相容化之液晶聚酯與聚碳酸酯摻合物之機械性質

Abstract

本研究是探討液晶聚酯高分子(Poly(p-oxybenzoate-co- terephthalate))(40/60)與聚碳酸酯 (Poly(bisphenol-A carbonate)) PC摻合物酯交換的反應機構與程度。以熱差儀來分析摻合物玻璃轉換點溫 度，可以得知相容性隨著反應時間而提高，而加入含磷之抑制劑可以有效 地控制酯交換反應。以核磁共振儀來研究酯交換摻合物的化學結構，得知 於260℃持溫時的terephthalate與PC的bisphenol-A先產生酯交換反應， 在反應30分鐘後P46的POB與PC的bisphenol-A開始有酯交換反應。將P46/ PC(60%/40%)加入抑制劑混拌16分鐘後產生相容劑。相容劑與poly( oxybenzoate-co-oxynaphthalate) (Vectra A950)/Polycar- bonate(20/80)，三成份經雙螺桿壓出機擠出後一起射出成型。此三成份 摻合物的機械性質(mechanical property)，加入2％相容劑，比沒有加入 相容劑的摻合物其tensile modulus 和tensile strength 分別增加24％ ，54％。而impact properties隨著相容劑的增加而降低。 The thesis is a study of transesterification in blends of poly (p-oxybenzoate-co-terephthalate ) (POB-PET)(40/60) (P46) and poly (bisphenol-A carbonate ) (PC). The miscibility of these blends has been investigated with differential scanning calorimetry (DSC). The mechanism of ester exchange was manifested through measurements by nuclear magnetic resonance (NMR). The ester exchange occurred first between PC and PET segment in P46 and then between PC and POB segment in P46. The controlled P46 and PC blends were intended to be used as a compatibilizer for liquid crystalline polyester and polycarbonate . These ternary liquid crystalline polyester blends displayed improved tensile modulus (24％) and tensile strength (54％), respectively as compared to that of binary Vectra blend in an injection molding process. The tensile properties of the ternary liquid crystalline polyester blends decreased with the concentration of the compatibilizer, the compatibilizer once is over 2 phr.