The Preparation And Performance Studies Of Mc Nylon Composites

MC nylon has attracted a great deal of attentions due to its high molecular weight,high mechanical strength, excellent self-lubricating performance and simple preparation process. However, the application of pure MC nylon is still limited because of its poor toughness, heat resistance, abrasion resistance, self-lubrication et al. This paper mainly researches the modification of MC nylon. To improve the toughness and thermostability of MC nylon, we prepared MC nylon/ modified graphene oxide(GO) nanocomposites.Besides, we prepared the oil filled MC nylon which has excellent friction and wear properties and mechanical strength.Firstly, GO which contains rich oxygen containing function groups was prepared successfully by improved Hummers method. The obtained GO was modified by cetyl trimethyl ammonium bromide(CTAB). FTIR and XRD testing results have proved that carboxyl anion of GO linked with nitrogen ions of CTAB successfully through the ionic bond. We prepared MC nylon/modified GO composites by anionic in situ polymerization.The results showed that the content of NaOH had notable effects on the dispersion of the modified GO. The impact strength of the composite was improved by 66% when 0.2 wt%of the modified GO was incorporated in the nylon matrix. Meanwhile, the tensile strength and flexural strength increased by 5 % and 1.4 %, respectively. The TGA testing results indicated that the composites had higher decomposition temperature in comparison with neat MC nylon.Secondly, GO was modified by glycidyl trimethyl ammonium chloride(GTMAC) by the electrostatic interaction, to introduce the epoxy group on the surface of GO. The high density polyethylene grafted GO(GO-g-HDPE) was prepared via a ring opening reaction between high density polyethylene grafted maleic anhydride(HDPE-g-MAH) and the modified GO by a solution process. Monomer casting nylon(MC nylon)/GO-g-HDPE composite was prepared by anionic in situ polymerization. The resulting MC nylon composite with 0.02 wt% of GO-g-HDPE demonstrates that the tensile strength, elongation at break, impact strength and compressive strength of the composite are enhanced by14.7 %, 21.0 %, 30.0 % and 27.2 %, respectively, meanwhile, the water absorption and thermal stability are also improved.At last, we prepared oil filled MC nylon. Scanning electron microscopy(SEM)characterization proved that the oil could disperse uniformly and stably in MC nylon matrix.The addition of oil improved the the friction and wear properties of MC nylon greatly.When the oil content was 3 wt %, friction coefficient of MC nylon was 0.16, the wear loss and wear scar width were 2 mg and 2.89 mm, respectively. Mechanical properties testing results showed that, when the oil content was 3 wt%, the tensile strength of the MC nylon was above 71.6 MPa, tensile modulus was more than 2900 MPa, the elongation at break was 60.5%, the flexural strength and modulus were 103 MPa and 2716 MPa, respectively,meanwhile compression modulus was more than 1520 MPa. Mechanical properties can meet the requirements of practical application.