کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5187151 1381122 2008 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermomechanical properties of stereoblock poly(lactic acid)s with different PLLA/PDLA block compositions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Thermomechanical properties of stereoblock poly(lactic acid)s with different PLLA/PDLA block compositions
چکیده انگلیسی

Stereoblock poly(lactic acids) (sb-PLAs), having abundant enantiomeric compositions of poly(l-lactic acid) (PLLA), were successfully synthesized by solid-state polycondensation (SSP) of the melt blends of medium molecular weight prepolymers: both PLLA and poly(d-lactic acid) (PDLA) that had primarily been prepared by melt-polycondensation. The molecular weight of the resultant PLLA-rich sb-PLA was effectively enhanced by the dehydrative coupling of abundant PLLA molecules followed by the increase in homo-chiral crystallinity. These sb-PLA were successfully fabricated into polymer films by solution casting to analyze their crystalline morphology and properties. Both DSC and WAXS revealed preferential stereocomplexation in spite of concomitant homo-chiral crystallization for these sb-PLA. Particularly, exclusive sc crystallization was observed with melt-quenched sb-PLA represented whose PDLA ratio was above 15%. Therefore, the stereoblock structure can suppress the homo-chiral crystallization and increase the sc crystallinity even with the non-equivalent PLLA/PDLA compositions. Their thermal resistivity up to 200 °C was supported by the dynamic mechanical analysis of the sb-PLA films.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 49, Issue 11, 27 May 2008, Pages 2656-2661
نویسندگان
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