| Aramid fiber is a new type of high-tech synthetic fiber with excellent properties such as ultra-high strength,high modulus and high temperature resistance,and light weight.For example,its strength,modulus and toughness are 5～6,2～3 and 2 times that of steel wire respectively,and its weight is only about 1/5 of that of steel wire.In view of these advantages,AF was widely used in rubber,textile,aviation and other industries.To improve the performance of rubber,filler reinforcement is a universal and efficient solution in the rubber industry,which has also formed a broad consensus in the industry.However,the compatibility between fillers and rubber is poor,and pretreatment modification of fillers was often required in the preparation of the filler/rubber composites.Inspired by the internal structure of radial tires,the skeleton network structure has important contributions to the performance of the rubber.Based on this background,in this paper,AF long fibers were filled into the rubber system to construct a long-fiber skeleton network structure to strengthen the rubber material.Based on this method,AF/NR(natural rubber)composites and AF/NR/SBR(styrene-butadiene rubber)composites were prepared respectively,and the influence mechanism of AF and the ratio of blend rubber on the mechanical and fatigue properties of rubber composite was revealed.The main contents are as follows:(1)Different modification methods were used to modify the AF,and the modified AF was characterized by Fourier transform infrared spectroscopy,thermogravimetric,X-ray diffraction,and scanning electron microscope to select the best modified AF.The modified AF was filled into the NR system to construct the skeleton network structure to explore the mechanical properties of the AF/NR composites,and to reveal the interfacial interaction between the AF and the NR.The results showed that KH550-UV dual modification AF has the best effect,and KH550-UV-AF/NR composite has the best mechanical properties,And has the highest residual tear strength and tear strength preservation rate.(2)KH550-UV-AF/NR/SBR composites were prepared,and the effect of the ratio of rubber combination on the mechanical properties of rubber composites was explored.The results show that with the increase of the content of SBR in the composite material,the mechanical properties gradually decrease.However,the tensile strength and elongation at break of KH550-UV-AF/NR/SBR composites decreased after hot air aging,but the tensile strength of KH550-UV-AF/NR/SBR composites after thermal oxygen aging decreased.The tensile strength first increased and then decreased with the increase of SBR,and reached the maximum value at the ratio of 60NR/40 SBR.(3)Using the matrix of 60NR/40 SBR ratio,the effect of aramid fiber modification on the fatigue properties of rubber composites was initially explored.The results show that: after UV irradiation,KH550 secondary modified aramid filaments can form good interfacial compatibility with the combined rubber matrix,and the interaction between the two can be greatly improved.The interface effect of KH550-UV-AF/60NR/40 SBR composite material is strong,and the fatigue life is significantly improved,and the high-strength fatigue cycle requires very high interfacial compatibility between the reinforcement and the matrix. |
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