Title: Transparent, High Glass-Transition Temperature, Shape Memory Hybrid Polyimides Based on Polyhedral Oligomeric Silsesquioxane

Author: Zhongxu Lan, Xueli Chen, Xiao Zhang, Chongyu Zhu, Yanlei Yu, Jia Wei *

Journal: Polymers, 2019, 11(6), 1058

Abstract:

Optically transparent polyimides with excellent thermal stability and shape memory effect have potential applications in optoelectronic devices and aerospace industries. A series of optically transparent shape memory polyimide hybrid films are synthesized from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2'-bis-(trifluoromethyl)biphenyl-4,4'-diamine (TFMB) with various polyhedral oligomeric silsesquioxane (POSS) contents and then subjected to thermal imidization. The hybrid films show good optical transparency (>80% at 400 nm and >95% at 500 nm) with cutoff wavelengths ranging from 318 to 336 nm. Following the incorporation of the inorganic POSS structure, the hybrid films exhibit excellent thermal stability with glass transition temperature (Tg) ranging from 351 to 372 ℃. The hybrid films possess the highest Tg compared with the previously-reported shape memory polymers. These findings show that POSS is successfully utilized to develop transparent polyimides with excellent thermal stability and shape memory effect.

Fulltext Link: https://www.mdpi.com/2073-4360/11/6/1058

In this study, we obtain a series of thermoset PI-POSS hybrid films with good transparency, excellent thermal stability and shape memory effect by copolymerizing various contents of polyhedral oligomeric silsesquioxane (POSS) with fluorinated monomers (6FDA/TFMB). Fluorine-contained diamine and dianhydride are used as monomers to render the PI films good transparency. Following the incorporation of the inorganic POSS structure, the hybrid films exhibit excellent thermal stability with glass transition temperature ranging from 351 to 372 °C, which shows POSS is successfully utilized to develop transparent polyimides with excellent thermal stability and shape memory effect.