反應摻合液晶高分子POB/PET(60/40)與聚碳酸酯高分子

Abstract

本文為有關研究以熱熔高溫混合不同成份聚碳酸酯與實驗室合成之共聚酯 型液晶高分子所製備之摻合物。利用熔融摻合法將P64/PC進行聚摻合反 應,摻合系統的熱性質可藉由微差掃瞄式卡計(DSC)加以分析，觀察發現摻 合物的玻璃轉移溫度(Tg)隨著P64濃度，摻合反應溫度以及摻合反應時間 的增加而降低。紅外光線(FT-IR)，及核磁共振(NMR)光譜研究PC與P64聚 摻合反應的酯交換反應動力學，發現LCP含量愈多，摻合溫度愈高，摻合 時間愈久，酯交換反應愈明顯。流變性質分析得知由於LCP分子的切變稀 化(shear-thinning)效應,使摻合系統的粘度值介於PC與LCP的粘度值之間 。電子顯微鏡(SEM)觀察得LCP分子以圓形或橢圓形的顆粒狀分佈於PC的連 續相中，而且顆粒狀尺寸隨摻合時間及溫度的增加逐漸減少，表示有發生 酯交換反應。偏光顯微鏡分析了解摻合系統有液晶結構存在，且雙折射現 象隨摻合時間的增加而減少。 Blends of bisophenol-A Polycarbonate (PC) and copolyesters such as liquid crystalline Poly (p-oxybenzoate-co-ethylene terephthalate) (60/40, P64) were prepared by melt-mixing at high temperatures. The thermal property of the blends was studied with Differe- ntial Scanning Calorimetry (DSC). It found that the glass trans- ition temperature (Tg) of the blends decreased with increasing mixing time and the concentration of P64 (LCP) in the blends. The kinetics of the transesterification reaction between the PC and the P64 was studied with Fourier Transformed Infrared sp- ectroscopy (FT- IR) and Nuclear Magnetic Resonance spectroscopy (NMR) during the mixing.The results indicated that the miscibil- ity between the PC and the P64 increased with the P64 concentra- tion and the blending temperature and time. The rheology of the copolyester (P64), PC, and their blends was measured with a controlled stress (CSL-100) rheometer, In t- he whole shear range, the viscosity of the host PC blends was r- educed by the presence of the P64. The miscibility of the blends was found to be influenced by the ester exchange reaction through Scanning Electron Microscopy (SEM).SEM observation indicated that in the beginning the copol- yester (P64) existed in the form of droplet in the PC matrices. The size of the droplets decreased with the blending time, and the number of the droplets seem to decrease with the blend- ing temperature, indicating the ester exchange reaction took p- lace. Polarizing optical microscopy showed the liquid crystalline structure existed in the blends system,and the birefrigence phe- nomenon decreased when the blending time was prolonged.