Intermolecular interactions of bio-modified halloysite nanotube within high-impact polystyrene and linear low-density polyethylene

Abstract

Recently, the merits of using aspen-wood-derived bio-crude (WB) have been discussed as a compatibilizer and dispersing agent for halloysite nanotube (HNT) in a polymeric matrix of high-impact polystyrene (HiPS) polymer. While active sites (functional groups) of WB compounds are effectively involved in non-covalent functionalization of HNT, here, we study the inherent potential of WB compounds and the mechanism through which they effectively interact with HiPS polymer, and play their role as a bridge between hydrophilic HNT and hydrophobic HiPS. On the basis of energy decomposition analysis performed in the framework of density functional theory, performance of the substituted aromatic compounds of WB towards phenyl groups of the HiPS polymer is strongly affected by three features of the substituents: their bulkiness, substitution pattern, and chemical nature. Despite the not-so-successful performance of non-covalent interactions of aromatic components of WB with HiPS, they benefit from the possibility of the formation of fused polycyclic aromatics through sharing covalent bonds with the phenyl group of the HiPS polymer. On the basis of our theoretical findings, no successful performance is predicted for using WB-treated HNT in the matrix of linear low-density polyethylene (LLDPE) polymer. This was evidenced by thermogravimetric and rheological analyses showing that while wood-based bio-crude can organically modify HNT to be compatible with HiPS, it remains incompatible with LLDPE, regardless of the modification process.