Effect of Ammonia Fiber Expansion (AFEX) and Silane Treatments of Corncob Granules on the Properties of Renewable Resource Based Biocomposites

Abstract

Development of economically and ecologically attractive composite technologies is possible through the use of renewable biomass based resources such as polymeric matrices and reinforcement filler materials. The processability and physical properties of these composite materials are very important parameters for product performance. This study develops the enabling technology needed to transform corncobs, an abundant agricultural residue from the corn grain industry, into reinforcement filler material for manufacturing biocomposites. We have successfully fabricated biocomposite materials from poly(lactic acid) (PLA) and corncob granules (CCG) that were produced by a microcompounding molding system. To ensure appropriate interfacial interactions between the matrix and composite material, surface properties of the biocomposite filler must be modified accordingly. CCG-matrix adhesion was promoted by surface modifications using ammonia fiber expansion (AFEX), liquid ammonia treatment, and silane treatment. The final composite materials have improved mechanical and thermomechanical properties such as high flexural properties, high impact strength, and modulus at higher temperature. The surface morphology, as indicated by scanning electron microscopy (SEM), showed good dispersion of CCG in the PLA matrix. Modification of the CCG surface showed an improved adhesion and dispersion within the matrix. Overall, the results demonstrated the potential of CCG as reinforcement filler material for a renewable source based polymeric matrix.