Polymer Adhesion to Geopolymer via Silane Coupling Agent Additives

Abstract

Silane coupling agents were successfully incorporated into alkali‐activated aluminosilicate geopolymers ( GP ) through simple mixing into the precursor liquid. This allowed for synthesis of thick coatings with meaningful long‐term shear and tensile adhesion to organic polymer substrates. Adhesion of GP to high‐impact polystyrene sheets and extruded polystyrene foam was quantitatively evaluated. GP drying shrinkage and coating‐substrate thermal expansion mismatch were identified as the major obstacles to adhesion, and these were mitigated by the easy yielding of polystyrene foam. The coupling agent‐modified GP experienced decreased splitting strength, but F ourier transform infrared spectroscopy, X ‐ray diffraction, and scanning electron microscopy were used to verify that the coupling agent addition did not inhibit geopolymerization.