Study On The Properties Of Ultra-high Molecular Weight Polyethylene Fiber Modified And Reinforced Polymer Matrix Composites

Owing to its excellent thermo-physical properties such as high specific strength and modulus,high fatigue strength,fiber reinforced polymers(FRPs)have been widely used in automobile,aerospace,sports and civil engineering industries.With the rapid development of fiber-reinforced polymers,Ultrahigh molecular weight polyethylene(UHMWPE)fiber reinforced epoxy resin composites have been used in many fields due to their excellent properties.UHMWPE fiber has excellent mechanical properties such as high strength,rigidity,chemical resistance,low density and good mechanical properties at low temperatures.However,the weak interfacial adhesion with epoxy resin matrix due to fiber chemical inert limits its application.In this study,UHMWPE fiber was modified by tannic acid(TA)-Na+ complex to increase interfacial adhesion with epoxy resin.Firstly,UHMWPE fiber was modified by tannic acid(TA)-Na+ complex.Fourier transformed infrared spectroscopy(ATR-FTIR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)confirmed that the surface of modified fiber was coated by a uniform and dense TA-Na+ complex.The water contact angle(CA)measurement showed that hydrophilicity of fiber has a significant improvement.The results of monofilament breaking strength test showed that the mechanical property of the fibers has no change after modified.When the concentration of TA was 2 mg/mL,the reaction time was 6 h and the pH of solution was 8,the interfacial shear strength(IFSS)of the TA-UHMWPE fiber./epoxy resin was improved by 43.34%compared with pristine UHMWPE fiber.Transverse fiber bundle tension(TFBT)test and fiber reinforced epoxy resin composites test showed that the properties of composites prepared by TA-UHMWPE were obviously improved.TA-UHMWPE fibers were secondly modified by cyanuric chloride and phenylenediamine.The results of FTIR,XPS and SEM showed that phenylenediamine was successfully grafted on the surface of UHMWPE fibers and the amine functional groups were introduced at the same time.In addition,the surface roughness of second functionalization modified fibers increased significantly.When the concentration of phenylenediamine was 2 mg/mL,the grafting times reached 3 times,the interface shear strength of UHMEPE fiber and epoxy resin was maximum value(1.397 MPa),increasing by 89.98%compared with pristine fiber.Compared with the pristine UHMWPE fibers reinforced epoxy resin composites,the properties of the composite prepared by modified fibers have been further improved.