Sulfonated copolymers with SO3H and COOH groups for the hydrolysis of polysaccharides

The well-defined sulfonated block copolymer poly(acrylic acid)-block-poly(styrene sulfonic acid) (PAA-b-PSSH) and the random copolymer poly(acrylic acid)-random-poly(styrene sulfonic acid) (PAA-r-PSSH) were prepared by direct thermolysis of the precursor copolymers poly(tert-butyl acrylate)-block-poly(neopentyl styrenesulfonate) (PtBA-b-PNSS) and poly(tert-butyl acrylate)random-poly(neopentyl styrenesulfonate) (PtBA-r-PNSS), which were synthesized by living radical polymerization (MWD < 1.10) catalyzed with CuBr. GPC, EA, H-1 NMR and FT-IR spectra were employed to characterize the structure of the synthesized acid polymers. The catalytic performance of the acid polymers was evaluated for the hydrolysis of starch and cellulose in aqueous solution under microwave irradiation. With the same effective acid concentration, the random copolymer PAA-r-PSSH gave the highest glucose yield among the prepared catalysts. It is believed that the good results were caused by the synergic effect of the SO3H and COOH groups in the polymer chain. In addition, microwave irradiation led to better glucose yields in the hydrolysis of polysaccharides than the conventional heating method with acid polymers as catalysts.