Biopolymer composites of wheat gluten with silica and alumina

Two composite systems were explored to assess the effect of particle dispersion on the properties of filled wheat gluten composites. Nanosilica particles and micro-alumina particles were combined with several silane coupling agents by various methods to perform a broad brush survey of chemical and physical interactions. Thermo-gravimetric analysis (TGA) was used to assess surface coverage on coated particles. Electron microscopy (scanning and transmission) techniques were used to assess particle dispersion and surface interactions. Producing the silica particles in the wheat gluten matrix led to better physical properties, as measured by 3-point bending, than producing the silica particles first, and then mixing them into the wheat gluten. Similarly, coating the alumina particles with silane coupling agents in the wheat gluten matrix led to better mechanical properties than first coating the alumina with silane and then mixing the coated particles into the wheat gluten. (C) 2011 Elsevier Ltd. All rights reserved.