Cationically photopolymerizable epoxy-functionalized thermoplastic polysilsesquioxanes: synthesis and properties

Abstract

A series of epoxy-functionalized inorganic–organic hybrid ladder-like structured polysilsesquioxanes were synthesized in one-batch via a base-catalyzed co-solvent system. Two types of epoxy functionalities were examined: aliphatic and cycloaliphatic. Obtained polymeric epoxy-functionalized ladder-like polysilsesquioxanes were cationically photopolymerized under UV irradiation over glass and plastic substrates. Obtained cross-linked films were examined as hardcoating materials as their thermal, optical, mechanical, and barrier properties were studied. These materials showed superior thermal properties (T_d > 400 °C), high optical transparency (>95%), high pencil hardness (4H–9H), low dielectric constant (3.0–3.6), and good barrier properties (WVTR < 10¹ g m⁻² day⁻¹, OTR < 10² g m⁻² day⁻¹).