Preparation And Study Of Properties Of Reactive Compatibilization Water Swelling Nitrile Rubber

WSR exhibits excellent elastic and water-swelling properties, which consists of rubber matrix, water absorbent resin, additives, can further be used in sealing or caulking application. In order to overcome the defect that hydrophilic super water-absorbent resin (SAR) cannot disperse well in the rubber, for intrinsic differences between rubber and water absorbent resin and runs off from the rubber matrix easily. Nitrile rubber-g-Maleic anhydride (NBR-g-MAH), acting as reactive compatibilizer, were prepared to improve the incompatibility of them.NBR-g-MAH(s) and NBR-g-MAH(m), were prepared by solution and melt grafting method, certified the presence by The Fourier transform IR(FTIR) and Thermo-gravimetric(TG). The content of MAH grafted onto NBR-g-MAH is determined by measuring the acid concentration using titration. Meanwhile the influential factors on content of MAH of NBR-g-MAH were discussed. As for solution grafting, grafting degree increased with the MAH, Benzoyl peroxide (BPO) and temperature at a certain extent. But excessive MAH and BPO accelerated up the gelling of nitrile rubber. Grafted degree come to ultimate value 4.12% when MAH is 1.30g, BPO is 0.06g at 65? for solution grafting. While for melting grafting DCP is 1 phr, MAH comes to 7.5 phr, the grafting reached the maximum 2.41%. Therefore the grafted degree of NBR-g-MAH fabricated by solution was a little higher than melt solution.The mechanical properties were significantly improved with appropriate amount of NBR-g-MAH(s) or NBR-g-MAH(m). Once 8 phr NBR-g-MAH(s) added, tensile strength and elongation at break comes to 9.58MPa,1390.8% which increased by 31.4%,68.5% for specimens without NBR-g-MAH, respectively. As for 8 phr NBR-g-MAH(m) tensile strength and elongation at break comes to 8.55MPa,978.31% which increased by 17.28%, 18.52%.NBR-g-MAH acting as a reactive compatibilizer, improved water absorbent properties of water swelling nitrile rubber. Mass water absorption and mass loss (dry after swelling) rose with increasing amount of water absorbent resin. Maximum mass water absorption is 521.68%. Meanwhile water absorbent rate accelerated with increasing PEG6000. Maximum mass water absorption comes 338.51% and mass loss reaches 10.56% at 10 phr water absorbent resin and 8 phr PEG6000 without compatibilizer. The equilibrium swelling absorbency of WSR comes to 496.15% at distilled water, increased by 46.8% while weight loss at distilled water is 5.77% decreased by 45.9% for neat NBR when 8 phr NBR-g-MAH(s) was added. After 4 times absorbency-dry, the equilibrium swelling absorbency of remains 458.65%. It just takes 24h to reach the maximum water absorbency 446.10% and remains 436.32% for equilibriums at 80?. Immersed in 0.9% and 2.0% sodium chloride solution, equilibrium swelling absorbency of WSR comes to 139.53%, 110.58%, while weight loss is just 1.82%?1.14%, decreased by 580.7%,802.6% for WSR without NBR-g-MAH(s). As for NBR-g-MAH(m), WSR exhibited 497.70% for equilibrium swelling absorbency and 6.34% to mass loss if 8phr NBR-g-MAH(m) was put in. In contrast, NBR-g-MAH(s) outperforms NBR-g-MAH(m) at the compatibility for WSR.The scanning electron microscope of fractures of neat WSR and WSR with 8 phr NBR-g-MAH showed a clear enhancement for the dispersed of SAP and additives. Moreover, it improves the compatibility of CSP and NBR.