The blending of polymethyltrifluoropropylsilicone-modified acrylonitrile–butadiene rubber (MNBR) and fluorosilicon rubber (FSR) at 70 : 30 ratio was investigated. The grafting of mercapto-functionalized polymethyltrifluoropropylsilicone onto acrylonitrile-butadiene rubber (NBR) by thiol-ene reaction was carried out with 2,2′-azobisisobutyronitrile as initiator in a Haake torque rheometer. The rheological properties of NBR grafting obtained at varying dosages of polymethyltrifluoropropylsilicone in a Haake torque rheometer were studied using torque curves. Grafting reaction was confirmed by ¹H nuclear magnetic resonance and energy-dispersive X-ray spectroscopy. Results of scanning electron microscopy and dynamic mechanical analysis showed better compatibility of MNBR/FSR blend than NBR/FSR reference blend. Meanwhile, the macro-mechanical properties of the blend significantly improved. The tensile strength and tear strength of MNBR/FSR blend were improved to 14.34 MPa and 44.94 KN/m, respectively, which were 2.92 MPa and 13.03 KN/m higher than those of NBR/FSR reference blend. The low-temperature brittleness of the blend was improved to −57°C, an increase of −6°C compared with that of NBR. These results indicated that MNBR/FSR blend at 70 : 30 ratio had improved compatibility because of the grafting chains that acted as interfacial agents. The low-temperature resistance of the blend was also enhanced. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42328.

Random copolymer poly(dimethylsiloxane-co-diethylsiloxane) is synthesized through anionic ring-opening polymerization. Two-component room-temperature vulcanization (RTV-2) silicone rubbers with excellent low-temperature resistance are prepared using the poly(dimethylsiloxane-co-diethylsiloxane) and hydrosilicone. The mechanical properties of RTV-2 rubbers with different formulas are investigated, and the optimized formula is obtained. Moreover, the curing kinetic analysis of RTV-2 silicone rubber with optimized formula is conducted using in situ Fourier transform infrared spectroscopy. The obtained kinetic equations are used to forecast the tack-free time at different temperatures. The results converge with the actually measured tack-free time. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42656.

In this study, the blending system of natural rubber (NR) and silicone rubber (SR) at 70/30 ratio was investigated. Two kinds of graft polymers, polysiloxane-g-octane with different grafted ratios (polymers A, B, and C) and polysiloxane-g-(3,7-dimethyl-6-octylene) (polymer D), were designed and synthesized to serve as compatibilizers. Dynamic mechanical analysis and scanning electron microscopy analyses showed that the compatibilizers improved the compatibility between NR and SR, and resulted in improved mechanical properties. For example, the tensile strength of the blends with compatibilizer C was 11.7 MPa, whereas that of the blends without any compatibilizer was only 7.86 MPa. The larger the grafted ratios, the better the compatibilization effect of the graft polymer. The differences in compatibilization effects between non-reactive (polysiloxane-g-octane) and reactive [polysiloxane-g-(3,7-dimethyl-6-octylene)] compatibilizers can be attributed to their different chemical compositions. The crosslink density obtained from solid-state nuclear magnetic resonance indicated that the reactive compatibilizer (polymer D) engaged in the crosslink reaction through the active vinyl at the side chains, which effectively inhibited the decreasing trend of the crosslink density caused by the addition of compatibilizers. POLYM. ENG. SCI., 54:355–363, 2014. © 2013 Society of Plastics Engineers

The curing retardation and mechanism of high-temperature vulcanizing silicone rubber (HTV SR) filled with superconductive carbon black (CB) BP2000 have been studied experimentally and theoretically. The results show that both rubber matrix and CBs have influences on the peroxide curing of rubber/CBs composites. The retardation does not appear as prominent in nature rubber (NR)/BP2000 composites as in HTV SR/BP2000 composites. Quantum chemistry calculations reveal that the curing retardation of HTV SR/BP2000 composite should not be attributed to the curing reaction dynamics of HTV SR molecules. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses of CBs show that the effect of radical scavenging of phenol-OH groups existing on BP2000 surface is the main reason for the retardation in the peroxide curing reaction. The effect is found to be more effective in HTV SR/BP2000 composite and thus retards its curing. The curing retardation does not appear in silicone rubber (SR)/BP2000 composites vulcanized by condensation reaction, and the resulting vulcanizates have excellent physical properties. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.