聚碳酸酯在陽離子聚合環氧樹脂中結晶行為及相分離機構之研究

Abstract

純化的DGEBA型環氧樹脂在陽離子起始劑BF3-MEA的誘發下，可進行反應級數為1，反應機構為ACE（活性末端基）的聚合反應。一般級環氧樹脂因含有二元醇、二級醇等親核性結構，而使得陽離子聚合反應出現AM（活性單體）機構。 陽離子聚合系統的DSC升溫掃瞄圖譜呈現出數個放熱峰訊號，適合以ASTM E698法來得到其動力學參數。在考慮溫度效應下，本研究以動力學結果證實ACE機構呈現出一次反應。 聚碳酸酯分子鏈在純化的環氧樹脂中不會產生酯交換反應。在樹脂單體的溶劑效應影響下聚碳酸酯分子鏈會進行加速排列成為結晶構造。以X光繞射儀可觀察到一個過渡的大尺度結晶，然後迅速的轉變成球晶結構。而光敏電阻法配合DSC的分析更可推知聚碳酸酯的相對結晶度。 聚碳酸酯對純化環氧樹脂的陽離子聚合反應有加速的效果，而系統仍維持一次反應不變。此外，本研究證實形態學為異相之系統中，聚碳酸酯在析出過程中仍會藉由分子鏈排列而產生結晶，並導致機械性質的改善效果不明顯。

The polymerization of purified DGEBA (diglycidyl ether of bisphenol A) type epoxy resin follows the first order reaction and the ACE (active chain end) mechanism induced by the cationic initiator BF3-MEA. The general grade epoxy resin follows the AM (activated monomer) mechanism because it possesses glycol and hydroxyl groups. The ASTM E698 method is used for the multiple exotherm peaks during the cure procedure. The kinetics confirms that the ACE mechanism follows a first order reaction. PC (polycarbonate) will not react (through esterification) with purified epoxy resin. The solvent effect of resin monomer induces the PC crystallization. X-ray diffractor is able to detect the transitional larger scale ordering structure at crystal initiation, which transfers to spherulites quickly. Photoresistor technique records the crystallization process of PC, and obtains the relative crystallinity by the auxiliary of DSC. The presence of PC accelerates the cationic polymerization of the purified epoxy resin, and the system maintains the first order reaction. The PC chains rearrange to form crystals during the phase separation process, which limits the improvement on mechanical properties.