Preparation of 2,5-bis(methylallyl thioester)-thiadiazole with high refractive index and its coatings

New high refractive index monomer of 2,5-bis(methylallyl thioester)-thiadiazole (BMATETDZ) containing thioester and dithiazole was synthesized by a one-step condensation reaction with methyl acryloyl chloride and 2,5-dimercaptothiadiazole (DTD). N–N=(C), C=O, and C–S with high molar refraction groups were introduced into the structure of BMATETDZ. FTIR and 1H NMR were used to characterize the molecular structure of BMATETDZ. The refractive index of BMATETDZ was 1.661. The coatings of poly (2,5-bis(methylallyl thioester)-thiadiazole) (C-PBMATETDZ) on polyethylene terephthalate (PET) film were prepared by photopolymerization under UV irradiation. The C-PBMATETDZ coatings exhibited better comprehensive properties with high refractive index, high hardness, good adhesive force, excellent thermal stability, and high transparency in range of 200–900 nm.