A Containing Sulfonic Acid Ester Affinity Changes Of Synthetic Resin As The Imaging Medium

Isopropyl p-styrenesulfonate as monomer was synthesized and then copolymerized with methyl-methacrylate and methacrylic acid yielding a series of bipolymers and terpolymers with pendant group of styrene-sulfonate. The f1-F1 curves of copolymerization and the structures as well as thermolysis properties of the bipolymers and terpolymers 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 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 a self-accelerated process, in which decomposition of the sulfonate group was accelerated by its corresponding acid released during the decomposition. It was found that aqueous solubility of the copolymers was strongly dependent on content of the sulfonate group. After baked, 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, generating pronounced changes in affinity by less thermal energy and ultimately leading to high sensitivity. Preliminary studies were conducted on the possibility of applying these polymers as photo-sensitive imaging media. When used with PAG that generates hydrochloric acid, it was found that the hydrochloric acid generated by the PAG could not catalyze the thermolysis reaction of sulfonate units. On the contrary, sulfonic acid generated by the pendant sulfonate units during baking treatment could effectively catalyze the thermolysis reaction of the PAG. The reason is that the acidity of hydrochloric acid generated by the PAG is not strong enough to decompose the pendant sulfonate group. The results showed that PAG that is able to generate sulfonic acid or other stronger acid is necessary. Investigation was also done on the possibility of applying these polymers as thermo-sensitive imaging media to which an IR dye absorbing effectively at 830 nm was added. It was found that the bipolymers could match well with the IR dye. When exposure energy increased from 0 J/cm2 to 60 J/cm2, the surface contact angle of water free of ion to the sample film decrease from 35°to 12°(the surface contact angle to aluminum substrate with ground surface was 29°under the same measuring condition), showing that the exposed resin film was highly hydrophilic. It was also found that the terpolymers bearing methacrylic acid group as third component could not match with the IR dye. The absorption of the IR dye at 830 nm greatly decreased when terpolymer (containing 28% mol acrylic acid group) was added. This result was possibly due to some chemical reaction between methacrylic acid units and the IR dye...