Research On The Properties Of Ultra-high Molecular Weight Polyethylene Fiber Reinforced Epoxy Resin Composites

Fiber reinforced composites are widely used in many fields such as aerospace,military defense and sporting goods.Ultrahigh molecular weight polyethylene?UHMWPE?fiber reinforced composites occupy a leading position in military defence,because of excellent properties such as high specific strength and high specific modulus.However,composites are tended to degumm as well as resin matrix cracking,due to fibers smooth surface and inactive group,which result poor interfacial adhesion with resin matrix,serve restrict its widespread.In this paper,"bridging"effect,intermolecular force and chemical bonding effect are formed at the interface to improve the interfacial strength between fiber and resin matrix,thus improving the overall performance of fiber reinforced composites.In order to increase the interfacial adhesion strenghth,UHMWPE fibers are modified with tannic acid and the epoxy resin is blended with tannic acid.The mechanical properties of epoxy resin are improved,and a large number of hydroxyl groups are introduced into the resin matrix.The tannic acid on the fiber surface and the tannic acid in the resin matrix form a"bridge"effect at the interface.When the loading of tannic acid reaches 1 wt%,the interfacial shear strength between the fibes and the resin matrix reaches a maximum of 2.22 MPa,which is 64.8%higher than the original,which also improve the mechanical properties of the fiber reinforced composites.Furtherly,tannic acid and polyethyleneimine functionalized MWCNTs modifies epoxy resin.Amino and hydroxyl functional groups are successfully introduced into the resin matrix.Ascribe to fibers surface hydroxyl groups interact with hydroxyl groups and amino groups exisit in resin matrix,the strong hydrogen bonds are formed in the interface,thus improve the interfacial Van der Waals force between fibers and resin matrix.When the loading capacity of M-MWCNTs is 0.1 wt%in the resin,the interface shear strength reaches the maximum of 2.68 MPa,which is 67.8%higher than the original,and the mechanical properties of the fiber reinforced composites are significantly improved.UHMWPE fibers are oxidized using K₂S₂O₈/Ag NO₃ system to produce a large amount of carboxyl groups on the fiber surface.After the esterification reaction,epoxy groups are formed on the surface of the carboxylated fiber.When amine curing agents are used,the fibers and the resin matrix are tightly bonded via chemical bonding.Surface epoxy groups content of fibers are altered by different reaction time,when reaction 16 h,as-fibers exhibit the best interfacial shear strength,reaches 3.16MPa,which is 98.1%higher than that of UHMWPE fibers,significantly improve the properties of fiber reinforced composites.