Designing and Engineering a New Biocomposite Material from Distillers' Grains and Bioplastics

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Date

2014-05-13

Authors

Zarrinbakhsh, Nima

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Volume Title

Publisher

University of Guelph

Abstract

In recent years, the expansion of the corn ethanol industry has generated surplus amounts of solid coproducts mainly in the form of dried distillers’ grains with solubles (DDGS). In order to help economic viability and sustainability of the industry, research is being conducted to find new, more profitable applications for this coproduct besides its traditional usage as animal feed. In the present project, the capabilities of DDGS are evaluated for using as a filler and/or reinforcement in producing green biocomposites with a number of bioplastics. The bioplastics used here are partially originated from renewable resources with end-life biodegradability in compost conditions. The focus of this research is to design and engineer material formulations with balanced performance. Extrusion and injection molding techniques have been employed to produce the biocomposites and the performance of the produced materials was evaluated through several mechanical, thermomechanical and physical properties. The discussions are augmented with thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results are conclusive in that DDGS is a better filler for polymeric biocomposites when it undergoes a water treatment before processing with polymer melts. The treated DDGS shows a thermal degradation rate four times less than as-received DDGS at 180 °C, the processing temperature of the composite materials. The DDGS biocomposites are produced with a range of biodegradable plastics and the effect of a polymeric isocyanate compatibilizer is evaluated. The compatibilizer improves the interfacial adhesion between DDGS particles and the polymeric matrix, as evidenced by SEM, and thus, enhances the strength and modulus; however, reduces the impact strength. A high-impact DDGS biocomposite is produced using a combination of compatibilizer and lubricant as additives. The optimization of the material’s formulation is approached statistically based on a full factorial design of experiment (DOE) for additive amounts, followed by a response surface methodology (RSM) for mechanical and physical properties. With this approach, biocomposites of DDGS and bioplastics are successfully designed which exhibit acceptable performance such as tensile strength of more than 20 MPa, flexural modulus of more than 1 GPa, impact strength of more than 100 J/m and melt flow index of more than 5 g/10min.

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Keywords

Materials Science and Engineering, Biocomposite, Corn ethanol coproduct, Distillers' grains, Dried distillers' grains with solubles (DDGS), Mechanical properties, Thermo-mechanical properties, Characterization methods, Scanning electron microscopy (SEM), Design of experiment (DOE), Response surface methodology (RSM), Biofuel sustainability, Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Compatibilizer, Formulation optimization, Dynamic mechanical analysis (DMA), Biodegradable, Melt flow index (MFI), Melt extrusion, Injection molding

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