Natural fiber composites require coupling agents between phases to prevent poor adhesion between lignocellulosic fiber and a polymer matrix, which leads to a material that is not fully biodegradable. This work proposes the use of starch gum as a coupling agent for cotton fibers. The gum formation and fiber coating were characterized based on the starch paste solubility, clarity level according to UV-visible spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, heated optical microscopy, and fiber weight coating. Water-starch solutions were heated at 70 ℃ for 5, 10, and 24 h with two concentrations (3 and 8 wt.%) to obtain six different systems of gelatinized starch and starched fibers. The fibers are coated during the process of gelatinization and then dried and vacuum filtered. The gelatinization occurs at 70 ℃ for bath samples heated for more than 5 h, which exhibits a more branched structure, higher thermal stability, and increased weight coating up to 140 wt.%. The recoating process promoted stronger fiber adhesion, which would make this reinforcement applicable in an industrial-scale process to produce fully biodegradable composites.
Study of the Preparation and Properties of TPS/PBSA/PLA Biodegradable Composites
