Synthesis and characterization of water swellable natural rubber vulcanizates

► Cassava starch-g-polyacrylamide SAP was made by reactive batch processing. ► SAP/bentonite, SAPC, gave high water absorbency of 606 g g−1. ► WSNR was prepared by blending high-ammonia NR or ENR or MNR with SAPC, PEO and/or TMPTMA. ► WSNRs with 10 phr PEO and TMPTMA gave higher mechanical strength and water absorbency. ► Increasing PEO loadings more than 10 phr gave higher absorbency with lower mechanical strength.