Effect of thermal annealing on crystal structure and properties of PLLA/PCL blend

• Published in: Journal of polymer research Vol. 27; no. 8
• Main Authors: Chen, Jin, Deng, Chengji, Hong, Rui, Fu, Qiang, Zhang, Jie
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2020; Springer Nature B.V
• Subjects: Annealing; Biodegradability; Biodegradable materials; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Crystal structure; Crystallinity; Impact strength; Industrial Chemistry/Chemical Engineering; Injection molding; Melt blending; Original Paper; Polylactic acid; Polymer Sciences; Thermodynamic properties; Toughness; Heat resistance; Toughness; Poly(L-lactide); Crystallinity; Thermal annealing
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-020-02206-1

As far as we know, to enhance the toughness of poly(L-lactide) (PLLA) without compromising its inherent biodegradability, melt blending PLLA with flexible biodegradable polymers is the most effective and universal method. However, most of research results show a slight improvement in impact toughness due to the amorphous PLLA matrix. In other words, effective impact toughness can be achieved only if PLLA blend is in a highly crystalline state. In this work, blend of PLLA with 20 wt% PCL was prepared and then samples made by injection molding were applied to thermal annealing at different temperatures for 2 h to increase the crystallinity of PLLA matrix. The results show that the crystallinity of PLLA/PCL blend annealing at 80 °C is exceeding 40% and impact strength of the samples increases from 5.92 KJ/m
2
of unannealed neat PLLA to 26.81 KJ/m
2
. At the same time, the thermal properties are also improved by a large margin.