Studies On Water Swelling Rubber Made By Natural Rubber Latex Grafted With Acrylate And Acrylamide

Water swelling rubber(WSR) is a new functional polymer material, it has water swelling competence. This paper use graft copolymer modification method prepared it.It was made by (NH4)2S2O8/K2S2O8 with Na2S2O3 oxidation-reduction initiate system, acrylate[AA(Na)] and acrylamide(AM) grafting natural rubber latex. The effect of initiator, reaction temperature, dosage of monomer and cross-linking agent on quantity graft rate, grafting efficiency, rate of water adsorption, water swelling capacity and repeat water adsorption property of the product was studied. The structure and properties of natural rubber(NR), graft copolymer and homopolymer were characterized by FTIR, DSC, TG and DTG. At last, the mechanical properties of vulcanization products were tested.The results have been showed that the effect of reaction temperature, dosage of initiator and monomer have obvious influence on water adsorption capacity, graft rate and efficiency. The NR-g-AA(Na) graft copolymer optimum preparation condition is: 40℃reaction temperature, (NH4)2S2O8/Na2S2O3 initiator system, the amount of initiator is 0.7%～0.9%(occupying rubber and monomer's quality percent, the same to undersides), the water swelling multiplying power get to 826.0g/g by NR:AA(Na)=1:2.5; the condign technical methods of AM grafting onto NR was attained: reaction temperature is 35℃, K2S2O8/Na2S2O3 initiator system, the amount of initiator is 0.5%, cross-linking agent is 1.75×10-4mol. Acrylate/acrylamide definitely grafted onto NR, which was proved by FTIR; TG and DTG proved that the NR-g-AA(Na) and NR-g-AM graft copolymer had the better heat resistance than NR; DSC show the WSR after water swelling is contained the most water is nature water. The result of mechanical property showed that: the better comprehensive mechanical properties of the vulcanized graft copolymer were obtained when the dosage of sulfur is 6.6g(graft copolymer is 200g).