Influence of applying microwave radiation on the LDPE/MWCNTs nanocomposite

Low density polyethylene (LDPE) and multiwall carbon nanotube (MWCNT) nanocomposites of varying MWCNT contents were prepared by melt blending and compression molding. The sample sheets were exposed to microwave irradiation and the effect on chemical, mechanical, and thermal properties as well as the sheets' morphology were determined and compared with that of nonirradiated samples with similar compositions. The percentage crystallinity of the LDPE/MWCNT nanocomposites declined after irradiation due to the degradation of polymeric chains. However, the melting temperature was hardly changed. The chemical degradation due to irradiation was also verified from the increase in the carbonyl index as determined from the Fourier transformed-infrared spectroscopy study and the decline in the storage modulus of the dynamic mechanical analysis study. The microcalorimetry study revealed that the MWCNT nanofillers were effectively acting as a heat absorption shield by reducing the heat release rate of polymer during combustion. The Raman spectra and scanning electron microscopy photographs demonstrated improved interaction of MWCNT with the LDPE matrix after microwave irradiation.