Studies on the properties of natural fibers-reinforced thermoplastic starch composites

As the matrix of natural fiber, thermoplastic starch (TPS) was prepared with urea and formamide as the mixed plasticizer. This TPS could effectively restrain starch retrogradation. SEM micrographs showed good dispersion and adhesion between starch and fiber. Studies in the dependence of mechanical properties of reinforced TPS on the contents of fiber and water demonstrated that with increasing fiber content from 0 to 20%, the initial tensile strength was trebled up to 15.16 MPa, while the elongation was reduced from 105 to 19%. The reinforcement effect was gradually weakened with the increasing of water contents, but at the high water contents (>30%) both the fiber and water contents had no effect on the tensile strength. The thermal stability and water resistance of TPS reinforced by fiber were obviously improved. X-ray diffractograms illustrated that this matrix still restrained the retrogradation of starch when the fiber content was below 20%.