Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary.
Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary; Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary.
Carbohydr Polym. 2014 Feb 15;102:821-9. doi: 10.1016/j.carbpol.2013.10.083. Epub 2013 Nov 5.
Thermoplastic starch (TPS)/wood composites were prepared from starch plasticized with 36 wt% glycerol. The components were homogenized by dry-blending, extruded and injection molded to tensile bars. Tensile properties, structure, deformation, water adsorption and shrinkage were determined as a function of wood content, which changed between 0 and 40 vol% in 7 steps. The modification of TPS with wood particles improves several properties considerably. Stiffness and strength increases, and the effect is stronger for fibers with larger aspect ratio. Wood fibers reinforce TPS considerably due to poor matrix properties and strong interfacial interactions, the latter resulting in the decreased mobility of starch molecules and in the fracture of large wood particles during deformation. Strong interfacial adhesion leads to smaller water absorption than predicted from additivity, but water uptake remains relatively large even in the presence of wood particles. The shrinkage of injection molded TPS parts is very large, around 10%, and dimensional changes occur on a very long timescale of several hundred hours. Shrinkage decreases to a low level already at 15-20 vol% wood content rendering the composites good dimensional stability.
热塑性淀粉（TPS）/木材复合材料由 36wt%甘油增塑的淀粉制成。将各成分通过干法混合进行均化，然后进行挤出和注塑成型，制成拉伸棒。根据木材含量的不同（分 7 步，在 0 到 40 体积%之间变化），测定了拉伸性能、结构、变形、吸水性和收缩率。用木颗粒对 TPS 的改性可以大大改善多种性能。刚度和强度增加，长径比更大的纤维效果更强。由于基体性能较差和界面相互作用较强，木纤维会显著增强 TPS，后者导致淀粉分子的迁移率降低，在变形过程中较大的木屑颗粒断裂。强界面附着力导致吸水率低于加和性预测值，但即使存在木屑，吸水率仍相对较高。注塑成型的 TPS 零件的收缩率非常大，约为 10%，而且尺寸变化发生在几百小时的非常长的时间尺度上。收缩率在 15-20 体积%的木材含量下就降至较低水平，从而使复合材料具有良好的尺寸稳定性。
