Preparation And Properties Of Functional Particle Modified Polyurethane Damping Composite

Due to the progress of science,damping materials,which can bring people a comfortable and healthy production and living environment,have become a new pursuit of people and have been widely used in people’s production and living.The diversity of damping materials application urgently requires us to develop materials with high damping and wide temperature range.The functionalized graphene not only has a large specific surface area and strong interfacial friction between the polymer,but also the covalent bonding generated by the reaction between the functional groups on the surface of the functionalized graphene and the polymer makes it strongly interact with the polymer,restricting the polymer molecules.The chain motion increases the energy loss during the strain process of the composite material,thereby enhancing the damping performance of the composite material.In this thesis,graphene sheets and functionalized graphene with different functional groups were selected as functional particles,and functional particle-modified polyurethane/ethyl methacrylate interpenetrating network polymer was successfully prepared.The effects of different functionalized graphene on the morphology,phase structure,damping properties and thermal properties of polyurethane-based composites were explored.To further explore the different changes in the damping properties of the composites caused by the changes in the internal phase structure of the composites caused by various functionalized graphene.The results of the study are as follows:Graphene-modified polyurethane/ethyl methacrylate interpenetrating network polymer(GNP-PU/PEMA IPN)was successfully prepared by adding different amounts of graphene sheets(GNP).Studies have shown that the graphene sheets without surface modification are not uniformly dispersed in the composites,resulting in a decrease in the tanδ of GNPPU/PEMA composites compared with pure PU/PEMA,although with the increase of GNP content.The tanδ of the composite increased continuously,but still did not exceed the tanδof pure PU/PEMA(0.48).The addition of GNP did not change the thermal degradation mechanism of the composite but improved the thermal stability of the composite.Compared with pure PU/PEMA,the 20% weight loss temperature of 0.7% GNP-PU/PEMA increased from 337℃to 341.7℃.Graphene oxide(GO)modified polyurethane/ethyl methacrylate interpenetrating network polymer(GO-PU/PEMA IPN)was prepared by using different amounts of GO.The results showed that the loss factor of GO-PU/PEMA increased first and then decreased with the increase of GO content.When 0.3%GO was added,the maximum tanδ reached0.53,which was 10.4% higher than that of pure PU/PEMA.Because some soft and hard segments of polyurethane are covalently bonded by GO,the molecular chain movement in the composite is restricted.With the increase of GO content,the limiting effect is enhanced,and the damping temperature domain of the composite moves to high temperature continuously.GO addition destroys the regularity of the composite system,and the thermal stability of GO-PU/PEMA decreases.The study of the thesis carboxylated graphene-modified polyurethane/ethyl methacrylate interpenetrating network polymer(CFGNP-PU/PEMA IPN)found that unlike GO,the carboxyl groups on the surface of CFGNP only covalently interact with the polyurethane soft segment during the reaction process.Bonding,with the increase of CFGNP content,the degree of phase separation in the composites intensified,and the loss factor-temperature curve appeared a new damping peak at higher temperature(5-50℃).The loss factor of CFGNP-PU/PEMA increased first and then decreased with the increase of CFGNP content,and the covalent bonding between CFGNP and the polymer matrix had obvious effect on enhancing the interfacial friction.After adding 0.5% CFGNP,the tanδvalue of the composites increased by 12.5% compared with pure PU/PEMA,and the tanδvalue increased from 0.48 to 0.54,which was comparable to the effect of GO.The research on the prepared aminated graphene-modified polyurethane/ethyl methacrylate interpenetrating network polymer(NGNP-PU/PEMA IPN)showed that the amino groups on the surface of NGNP were covalently bonded to the polyurethane hard segment,and the covalent bond was covalently bonded to the polyurethane.New hydrogen bonds were generated between the hard segments,and under the combined action of the two,the tanδ value of NGNP-PU/PEMA was the largest compared with the composite materials in the previous chapters.After adding 0.7% NGNP,the tanδ value of the composites increased by 22.7% compared with pure PU/PEMA,and the tanδ value increased from 0.48 to 0.58.Compared with GO/CFGNP-PU/PEMA,the maximum value of tanδ was increased by 9.4% and 7.4%,respectively.The damping temperature domain of NGNP-PU/PEMA shows a similar law to that of GO-PU/PEMA,and it moves towards high temperature with the increase of NGNP.