液晶共聚酯高分子與聚芳香酯高分子之相容性

Abstract

本實驗是利用掃描式熱分析儀(DSC)及偏光顯微鏡(POM)來研究液晶 共聚酯高分子(Poly(p-oxybenzoate-co-p-phenyleneisophthalate), HIQ)與聚芳香酯高分子(poly-arylate, PAr)間的相容性. 其摻合物採用 solution blending 方式, 以50/50 phenol/tetrachloroethane 之混合 溶劑來製備. 從熱分析結果得知,當 HIQ 的含量低於40% 時,其熱分析曲 線僅出現單一Tg點;而當HIQ的含量大於等於40%時,於熱分析曲線中則出現 兩個Tg點,其中較低溫之Tg點則維持於138℃,不受成分之影響而改變,而較 高溫之Tg點則從HIQ含量為40%時,為183℃降低至HIQ含量為80%時,為173℃ 且其間之相容性隨HIQ含量之提高而逐漸之增加. 而HIQ/PAr(60/40)之摻 合物在高於HIQ之Tm點以上315℃持溫時,在數分鐘內此摻合物由部份相容 變為完全相容之摻合物,可由單一Tg點來證實之;而此摻合物相容性之增加 乃是因HIQ與PAr間具有反應發生,可由核磁共振儀(NMR)得知,且反應初期 是由HIQ內之HQ單位先參與反應而接於PAr上,隨後HBA及IA單位才加入反應 而接於PAr上,此外HIQ/PAr(60/40)摻合物之相容性亦可從偏光顯微鏡( POM)照片中,anisotropic的液晶相,明顯的隨持溫時間增加而逐漸轉變為 isotropic相. 而摻合物的極限黏度有隨持溫時間而增加,然尚待證實及解 釋. The miscibility of blends of liquid crystalline copolymer of poly(p-oxybenzoate-co-p-phenyleneisophthalate) (HIQ) with polyarylate (PAr) has been investigated with differential scanning calorimetry (DSC). HIQ/PAr blends were prepared by solution blending of both polymers in a mixed solvent of 50/50 phenol/tetrachloroethane. The phases in blends have been studied with polarizing microscopy (POM). A single glass transition temperature was obtained for the HIQ/PAr blends when the weight ratio of HIQ/PAr in these blends was less than 40%. Two glass transition temperatures were obtained when the weight ratio of HIQ in these blends was larger than or equal to 40%. The lower glass transition temperature around 138℃ remains almost changed, but the higher glass transition temperature decreased from 183℃ to 173℃ as the weight ratio of HIQ increasing from 40% to 80%. Annealing blends of HIQ/PAr at 315℃ for a few minutes, reaction occurred as confirmed by Nuclear Magnetic Resonance (NMR) spectroscopy. It was found that the HQ in HIQ reacted with PAr in 3 min, and then HBA and IA reacted with PAr after 6 min's annealing from both proton and carbon NMR. The fact that the intrinsic viscosity of HIQ/PAr blends increased with annealing time needs to be reconfirmed and explained.