Interphase bonding in organic-inorganic hybrid materials using aminophenyltrimethoxysilane

Several types of silica and titania-aramid hybrid materials were prepared u sing 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 dime thylacetamide. Addition of different amounts of tetraethoxysilane and tetra propylorthotitanate in the polymer solution, and their subsequent hydrolysi s-condensation yielded silica and titania networks, respectively. in the ar amid matrix. The chemical bonding between the organic and inorganic phases was achieved by end-capping the aramid chains with aminophenyltrimethoxysil ane. In-situ hydrolysis/condensation of tetraethoxysilane or tetrapropylort hotitanate 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 we re prepared. The storage and the loss moduli as a function of temperature w ere measured using dynamic mechanical thermal analysis. A greater shift in the alpha-relaxation associated with the glass transition temperature (T-g) was observed in case of chemically bonded ceramers as compared to the unbo nded and has been explained in term of greater interaction between the orga nic and inorganic phases. (C) 1999 Elsevier Science Ltd. All rights reserve d.