Enhanced Heat Deflection Resistance via Shear Flow-Induced Stereocomplex Crystallization of Polylactide Systems
| Autor: | Zhong-Ming Li, Gan-Ji Zhong, Ruyin Wang, Xu Ji, Zheng-Chi Zhang, Zi-Hong Sang, Jia-Feng Ru, Yan-Fei Huang |
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| Rok vydání: | 2017 |
| Předmět: |
Vicat softening point
Materials science Renewable Energy Sustainability and the Environment General Chemical Engineering 02 engineering and technology General Chemistry Molding (process) 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Shear (sheet metal) law Boiling Melting point Environmental Chemistry Heat deflection temperature Crystallization Composite material 0210 nano-technology Shear flow |
| Zdroj: | ACS Sustainable Chemistry & Engineering. 5:1692-1703 |
| ISSN: | 2168-0485 |
| Popis: | Stereocomplex crystals (SCs) of polylactides (PLAs) with melting points over 220 °C show great potential to improve the heat deflection resistance of PLAs. However, it is still a challenge to fabricate PLA materials with high SC contents due to the requirement for high production efficiency and thus an extremely large cooling rate. In the present work, an upgraded injection molding method, i.e., oscillation shear injection molding (OSIM), was employed to impose intense shear flow on poly(l-lactide) (PLLA)/poly(d-lactide) (PDLA) samples. It is proved that even though a large cooling rate existed, the intense shear flow provided by OSIM induced higher crystallinities of the SCs and well-defined lamellar structure in comparison with conventional injection-molded ones, which subsequently resulted in a high Vicat softening temperature (close to 200 °C) and superb heat deflection resistance in boiling water. To clarify the mechanism of shear-induced SC formation, in situ characterization with precisely controll... |
| Databáze: | OpenAIRE |
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