Understanding the Morphology and Cross-Link Density in Silicone Rubber-Multiwalled Carbon Nanotube Composites via Solvent Transport Studies

The diffusion characteristics of silicone rubber-based nanocomposites have not been extensively studied in the literature. This study aims to provide a comprehensive analysis of the solvent transport properties of these materials, incorporating detailed dissolution modeling. This study reported a novel approach to elucidate the morphological and diffusion characteristics of silicone rubber-MWCNT (multiwalled carbon nanotube) composites. FESEM micrograph analysis reveals structural changes with the lower loadings forming continuous networks and higher loadings leading to agglomeration of the fillers. Diffusion studies highlight reduced solvent uptake over time due to compact physical networks, while Kraus plot analysis confirms MWCNTs' reinforcing ability. Dissolution modeling using Korsmeyer–Peppas and Peppas–Sahlin models indicates the type of solvent release behavior, with the latter offering a superior fit. Mode of transport analysis suggests a less Fickian mode influenced by MWCNT loading, while swelling parameters demonstrate hindered solvent transport with increasing MWCNT content. The molecular mass between successive cross-links and the cross-link density decreases with rising MWCNT loading, which is theoretically predicted by the affine model. This study also focused on the complex interplay between filler loading, composite structure, and solvent transport behavior in silicone rubber-MWCNTs composites, offering valuable insights for their potential applications in various fields.