Use of ionic monomers to prepare halloysite polymer nanocomposites with reinforced mechanical performance

Pristine halloysite (Hal) nanotubes were used to fabricate polymer-based nanocomposites via in situ polymerization: Methyl methacrylate (MMA) was selected as main monomer, and respectively copolymerized with a small quantity of ionic comonomer 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTC) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), meanwhile Hal was added during the polymerization process. The noncovalent interactions between Hal and ionic comonomers are key factors of successful preparation of Hal P(MMA-co-MTC) nanocomposite and Hal P(MMA-co-AMPS) nanocomposite. The mechanical properties of nanocomposites were investigated in detail. The results indicate that, the nanocomposites demonstrated excellent mechanical performance due to strong interfacial adhesion ameliorated by noncovalent interactions; Hal exhibited much stronger interfacial adhesion with P(MMA-co-MTC) matrix compared to that with P(MMA-co-AMPS) matrix; and the nanocomposites containing 1.5 wt% Hal content and 10 wt% MTC content showed the highest tensile strength and flexural strength, respectively improved by 47.5% and 165.6% compared with neat PMMA. The highlight of this work is to provide a simple and feasible Hal polymer nanocomposites preparation technique with high mechanical performance improvement and slight Hal loadings.