Preparation And Studies On Damping Materials Of PMPS/PMAc SIN

In this paper, the damping materials of simultaneous interpenetrating polymer networks (SIN) based on polysiloxane (PMPS) and polymethacrylate (PMAc) were prepared by using several types of PMPS oligomer and MAc monomers. The reaction mechanism, reaction kinetics, damping properties and the morphology of the PMPS/PMAc SIN were investigated.Different type of a , u -dihydroxide polysiloxane oligomer were synthesized by hydrolyzing methyphenyldiethoxylsilane and then copolymeration with polydimethysiloxane (PDMS), and the structures of the resulting polysiloxane oligomer were characterized by Gel Permeation Chromatography (GPC), fourier transform infrared (FTIR) and hydrogen nuclear magnetic resonance (1H-NMR). The molecule weight of PMPS, the content of hydroxide groups and phenyl groups were calculated.The reaction kinetic were investigated by tracing the reaction using FTIR, and the reaction mechanism of PMPS/PMAc SIN were studied. Several factors influencing reaction kinetics of SIN such as temperature, composition, catalyst concentration, initiator concentration and molecule weight of PMPS oligomer have been examed. It is concluded that the PMPS oligomer reaction follows the second order kinetic mechanism and the MAc reaction follows the first order kineticmechanism. When more high temperature and more catalyst of PMPS oligomer are used, the both reaction to form two networks are accelerated. While more initiator and cosslinkers are employed, the reaction of forming the networks are speeduped, but the reaction of other networks are restrained.Polymer materials consititute useful damping properties near their glass transition temperature (Tg) of the SIN. The damping behavior of the SIN were examined by dynamic mechanical analyzer (DMA) and differential scanning calorimetry (DSC). The results show that the damping ability is varied with the change of composition, compatibility, content and crosslinkers. The excellent damping materials in the papers are PMPS/PEMA SIN, which have the range of tan 8 max from 0.47 to 1.4, and damping functional temperature range with tan 8 >0.3 is 180~80C, TA is 70-87, and LA is 1.2~9.8GPa C.The morphology and structure of PMPS/PMAc SIN were characteried by atomic force microscope (AFM). It shows that PMPS-6/PEMA SIN containing 5% crosslinkers is monophase dispersion with large phase domains, while PMPS-6/PEMA SIN containing 9% crosslinker exhibits dualphase continuous morphology with smaller phase domains since the more crosslinks limits the domain size. Because of better compatibility, PMPS-8/PBMA SIN and PMPS-9/PEMA SIN display a dualphase continuous morphology.