Biodegradable green composites from bioethanol co-product and poly(butylene adipate-co-terephthalate)

This work summarizes the development of green composites from distillers dried grains with solubles (DOGS), a major co-product of the corn ethanol industry, and poly (butylene adipate-co-terephthalate), PBAT. The composites were fabricated using a twin-screw micro extruder with micro injection molding. The DDGS was pretreated, yielding a noticeable improvement in the degradation onset temperature of DDGS from 140 to 240 degrees C, which was shown by thermogravimetric analysis (TGA). The composite fabricated with pretreated DDGS showed better mechanical and thermal properties compared to the composite with non-treated DOGS. TGA analysis showed that the maximum degradation rate shifted slightly to lower values with the increase of filler content. Differential scanning calorimetry (DSC) analysis showed that the glass transition temperature (T-g) of the matrix increased slightly with an increase in filler content, indicating that filler did not lead to significant change in crystalline structure. The biodegradability study showed that, PBAT/treated DOGS composite was found to be the most bio-susceptible material, being totally biodegraded. This suggests that DOGS domains were preferentially attacked by microorganisms, and increased the percentage of biodegradation. All composite materials showed a degree of biodegradation similar to the biodegradation rate of DOGS and cellulose. This study showed that the incorporation of DOGS into a PBAT matrix can produce green composites with enhanced biodegradability. (c) 2012 Elsevier B.V. All rights reserved.