Crystallization kinetics of chain extended poly(L-lactide)s having different molecular structures
Poly(L-lactide)s (PLLAs) with different chain structures were prepared by reactive melt processing and using Joncryl ADR as chain extender. Results of gel permeation chromatography (GPC) revealed that chain extended PLLAs had high molecular weights and two differentiated molecular weight distributio...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/171482 |
| Acceso en línea: | https://hdl.handle.net/2117/171482 https://dx.doi.org/10.1016/j.matchemphys.2019.122217 |
| Access Level: | acceso abierto |
| Palabra clave: | Polylactic acid Crystallization Chain extended PLLA Molecular structure Rheological properties Crystallization kinetics Àcid polilàctic Cristal·lització Àrees temàtiques de la UPC::Enginyeria dels materials Àrees temàtiques de la UPC::Enginyeria química |
| Sumario: | Poly(L-lactide)s (PLLAs) with different chain structures were prepared by reactive melt processing and using Joncryl ADR as chain extender. Results of gel permeation chromatography (GPC) revealed that chain extended PLLAs had high molecular weights and two differentiated molecular weight distributions. Linear rheology was sensitive to the obtained molecular structures and revealed as the increase on the amount of chain extender gradually led to a decrease of the loss factor in the whole frequency region and to an increase of melt viscosity and both storage and loss moduli. In addition, the entanglement density increased significantly with addition of chain extender and had a significant influence on crystallization kinetics. Correlation of molecular weight, viscosity and entanglements changed the crystallinity and crystallization kinetics of chain extended PLLAs in both isothermal and non-isothermal crystallizations. Specifically, samples prepared from 1 wt-% of Joncryl (PLLA1R) revealed the highest nucleation and the fastest crystallization rate. |
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