Study On MC Nylon Composite Modification And The Preparation Of Gradient Pipe

In order to further enhance the MC nylon pipe strength and wear resistance, to meet the special requirements of waterway dredging, thermal power, metallurgy, mining and other industries, glass fiber, fly ash and nano-silica particles were selected to modify MC nylon. The effect of different enhancement surface pretreatment and their reinforced mechanisms were respectively investigated. Analysising combined with the material properties and the production cost, two kinds of enhancements synergistic reinforced nylon composite material was prepared and the nylon gradient composite tube was produced, which realize industrial production. The main conclusions are as follows:(1) The coupling surface pretreatment for enhancement is the key and prerequisite to composite modification MC nylon. Different enhancements needed different coupling agent with suitable dosage. The amido of silane coupling agent could attack carbonyl group of imido group to form a chemical bond matrix and reinforcement during polymerization reaction. Original fly ash grains were so crassitude and loose that machine milling activation and coupling surface pretreatment were needed before they were added into basement.(2) The shape of enhancement has an important influence to strengthen nylon with different forms of reinforcement mechanism. Glass fiber endured most load transferred through interface and increased nylon strength and modulus. Fly ash particles and nanometer SiO2particles could change the stress field in the composite, hinder the crack or change the crack direction, and improve nylon strength and plasticity.30%glass fiber reinforced nylon composite material had the most obvious effect and its tensile strength was46.6%higher than that of pure nylon.(3) Three kinds of reinforcement can effectively improve the performance of friction composites. Glass fiber could reduce the friction coefficient just by increasing the stiffness and hardness. Fly ash could form the friction film on the worn surface, which effectively reduce the wear and tear. Nano SiO2particles were micro rolling on the worn surface, so that sliding friction was changed into rolling and sliding friction and the friction coefficient and wear rate were reduced. The most obvious improvement effect was1%nano SiO2.(4) Different kinds of enhancements have a synergetic reinforcement effect when they are simultaneously added into nylon composites. The mechanical properties of composites coexistent with fiber glass and fly ash were higher than sum of composites only with one kind of filler. When glass fiber was30%and fly ash10%, the tensile strength of synergetic reinforced composite was7.5%higher than that of30%glass fiber composite and47.4%higher than that of10%fly ash composite.(5) Nylon composites pipe with functionally gradient were invented and its industrialization were realized. In the field of centrifugal force, fly ash particle could enrich in inner tube with negative grade distribution from inner to outer and glass fiber enriched in outer, which made ideal structure in nylon composites pipe with inlayer abrasion resistant and outer high strength. Compared with MC nylon, the compressive strength of nylon composites pipe was increased by1times and the costs reduced20%, which made nylon pipe successfully applied in waterway dredging, thermal power, metallurgy, mining and other industries, and achieved remarkable economic and social benefits.