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標題: Preparation and Physical Properties of Liquid Crystalline Polymer / Montmorillonite Nanocomposites
作者: 范正欣
Fan, Cheng-hsing
關鍵字: Liquid Crystalline Polymer;液晶高分子;Montmorillonite;Nanocomposite;蒙脫土;奈米複合材料
出版社: 化學工程學系
In this research, surface agents including DTPPB and 2P4QCA were used as templates for the modification of montmorillonite (MMT) surface.According to the technology of thermotropic liquid crystalline polymer Type Ⅱ Vectra’s polymerization,
each acetoxy-monomer ( (A-HBA , A-HNA , A-BP) mole (%) = ( 73 , 27 , X ) X=0、0.5、1.0) of LCP and 1 phr modified MMT were made into LCP / MMT nanocomposites through melt polycondensation reactions.With 2P4QCA content increase, it increase the dispersion of modified clay in the nanocomposites, because it can react with acetoxy-monomers and produce acetic acid.Therefore thermal, mechanical and other properties of the nanocomposites will increase.The addition of small amounts of acetoxy-BP will control molecule weights of LCP.It can react with acetoxy-monomers and produce acetic acid to form copolyesters, because more acetoxy groups will increase reactive rate and lower the time of polymerization. Therefore it will terminate the reaction and control molecule weights of LCP and thermal and mechanical properties of the nanocomposites will lower.TEM reveals that most clay layers of organoclay were intercalated.DSC result showed that Tm and Tc of LCP / MMT nanocomposites increase 0.5~1.5 oC, POM reveals that LCP / MMT nanocomposites still have liquid crystallinity and were nematic schlieren textures.The isotropic temperature lower 2~3 oC owing to the addition of modified MMT, DMA reveals that storage modulus (E'') of nanocomposites increase 10~30 (%).

本研究藉由吸附兩種表面改質劑 (DTPPB、2P4QCA) 改質蒙脫土,依據合成熱向性液晶高分子Type Ⅱ Vectra®系列液晶共聚酯的技術,分別以乙醯化後HBA / HNA / BP mole (%) = (73 , 27 , X) X = 0、0.5、1.0,與1 phr吸附不同層數兩種改質劑改質單層的蒙脫土熔融聚合成液晶高分子/蒙脫土奈米複材。隨著2P4QCA改質劑量的增加,因為羧基在與LCP聚合時和乙醯化後的單體乙醯基脫掉醋酸,提升改質黏土在複材之分散效果,可提升液晶高分子/蒙脫土奈米複材的機械、熱性質及其他性質。少量的乙醯化BP添加為控制聚合時的分子量,因羧酸與乙醯基會脫掉醋酸形成共聚酯,較過量的乙醯基會提高反應速率與縮短聚合的時間,且抑制反應的一直進行以控制聚合時的分子量,造成熱、機械性質下降。TEM分析其皆為插層型的液晶高分子/蒙脫土奈米複材,且其層數大小不等。DSC分析發現液晶高分子/蒙脫土奈米複材Tm、Tc有稍微的提升0.5 ~ 1.5 oC。POM圖形顯示出,蒙脫土插層聚合後並沒有失去其液晶性,觀察到是向列相schlieren組織,為具有液晶性的液晶高分子/蒙脫土奈米複材。液晶消失的溫度 (Ti) ,因改質蒙脫土的加入而下降2 ~ 3 oC,DMA測試發現液晶高分子/蒙脫土奈米複材的儲存模數提升10 ~ 30 (%)。
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