High Refractive Index and High Abbe Number Polymer Based on Norbornadiene

Optical polymers, as excellent potential candidates for inorganic materials, have great advantages in the development of high integration optical components with lightweight, easy processing, and tunable properties. This paper introduces a series of fresh sulfur-containing heterocyclic optical monomers with a high refractive index and a high Abbe number that were designed and synthesized by a one-pot Wittig reaction of norbornadiene, tri-n-butylphosphoniodithioformate (TBPD), and aldehydes. On this basis, high refractive index polymers (HRIPs) were synthesized from these monomers and polythiols via thiol-ene click reactions. The polymers possess good thermal stability (T-g > 107 degrees C and T-d5% > 200 degrees C) and mechanical properties (tensile strength >57 MPa), excellent visible light transmittance (>85%), a tunable high refractive index (n = 1.6055-1.6274), and an extremely high Abbe number (v > 59). Combining the ring structure of norbornadiene and the sulfur-containing heterocycle, the prepared HRIPs achieve a high balance between the refractive index and the Abbe number, which provides a new idea for the preparation of high refractive index and high Abbe number polymer materials.