Water absorption and mechanical properties of water-swellable natural rubber

Abstract

Water-swellable rubber (WSR) was prepared by blending superabsorbent polymer (SAP) of crosslinked poly(acrylamide-co-sodium acrylate) with natural rubber in latex condition. The crosslinked poly(acrylamide-co-sodium acrylate) was first prepared by inverse suspension polymerization from acrylamide and sodium acrylate monomers with potassiumpersulfate initiator and N,N-methylenebisacrylamide crosslinker. The reaction was carried out at 60oC for 40 mins. Water absorption properties, such as the degree of water absorption, water absorption rate, degree of weight loss, and mechanicalproperties of WSR were then investigated. It was found that the degree of water absorption, water absorption rate, and thedegree of weight loss increased, while tensile strength and elongation at break decreased with increasing quantity of SAP inthe blends. However, the degree of water absorption, degree of weight loss, and elongation at break decreased, but tensilestrength increased with increasing quantity of the N-tert-butyl-2-benzothiazyl sulphenamide (TBBS) accelerator used in thecompounds formulation.