Polyurethane-based Interpenetrating Polymer Network Damping Materials

According to the damping mechanism of interpenetrating polymer network(IPN), polyurethane/vinyl ester resin(PU/VER) IPN damping materials with high damping properties were prepared based on the idea of molecular devise. Meanwhile PU/modified VER IPN damping materials in which chemical cross-linking structure didn't exist between the two network were prepared by sealing the secondary hydroxyl groups of epoxy acrylate(AAEP) in the VER. The infrared spectrum (IR) was adopted to study the influence of the reagents used to seal the hydroxyl groups, reaction temperature, feed molar ratio and the treatment condition on the sealing effect of hydroxyl groups of AAEP. The optimal technical condition was determined. The damping and mechanical properties of PU/VER IPN and PU/modified VER IPN were compared. The results showed that because the hydroxyl groups in VER were sealed and no chemical cross-linked structure existed between the two networks, the tensile strength of modified IPN decreased, while its break elongation increased. The effect damping temperature range of modified IPN was broadened and its damping performance was improved.In order to improve the damping properties of IPN, BT/IPNå'ŒPZT/IPN composites were prepared by the composites of barium titanate (BT), lead zirconate titanate(PZT) and PU/VER IPN. The optimal condition of polarization was determined and damping performance of IPN composites was improved because of polarization. The results of SEM showed that piezoelectric powder dispersed in polymer matrix uniformly and there were less holes and defections. The influence of the types and contents of piezoelectric ceramic on mechanical property, damping performance, relative dielectric constant and piezoelectric constant (d33) was studied. The results showed that generally damping performance was improved, tensile strength and break elongation decreased, elastic modulus increased, dielectric and piezoelectric constant increased with the increase of piezoelectric ceramic content. The optimal content of piezoelectric powder was determined at 75%(wt%). Although BT piezoelectric powder aggregated in the local region, sizes of BT piezoelectric powder are smaller which made the mechanical property, damping performance, dielectric and piezoelectric constant of BT/IPN composite better than those of PZT/IPN composite...