Study On Synthesis And Properties Of Super Absorbent Polyer With Interpenetrating Network

Sodium Polyvinyl alcohol sulfate(SPS) was prepared through the sulfonation of the hydroxyl groups of Polyvinyl alcohol(PVA) using oil of vitriol as sulfonating agent. Partly netralized acrylic acid,starch and SPS were used as raw materials of solution polymerization to synthesize starch-g-acrylic acid superabsorbents interpenetrated with SPS(SA-IP-SPS),and N,N'-methylene bisacrylamide(NMBA) as crosslinker and ammonium persulfate(APS) as initiator.The infrared spectrum analysis of SPS showed there were relatively strong stretching vibration band and very strong bending vibration bands at 1131cm-1 and 617cm-1. Through comparing,it can be found the two absorption peak did not appear in PVA,and this result explained there was sulfonic group on molecular chains of SPS. Its esterification degree was measured and it was 74%~76%.In this paper,the polymerization conditions of SA-IP-SPS,including reaction temperature,the degree of neutralization and the dosage of starch,crosslinker,initiator and SPS were investigated respectively by ways of signal fator analysis experiments and optimized by orthogonal design experiment.The experiment results showed the optimal polymerization conditions were as follow: the dosage of starch, SPS,crosslinker,initiator , was 3.3%,8.0%,0.067%,0.27% respectively(taking the dosage of AA as cardinal number),and the reaction temperature was 70℃,and the degree of neutralization was 90%. Under the optimal conditions,the highest water absorbency and saline absorbency of the product were about 1784.27g/g and 128.69g/g respectively.The water absorbability of the products in different kinds of solution,under different temperature and repeating absorbability were discussed. The experiment results showed that inflated behavior could be explained by Flory'inflation theory. The water absorbability in electrolyte solution was less along with the anti-ions'charge for the same cation or anion.The absorbability in alcohol solution was more than that in electrolyte solution. The water absorbability in different solution containning N element reduced with the anion charge increasing, and the best absorbability has been received in pH=7.Under 200℃,the effect of temperature on absorbency was slight.Besides, repeating absorbability of product was good.The water retention in high-speed centrifugation conditions and in nature conditions for the products have been studied. The experiment results showed that the product exhibit excellent water retention in high-speed centrifugation conditions,and they losted absorbed water when they were prolonged in nature conditions.Water absorption rate and gel transition in organic solvent of SA-IP-SPS were also investigated. SA-IP-SPS is ionic SAP,so water absorption rate is relatively slow and reaching satuiated water adsorptive needs 5h.In the solvent mixture of water and acetone, SA-IP-SPS occurred gel transition and the volume reduced with increase of the acetone amount,which leaded to decrease of the water absorbability.The IR, TG-DSC and SEM indicated that SPS had been embedded in the polymeric network of polyacrylate through en-tanglement with polymeric chains.SA-IP-SPS was an novel superabsorbent with the interpenetrating network structure.And Thermal Stability of SA-IP-SPS was better than SA's.