Studies on Ceramic-Polymer Composites (II)

Abstract

In the recent works the procedure of monomer impregnation and in situ polymerization has improved the physical and mechanical properties of porous materials such as wood, concrete and gypsum.The purpose of this work was to apply these technique above to fired clay bodies (base materials), which prepared by firing the bodies consisting of 63% Nopporo clay, 27% sand and 10% chamotte at temperature ranging from 800°C to 1, 000°C. This study was directed toward the correlation between polymethyl methacrylate (PMMA)-impregnation treatments for the fired bodies and their properties of bending strength, abrasion resistance, water absorption, freezethaw durability and chemical resistance. Its procedure was that MMA monomer containing 0.1-1.0% benzoyl peroxide (BPO) was impregnated into the fired specimen and polymerized by heating at 70-90°C in a closed vessel after wrapping in aluminum foil. At above 50vol% of monomer loading, polymerization was almost completely performed. It was observed in scanning electron photomicrographs that the impregnated polymer gradually deposited to the innerface of pore with increasing polymer. The physical and mechanical properties of PMMA-impregnated specimen were more improved with increasing Pp which means volume percent of pore filled with polymer. The most remarkable improvements were obtained from the specimens impregnated with MMA under vacuum, and the Pp was about 75vol%. Polymer efficiency for bending strength strongly increased when Pp reached to above 50-60vol%. The maximum value of the increase of bending strength per a gram of polymer was obtained using the specimen fired at 1, 100°C. Abrasion resistance was also improved from 120-140mg for unimpregnated specimens to 40-50mg for the impregnated ones. Water absorption decreased to less than 1.0wt% above 50-60vol% of Pp, and the impregnated specimens were not failed even after freeze-thaw test of 300 cycles.It comes to the conclusion that polymer impregnation procedure was of great advantage to the improvement of the fired clay bodies (i.e. stone wares) of which the ceramic raw materials are relatively abounding in resources in our country.