Abstract
聚亞醯胺樹酯具極佳之熱穩定性、耐溶劑性，於本研究中，盼以引入具有 穩定液晶性質之聚酯系統進行共聚合的改質方式，提升其應用性。首先， 以含單一亞醯胺鍵結之雙酸單體N-(10-carboxyalkylene) trimellitic imide(DIA-10)與triethyleneglycol bis(4-carboxyphenyl)ether (PEG3)、diacetoxy biphenol(BP)進行共聚合。X DIA10系列共聚合物具 有穩定之向列液晶相，其耐熱性隨亞醯胺鍵結含量提高而提升的效應並不 十分明顯。將單體DIA-10更換為較短脂肪族鏈段較短之N-(5-carboxy- alkylene) trimellitic imide(DIA-5)，則所合成之X DIA5系列聚亞醯胺 酯因主鏈結中柔曲間隔鏈長的差異性，使結晶性、熔點明顯下降，於融熔 態下向列液晶相存在於更寬廣的溫度範圍內；另外，由動態黏彈測試結果 得知，在Tg點附近亦表現出顯著的鬆弛效應。因縮短共聚合單體間隔鏈長 的方式對熱穩定性幫助仍有限，故再選用含有雙亞醯胺鍵結之單體1,10- diaminoalkane bistrimellitimide (DIAC-10)或1,12-diaminoalkane bistrimellitimide(DIAC-12)與PEG3、BP進行共聚合的改質。X DIAC10、 X DIAC12兩系列共聚合物雖耐熱性與Tg點有相當明顯的提升，但仍不及全 芳香族系列；在液晶行為方面，則隨兩種共聚合雙酸單體比例變化，於融 熔態下分別出畢V列(Nematic)或層列(Smectic-A)液晶相，由偏光顯微鏡 的觀察與SAXS測試的結果可確認之；Tg點附近之鬆弛行為表現於動態黏彈 測試中，隨相對結晶性的提高而愈不明顯。由毛細管流變儀的測試結果發 現，所有的液晶共聚合物皆具剪切致稀的特性，流動性佳，僅亞醯胺鍵結 含量較高、具層列液晶相之組成有較高的融熔黏度。 Diacids with various flexible spacers and aromatic imide ring contents were prepared by trimellitic anhydride,ω-amino acids, and α,ω-diamines. N,N'-alkane-α,ω-diylbis(trimellitimide)s with ten or twelve methylene units and two aromatic imide rings possess symmetrical structure but N-(ω-carboxyalkene) trimellitric imides with ten or five methylene units and only one aromatic imide ring don't. In this investigation four series of copoly(ester imide)s were synthesized by triethyleneglycol bis(4-carboxyphyl)ether, diacetoxy biphenol,and one of the diacids with imide bonds in the aromatic ring systems. Thermal gravimetric analyses(TGA) imply that X DIAC10 and X DIAC12 posess higher thermal stability. The effects of copolymerization on the changes of Tg, Tm, and Ti are examined by global TSC and DSC traces. Strong stir opalescence phenomenon and the observation from polarized optical microscopy identified that X DIA10 and X DIA5 possess typical Schlieren texture of an enantiotropic nematic mesophase. The bireigent melt of X DIAC10 and X DIAC12, however,display particular liquid crystalline behavior. Copolymers with higher aromatic imide ring contents form layered structure and enantiotropic smectic-A mesophase in the melting state.The rheology is also studied by capillary rheometer and RDS.