熱向型液晶共聚酯及聚芳香酯三成份摻何物之即成複合材料

Abstract

本實驗是利用掃瞄式熱分析儀（DSC）、動態機械分析儀（RDS）及偏 光顯微鏡（POM）來研究液晶共聚酯（copoly(oxybenzoate-p-ethylene terephthalate)）POB-PET與聚芳香酯高分子polyarylate，PAr，之間的 相容性，以及測量POB-PET，PAr及全芳香族液晶共聚酯所形成之三成份摻 合物的機械性質，並利用掃瞄式電子顯微鏡（SEM）觀察其形態。 經由 結果發現POB-PET中的PET無定型部份與聚芳香酯產生部份相溶。以此對酯 化的POB-PET/PAr及第二液晶高分子POB-PET充當摻合物液晶共聚酯（ Vectra）及聚芳香酯的相容劑，並且利用雙螺桿擠出機製備三成份液晶高 分子摻合物。這些摻合物經由射出成型加工而形成即成複合材料。由這些 摻合物的抗伸張力及無缺口衝擊強度隨著POB-PET或相容劑之量而增加， 與兩成份Vectra和PAr摻合物比較分別增加了40﹪及70﹪。由掃瞄式電子 顯微鏡觀察結果發現加入POB-PET或相容劑使得各成份間的界面接著增加 而且使得TLCP在三摻成份摻合物裡面產生的纖維變的更細，兩成份 Vectra/PAr(20/80)摻合物當加入POB-PET 6 phr後使得其在樣品蕊部份的 Vectra平均顆粒由原來的1.5μm降為1μm。由核磁共振光譜分析這些射出 成型之三成份摻合物中的POB-PET和PAr成份時發現有酯交換發生。 The miscibility of melt blends of liquid crystalline copoly( oxybenzoate-p-ethylene terephthalate)((POB-PET)) and polyarylate (PAr) was investigated with differential scanning calorimetry (DSC)，rheometric dynamic spectroscopy (RDS) and polarizing optical microscopy (POM). The mechanical properties of the in- situ composites of the ternary blends of PAr，Vectra and POB-PET or compatibilizer were measured. Their morphology was also observed with scanning electron microscopy (SEM). It was found that the amorphous PET phase from POB-PET is partially miscible with PAr, which leads to a decrease in the glass transition temperature of PAr in the blend. The Transesterified POB-PET/PAr blend and the second liquid crystalline copolyester POB-PET were used as compatibilizers for blends of copoly( oxybenzoate-p-naphthalate) ( Vectra ) and polyarylate. The ternary blend liquid crystalline polymer blends of Vectra, PAr and POB-PET were prepared in a twin-screw extruder. These blends were then injection-molded to form in-situ composite. The ultimate tensile strength and the unnotched impact strength of these in-situ composites of these ternary liquid crystalline polymer blends were found to be substantially (40﹪and 70﹪) higher than that of their corresponding binary blend of Vectra and PAr by the addition of a small of amount of these compatibilizers. SEM revealed that the interfacial adhesion of the components were improved and finer fibrils of TLCP in the ternary blend were formed. The Vectra droplets in the core section of tensile bar of binary blends of Vectra/PAr(20/80) has an average size about 1.5 micron. When 6 phr POB-PET was added into Vectra/PAr(20/80) blend, the size of Vectra droplets was reduced to about 1 micron. Transesterification between POB-PET and PAr was confirmed with nuclear magnetic resonance to be present in the injection molding of these ternary blends.