Melting of Conformationally Disordered Crystals (α′-Phase) of Poly(l -lactic acid)
| Autor: | Christoph Schick, Maria Laura Di Lorenzo, René Androsch |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Poly l lactic acid
Materials science Polymers and Plastics Organic Chemistry Melting Condensed Matter Physics Kinetics Crystallography Polymorphism (materials science) Poly(lactic acid) Polymer chemistry Materials Chemistry Crystal reorganization Polymorphism Physical and Theoretical Chemistry Crystallization |
| Zdroj: | Macromolecular chemistry and physics (2014). doi:10.1002/macp.201400126 info:cnr-pdr/source/autori:René Androsch, Christoph Schick, Maria Laura Di Lorenzo/titolo:Melting of Conformationally Disordered Crystals (a'-Phase) of Poly(L-lactic acid)/doi:10.1002%2Fmacp.201400126/rivista:Macromolecular chemistry and physics (Print)/anno:2014/pagina_da:/pagina_a:/intervallo_pagine:/volume |
| ISSN: | 1022-1352 |
| DOI: | 10.1002/macp.201400126 |
| Popis: | Melting and reorganization of conformationally disordered crystals (??-phase) of poly( L -lactic acid) (PLLA) are analyzed as a function of the rate of heating in a wide range between about 10 -1 and 10 3 K s -1 . It is found for the fi rst time that the reorganization of conformationally disordered ??-crystals into stable ?-crystals can be suppressed by fast heating. Heating of ??-crystals of PLLA at a constant rate, faster than 30 K s -1 , leads to its complete melting between 150 and 160 °C and suppression of formation of ?-crystals on continuation of heating. Non-isothermal reorganization of ??-crystals into ?-crystals only occurs when heating at a rate slower than 30 K s -1 . It is evidenced that isothermal reorganization of ??-crystals into ?-crystals at 150-160 °C proceeds via melting followed by recrystallization rather than a solid-solid phase transition. |
| Databáze: | OpenAIRE |
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