Preparation And Properties Of High Damping Polyborosiloxane Composites

The accuracy,stability and service life of equipment were affected seriously by generally problems of shock and vibration in modern industrial society.Therefore,some excellent damping materials are needed to reduce the damage caused by vibration and impact.In this paper,a high damping polyborosiloxane(PBS-Gel)was prepared with boric acid(BA)and hydroxyl silicone oil as raw materials.The basic properties of PBS-Gel were investigated by infrared spectroscopy,thermo mechanical analysis and thermal weight loss analysis.The viscosity of hydroxy silicone oil,the reaction temperature and the amount of boric acid were gradually optimized according to the experimental results.The experimental results showed that when the viscosity of the hydroxyl silicone oil at 500cSt,the mole ratio of B:Si at 1:10 and the reaction temperature at 120?,PBS-Gel damping materials exhibited the best comprehensive performance with 2.97 maximum loss factor,110? damping temperature range of tan?>0.3,and 152? the initial decomposition temperature(T5).In order to further expanded the damping temperature range of materials and improve the mechanical properties of materials,PBS-Gel and methyl vinyl silicone rubber(VMQ),chlorobutyl rubbrer(CIIR),hindered phenol AO-80 and multi walled carbon nanotubes(MWCNTs)were gradually combined.The effect of the filling amount of each materials on the properties of the composites was studied by thermo mechanical analysis,thermal weight loss analysis and mechanical analysis.The experimental results showed that when the mass percentage of PBS-Gel:VMQ:CIIR:AO-80:MWCNTs with 24.5025:8.1675:26.73:39.6:1,the synthesized PBS-Gel/VMQ/CIIR/AO-80/MWCNTs damping composites had the best comprehensive performance.The maximum loss factor of the composite was 1.09,the damping temperature range of tan?>0.6 was 158?,the initial decomposition temperature(Ts)was up to 315?,and the tensile strength was 0.83MPa.The composite exhibited excellent self healing property.The tensile strength of the composite can be restored to 44.5%after a day of repair at room temperature,and the recovery rate of the fractured surface after coating is 71.1%.At the same time,a new mechanism of "secondary bonds" fracture healing is proposed on the basis of the existing research and the high damping and self healing properties of the composites.