Effect of interfacial sacrificial bonds on the vulcanization and mechanical properties of styrene butadiene rubber/talcum powder composites

Talcum powder (Talc) contains large amounts of silica; however, its poor surface compatibility with diene rubber makes it difficult to develop its application in styrene-butadiene rubber (SBR). Herein, a method to enhance the compatibility of Talc with SBR via interfacial sacrificial bonds of 4-vinylpyridine and Mg2+/Zn2+ is proposed. Poly(isoprene-co-4-vinylpyridine) copolymers, designated PIPVP-10 and PIPVP-20, were synthesized via reversible addition-fragmentation chain transfer polymerization. PM1-Talc and PM2-Talc were obtained by spraying PIPVP-10 and PIPVP-20 solutions onto the Talc surface, followed by drying. During thermal vulcanization, the double bonds in the copolymers can be grafted directly onto the rubber skeleton. The vulcanization rates of the SBR/PM1-Talc and SBR/PM2-Talc complexes were accelerated by 65% and 77%, respectively, compared with that of SBR/Talc. Simultaneously, the interfacial interaction between SBR and Talc is enhanced owing to the formation of metal-ligand bonds between pyridine and Mg2+/Zn2+. As a result, the tensile strengths of SBR/PM1-Talc and SBR/PM2-Talc are 5.8 and 7.9 MPa, 65% and 127% higher than that of SBR/Talc (3.5 MPa). Poly(isoprene-4-vinylpyridine) accelerates curing of SBR/Talc compounds. SBR/PM1-Talc and SBR/PM2-Talc compounds are cured at times 65% and 77% faster than the SBR/Talc compounds, respectively. An effective method for preparing high-performance nanocomposites is provided by constructing interfacial sacrificial bonds of pyridine and Mg2+/Zn2+. The tensile strengths of SBR/PM1-Talc (5.8 MPa) and SBR/PM2-Talc (7.9 MPa) composites increase by 65.3% and 127% compared with SBR/Talc composites (3.5 MPa) at 50 phr filler parts. image