Isothermal crystallization and chain mobility of poly(L-lactide)

✍ Scribed by S. Iannace; L. Nicolais

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 217 KB
• Volume: 64
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970502)64:5<911::aid-app11>3.0.co;2-w

✦ Synopsis

Isothermal melt crystallization of poly( L-lactide ) (PLLA) has been studied in the temperature range of 90 to 135ЊC. A maximum in crystallization kinetic was observed around 105ЊC. A transition from regime II to regime III is present around 115ЊC. The crystal morphology is a function of the degree of undercooling. At crystallization temperatures (T c ) below 105ЊC, further crystallization occurs upon heating; this behavior is not detected for T c above 110ЊC. The analysis of the heat capacity increment at glass transition temperature ( T g ) and of dielectric properties of PLLA indicates the presence of a fraction of the amorphous phase which does not relax at the T g , and the amount of this so-called rigid amorphous phase is a function of T c .