Silsesquioxanes functionalized with one or two side-chain amino groups as coinitiators of camphorquinone in photoinitiated polymerization of methacrylate monomers

Abstract

Organotrialkoxysilanes (APS-PGE2) and (DAS-PGE3) were synthesized by reacting 1 mole of 3-(aminopropyl)triethoxysilane (APS) with 2 mole of phenylglycidylether (PGE) or 1 mole of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (DAS) with 3 mole of PGE respectively. Polyhedral oligomeric silsesquioxanes functionalized with bulky amino groups (ASSQO) were prepared by hydrolytic condensation of both APS-PGE2 and DAS-PGE3 using formic acid a a catalyst. The polymerization of methacrylate resins photoinitiated by camphorquinone (CQ) in combination with the synthesized ASSQO was investigated. The progress of monomer conversion vs. irradiation time showed that the CQ/ASSQO pair constitutes an efficient photoinitiator system because a fast reaction and high conversion result from 60 s irradiation at 600 mW/cm2. The mechanical behaviour of these systems in flexural and compressive tests was highly dependent on the structure of the ASSQO.