Multi-walled carbon nanotube reinforcement in polypropylene nanocomposites: comprehensive analysis of thermal behavior, mechanical properties, and dispersion characteristics

This study examines the impact of multi-walled carbon nanotubes (MWCNTs) on polypropylene (PP) nanocomposites, with an emphasis on the thermal characteristics of the materials. Employing a twin-screw extruder and injection molding techniques, the author aimed to elucidate the effects of varying MWCNT concentrations and dispersion patterns, deliberately excluding a compatibilizer from the study. The findings revealed a marginal increase in the crystallization peak temperatures of PP under non-isothermal conditions upon the addition of MWCNTs. Crucially, the research identified a significant "percolation threshold" of 0.5 mass% of MWCNTs, beyond which substantial improvements in physical properties were observed in the absence of a compatibilizer. Below this threshold, an augmented interfacial area between PP and MWCNTs notably enhanced PP's thermal stability. Noteworthy is the discernible reinforcing impact of MWCNTs, particularly evident at elevated temperatures, as indicated by the elucidated "n" index. Furthermore, the investigation showcased reduced shrinkage in composite fibers compared to control fibers, with heat-treated fibers exhibiting a narrow melting peak at 170 °C. This work is essential to the development of materials with improved physical characteristics because it provides valuable insights into the effects of MWCNTs on PP nanocomposites.