Phase structure, compatibility and toughness of PLA/PCL blends: a review
- 1Institute of Macromolecular Chemistry (ASCR), Czechia
- 2University of Trento, Italy
Results of the studies dealing with the toughness of polylactic acid/polycaprolactone (PLA/PCL) blends are analyzed with respect to the PCL particle size, PLA matrix crystallinity, and presence of a compatibilizer. It is shown that a high toughness or even »super-toughness« of PLA/PCL blends without a compatibilizer can be achieved for blends with the proper size of PCL particles. Nevertheless, the window for obtaining the super-tough PLA/PCL blends is quite narrow, as the final impact strength is very sensitive to multiple parameters: namely the blend composition, PLA matrix crystallinity, and PCL particle size. Available literature data suggest that the optimal composition for PLA/PCL blends is around 80/20 (w/w). The PLA/PCL(80/20) blends keep high stiffness of PLA matrix and the concentration of PCL particles is sufficient to achieve high toughness. The PLA/PCL(80/20) blends with low-crystallinity PLA matrix (below ca 10 %) exhibit the highest toughness for bigger PCL particles (weight average diameter above 1 μm), while the blends with high-crystallinity PLA matrix (above ca 30 %) exhibit the highest toughness for smaller PCL particles (weight average diameter below 0.5 μm). The addition of a compatibilizer may improve the toughness only on condition that it helps to achieve a suitable particle size. The toughness of both non-compatibilized and compatibilized PLA/PCL blends with optimized morphology can be more than 15 times higher in comparison with neat PLA.
Keywords: Biopolymer blends, poly(lactic acid), polycaprolactone, impact strength, crystallinity, Particle size distribution
Received: 26 Jun 2019;
Accepted: 09 Aug 2019.
Edited by:Alfonso Maffezzoli, University of Salento, Italy
Reviewed by:Veronique Michaud, École Polytechnique Fédérale de Lausanne, Switzerland
Johnny De Nardi Martins, Federal University of Santa Catarina, Brazil
Copyright: © 2019 Fortelny, Ujčić, Fambri and Slouf. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. Miroslav Slouf, Institute of Macromolecular Chemistry (ASCR), Prague, Prague, Czechia, email@example.com