Synthesis, Structure And Characterization Of Carbon Fiber/MC Nylon 6 In-Situ Composite

As an important class of engineering plastic, MC nylon 6 has developed and used extensively since 1960s with the development of the anionic polymerization of caprolactam for its various merits, including low polymerization temperature, simple process, high crystallinity, high molecular weight as well as excellent mechanical properties, etc. However, because of the strong water absorptivity and poor dimensional stability, the application of MC nylon 6 was limited in a certain condition.In this paper, a new approach for preparing carbon fibre/MC nylon 6 composites was proposed. To begin with, the -COOH and -OH groups on the surface of the carbon fibre were isocyanated followed by stabilized by caprolactam. According to the results of Scaning Electron Microscopy (SEM), the surface of carbon fibre was grafted with TDI. Moreover, IR spectra demonstrated that the surface of carbon fibre was grafted TDI and the stabilized caprolactam end capping. Thermogravimetric analysis demonstrated that the graft ratio was 2.69%.then the carbon fibre was added to melting caprolactam monomer. Subsequently, the carbon fibre was added to the melt caprolactam, and then caprolactam grafted carbon fibre/MC nylon 6 in situ composites were prepared via anionic polymerization.The crystallization and melting behaviors of such materials were investigated by Differential Scanning Calorimetry (DSC). The results of nonisothermal crystallization and isothermal crystallization demonstrated that, carbon fibres could improve both of the initial crystallization temperature and the crystallization rate of the composites, the carbon fibres served as heterogeneous nucleation reagent. Caprolactam grafted carbon fibre could improve the initial crystallization temperature and the crystallization rate more obviously than ungrafted carbon fibre. The crystallization of nylon 6 was determined by nucleation. The nonisothermal crystallization dynamics was well coincident with the rule of both of Jeziorny and Liu equation. isothermal crystallization dynamics fitted to Avrami equation. The melting results after nonisothermal crystallization and isothermal crystallization both demonstrated Carbon...