Carbon nanotube functional group-dependent compatibilization of polyamide 6 and poly(methyl methacrylate) nanocomposites

Nanocomposites of polyamide 6 (PA6)-poly(methyl methacrylate) (PMMA)-functionalized single-wall carbon nanotubes (f-SWCNTs) with hydroxyl (SWCNTOH) and carboxylic acid (SWCNTCOOH) in weight ratios of 79.5-19.5-1, 49.5-49.5-1, and 19.5-79.5-1 were fabricated and investigated in terms of morphology, mechanical and XRD studies. Blends of 80-20, 50-50, and 20-80 weight ratios of PA6-PMMA have functioned as references. The scanning electron microscopy images of nanocomposites showed a relatively uniform dispersion of PMMA domains as co-continuous phase morphology in the continuous phase of PA6 compared to their respective blends. The f-SWCNTs acted as functional group-dependent compatibilizers for the PA6-PMMA blend system. Compatibilization of PA6-PMMA blends was higher in the presence of functionalized SWCNTs. XRD analysis indicated that the alpha(I) and alpha(II) phases of the PA6 were dependent on the weight ratio of the PA6 and PMMA and the nature of the f-SWCNTs. The PMMA-rich blends and nanocomposites exhibited the rich alpha(I) phase. The melt strength of the nanocomposites was higher compared to that of the PA6-PMMA blends. All the nanocomposites exhibited higher tensile strength than their corresponding blends. Tensile modulus increased with increasing weight percent of PMMA in blends (from 810 to 1135 MPa) and in nanocomposites (from 854 to 1298 MPa). PA6-PMMA-SWCNT(OH)19.5-79.5-1 nanocomposites exhibited higher tensile modulus (1298 MPa) compared to all the blends and PA6-PMMA-SWCNTCOOH nanocomposites.