Thermal stability and mechanical properties of ethylenediamine‐modified GO/co‐polyamide nanocomposites

Abstract

We describe ethylenediamine‐modified graphene oxide (GO)/co‐polyamide (GO‐EDA/CO‐PA) nanocomposites prepared via solution blending with EDA‐modified GO (GO‐NH2/EDA). GO was prepared via the improved Hummers method, and EDA was used to modify the GO to add amine groups to graphene. X‐ray diffraction, Fourier‐transform infrared spectroscopy and atomic force microscope analysis showed that the thickness of GO‐NH2/EDA was 1.2 nm. Amino functional groups were introduced onto the GO sheets. Due to the steric hindrance effect of the amino on modified graphene as well as the strong, specific interactions between aminos and carboxyls on CO‐PA, the GO‐NH2/EDA filler was homogeneously dispersed in the matrix, and the interface reaction was effectively improved. The GO‐NH2/EDA could change the crystal structure of pure nylon and the glass transition temperature (Tg). The mechanical properties of the nanocomposites increased dramatically when the GO‐NH2/EDA content is 0.6 wt%. The tensile strength and yield strength of the nanocomposites increased by 50.3 and 134.8%, respectively. The effects of interfacial interaction, increased crystallization, and prevention of agglomeration of GO‐NH2/EDA improved the thermal properties of the GO‐EDA/CO‐PA nanocomposites. This is because the 50% thermal degradation temperature (T‐50%) and the thermal degradation temperature (Td,max) of the nanocomposites increased by 16 and 15°C when the GO‐NH2/EDA content is 0.8 wt%. The nano‐filler improves the thermal diffusivity of the nylon matrix at low temperature. POLYM. COMPOS., 40:3315–3324, 2019. © 2018 Society of Plastics Engineers