Surface Modification Of Continuous Basalt Fiber And Study On Mechanical Properties Of Reinforced Nylon

With the increasing emphasis on environmental protection and sustainable development,fiber reinforced thermoplastic composites have gradually replaced thermosetting composites due to their recyclability.Fiber reinforced nylon has been well studied and applied to all aspects of life.Basalt fiber is a new type of inorganic environmentally-friendly fiber with highperformance.The continuous basalt fiber reinforced thermoplastic(nylon)composite material has the characteristics of good mechanical properties and recyclability,in line with the concept of green development and sustainable development.However,the reinforcing fibers commonly used are chopped fibers.And the interface between the basalt fiber and the nylon resin is poor.And the composite material with desirable mechanical properties cannot be obtained.In this paper,due to the problem that weak adhesion between basalt fiber and nylon interface and the effect of short-cut fiber reinforcing composites.The basalt fiber was modified with coupling agent/emulsion,and the preparation and mechanical properties of continuous fiber reinforced nylon(PA6)were studied.The composite materials with good interfacial properties and improved mechanical properties were obtained.The main research work is:Firstly,the surface of basalt fiber was modified by chemical surface coating with phenoxy emulsion and amide emulsion with silane coupling agent.It was found that when the concentration of amide emulsion was 8wt% and the concentration of silane coupling was 1.5wt%,the modification effect was the best.At this time,the surface of the fiber is covered with a uniform layer of modified layer,and the surface energy and polarity components are improved,and the interlaminar shear strength was also improved,indicating the interfacial adhesion between the modified basalt fiber and the PA6 matrix was significantly enhanced.Secondly,for the comprehensive comparison of the properties of basalt fiber and glass fiber reinforced thermoplastic composites,the basalt fiber reinforced PA6 mechanical properties was the main research content.Basalt fiber reinforced PP,glass fiber reinforced PA6 and PP were compared by the same time.The basic properties of two basalt fibers reinforced PA6,basalt fiber reinforced PP and two glass fibers reinforced PA6 and PP were tested and analyzed.Subsequently,continuous prepreg tapes were prepared with various fibers,and their tensile properties and porosity were tested and analyzed.It was found that the strength of various continuous fiber monofilaments satisfied the Weibull distribution and belongs to brittle fracture.The diameters of the three basalt fibers are all about 13?m,and the diameters of the two glass fibers are 15?m and 17?m,respectively,which are larger than the basalt fiber,but the fiber diameter distribution is relatively stable.In addition,the monofilament strength and fiber stability of the modified basalt fiber were improved.Both glass fiber reinforced prepreg tapes have higher tensile strength and lower porosity,but due to the excellent mechanical properties of basalt fiber,the tensile modulus of three basalt fiber reinforced prepreg belts were higher than that of the two types of glass fiber reinforced prepreg tape.The tensile strength and tensile modulus of the modified basalt fiber reinforced PA6 prepreg were increased by 5.2% and 7.2%,respectively,compared with those before modification.After modification,the porosity between the basalt fiber and the PA6 resin were also reduced.Finally,the continuous basalt fiber reinforced PA6 composite sheets using basalt fiber before and after modification were prepared by two methods of weaving and one-way laying.It was found that the modified continuous basalt fiber reinforced PA6 composites were significantly better than the unmodified ones in terms of tensile properties,bending properties,impact properties and interlaminar shear properties.At the same time,continuous basalt fiber reinforced PP composite sheet,continuous glass fiber reinforced PA6 composite sheet and continuous glass fiber reinforced PP composite sheet were prepared.The results show that the mechanical properties of the composite sheet which enhanced PA6 matrix were significantly better than those of the composite sheet which enhanced PP.In addition to the tensile properties of the unidirectional composite sheets,the mechanical properties of the glass fiber reinforced PA6 were better than those of the basalt fiber reinforced PA6,mainly due to the good combination of glass fiber and PA6.Basalt fiber reinforced PA6 composites have higher tensile strength and better resistance to deformation due to the excellent mechanical properties of basalt fibers in the unidirectional laying reinforcement mode.In the future research,if the basalt fiber and PA6 interface can be further improved,a continuous fiber reinforced thermoplastic composite material with excellent mechanical properties in all aspects will be obtained...