Preparation Of Superabsorbent NBR And Study On Its Reinforcing Mechanism

Water Swelling Rubber(WSR)is a new type of functional polymer material,which has received extensive attention since its introduction in the late 1970 s.WSR is based on the introduction of hydrophilic substances in the matrix(rubber),while ensuring its own flexibility and mechanical properties almost unchanged,but also have some water absorption.In this paper,NBR was used as the matrix,sodium polyacrylate(PAANa)as the water-absorbing component,and the water-swelling rubber was prepared by physical blending method.The water-absorbing additive polyethylene glycol(PEG-6000),While adding reinforcing agent carbon black,white carbon black,calcium sulfate whisker,polyurethane prepolymer to improve the physical and mechanical properties of water-swelling rubber,through the rotorless vulcanizing analyzer,rubber processing analyzer,universal tensile testing machine and scanning The rheological properties,rheological properties,mechanical properties,water absorption properties and compatibility of the water-swelling rubber were analyzed by SEM and SEM.At the same time,FTIR and TG were used to analyze the precipitates,and Raman images were used to analyze the water absorption process before and after the reinforcement of water-absorbing expanded rubber.The results were as follows:(1)With the increase of sodium polyacrylate content,the physical and mechanical properties of water-swelling rubber will decrease,the water-swelling property will increase,and the mass loss rate will increase.Sodium polyacrylate has a poor compatibility with nitrile butadiene rubber,and a large amount of water absorbing resin is precipitated in the form of gel during water absorption.With the increase of water absorbing resin content,"warping" occurs after water absorption of WSR.The particle size of sodium polyacrylate is reduced and the overall performance of WSR is improved.The addition of water-absorbing additivePEG-6000 helps to enhance the water absorption of WSR but has a negative effect on the physical and mechanical properties.(2)From the perspective of the filler system,when the carbon black / white carbon synergistic reinforcement,with the increase of the proportion of carbon black,physical and mechanical properties significantly increased,while the water swelling significantly decreased,and when the proportion of silica increased,The mechanical strength is not as good as carbon black,but the water absorption is better.When fully reinforced with silica,the water swelling rate can reach 93.57%.When the ratio of carbon black / silica is 30/20,WSR shows better comprehensive properties,water swelling rate of 54.78%,tensile strength of13.75 MPa and mass loss rate of 3.6%.(3)The addition of calcium sulfate whiskers to carbon black / silica fume enhances the overall performance of the WSR while whiskers with aspect ratios provide access to water molecules to enhance water absorption Expansion rate.Through the silane coupling agent KH570,11-100 whisker surface treatment,the treated whisker reinforcement WSR is better,especially the 11-100 treatment,the tensile strength reaches 15.115 MPa,the water swelling coefficient is 77% The rate of mass loss is 3.54%.(4)Polyurethane prepolymer as a compatibilizer to improve the dispersion of silica in rubber to improve the physical and mechanical properties of water-swelling rubber,while indirectly improving the dispersion of sodium polyacrylate in the rubber matrix,slow down The water absorption rate,but increased swelling of the water-swelling rubber final swelling,reducing the rate of mass loss.(5)The strength of unreinforced rubber sample is mainly affected by vulcanization,and its strength is relatively low.Raman images show that the absorbent resin is easy to precipitate from the sample without reinforcement,but after reinforcing with carbon black,the absorbent resin is easy to precipitate from the sample in the same time.The absorbent resin is simply swelling and does not precipitate.