Hydrophobic Modification And Application Of High-strength And High-modulus Polyacrylonitrile Fiber

Polyacrylonitrile?PAN?fiber has high strength,stable chemical properties and good compatibility with asphalt.It can be used as the reinforcement of asphalt concrete to improve the high temperature deformation resistance and high temperature cracking resistance of asphalt mixture pavement.However,the dispersion of conventional polyacrylonitrile fibers in the asphalt system is poor,and the direct mixing of polyacrylonitrile fibers in the asphalt matrix is prone to tangle,which affects the mechanical properties of asphalt composites.Therefore,improving the dispersion of polyacrylonitrile fiber in asphalt matrix is the key to improve the mechanical properties of fiber reinforced asphalt composites.A novel water-borne epoxy resin?PAERK?was prepared by using phosphoric acid and epoxy resin E20.Through the discussion of reaction time,reaction temperature and reaction feed ratio,the optimum synthesis process of waterborne epoxy resin was determined by taking into account the factors of epoxy value,conversion rate,water solubility and particle size.Then,polyacrylonitrile hydrophobic modifier?PAERKF?was prepared by compounding water-based epoxy resin with fluorine-containing anionic surfactant?FP-6812?,etc.,and fp-6812,graphene oxide?GO?,etc.,to produce highly hydrophobic polyacrylonitrile modifier?GO/PAERKF?.Through to the dosing raio of reaction time,reaction temperature,reaction,comprehensive consideration,water-soluble epoxy value,conversion,particle size and other factors,and ultimately determine the best synthesis technology of waterborne epoxy resin is:to E20 phosphoric acid and epoxy resin as raw material,acetone and water as the solvent,feeding ratio of n?E20?:n?H₃PO₄?=1:2.2,the reaction temperature is 70?,reaction time is 4 h.Developed by use of modifier on the PAN fiber surface treatment and application performance of modified agents was studied,and modified polyacrylonitrile fiber surface morphology,dispersion,contact Angle and other performance tests show that the best modifier using emulsion concentration was 0.6%,the best PAERKF fluoride was 0.15%,the optimum modification of cladding is 5.0 mg/g,the best content of graphene oxide 0.06%,after PAERKF shi coating modification of PAN fiber and water contact Angle is 146.94°,dispersion coefficient in the epoxy resin matrix of?=0.89;The optimum GO/PAERKF content was 0.06%.The contact Angle between GO/PAERKF coated PAN fiber and water was up to 151.21°,and the dispersion coefficient in the epoxy matrix was up to 0.94.Finally,PAN fiber reinforced asphalt composite was prepared by mixing PAN fiber modified by two kinds of modifiers and non-surface modified with no.70 road petroleum asphalt as matrix.The mechanical properties of asphalt composites were tested by universal testing machine.Results show that the obtained with PAERKF PAN fiber asphalt composite bending strength increased by 34.98%,the compression strength increased by 37.29%,obtained with the GO/PAERKF PAN fiber asphalt composite bending strength increased by 37.53%,the compression strength increased by 49.46%,use the GO to enhance modifier processing of fiber bending strength and compression strength of the asphalt composites increase,respectively,show the two kinds of modified agent of fiber asphalt,the mechanical properties of composite materials are got improved significantly,the GO enhanced modifier modified effect is more outstanding.