Effect of graphite nanoplatelets on melt drawing and properties of PCL/PLA microfibrillar composites

The study deals with upgrading of a poly (ɛ‐caprolactone) (PCL)‐based biodegradable material using graphite nanoplatelets‐aided in‐situ formation of reinforcing microfibers, that is, preparation of a microfibrillar composite (MFC) based on the PCL/poly lactic acid (PLA) 80/20 blend. Recently, we have found that effective melt‐drawing is impossible due to flow instability and that PLA fibrils formation is only possible with addition of high‐aspect‐ratio nanofillers (NF), such as momtmorillonite or halloysite. This work concerns modification of the PCL/PLA blend with graphite nanoplatelets (GNPs). Results indicate that relatively large GNPs excellently support stability of extrusion which leads to better drawability in comparison with other NF. Hence, reinforcement of the components by GNP and fibrils formation accompanied by increased PLA crystallinity lead to a biocompatible and biodegradable material with good performance. Increased PLA crystallinity due to its annealing during subsequent processing and substantial suppression of cold crystallization is another advantage of the MFC concept in the PCL/PLA system. POLYM. COMPOS., 39:3147–3156, 2018. © 2017 Society of Plastics Engineers