Dual purpose, bio-based polylactic acid (PLA)-polycaprolactone (PCL) blends for coated abrasive and packaging industrial coating applications

The purpose of this study is to replace the existing synthetic kraft paper with a biodegradable PLA-PCL kraft paper that can serve as a valuable coated abrasive and packaging products replacing the conventional petroleum based products. PCL toughens the brittle PLA polymer due to its plasticizing action. The toughening effect of 10% PCL in PLA is found to be maximum towards improving its better set of properties than that of neat PLA and other PLA-PCL compositions. Accordingly, the percentage of PCL in PLA was optimized to 10%. It was interesting to observe that PCL increases the crystallinity of the PLA, which enables the PLA-PCL blend to exhibit better gas barrier behaviour on Kraft paper. Furthermore, the blend also showed better heat seal strength with the highest value of 76.6 kPa at 10% of its content. FT-IR analysis confirmed the possible interaction that occurred between PLA and PCL, due to which a shift in vibration frequency of the PLA carbonyl group is observed. DSC analysis shows that PLA is completely miscible with 10 wt % of PCL exhibiting a melting peak at 148.8 degrees C with its corresponding enthalpy value at 29.14 J.g(-1) and a crystallinity value of 34.6%. The onset of the second heating crystallization temperature was noticed at 76.9 degrees C, and the enthalpy at 19.82 J.g(-1). Furthermore, this work proves that blending of PCL with PLA enhances the properties of PLA, which can be exploited for making industrially valuable products.