Kunwei Liu, Timothy Jobes, Samy Madbouly, James Schrader, Gowrishanker Srinivasan, David Grewell, and Michael Kessler
Iowa State University
Polyhydroxyalkanoates, a biopolymer resin produced through a fermentation process of plant-derived sugar, was successfully blended with lignin using a twin-screw extruder. The effects of the concentration of lignin on the thermal properties of the composites were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis. The morphologies of the composites were investigated using scanning electron microscopy and optical microscopy. DMA results indicated that the concentration of lignin has little effect on the glass transition temperatures of the composites. DSC showed that the melting temperatures and the crystallization points of the composites systematically shifted to lower values as the concentration of lignin increased. The obtained composites were found to be thermally stable up to 200°C and exhibited a major thermal degradation with a maximum degradation rate at around 260°C. These low cost, biorenewable, and biodegradable composites possess good thermal properties, and may have potential applications in bioplastic container cropping systems and packaging industries.