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TPU/PLA blend foams: Enhanced foamability,structural stability,and implications for shape memory foams |
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| Authors: | Mohammad Faisal Ahmed Yan Li Zhen Yao Kun Cao Changchun Zeng |
| Affiliation: | 1. Industrial and Manufacturing Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310;2. Industrial and Manufacturing Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310
High-Performance Materials Institute, Florida State University, Tallahassee, Florida 32310;3. Institute of Polymerization and Polymer Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027 People's Republic of China;4. Institute of Polymerization and Polymer Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027 People's Republic of China State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027 People's Republic of China |
| Abstract: | A series of thermoplastic polyurethane (TPU)/poly(lactic acid) (PLA) blends are studied in terms of morphological, thermal, and rheological properties by scanning electron microscopy, differential scanning calorimetry, and rheometry. Using supercritical CO2 batch foaming, the foamability of the blends is systematically investigated. It is found that the 80/20 (wt %/wt %) TPU/PLA blend (TPU80%) shows vastly enhanced foamability over a wide range of foaming conditions to produce foams with a myriad of cellular morphology. The foamability enhancement results from the improved cell nucleation and growth, and the changes in the polymer microstructure. Compared to elastic TPU foams, the TPU80% retain their shapes 3.4 times better. Mechanism for the enhanced stability is proposed and verified using Kohlrausch–Williams–Watts model. The materials developed in the study and the mechanistic understanding of the shape fixation process may facilitate the advancement of elastomeric foams in conventional use as well as in novel shape memory applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47416. |
| Keywords: | blend foams elastomeric foams foam morphology relaxation shape fixity |
