Effects of thermal treatment and nucleating agents on crystallinity, toughness, and stiffness of PLA/PCL blends

• Published in: Express polymer letters 2022-03, Vol.16 (3), p.221-233
• Main Authors: Ujcic, Aleksandra, Fortelny, Ivan, Krejcikova, Sabina, Pavlova, Ewa, Hodan, Jiri, Slouf, Miroslav
• Format: Article
• Language: English
• Subjects: Annealing; Biodegradation; Coalescing; Crystal structure; Crystallinity; Crystallization; Dynamic mechanical analysis; Heat treatment; High temperature; Impact strength; Mechanical properties; Mixtures; Molecular weight; Morphology; Particle size; poly(lactic acid); polycaprolactone; Polylactic acid; Polymer blends; polymer blends and alloys; Pressure molding; Reagents; Stiffness; Storage modulus; Temperature; Toughness; Viscosity
• ISSN: 1788-618X; 1788-618X
• DOI: 10.3144/expresspolymlett.2022.18

The effects of the thermal treatment and nucleating agents on the morphology, crystallinity, and mechanical properties of poly(lactic acid)/poly(s-caprolactone) (PLA/PCL) blends were studied in order to obtain PLA/PCL blends with both high stiffness and toughness. The standard thermal treatment of the melt-mixed blends (a compression molding without annealing) resulted in the systems with optimized morphology (at PLA/PCL ratio 80/20) and very high toughness (ca 16· higher with respect to neat PLA), but the stiffness at elevated temperatures (above Tg of PLA at 65 °C) was low due to the low crystallinity of the PLA matrix (60 °C by ca two orders of magnitude. The achieved combination of the PLA/PCL toughness and stiffness was one of the highest, according to the available literature.