摘要：本文以4,4-六氟异丙基邻苯二甲酸酐(6FDA)、4,4’-氧代双邻苯二甲酸酐(ODPA)为二酐单体，4,4’-二氨基-2,2’-双三氟甲基联苯(TFMB)为二胺单体，低温缩聚得到无色聚酰胺酸(PAA)溶液，利用超声分散法把TiO2颗粒掺杂进PAA溶液，涂膜，程序升温去溶剂和亚胺化后制得PI纯膜和一系列不同掺杂度的PI/TiO2复合薄膜。利用傅里叶变换红外光谱仪(FTIR)、扫描电镜(SEM)、紫外可见分光光度计、白度计、热失重分析仪、微机控制电子万能试验机等对薄膜进行结构、光学性能、热学性能和力学性能等测试。

结果表明，随着TiO2掺杂量的提高，PI/TiO2复合薄膜的T%λ=400nm、T%max值先呈显著降低，后变化不明显。当TiO2掺杂度在10wt%以上时，PI/TiO2复合薄膜最大透过率从85.8%下降到1%以下；白度则显著增大，当TiO2掺杂度为20wt%时，其白度从42.6(1wt%)上升到63.4。随着复合薄膜厚度的增大，其最大透过率显著下降，当厚度在20um以上，最大透过率降至1%以下，基本不透明。TiO2的加入并没有明显降低复合薄膜的热学和力学性能。综上所述，掺杂纳米TiO2粒子是改善聚酰亚胺薄膜遮光性能和提高其白度值的有效方法。TiO2掺杂度为10wt%，厚度在20um以上的PI/TiO2复合薄膜综合性能最好且最经济(最大透过率<1%和白度>57.6)。

关键词 聚酰亚胺 纳米TiO2 遮光性 复合薄膜

毕业设计说明书外文摘要

Title Preparation and Properties of Shading White Polyimide Films

Abstract：Colorless poly(amic acid) was synthesized with fluorine dianhydride 4,4’-(hexafluoroisopropylidene)diphthalic anhydride(6FDA), 4,4’-oxobisophthalic anhydride (ODPA) and 2,2’-bis(trifluoromethyl)-[1,1’-biphenyl]-4,4’-diamine (TFMB) in the polar aprotic acid DMAc by low temperature polycondensation and the TiO2 particles were doped into PAA solution by ultrasonic dispersion method. Polyimide film and polyimide/TiO2 composite films were prepared by coating followed with remove of solvent and thermal imidation. Fourier Transform Infrared Spectrophotometer, SEM, UV-VIS Spectrometer Lambda 35 Perkin Elmer Model, Whiteness Meter, Shimadzu DTG-60 and SANS-CMT 5105 Electronic Universal Testing Machine were used to study the structures, optical properties, thermal properties and mechanical properties of the prepared films.

The results showed that the T%λ=400nm and the T%max value of the PI/TiO2 composite film were first significantly decreased with the increase of TiO2 doping amount, then the change was not obvious. When the TiO2 doping amount was above 10 wt%, the maximum transmittance of PI/TiO2 composite film decreased from 85.8% to 1%. The whiteness of PI/TiO2 composite films increased significantly with the increase of TiO2 doping, and the whiteness increased from 42.6 (1 wt%) to 63.4 (20 wt%). With the increase of the thickness of the composite film, the maximum transmittance decreased significantly and when the thickness is above 20um, the maximum transmittance of PI/TiO2 composite films dropped below 1% and PI/TiO2 composite films were basically opaque. The addition of TiO2 did not significantly reduce the thermal and mechanical properties of the composite films. In summary, the doping of nano-TiO2 particles is the effective method to improve the shielding performance of polyimide film and to improve its whiteness value. PI/TiO2 composite film with 10 wt% TiO2 and thickness of 20 um or more is the best and most economical candidate.