Damping Property Of Polyurethane/Poly(Methylmetha Crylate-Butylmethacrylate-2-Hy Droxyethyl Methacrylate)Interpenetrating Polymer Networks

Vibration and noise control in transportation has extensive applications not only on the environment but also for the safe operation. High damping materials are more widely used to reduce significantly noise and vibration in high-speed train. The study of IPNs has received considerable interest because of their higher mechanical properties than their individual networks.Polyurethane/poly(methylacrylate-butylmethacrylate-2-Hydroxyethylmethacrylate) Interpenetrating polymernetworks (IPNs) were prepared by sequential polymerization. The method of DSC was used to analyze the phase separation. Also, the influences of temperature and frequency on damping properties of the IPN were addressed.The hardness of the IPN polymers is between17.2and84.61RHD at room temperature. When the PMMA content increases from20to60%by weight, the range of the glass transition temperature increases from89℃to94℃. The interaction of the polar groups contributes to intermolecular attraction which improve the friction between molecular chains and increase the range of glass transition temperature.The temperature influences on the dynamic mechanical properties of materials were studied in glass transition temperature range. The maximum value of tanδ is0.55and the temperature range is63℃. Actually, the dynamic properties of damping polymers rely on their macrostructure. Side groups of methyl acrylate greatly increase the friction among the molecules. Long ester groups in BMA increase intermolecular free volumes, which is more than their stereo-hindrance effect. The thermal aging of IPN largely decreases the properties at the temperature of120℃. While the properties increase at the beginning, and then decrease seriously with the increasing temperature.Special attention was paid to the influences of frequency on the dynamic mechanical properties of the materials. According to the experimental results, the tan δ values are all above0.3when the frequency is from10Hz to1300Hz. The widest frequency range is1019Hz. Due to polarity of polyurethane chemical structures, dispersion interactions, hydrogen bonding, the damping properties are improved.