A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by p...A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by potassium persulfate(K2S2O8),with N,N′-methylene-bis-acrylamide(NMBA)was used as crosslinking agent .The relationships between the water absorption of the resin and the amounts of initiator,crosslinker,AA and AM as well as reaction temperature,reaction time were studied.This superabsorbent polymer was capable of absorbing distilled water up to 720 times and 0.9%NaCl solution 110 times in its saturated state at ambient temperature when the mass ratio of KGM to monomer was 1∶4,the amount of initiator was 0.35%(based on the weight of monomer),the neutralization degree of monomer was 80 %,the reaction temperature was 55～65℃,and the amount of crosslinker was 0.075%(based on the weight of monomer).Experimental results indicated that the introduction of nonionic group would be suitable for improving absorption ability and salt-resistance of the resulting hydrogels.展开更多
The grafting of maleic anhydride onto a granular polypropylene (PP) using supercritical CO-2 as a solvent and swelling agent was studied to prepare granular PP-g-MAH polymers.The factors affecting the graft degree of ...The grafting of maleic anhydride onto a granular polypropylene (PP) using supercritical CO-2 as a solvent and swelling agent was studied to prepare granular PP-g-MAH polymers.The factors affecting the graft degree of PP,such as the monomer content,initiator content,reaction temperature and reaction pressure were discussed.The maximum graft degree of PP with MAH in supercritical CO-2 medium was 5^23% under the optimal reaction conditions at 125℃ and 15 MPa for 5 h.By using the supercritical CO-2 technique the operation of grafting reaction and separation of products became simple and easy to deal with.The formation of PP-g-MAH grafting copolymer was evidenced by FTIR measurements.An absorption peak at 1720^6 cm -1 assigned to the stretching vibration of carbonyl groups was observed.DSC results indicated that the grafting gave almost no influence of T-g values,but may increase the crystallinity of PP.展开更多
文摘A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by potassium persulfate(K2S2O8),with N,N′-methylene-bis-acrylamide(NMBA)was used as crosslinking agent .The relationships between the water absorption of the resin and the amounts of initiator,crosslinker,AA and AM as well as reaction temperature,reaction time were studied.This superabsorbent polymer was capable of absorbing distilled water up to 720 times and 0.9%NaCl solution 110 times in its saturated state at ambient temperature when the mass ratio of KGM to monomer was 1∶4,the amount of initiator was 0.35%(based on the weight of monomer),the neutralization degree of monomer was 80 %,the reaction temperature was 55～65℃,and the amount of crosslinker was 0.075%(based on the weight of monomer).Experimental results indicated that the introduction of nonionic group would be suitable for improving absorption ability and salt-resistance of the resulting hydrogels.
文摘The grafting of maleic anhydride onto a granular polypropylene (PP) using supercritical CO-2 as a solvent and swelling agent was studied to prepare granular PP-g-MAH polymers.The factors affecting the graft degree of PP,such as the monomer content,initiator content,reaction temperature and reaction pressure were discussed.The maximum graft degree of PP with MAH in supercritical CO-2 medium was 5^23% under the optimal reaction conditions at 125℃ and 15 MPa for 5 h.By using the supercritical CO-2 technique the operation of grafting reaction and separation of products became simple and easy to deal with.The formation of PP-g-MAH grafting copolymer was evidenced by FTIR measurements.An absorption peak at 1720^6 cm -1 assigned to the stretching vibration of carbonyl groups was observed.DSC results indicated that the grafting gave almost no influence of T-g values,but may increase the crystallinity of PP.
