Study On Polyurethanes And Its Damping Properties Modified By Interpenetrating Network Polymers

The vibration and noise problem affect the equipment normal operation,shorten the life,reduce the accuracy of equipment,reduce the working efficiency and cut down the production efficiency.The vibration damping material can effectively improve the vibration and noise problem.Among the polymer damping materials,polyurethane(PU)has a good wear resistance and high elasticity,etc.It can obtain an ideal damping property in required temperatures.However,there are still some disadvantages of polyurethane,such as insufficient strength,unstable damping performance in high temperature range,insufficient water resistance and solvent resistance.In this paper,polyurethane and epoxy resin with high modulus,high adhesion and low shrinkage,chemical resistance to corrosion was used to form interpenetrating network polymer(IPN),which can improve the damping property and the corrosion resistance and mechanical properties of polyurethane.Furthermore,the novel polyurethane curing agent was prepared through copolymerization by bisphenol fluorene containing large volume fluorene structure with two nitrogens innovatively,which can improve the damping capacity of polyurethane material at higher temperature.Finally,the coating formulation was designed through orthogonal experiments based on the resin which was screened in the early stages and the damping coating with good damping property was explored initially.The research results are as follows:(1)Based on the polyurethane polymer,the interpenetrating network polymer formed with epoxy resin.The damping properties,thermodynamic properties,mechanical strength and bonding strength of the material increased to a certain extent.In terms of damping properties of the material,the results of dynamic mechanical analysis(DMA)analysis indicate that the interpenetrating polymer network performed better damping properties when a ratio of resin polyurethane/epoxy was 7:3.(2)The novel polyurethane curing agent with special structure of diazepin fluorene was prepared by copolymerization reaction.There are higher glass transition temperature,wider damping temperature range and higher temperature as the polyurethane materials cured by novel curing agent.With the analysis of bisphenol-diazafluorene-modified polyurethane/epoxy interpenetrating polymer network,the novel curing agent improves the adhesion and mechanical properties of the coating,in addition,the interpenetrating network polymer showed better mechanical and thermodynamic properties.While there is not obvious decline and rise in damping factor at the moderate temperature range after the interpenetrating network polymer was formed.(3)The coating formulation with larger damping temperature and higher damping factor was obtained by designing the orthogonal experimental based on the above bisphenol-diazafluorene-modified polyurethane/epoxy interpenetrating polymer network.Furthermore,combining the adhesion and combustion behavior analysis,the simulation of the marine corrosion analysis and electrochemical test and analysis of coating before and after immersion was carried out.The proportion of coating showed the best properties when the mica powder was 1250 mesh,the ratio of barite and flame retardant was 1:7 and the PVC was 0.28.