端基对脂肪族超支化聚酯性能的影响  

Effect of Terminal Groups on the Properties of Aliphatic Hyperbranched Polyester

作　　者：刘晶如[1] 张建勋[1] 巢玲玲[1] 俞强[1] 

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164

出　　处：《高校化学工程学报》2011年第6期1051-1056,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：常州大学校基金项目(ZMF08020068)

摘　　要：用十八酸对端羟基脂肪族超支化聚酯进行改性,采用差示扫描量热分析(DSC)、热重分析(TG)、旋转流变仪研究了不同端基对超支化聚酯的玻璃化转变温度、热稳定性和流变性能的影响。结果表明,端基对超支化聚合物的玻璃化转变和结晶有显著影响,通过端基长链烷烃链段的有序排列可以显著提高超支化聚合物的结晶性能;端羟基超支化聚酯的热分解分为三个阶段,用十八酸对其进行端基改性后,热分解过程仅由一个阶段组成,表观活化能和指前因子均有所提高,十八酸改性的超支化聚酯的热稳定性优于端羟基超支化聚酯;第一至三代端羟基超支化聚酯熔体以及第一至五代十八酸改性的超支化聚酯熔体均表现出假塑性流体的剪切变稀行为,第四、五代端羟基超支化聚酯熔体则表现为牛顿流体的流变行为,超支化聚酯熔体剪切黏度与分子量之间的关系主要取决于分子间作用力,而剪切黏度与剪切速率之间的关系主要取决于链缠结作用。Aliphatic hyperbranched polyester with terminal hydroxyl groups was modified by stearic acid.The effect of terminal groups on the glass transition temperature,thermo stability and rheological properties of hyperbranched polyester was studied by differential scanning calorimetry（DSC）,thermogravimetric analysis（TG） and rotation rheometers,respectively.The results show that the terminal groups have obvious effect on the glass transition and crystalline characters of the hyperbranched polyester.The improvement of crystalline characters of the hyperbranched polyester can be realized by ordering the arrangement of the long alkyl chains in the terminal groups.The thermal decomposition process of the hyperbranched polyester with terminal hydroxyl groups is composed of three stages,while the thermal decomposition process of hyperbranched polyester modified by stearic acid is composed of only one stage;at the same time,its apparent activation energy and the pre-exponential constant increase.Compared with hydroxyl-terminated hyperbranched polyester,hyperbranched polyester modified by stearic acid has better thermostability.The hydroxyl-terminated hyperbranched polyesters of the first to the third generation and the modified hyperbranched polyesters of each generation show shear-thinning behavior of pseudoplastic fluid,but the fourth and the fifth generation hyperbranched polyesters show Newtonian fluid behavior.The relationship between the shear viscosity and molecular weight is dependent on the intermolecular forces,and the relationship between the shear viscosity and shear rate is dependent on the chain entanglements.

关 键 词：超支化聚酯 端基改性 玻璃化转变温度 热稳定性 流变性能 

分 类 号：O631[理学—高分子化学]