Orientation Analysis of Polymer Chains in Optically Transparent Biopolyimides Having Rigid and Bending Backbones

Abstract

Optically transparent and heat-resistant polymer films are useful in the field of organic glasses usable for electric insulators for panels, windows, optical devices, etc. A series of biopolyimides having non-π-conjugated backbones prepared using a renewable diamine, 4,4'-diaminotruxillic acid dimethyl esters, and various dianhydride monomers were prepared and cast onto substrates to form transparent films with high heat resistances and good electric resistance. The second order orientation coefficients (P 200 ) of the biopolyimide films were evaluated by polarized attenuated total reflection Fouriertransform infrared spectroscopy, and the P 200 values for the CÀ N stretching vibrations at a wavenumber of 1365 cm À 1 displayed a good correlation with that for the aromatic CÀ C stretching at 1510 cm À 1 , regardless of the dianhydride structure. The in-plane/out-of-plane birefringence and coefficients of linear thermal expansion exhibited strong correlations with P 200 except for those of a few samples. Most of the biopolyimide films exhibited good transparencies with low birefringence and high electric resistance, which are applicable to flexible substrates with a low coefficient of thermal expansion for panel displays.

Advancements in Synthesis Strategies and Optoelectronic Applications of Bio-Based Photosensitive Polyimides

“…Saranyoo's research focuses on the development of biobased polyimides, which are synthesized from renewable diamine and various dianhydride monomers [97]. Te resulting materials form transparent flms that exhibit remarkable thermal and electrical resistances.…”