MICROWAVE CROSSLINKING OF POLYACRYLIC COMPOSITIONS CONTAlNING DEXTRIN AND THEIR APPLICATIONS AS MOLDING SANDS BINDERS

摘要

Three polymeric compositions being the mixtures of aqueous solutions of either polymerylic acid) or poly (sodium acrylate) or sodium salt of maleic acid/acrylic acid copolymer and dextrin (biopolymer) were elaborated. These compositions were crosslinked by microwave radiation and then the changes of chemical structures,caused by radiation,were evaluated by FT-IR method (Table 1-3,Fig. 1-4). Molding sands were prepared from high-silica sand as a matrix and non-crosslinked polymer compositions mentioned above as the binders. Molding sand hardening was carried out under microwave radiation. Compression strength (R_c~u) of hardened molding sands was investigated (Fig. 5). The molding sands containing poly(acrylic acid) + dextrin composition (composition I) show the best compression strength. The morphology of crosslinked material prepared with use of composition I was characterized by SEM method (Fig. 6).