Interphase bonding in organic–inorganic hybrid materials using aminophenyltrimethoxysilane

Abstract

Several types of silica and titania-aramid hybrid materials were prepared using a sol–gel process. The aramid chains were prepared by the reaction of a mixture of m- and p-phenylene diamines and terephthaloyl chloride in dimethylacetamide. Addition of different amounts of tetraethoxysilane and tetrapropylorthotitanate in the polymer solution, and their subsequent hydrolysis-condensation yielded silica and titania networks, respectively, in the aramid matrix. The chemical bonding between the organic and inorganic phases was achieved by end-capping the aramid chains with aminophenyltrimethoxysilane. In-situ hydrolysis/condensation of tetraethoxysilane or tetrapropylorthotitanate along with that of aminophenyl-trimethoxysilane was carried out to produce silica and titania networks chemically bonded to aramid chains. Thin transparent and tough films containing up to 20 wt% of metal oxides were prepared. The storage and the loss moduli as a function of temperature were measured using dynamic mechanical thermal analysis. A greater shift in the α-relaxation associated with the glass transition temperature ( T g ) was observed in case of chemically bonded ceramers as compared to the unbonded and has been explained in term of greater interaction between the organic and inorganic phases.