Environmentally Friendly Polylactic Acid/Modified Lignosulfonate Biocomposites

Ammonium lignosulfonate was modified with carboxylic acids (lactic, oleic) and butyrolactone by physical non-polluting radio frequency cold plasma method. Modified lignosulfonates/polylactic acid (PLA)-based biocomposites with enhanced dielectric and thermal properties have been prepared by melt mixing technique. Some modified lignosulfonates improved processability and rheological properties of PLA. A homogeneous dispersion of lignosulfonates in PLA matrix assures the improvement of hydrophilicity, dielectric, rheological properties and thermal performance of the PLA polymer as they act as nucleating agents increasing crystallinity degree. The dielectric characteristics followed in a large frequency and temperature range. Relaxation transitions and their activation energies were found to be dependent on modified lignosulfonate type incorporated in biocomposites. As PLA is recognized by its biodegradability and the composites containing modified lignosulfonates disintegrate by bio- and environmental degradation even they are incorporated in much resistant matrices as polyolefins, it can supposed that such biocomposites could be considered as medium term degradable ones. Increasing modified lignosulfonates content environmental disintegration period could be shorten.