Kunwei Liu, Samy Madbouly, James Schrader, Gowrishanker Srinivasan, David Grewell, and Michael Kessler
Iowa State University
Environmentally friendly biobased composites of polyamide and lignin fiber have been prepared as a function of composition using a twin-screw extruder. The effects of the concentration of lignin on the thermal and mechanical properties of the composites were studied using differential scanning calorimetry, dynamic mechanical analysis (DMA), thermogravimetric analysis, and mechanical testing. The morphologies of the composites were investigated using scanning electron microscopy. The glass relaxation process of the composites was shifted systematically to higher temperature with increasing concentration of lignin. The elastic modulus obtained from the DMA in the glassy state was also increased with increasing lignin content. In addition, the thermal stability of the composites was found to be strongly influenced by the concentration of lignin, i.e.; the onset of the degradation process shifted to lower temperature with increasing lignin content. On the other hand, the thermal stability of the composites increased significantly at high temperature as the lignin content increased. These low cost, biorenewable composites possess good thermal and mechanical properties, and may have potential applications in bioplastic container cropping systems.