Kwanruethai Boonsong, Manus Seadan, and Natinee Lopattananon

pp. 491 - 499

Abstract

A rubbery ionomer of zinc salt of sulfonated natural rubbers (Zn-SNR) was synthesized and used as a new compatibilizer for the blends of natural rubber (NR) and chlorosulfonated polyethylene (CSM). Epoxidized natural rubber (ENR) was also used for the preparation of NR/CSM blends. The effect of ionomer concentration on melt viscosity of the 50/50 (%wt/wt) NR/CSM blends at different constant shear rates was characterized. It was found that the incorporation of ionomer increased shear viscosity of the blends, indicating an increase in interfacial interaction between the NR and CSM. The maximum shear viscosity was observed when the ionomer of 10% by weight of NR was added into the blends. The tensile, tear, oil resistant properties and morphology of the various 20/80 NR/CSM blends with and without the Zn-SNR and ENR at the 10% wt of NR were examined. The 100% modulus, tensile strength, tear strength and oil resistance of the compatibilized blends improved over those of the uncompatibilized blends. The blends compatibilized with the Zn-SNR showed higher levels of improvement in modulus, tensile and tear strength than those of ENR. The tensile strength of 20/80 blends with the Zn-SNR and ENR compatibilizers increased by 38 and 30% over the corresponding neat blends. Furthermore, the addition of ionomer and ENR resulted in decreased domain of dispersed NR phase size and improved interfacial adhesion between the NR and
CSM, indicating enhanced blend compatibility. These results suggest that the Zn-SNR is a new effective compatibilizer for NR and CSM blends.