Interfacial dynamics analysis in starch nanocrystal/ poly (butyl methacrylate) nanocomposites: Impact of the reinforcement’s functionalization

Abstract

Nanocomposites based on waterborne polymer dispersion and biobased nanoparticles have gained significant interest because they offer a wide range of dimensionality and shape, and they are abundantly available from renewable biobased sources. Although polymer-filler interaction is key to the resulting performance of the nanocomposites, these interfacial properties are challenging to measure and analyze. In the present work, dielectric spectroscopy was used to investigate the interfacial characteristics of nanocomposites based on Poly(Butyl-methacrylate) (PBMA) and starch nanocrystals (SNCs) prepared by in-situ emulsion polymerization, where SNCs was the sole stabilizer. Unmodified and vinyltriethoxysilane-functionalized SNCs (VTES-SNCs) were used as both reinforcements and colloidal stabilizers to control the degree of binding of SNCs on PBMA. Two main relaxation processes were detected and identified as Maxwell-Wagner-Sillars (MWS) polarization and dipolar relaxation. The origin of these relaxations and their evolution based on the SNCs content and functionalization were discussed in terms of the SNCs-polymer matrix interaction mechanism. Most notably, an apparent effect of SNCs loading on the electrical conductivity of nanocomposites was revealed, pointing to evidence of percolation of the SNCs despite their non-conductive character.