Preparation And Studies On Damping Materials Of Semi-IPN Based On IIR

Damping materials are finding numerous applications in the aircraft, automobile, and machinery industries for both the reduction of unwanted noise and the prevention of vibrational fatigue failure. Polymer material is widely used for damping material because its particular structure which can lose heat easily. Due to their viscoelastic nature, polymers have the ability to absorb the mechanical energy and transform it into heat. Whereas, common polymer material's temperature range with high tanδis very thin. Moreover, being a useful damping material, it must have a high tanδwith large temperature range. Three methods have been used to broaden the viscoelastic transition region:(1) the addition of plasticizer;(2) block copolymerization or blending various polymers together;(3) creating interpenetrating polymer network(IPN).Butyl rubber (isobutylene-isoprene copolymer, IIR) have a high barrier to internal rotation which is consist of a linear C-C main chain with two methyl substituents. During the temper ture region of relaxation transition of a polymer from the glassy state into the highly elastic one,there are not only a a- transition but also a liquid-liquid transition(T_II ). The tanδpeak of butyl rubber is very broad (covering a temperature range of-60 to 10℃) ,but above 10℃, the damping function almost lose . Therefore, how to broaden the damping functional region become the research direction of high performance butyl rubber. This paper is aimed at preparing broad damping temperature and high tan 8 materials based on IIR. Blending various polymers and interpenetrating polymer network are studied separatedly. Dynamically cured blends of butyl rubber and polyvinylchloride were prepared by melt mixing. The effect of various component ratios, curing systems,fillers on the compression set of IIR/PVC blends is investigated. Then, I choose butyl rubber,the copolymer of styene, methyl methacrylate and butyl methacrylate to synthesize interpenetrating polymer network damping materials. Some conclusions were obtained as follows: (1) The influence of polymerization time, mass ratio of IIR/P(St-MMA), crosslinking agent(DVB) on damping properties of IIR/ P(St-MMA) IPN materials was investigated by FTIR and dynamic mechanical analysis (DMA) .The results showed that the IPN material with mass ratio of IIR/P(St-MMA) =1:2 and 1% crosslinking agent(mass ratio) by solution polymerization can get a good damping property.(2) Considering that IIR and St and MMA revealed great discrepancy in the glass transition , IIR/P(St-MMA-BMA) IPN was synthesized with the addition of BMA by multicomponent cohesion technology. The result shows that the Tg peak of the St-MMA-BMA phase appears to shift slightly towards lower temperatures and increase significantly in intensity.