کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10609880 | 984736 | 2011 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Influence of crystal polymorphism on mechanical and barrier properties of poly(l-lactic acid)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The effect of crystal polymorphism on barrier and mechanical properties of PLLA is detailed in this contribution. PLLA films containing different amounts of α and αⲠcrystal forms were prepared by annealing quenched PLLA at different temperatures. The polymorphic structure of the films was analyzed by X-ray diffraction. Mechanical properties and permeability to water vapor were investigated as a function of degree of crystallinity (wC) and related to crystal polymorphism developed during annealing. The polymorphic structure of PLLA significantly affects mechanical and barrier properties. The α crystal modification provides a better barrier to water vapor and a higher Young's modulus, compared to films containing the αⲠmodification, but a lower elongation at break. The varied barrier and mechanical properties were correlated to the different packing of PLLA chains in the two analyzed polymorphs. The conformational disorder of the αⲠform makes this structure a mesophase (condis crystal), with remarkable effects on material properties.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Polymer Journal - Volume 47, Issue 5, May 2011, Pages 1073-1080
Journal: European Polymer Journal - Volume 47, Issue 5, May 2011, Pages 1073-1080
نویسندگان
Mariacristina Cocca, Maria Laura Di Lorenzo, Mario Malinconico, Vincenzo Frezza,