Abstract: A series of bipolymers and terpolymers bearing isopropyl p-styrenesulfonate group in the side chain were synthesized and their structures,f1-F1 curves and thermolysis properties were investigated.DSC data showed that with the increase of sulfonate unit in content,its thermo-decomposition temperature decreased from 170 ℃ to 120 ℃,while its thermo-decomposition energy increased from 20 kJ/mol to 30 kJ/mol.This low energy range indicated that the sulfonate group studied in this work should be attributed to ester groups of low decomposition energy for acid protection.Kinetics studies revealed that thermo-decomposition of the sulfonate group was an auto accelerated process,in which decomposition of the sulfonate group was accelerated by its corresponding acid released during the decomposition process.It was found that aqueous solubility of the copolymers was strongly dependent on content of the sulfonate group.After baking treatment,bipolymers containing 27% mol or more sulfonate group were highly soluble in neutral water,while terpolymers of 21% mol sulfonate group with another 28% mol acrylic acid as the third component became highly soluble in neutral water. This result indicated that addition of acrylic acid as third component to the copolymer could effectively reduced the content of sulfonate group necessary for achieving excellent aqueous solubility after thermo-decomposition,leading to pronounced changes in affinity by less thermal energy and ultimately to high sensitivity.

Key words: sulfonate containing resin, thermolysis, affinity change