| Epoxy resin(Epoxy)as a kind of composite material resin matrix,has good adhesion,low curing shrinkage,excellent insulation performance,simple molding process,strong mechanical properties and other excellent properties.Epoxy resin is one of the most important thermosetting resin,widely used in the fields of aerospace,aviation,electronics electrical,adhesives,paint and so on,which has the broad application prospect.Due to the crosslinking curing of epoxy resin,the impact resistance of epoxy resin becomes worse,so it is attracting the attention of many researchers in order to improve the impact toughness of epoxy resin.We solve the problem of impact resistance of epoxy resin composite material,through the design and synthesis of rigid and soft liquid crystal polymer chain structure(LCP).The LCP toughened epoxy resin and glass fiber(GF),polyester fiber(PET),glass fiber / polyester fiber were prepared by hand paste.The impact resistance of Epoxy/GF/LCP,Epoxy/PET/LCP and Epoxy/GF/PET/LCP composites was studied,and the effect of hybrid fibers on the composites was studied.Design and synthesis of LCP with toughening effect,and the results of FT-IR show that the synthesized product has the characteristic group.The DSC results show that the 149? is the smectic phase transition of LCP,and the transition temperature from solid state to liquid crystalline state is 177?.The results of TGA showed that LCP had good thermal stability.The properties of Epoxy/GF/LCP composites research shows that:(1)the addition of LCP can significantly improve the impact resistance performance of epoxy resin composites reinforced with glass fiber,adding 5% LCP can make the impact strength of the composite increased from 25kJ/m2 to 33.84kJ/m2,the impact strength increased by 35.4%;(2)the addition of LCP reduces the dynamic storage modulus of composites and glass transition temperature,but it can improve the composites crosslinking degree.The properties of Epoxy/PET/LCP composites research shows that:(1)polyester fiber reinforced epoxy resin composites with the addition of LCP have increased the impact strength,the amount of 0%LCP is 7.11kJ/m2 and the amount of 5%LCP is 13.385kJ/m2,increased by 88.3%;(2)TGA results showed that LCP can increase the decomposition temperature of composites.The thermal stability is improved;(3)the addition of LCP can reduce the dynamic storage modulus of the composites,the composites' tan delta increased first and then decreased.The properties of Epoxy/GF/PET/LCP composites research shows that:(1)the impact strength of hybrid fiber composites increased with the addition of LCP,the impact strength increased by 20.9%;(2)compared with Epoxy/PET/LCP composites,the impact strength of Epoxy/GF/PET/LCP composites increased by 36.5%;(3)DMA results showed that the addition of LCP reduced the dynamic storage modulus and loss modulus,the summit of loss modulus becomes wider,glass transition temperature improved,the addition of LCP improved the compatibility of the composites fiber layer,.(4)the thermal stability of the composites decreased with the addition of LCP.In conclusion,the addition of LCP significantly improved impact properties of epoxy resin based fiber reinforced composites;The hybrid structure of the glass fiber / polyester fiber improves the impact resistance of the polyester fiber composites.The addition of LCP improves the interfacial bonding properties of the hybrid fiber composites. |
PDF Full Text Request