Effect of poly(ε-caprolactone) as plasticizer on the properties of composites based on polylactide during hydrolytic degradation

The aim of this work was to determine the impact the plasticizing agent has got on hydrolytic degradation of polylactide-based composites in the form of films. The research involved polylactide composites where Nanofil2 or Montmorillonite K10 were used as nanoclays and (poly(ε-caprolactone)) was introduced into the polymer matrix as plasticizer. Hydrolysis was carried out in phosphate buffer solution (pH 7.40) at 37 °C. Degradation process of polylactide-based composites was studied by incubating samples in 100 ml solution for a maximum of 180 days. In order to determine the influence of the plasticizer on hydrolysis, the materials were investigated by various analytical techniques. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used in order to investigate the thermal properties of samples during the degradation process. Gel permeation chromatography (GPC) was used to observe the decomposition of the polyesters. Morphology and structural changes during controlled hydrolysis were studied by atomic force microscopy (AFM). The results suggest that introduction of plasticizer into pure polymer as well as into PLA-montmorillonite system accelerates decompositions of investigated materials.