Preparation And Properties Of Polyurethane (urea) Composites Based On Fiber Reinforcement

Polyurethane elastomer has excellent comprehensive properties because of its unique molecular structure of soft and hard segments.Polyurethane elastomer has been widely used because of its excellent features which integratethe advantages of rubber and plastics.However,the heat resistance,flame retardancy,dielectric properties and thermal conductivity of polyurethane are still far fromsatisfactory.The addition of fiber to polyurethane elastomer can improve the mechanical and heat resistance effectively,the addition of glass hollow microspheres can improve the dielectric and thermal conductivity,and the addition of flame retardant can effectively improve the oxygen index.Therefore,the research of polyurethane composites has a very broad prospect.In this paper,polyurethane(urea)composites were prepared by one-step method.The properties of rigid polyurethane elastomer base materials and the effects of fibers on polyurethane elastomer properties were studied.Besides,we explored the effect of glass hollow microspheres on fiber / polyurethane composites and flame retardants on polyurethane elastomers.The study found that:(1)When the ratio of polyether polyol MN450 and PPG210 is 1/1,The properties of the material are better.Change the type of cross-linker found that the cross-linker TEOA the best comprehensive performance.When the index of isocyanate is 0.95,the comprehensive performance is better.By changing the type and proportion of isocyanate,it is found that when PM200 is used alone,the comprehensive performance is better.(2)It is found that the mechanical properties and heat resistance of aramid fiber improvewith the increase of AF content;when changing the type of glass fiber felt,it is found that the mechanical properties,heat resistance and flame retardant properties of glass fiber felt are improved,and the comprehensive effect of 450# glass fiber felt is the best.When changing the type of coupling agent,it is found that the coupling agent could enhance the mechanical properties and heat resistance of the material,among which the comprehensive properties KH580 the coupling agent are better;When the KH580 dosage of coupling agent was changed,it was found that the comprehensive performance was obviously improved with the increase of KH580 dosage,but the performance improvement was not obvious when further increase the dosage.When the KH580 dosage was 6,the effect was the best.(3)When changing the type of glass hollow microspheres,it is found that the thermal conductivity and resistivity of the GS20 materials are better,GS60 the mechanical properties and heat resistance of the materials are better,and the comprehensive properties of the GS40 are excellent.With the increase of GS40,the mechanical and thermal properties and dielectric properties become better.GS40 the dosage of 6 phr,the comprehensive effect is the best.(4)When changing the type of flame retardant,it is found that the mechanical properties of expanded graphite EG are better,the flame retardancy of dimethyl phosphonate DMMP and EG is better,and the heat resistance of ammonium polyphosphate is better.When changing the dosage of flame retardant,it is found that the mechanical properties and heat resistance decrease with the increase of the dosage,the flame retardancy is obviously enhanced,and the comprehensive properties are the best when the dosage is 10 phr;When the ratio of EG and DMMP was selected,it was found that the oxygen index increased firstly and then decreased.When the EG/DMMP ratio was 1/1,the flame retardant effect was the most excellent and the comprehensive effect was the most excellent.