Preparation And Properties Of Water-Swelling Rubber Based On SAR/NBR Blending

Water-swellable rubber(WSR)is a novel functional material with excellent properties of elastic and swelling. Due to the efficiency, convenience, stuff saving and low-price, WSR hold good applicable prospect and huge market demand. Preparation methods of WSR are mainly blending and grafting. Generally, regards for quality, process and cost, blending, which can be industrialized widely, is the most popular. The elastic, mechanical property of matrix material and compatibility between SAR and matrix material have vital influence on comprehensive performance. Currently, blending bring serious problems, such as bad compatibility, poor salt-resistant, low swelling rate and so on, which will restrict the application area of WSR.In the paper, the synthesis process of SAR, hydrophobic modification of SAR, preparation of WSR and its mechanical and swelling properties were investigated.In the thesis, acrylic acid(AA), 2-acrylamide-2-methylpropanesulfonic acid(AMPS)and diallyldimethylammonium chloride(DMDAAC)as functional monomers, potassium persulfate as initiator, Poly(ethylene glycol) diacrylate(PEGDA(Mw = 258))as cross-linking agent, a new amphoteric ionic super absorbent resin(SAR)based on inverse suspension copolymerization was synthesised successful. The effects of oil/water ratio, cross-linking agent, initiator, neutralization, comonomer ratio on the swelling property of SAR were studied. It showed that the preferable conditions were oil/water ratio was 4, WPEGDA = 0.55%, WKPS = 0.8%, neutralization of AA was 80%, WAA/WAMPS/WDMDAAC = 67.4: 29: 3.6, and the temperature of copolymerization was 70℃. The absorbent capability of SAR reaches up to 1170 g/g in distilled water and 405 g/g in tap water. The FT-IR, SEM and TG analysis respectively showed that the SAR was a sphere copolymer at micron scale and have excellent thermal stability.For the purpose of improvement of compatibility between SAR and NBR, hydrophobic interpenetrating polymer network(IPN)modification of SAR was researched in the experiments. BA, AA, initiator and cross-linking agent were mixed with SAR, and polymerized in situ after swelling adequately, modified SAR(m-SAR)was prepared. The impacts of modified content on swelling compatibility were studied. The structure and thermal stability were investigated by FT-IR and DSC respectively.WSR was prepared by NBR, m-SAR, white carbon black(WCB)and all other addition agents blended. The effects of content of modified constituents and SAR on the mechanical and swelling capabilities were studied separately. Furthermore, the microcosmic structure was studied by SEM, thermal stability were investigated by DSC too. The results showed that after modification, the mass loss of WSR was lower, compatibility was improved to some degree. Besides, the WSR swelled quickly and could achieve equilibrium in much short time. The swelling capability of WSR at various environmental temperatures and in different salt solutions was investigated. The test result indicated that the swelling capabilities of WSR at the equilibrium lowered and the mass loss decreased with the rising of the environmental temperatures. similarly, the equilibrium swelling capabilities of WSR decreased with the concentration and valency of cation rised.