Study On Preparation And Properties Of Modified Graphene Oxide/MC Nylon Composites

Monomer casting nylon(MC nylon)has a higher relative molecular weight than common nylon,and has self-lubrication and wear resistance.MC nylon has been widely used in mines,machinery,military and national defense,and many other fields.Nano-particles modification is the most commonly used method in MC nylon modification.Graphene oxide(GO)is a two-dimensional nanomaterial that has high strength,high stiffness,and a large number of oxygen-containing functional groups as reactive sites,which are easy to fix its dispersibility and compatibility problem in the nylon matrix.GO is one of the ideal material of modified MC nylon.Due to the anionic polymerization characteristics of MC nylon,its formula and process change greatly affect the performance of the final materials and products,so the selection of an appropriate method to add GO into MC nylon has become the focus of modification.In this paper,the synthetic process of MC nylon was first studied.MC nylon has been prepared successfully and its structure and properties were characterized.And the optimum catalyst,amount of catalyst,polymerization conditions,and casting process were discussed.Then,modified nano filer GOPA6 filler was prepared by the in-situ polymerization method,and it was added into the MC nylon molding process as raw material,which solved the problem of poor compatibility between GO and MC nylon matrix and obtained MC nylon/GO composite material with excellent mechanical performance.The main research contents are as follows:1.A series of studies were carried out on the MC nylon anionic polymerization process.The preparation methods of different formulations and processes were designed.It was found that the influence of the content of NaOH and TDI on the conversion rate increased first and then decreased,and the conversion rate reached the highest when the content of NaOH and TDI reaches 0.2wt.%and 0.4wt.%of caprolactam,respectively.The optimum temperature is 165?,a higher temperature could produce a large number of pores affecting the use of materials,and a lower temperature will lead to the reaction speed and lead to the separation of filler and matrix2.Based on the hydrolysis polymerization of PA6,the process of preparing GOPA6 by in situ polymerization was designed.The hydrolysis polymerization of PA6 was used to disperse the GO lamellar layer,and the molecular weight regulator was used to control the molecular weight of PA6 in the GO lamellar layer.It was found that when the molecular weight regulator was sufficient,its content had a linear relationship with the melting point of PA6 and a logarithmic relationship with the molecular weight.GO also showed an effect on polymerization and reduced molecular weight in the in-situ polymerization process.In situ polymerization process can effectively graft GO and PA6 molecular chain,and successfully improve the dispersion and compatibility of GO in the PA6 matrix.3.The MC nylon 6/GOPA6 nanocomposite was prepared by adding GOPA6 into the MC nylon polymerization process,which successfully improved the dispersion of GO and enhanced the mechanical strength of the composite.Compared with GN and GO which were not modified,the tensile strength and impact strength of the composite materials was increased by 8.9%and 18%respectively.Meanwhile,the strength and toughness of the composite materials were enhanced to a certain extent.