In-situ Preparation, Characterization And Properties Of Nylon 11 /Graphene Oxide Nanocomposites

Nylon 11(PA11) is a kind of polyamide with very excellent performance,whichwas widely used in cars and electronics industries. However,it has formed a baptismfor the performance of materials with the development of science and technology andthe performance of pure nylon 11 is already difficult to meet the demands.Based onthese reasons, PA11/graphene oxide nanocomposite were in-situ polymerized usinggraphene oxide(GO) and 11-amino undecanoic acid as raw materials in this topic,andthe combination properties of composite ware investigated by thermo-gravimetricanalyzer (TGA), scanning electron microscopy (SEM), capillary rheometer, rotationalrheometer, differential scanning calorimeter (DSC), polarizing microscopy (POM)and fourier-transform infrared spectroscopy (FTIR), respectively. The research resultswere listed as following:1. The FTIR specttoscopy showed the existence of strong interaction betweenPA11 and GO.The tensile strength, bending strength and storage modulus ofnanocomposites increased continually with the increasing GO oncentration, and theimpact strength had slight variation at GO loading level≤0.2% and then reducedrapidly. The elongation at break achieved the maximum (194.4%) in the case of 0.4%GO loading level.PA11 and its nanocomposites displayed the characteristic of dualloss peaks, and the incorporation of GO had almost no effect of theβrelaxation butslightly increased the glass transition temperature of PA 11.2. The rheological behaviors of nylon 11/graphene oxide nanocomposites werestudied by using rotational rheometer. The experimental results showed that nylon11/GO nanocomposites were pseudo plastic fluid, and all specimens exhibited shearthinning behavior. The storage modulus, loss modulus and the complex viscosity ofnylon 11/GO decreased with the addition of GO. The curves of the nylon 11/GOnanocomposites, analyzed by the Cole-Cole theory, displayed two peaks indicatingthat the phase seperation occurred for nylon 11/GO nanocomposites, which was in accordance with the Han curves.3. Isothermal crystallization kinetics and melting behaviors of nylon 11 and itsnanocomposites were investigated using differential scanning calorimetry (DSC). Theexperimental results showed that the Avrami equation can describle well theisothermal crystallization kinetics. The crystallization rate of pure nylon 11 wascontrolled by the crystals growth rate, whilst the crystallization rate of thenanocomposites was controlled by the crystals growth rate or the nucleation rate inthe different range of crystallization temperatures. As comparison with pure nylon11, the nanocomposites displayed lower equilibrium melting temperature and surfacefolding energy.4. The rheological behaviours of PA11/GO nanocomposites were investigatedusing XLY-Ⅱrheometer.The experimental results showed that nylon 11/GOnanocomposites displayed pseudo plastic fluid, and all specimens exhibited shearthinning behavior. The value of the non- Newton index were less than 1. The value ofΔEγwfor nanocomposites was almost lower than that of neat nylon 11,whichindicating that the apparent viscosity of nanocomposites was less sensitive totemperature and was ready to be processed after adding GO.