在軟性電子產品的應用中，例如液晶顯示器(liquid-crystal display, LCD)、觸控式面板(touch panel)、軟性印刷電路板(flexible printed circuit, FPC)、電子書等，致力於開發輕、薄、可撓曲(flexible)、高透明度的設計，因此必須使用透明度高的塑膠材料，且該等材料還必須可耐受製程中約250℃以上之高溫，並符合其他設計上的特殊需求。由於聚醯亞胺膜大多具有良好的耐熱性，故為適用於軟性電子產品的材料。
聚醯亞胺膜因受到電荷移轉效應(charge transfer complex effect)之影響，而使得聚醯亞胺膜呈黃色或紅棕色。為了改善薄膜的無色透明度，已有相當多的研究提出各種透明無色聚醯亞胺的組成與製法。
本研究將以6FDA (4,4'-hexafluoroisopropylidene diphthalic anhydride)、DDS (3,3'-diaminodiphenyl sulfone)、TFDB (2,2'-bistrifluoromethyl benzidine)等單體在無水極性非質子溶劑DMAc (Dimethylacetamide)中進行縮聚合反應，合成出不同結構的聚醯亞胺前驅物，聚醯胺酸(Polyamic acid)，將其於300℃高溫環化以及在室溫下化學環化後得到不同結構的透明無色聚醯亞胺。

In the application of plastic electronic products, such as liquid-crystal display, touch panel, flexible printed circuit, e-book etc., it is tended to develop light, thin, flexible, high transparent design. However, the favorable material should have good thermal stability due to the high temperature process in the electronic industry. The goal of our research is to develop polyimide films, which have excellent mechanical properties, good electrical properties, thermal properties and high transparency.
In our research, the polyimide precursor, polyamic acid (PAA), was synthesized from 4,4'-hexafluoroisopropylidene diphthalic anhydride (6FDA), 3,3'-Diaminodiphenyl sulfone (DDS) and 2,2'-bistrifluoromethyl benzidine (TFDB) in N,N-dimethylacetamide (DMAc) for 24 hours in ice bath. The PAA was cured via thermal cruing at 300℃for 1 h or chemical imidization at room temperature.
In this study, PI-Ⅰ(6FDA/DDS), PI-Ⅱ(6FDA/0.5DDS/0.5TFDB) and PI-Ⅲ(6FDA-TFDB) were synthesized. For these PIs, the maximum tensile strength was around 96.9~122.8 MPa and elongation at break was 5.93~7.76 %. The coefficient of thermal expansion was 22.51~54.07 ppm/℃. The glass transition temperature was 267~310℃. The pyrolysis temperature was above 500℃. The water absorption was lower than 1 %. The UV-vis transparency was over 88% at 500~700 nm.

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