PC/PBT共混体系的研究(Ⅱ)PC、PBT熔融共混时的相容性

Studies of PC/PBT Blend System (Ⅱ) —The Compatibility of the Molten Blends of PC and PBT

采用ＤＳＣ测定了一系列ＰＣ／ＰＢＴ熔融共混物的Ｔｇ，结果显示ＰＣ、ＰＢＴ是部分相容的两相体系，ＰＣ、ＰＢＴ之间的酯交换反应有利于相容性的提高。通过对ＰＣ、ＰＢＴ两相中各组分表观质量分数的计算，发现ＰＣ溶于ＰＢＴ的能力要比ＰＢＴ溶于ＰＣ的能力大。通过对ＰＣ、ＰＢＴ相互作用参数χ１２的计算，发现在所研究的范围内（ＰＣ含量为３０～７０％）ＰＣ、ＰＢＴ之间的相互作用参数χ１２略大于其临界相互作用参数（χ１２）ｃ，表明ＰＣ、ＰＢＴ在熔融共混时会发生相分离。

In this paper, the T g of a series of PC/PBT molten blends was determined by DSC. It is concluded that PC - PBT is a partially compatible system and the transesterification is a useful reaction to increase the compatibility of them. From the measured T g and apparent mass fractions of PC and PBT dissolved in each phase, it appears that PC dissolves more in the PBT-rich phase than PBT does in the PC-rich phase. The values of the Flory-Huggins polymer-polymer interaction parameter χ 12 were determined. It was found that the values of χ 12 were a little more than the critical value of χ 12 , from which suggested the phase separation would occur during PC and PBT molten blending. That is to say, PC-PBT was partially compatible system.