支化PET的非等温结晶性能研究

Non-isothermal crystallization properties of branched PET

采用直接酯化缩聚法,以3-羟甲基丙烷（TMP）或季戊四醇（PER）为支化剂,制备支化PET;探讨了支化剂对其结晶性能的影响;利用差示扫描量热（DSC）法研究了支化PET的非等温结晶性能.结果表明：支化剂TMP或PER的加入可以有效增强PET的结晶能力,但过量的支化剂会抑制PET的结晶;支化PET的非等温结晶Avrami指数为3.03 ～4.42,其结晶机理为均相成核和异相成核相结合;支化PET的结晶活化能比常规PET的低,支化PET结晶对温度的依赖性降低.

Branched PET was prepared by using trimethylolpropane （TMP） or pentaerythritol （PER） as branching agent viadirect esterification and polycondensation. The effect of branching agents on the crystallization property was discussed. The non-isothermal crystallization behavior of the branched PET was studied by differential scanning calorimetry （DSC）. The resultsshowed that the addition of TMP or PER could efficiently enhance the crystallization capacity, but excess branching agents wouldinhibit the crystallization process of PET; the non-isothermal crystallization Avrami exponent of the branched PET was 3.03 -4.42, so it would be speculated that the crystallization mechanism of the branched PET was a combination of homogeneous nucle-ation and heterogeneous nucleation; and the branched PET had the lower crystallization activation energy and the crystallizationless dependent on temperature as compared with traditional PET.