熱向型液晶共聚酯和聚對苯二甲酸丁烯酯三成份摻合物之即成複合材料

Abstract

本實驗是對於 poly(butylene terephthalate)(PBT), poly( oxybenzoate-p-ethyleneterephthalate)(POB-PET), poly(oxybenzoate- co-oxynaphthate)(Vectra), 三成份摻合物之探討. 並利用雙螺桿擠出機 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. 利用掃描式熱分析儀 (DSC) 及偏光顯微鏡 (POM) 來研究 PBT 和 POB-PET 之間的相容性. Hoffman-Week interaction parametetr XAB 為負值, 在偏光顯微鏡下 POB-PET 的液晶相隨著持溫時間增加而慢 慢消失, 由以上兩結論可知PBT, POB-PET 是部份相容的. PBT, POB- HNA(Vectra) 及加入高分子相容劑的三成份摻合物, 終極拉伸應力強度及 無缺口衝擊應力強度, 比在相同條件下的兩成份摻合物分別高出13 %及34 %. 以廣角X-Ray 繞射儀分析這些摻合物之射出成型試片時發現, 摻合物 中 PBT 的結晶度會因 POB-HNA 的 存在而降低, 當第三成份之高分子相 容劑存在時, PBT 結晶度下降的情形愈是明顯. 由掃描式電子顯微 鏡 (SEM) 的結果發現, 兩成份摻合物的界面接著, 因相容劑的存在而獲 得改善, 而且有細的纖維在三成份摻合物中形成. 在兩成份摻合物中的斷 裂面中心部份, POB-HNA 以約 10 um 的球滴狀大小埋於 PBT 基材中, 當 5 % 的 POB-PET 相容劑加入後, POB-HNA 在基材中的球滴狀減小為 3 um . This thesis is a study of in-situ composites of ternary liquid crystalline polymer blends of poly(butylene terephthalate)(PBT), poly(oxybenzoate-co-oxynaphthate)(POB-HNA), and copoly(oxybenzoate-p-ethylene terephthalate)(POB-PET).The ternary blends were prepared in a twin-screw extruder. These blends were then injection-molded to from in-situ composites. Miscibility between POB-PET and PBT was studied with differential scanningcalorimetry and polarized optical microscopy. Hoffman-Weeks interaction parameter XAB between PBT and POB-PET was determined to be negative values. POM revealed that liquid crystal phase slowly disappeared as annealing time was increased. It indicated that partial miscibility existed in POB-PET and PBT. The ultimate tensile strength and unnotched impact strength of injection-moldedbar of ternary blends of POB- HNA ,PBT and compatibilizer or POB-PET werefound to be improved by 13 % and 34 % , respectively, compared to that of the corresponding binary blends. X-Ray diffraction patten indicated the crystallization of PBT was hinderedby the presence of POB-HNA, and was further decreased by the addition of the third component. SEM revealed that the interfacial adhesion of the ternary blends were improved as compared to that of the binary blends and finer fibrils of TLCP in the ternary blend were formed. The POB-HNA droplets in the core section of injection molded bars of PBT/POB-HNA(80/20) had an average size about 10 um. The POB-HNA droplets in the ternary blends of PBT/ POB-PET/POB-HNA(80/5/20) wasreduced to about 3 um.