The In Situ Polymerization And Characterization Of Graphene Oxide (GO)/PA6 Composites

Nylon 6(polycaprolactam)is a kind of polymer synthesized from caprolactam by polymerized reaction.Among the polymamide,nylon product is the largest one used in many areas.As the development of technology and life quality,the traditional nylon-6 material can no longer meet the needs of people.As a high-performance nano-materials,grapheme oxide(GO)provides a new way for developing the excellent material.As a result,modified GO can not only solve the question of bad interfacial bond strength,but also introduce the high-performance of GO,which makes it possible to prepare excellent composites.The main conclusions are as follows:1.In view of lots of functional groups such as hydroxyl group,carboxyl and epoxy group on the surface of GO,we select KH550 and TDI to modify GO to enhance dispersity.IR and XRD testing results confirmed that KH550 and TDI have grafted to the surface of GO successfully,respectively.Besides,modified GO can disperse well in the CPL melt.2.We synthesized composites through in-situ polymerization method.In the preparation of composites,NaOH and TDI were used as initiator and activator agents,respectively.By adding different content of GO and modified GO respectively,we successfully prepared three kinds of GO/PA6 composites.By using IR,TGA,DSC,and XRD methods,the structure and properties such as thermal property,crystal structure and mechanical property were studied in details.3.The result of IR confirmed that the reaction between KH550 or TDI and GO had taken place.The result of TG analysis showed that the adding of GO and modified GO had no effect on the thermal stability of PA6.The result of DSC testing exihibited that the addition of GO and modified GO had influenced the crystallization and melting bahaviors of composites in a way.4.The addition of modified GO was benefit for improvement of molecular weight and crystallinity of PA6.5.As demonstrated by the analysis of the isothermal crystallization kinetics,Avrami equation could well describe isothermal crystallization behavior of composites,which showed that the growth pattern of PA6 crystals was growing in two-dimensional and three-dimensional.The Avrami exponents of composites were between 1.38 and 1.50(modified by KH550)and between 1.20 and 1.47(modified by TDI)respectively,which could be concluded that bahaviors of crystallization of the composites might existe heterogeneous nucleation and second crystallization.6.The XRD testing results showed that the addition of GO and modified GO had been conductive to weaken the diffracted intensity of peak at 20.1° and strengthen the intensity of peak at 24°,which indicated that the addition of GO had an effect on crystal structure of composites.7.Mechanical and thermal performance testing results showed that the addition of a moderate amount of GO and modified GO had been beneficial to improve the elongation at break and thermal conductivity of PA6,which could increase the toughness and thermal conductivity of PA6.