共查询到18条相似文献,搜索用时 78 毫秒
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通过降解过程的质量损失率、相对分子质量及其分布、热性能、表面形貌等评价手段,重点考察了Aspergillus niger脂肪酶对聚丁二酸乙二醇酯(PES)和聚(丁二酸乙二醇-共-对苯二甲酸乙二醇酯)(PEST)的降解性能。结果表明:PES在脂肪酶溶液中具有较好的生物降解性能,随着对苯二甲酸摩尔含量的增加,PEST的质量损失率呈现先增加后逐渐减少的趋势;随着酶解时间的延长,残留部分的PES、PEST的相对分子质量均呈下降趋势;残留部分的PES、PEST的熔点随降解时间的延长变化不大,熔融热焓有所增加;聚酯薄膜表面产生了不同程度的沟槽、孔洞和裂纹。可以推测,PES及PEST的生物降解首先发生在无定形区,并且大分子链段发生的是随机断裂。 相似文献
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聚对苯二甲酸乙二醇酯合成催化剂研究进展 总被引:1,自引:0,他引:1
探讨了各类锑系催化剂、钛系催化剂(包括乙二醇钛)等不同类型的催化剂在聚酯缩聚反应中的催化性能研究的最新成果,指出在各种类型催化剂中,由于具有作为催化剂时不会带入多余的杂质进入反应体系等优点,乙二醇锑和乙二醇钛的应用前景较为广阔。 相似文献
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可降解高分子量聚丁二酸己二醇酯的合成与表征 总被引:2,自引:0,他引:2
以丁二酸和1,6-己二醇为原料,以十氢萘为溶剂,进行直接缩合,合成了高分子量的聚丁二酸己二醇酯,产率达到95.5%。用FTIR和1H-NMR对其结构进行表征,GPC测得其数均分子量为46503,DSC测得其熔点为61.3℃,拉伸强度为30.9MPa,断裂伸长率为869.5%。 相似文献
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以丁二酸和无水乙醇为原料,硫酸氢钠为催化剂合成丁二酸二乙酯,考察了影响收率的各种因素,确定了最佳反应条件为:丁二酸用量0.1mol时,无水乙醇与戊二酸的物质的量比为6.0,3.0g催化剂,25mL环己烷作带水剂,反应时间2.0h,收率达85.09%,结果表明,硫酸氢钠是合成丁二酸二乙酯的优良催化剂。 相似文献
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化学交联聚乙二醇水凝胶的制备方法 总被引:1,自引:0,他引:1
对化学交联聚乙二醇基水凝胶的研究进展进行了综述.介绍了该类水凝胶的制备方法,包括几种常见的前体制备方法和常用的交联方法,并讨论了影响水凝胶溶胀性能和力学性能的几种因素. 相似文献
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The fractional crystallization kinetics and phase behavior of PEO with different molecular weights (MWs) in its miscible crystalline/crystalline blends with PBS are studied. Both fractional crystallization kinetics and phase segregation of PEO in PBS/PEO blends are dramatically influenced by its MW. PEO with a medium MW (20 kDa) shows a significant fractional crystallization in the blends with PBS crystallized at a high TIC,PBS, which, however, is dramatically depressed in the blends with a very low or high MW of PEO. This indicates that the PEO component with a medium MW is more ready to segregate into the interlamellar region of PBS crystals than those with a very low or high MW. The MW‐dependent fractional crystallization kinetics and phase segregation of PEO component in the PBS/PEO blends are discussed.
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生物可降解聚丁二酸乙二醇酯的合成与降解性能研究 总被引:2,自引:0,他引:2
以丁二酸和乙二醇为原料,直接熔融聚合,合成了高相对分子量的聚丁二酸乙二醇酯(PES),用FTIR,1H-NMR表征其结构;考察了不同聚酯反应催化剂对其聚合反应的影响,结果表明:三氧化二锑的催化效果是最佳的。同时,利用酶降解和体外水解的方法,对聚合物降解性能进行研究,结果表明:PES是一种可生物降解的聚合物,且在体外具有一定的降解性。 相似文献
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环氧乙烷催化法合成乙二醇的研究进展 总被引:1,自引:1,他引:1
对环氧乙烷催化法合成乙二醇研究的最新进展作了综述。阐述了用于环氧乙烷催化水合反应中的多羧酸衍生物催化体系、离子交换树脂催化体系、大环螯合物催化体系、季鏻盐催化体系、多相水滑石型催化体系及其他催化体系近年来的研究进展;同时阐述了用于碳酸亚乙酯法合成乙二醇反应中的催化体系的新进展。 相似文献
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《国际聚合物材料杂志》2012,61(7):675-689
Blends of the commercial biodegradable polymer poly(hydroxybutyrate) (PHB) with the oligomeric polyester poly(ethylene succinate) (PES) were prepared by melt processing in the presence of Sm(acac)3. The occurrence of transesterification reactions during blend processing using the samarium catalyst was investigated. 1H NMR analyses showed no evidence of transreactions, even using high content of catalyst (4 wt%), long reaction times and high temperatures (200°C). Under the drastic reaction conditions employed, chain degradation characterized by a significant decrease in the molecular weight (MW) of PHB has taken place. PHB/PES blends form immiscible systems in which the PHB crystallizes as large spherulites, but its crystallization is significantly influenced by the presence of PES, which does not crystallize at conditions in which the poly(hydroxyalkanoate) is crystallized. 相似文献
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The spherulitic morphology and growth, overall isothermal crystallization kinetics and hydrophilicity of PBSU were investigated by POM, DSC and WCA measurements in its miscible blends with PEO. The Hoffman‐Lauritzen equation was employed to analyze the spherulitic growth rates of neat and blended PBSU, which show a crystallization regime transition between regime II and III. The overall crystallization rates of PBSU decreased with increasing crystallization temperature, regardless of blend composition, while the crystallization mechanism does not change. A significant improvement in the hydrophilicity of PBSU can be achieved by blending with different weight fractions of PEO, which may be essential for the practical application of PBSU/PEO blends.
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This study deals with the effects of pH and neutral salts on the adsorption of PET fiber with four kinds of poly(ethylene glycol terephthalate) condensated from dimethyl terephthalate (DMT) and poly(ethylene glycol) (PEG). The surface properties of the aqueous solution, the contact angle of polyol‐treated PET fabrics, and its parameters were also discussed. The pH of the solution or the adding of neutral salt in the polyol solution largely affected the contact angle of polyol‐treated PET fabrics as well as the surface tension of the solution. A lower pH of the polyol solution or adding neutral salts in the solution showed a lower surface tension and a lower contact angle that resulted in a better adsorption between polyol and poly(ethylene terephthalate) fibers. The lower pH of the solutions and a higher valence of the added neutral salt in the solution showed a largely positive effect on the adsorption parameters, and the order of effectiveness is Al2(SO4)3 > MgSO4 > Na2SO4. 相似文献