Preparation and properties of heat curable blended methylfluorosilicone rubber

Abstract

AbstractHeat curable blended methylfluorosilicone rubber (MFSR) was prepared by combination of methylsilicone rubber (MSR) and fluorosilicone rubber (FSR). 2,5‐Bis(tert‐butylperoxy)‐2,5‐dimethylhexane (DBPMH) was chosen as a curing agent. Poly(methylsiloxane‐co‐fluorosiloxane) with low molecular weight was used as an interfacial agent. Curing characteristics, mechanical properties, low temperature performance, and hot oil resistance of blended MFSR was studied in details. The results showed that MSR and FSR could reach co‐vulcanization by DBPMH in blended MFSR. Higher FSR content could improve the scorch safety, lower the rate of curing reaction, and lead to the poor processability of blended MFSR. An increase of FSR content also improved the hot oil resistance of blended MFSR. Interfacial agent could limit the phase separation of MSR and FSR, make the blended system more thermodynamically stable and elevate the mechanical properties of blended MFSR. Differential scanning calorimetry (DSC) measurements revealed that increasing MSR content lowered the glass transition temperature (Tg) and improved the low‐temperature flexibility of blended MFSR when MSR was no more than 15%. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers