-NMR and GPC investigations. Nine possible diads could be identified and assigned. The sequence distribution of V/B/E copolyesters tends to change from random to block with an increase of B content in the copolyesters. The sequence distribution also varies slightly with catalyst concentration and polycondensation time. GPC results suggest that the V/B/E copolyesters have narrower molecular weight distribution (MWD) than B/E copolyesters. The MWD of the copolyesters narrows gradually with increasing V content from zero to 5 mol-%. The GPC chromatograms of the most V/B/E copolyesters show double peaks, which is different from the single peak of the GPC chromatograms of the B/E copolyesters.     

Preparation and properties of copolyesters polymerized in a vented extruder

High molecular weight thermoplastic copolyesters from bisphenol A, neopentyl glycol, and terephthaloyl chloride have been prepared by a melt-polymerization technique carried out in a twin-screw, vacuum-vented extruder. Low molecular weight polymer, polymerized in a conventional melt reactor, was further polymerized to copolyesters with intrinsic viscosities, under the conditions investigated, of up to 0.76 dl/g. The optimum extruder reaction conditions with respect to temperature profile, vent configuration, and polymer throughput are described. A variety of properties for two representative copolyester compositions have been determined. Particular attention was given to melt viscosity and impact strength, two properties which depend markedly on whether the polymer is prepared by the subject melt process or, alternately, by a low temperature interfacial polycondensation. It is concluded, based on a study of deliberately branched, interfacially prepared copolyesters, that the property differences which depend on the polymerization method are attributable to the formation of branches in the copolyesters prepared by the high-temperature melt process.     

Synthesis and thermal properties of poly(ethylene 2,6‐naphthalate) copolyesters containing modified diacid monomer

A series of poly(ethylene 2,6‐naphthalate) (PEN) copolyesters was synthesized using three monomers (newly prepared 1,4‐bis[(methoxycarbonylethoxy)methyl]benzene, dimethyl 2,6‐naphthalenedicarboxylate, and ethylene glycol) with various molar ratios to investigate the effects of these compositions on thermal properties of the copolyesters. Copolyesters having weight average molecular weights of 11,000–22,000 were obtained by melt polycondensation in the presence of metallic catalysts. The structures and thermal properties of the resulting random PEN copolyesters were characterized by nuclear magnetic resonance, differential scanning calorimetry, thermal‐mechanical analyzer, and X‐ray diffraction analysis. The results of thermal measurements revealed that thermal properties depended on the corresponding new diacid comonomer content of the PEN copolyesters. Nonetheless, the crystal structures of PEN copolyesters and PEN homopolymer are identical. POLYM. ENG. SCI., 54:2641–2644, 2014. © 2013 Society of Plastics Engineers     

不同分子质量阻燃共聚酯的非等温结晶动力学

为了探究分子质量和共聚结构对阻燃共聚酯结晶动力学的影响,采用差示扫描量热仪对不同分子质量的阻燃共聚酯进行非等温结晶测试,并进行结晶动力学分析.结果表明:在聚酯中通过共聚反应引入共聚阻燃结构单元后,共聚酯的熔点降低,降温过程中的起始结晶温度和结晶峰温降低,分子质量较大的阻燃共聚酯的结晶温度有所下降,但这种影响并不明显;阻...     

Synthesis,characterization, and properties of degradable poly(l‐lactic acid)/poly(butylene terephthalate) copolyesters containing 1,4‐cyclohexanedimethanol

High‐molecular‐weight copolyesters based on poly(butylene terephthalate) as rigid aromatic segments and poly(l‐lactic acid) (PLLA) as degradable aliphatic segments were synthesized via the polycondensation of terephthalic acid, 1,4‐butanediol (BDO), 1,4‐cyclohexanedimethanol (CHDM), and PLLA oligomer. By tailoring the molar ratio of diols (BDO and CHDM), we investigated in detail the effects of the CHDM rigid hexacyclic ring on the synthesis, mechanical properties, thermal stabilities, and degradation behaviors of the copolyesters. With increasing CHDM content, the initial decomposition temperature increased from 282.5 to 322.2°C, and the tensile strength improved by nearly four times, from 5.4 to 19 MPa. When the molar ratio of BDO/CHDM was 95/5, the weight‐average molecular weight of the copolyester was 89,400 g/mol with a polydispersity of 1.96. In addition, hydrolytic degradation results in phosphate buffer solution indicate that the degradation rate of the copolyesters displayed a strong dependency on the temperature and CHDM composition. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011