Inorganic-organic hybrid and composite resin materials using carboxylate-alumoxanes as functionalized cross-linking agents

Chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) ar e used as the inorganic component of a new class of inorganic-organic hybri d materials. Lysine- or p-hydroxybenzoic acid-derivatized alumoxanes are re adily prepared from the reaction of boehmite, [Al(O)(OH)](n), with the appr opriate carboxylic acid. The peripheral organic hydroxides and amines of th ese carboxylate-alumoxanes either react directly with epoxide resins, such as the diglycidyl ether of bisphenol A (DER 332), to form a hybrid material , or in the presence of an organic resin and hardener system to form a comp osite material. SEM with associated EDX analysis, and AFM shows a uniform d istribution of alumina nanoparticles within the resin matrix. Solid-state C -13 and Al-27 NMR spectroscopy demonstrates that the carboxylate-alumoxane nanoparticles are chemically bound to the epoxide resin matrix. The model c ompounds PhOCH2CH(OH)CB2OPh (1), PhOCH2CH(OH)(CH2NHPr)-Pr-n (2), and PhOCH2 CB(OH)(CH2NHPr)-Pr-i (3) have been prepared to assist in the NMR characteri zation of the hybrid materials. The properties and cure times of the alumox ane hybrid and composite materials are distinct from both the pure resins a nd! from a physical blend of the resins with traditional ceramic fillers. A significant increase in thermal stability and tensile strength is observed for both the hybrid and composite resin systems. In addition, both carbon fiber and carbon/Kevlar matting have been successfully incorporated into th e hybrid resin systems resulting in further property improvements.