Study On Blend Of Styrene Block Copolymers/Styrene-butadiene Rubber/polychloroprene

Styrene-butadiene rubber (SBR) and Polychloroprene (CR) have different polarities and their blend system is incompatible. In this paper, the effects of copolymer on the structure and character of SBR/CR have been exploited with three different copolymer, hydrogenated styrene-butadiene-styrene (SEBS) , styrene-butadiene block copolymer ( SBS ) , and styrene-isoprene block copolymer ( SIS ) , both theoretically and experimentally.The compatibility of SEBS, SBS and SIS to SBR/CR blend has been calculated by means of the dispersion coefficient λ in Harkin-Hobbs equation, with the λ 13<0 and λ, 31>0. Therefore, it is predicted that preferential distribution of SEBS, SBS, and SIS at the interfaces between SBR and CR plays a vital role in the compatibility of SBR/CR blend.The structures of SBR/CR blend have been studied by measuring vitrification poit and swelling capacity in the solvent of toluene. Results show that the compatibility, effective sulfurizing ratio, and chemical crosslinking density have been improved and exhibit best when the dosage of copolymer is 3-7.The mechanical properties of the SBR/CR blend have been delved by testing tensile strength and fracture elongation rate. Results show that tensile strength and stress-strain have been improved to a large extent, and the optimal dosage of copolymer is 3-7.