The Research On Preparation And Flame Retardant Properties Of Ethylene Propylene Rubber/phenyl Silicone Rubber Blends

Performance requirements of rubber turned more and more critical with the rapid development of modern industry,which could not be satisfied by any single rubber.Therefore,it was a trend that blending two or more kinds of rubbers to obtain hybrid rubber materials with excellent comprehensive properties.In this research,ethylene propylene rubber(EPR)and phenyl silicone rubber(MPVQ)were blended with each other and a series of composites were obtained.Effects of varied mass ratio on vulcanization,mechanical properties,processing properties,thermal aging performance,fire resistance as well as compatibility between the two phases were detected.After that,hydroxide(MH)and aluminum hydroxide(ATH)were introduced as fire retardant,whose influences on the comprehensive properties of the blends were explored.Finally,MH and AIH were modified by stearic acid and 3-Methacryloxypropyltrimethoxysilane(KH570),respectively.Effects of modified metal hydroxide on fire resistance,vulcanization,mechanical and thermal properties of the blends were investigated.The details were as follows:(1)EPR/MPVQ hybrid rubber materials were prepared by using peroxide 2,5 as vulcanizing agent and the optimal formula was 2phr under 170℃.Vulcanization rate became faster and torque decreased with the increasing mass ratio of MPVQ.Excessive MPVQ declined mechanical properties of the blends as well as storage modulus and loss modulus.There was only one glass transition temperature(Tg)of EPR/MPVQ blends from results of DMTA spectrogram,which confirmed well compatibility between the two phases.It also could be observed from SEM images that the blends exhibited smooth fracture surface with few defects,which was due to the addition of KH570 and accorded with the DMTA results.In a word,incorporation of MPVQ enhanced fire resistance and ageing-resistant performance of the hybrid rubber materials.(2)MH and ATH were applied as fire retardant for EPR/MPVQ blending materials.Research results showed that vulcanization torque of the blends increased while mechanical properties decreased as the amount of MH and ATH enhanced.Meanwhile,thermal stability of the blends improved as well as ageing-resistant performance promoted slightly.Incorporation of MH and ATH improved fire resistance of the blends obviously especially while the dosage was higher than 50%:compared with the reference,the limiting oxygen index LOI went up from 27.6 to 39.2 and 38.6,the total heat released declined from 62.31 MJ/m~2 to 34.46MJ/m~2 and 35.17MJ/m~2 and the char yield increased from 38.0%to 59.7%and 59.8%,respectively.(3)MH and ATH were modified by stearic acid and KH570,respectively.Results of FTIR revealed that both SA and KH570 were successfully coated onto the surface of MH and ATH.Contact angle test showed that the hydrophobicity of the MH and ALH was remarkably improved:the contact angle of MH increased from 15° to 49°and 57° and ATH increased from 8° to 46° and 55°,respectively.Vulcanization torque and mechanical strength of the blends increased significantly while dosage of modified MH and ATH were 20phr.Besides incorporation of modified MH and ATH improved the thermal stability,aging resistance properties as well as fire retardant of as-prepared blends,the fire retardant effect is close to the blends with addition of 50 phr unmodified MH and ATH.