Synthesis and characterization of aromatic poly(phosphonate)s, poly(thiophosphonate)s, and poly(selenophosphonate)s for high refractive index

Abstract

Highly refractive poly(phosphonate)s (BPOP), poly(thiophosphonate)s (BPTP), and poly(selenophosphonate)s (BPSP) with aromatic backbones were prepared by the polycondensation of phosphonic dichlorides and diols. The polymers have high thermal properties including high thermal properties (T-d5% > 400 degrees C), glass transition temperature (T-g = 76 similar to 157 degrees C), and high optical properties such as transparency at 400 nm of over 80% for films of ca. 10 mu m thickness, and a refractive index in the range of 1.633-1.675. In particular, BPSP exhibited a high refractive index (1.675) with low birefringence (0.0025) due to the heavy atom effect of selenium.