Preparation of UV-curable acryl resin for high refractive index based on 1,5-bis(2-acryloylenethyl)-3,4-ethylenedithiothiophene

A highly refractive and transparent photo-curable polymer resin containing 3,4-ethylenedithiothiophene units in the polymer chain has been developed. The polymer derived from 1,5-bis(2-acryloylenethyl)-3,4-ethylenedithiothiophene (BASEDTT) was prepared by photopolymerization using diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide as a photo initiator under UV irradiation. The polymer exhibited high thermal properties, including a glass transition temperature (>134°C), and a 5% weight loss temperature of 308°C under nitrogen. The polymer also showed good optical properties, such as high optical transparency in the visible region, a low birefringence of 0.0043 and a high refractive index of 1.6444 at 637 nm.