Ground tire rubber (GTR) is a plentiful secondary polymer resource, but its aged, nonpolar surface limits compatibility with polar matrices. This study presents a scalable “graft-from” copolymerization of acrylic acid (AA) and methyl methacrylate (MMA) onto cryo-milled GTR, initiated by mechanoradicals generated during milling, eliminating the need for external initiators. By varying the AA:MMA ratio, copolymer grafts with tunable polarity were obtained and correlated with surface and dispersion properties. Spectroscopy confirmed successful co-grafting, with compositional trends identified by principal component analysis. Electron paramagnetic resonance indicated near-complete radical consumption. Thermogravimetric analysis confirmed surface-limited modification. Increasing AA content transformed fractured carbon-rich surfaces into continuous oxygen-rich films, with greater surface roughness. Contact angle tests showed rapid wetting on AA-rich surfaces versus poor wetting on neat or MMA-rich samples. Dielectric measurements showed that permittivity increased from 4.36 for the neat GTR to ∼11 for AA-rich grafts. The 50:50 AA:MMA composition achieved ∼8.0 at 100 Hz. Kelvin probe force microscopy confirmed increasing surface potential with AA content. Dispersion tests in mixed polar solvents showed that 50:50 and 60:40 grafted GTR remained suspended for over 8 h, while other formulations showed partial stabilization or faster settling, with significantly shorter suspension times for neat or homopolymer-grafted samples. These findings demonstrate a tunable, initiator-free method to enhance interfacial polarity, dielectric response, and colloidal stability of GTR, enabling its use in coatings, adhesives, and dielectric elastomers.
扫码关注我们
求助内容:
应助结果提醒方式:
