کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5191230 1381228 2005 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Deformation and damage upon stretching of degradable polymers (PLA and PCL)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Deformation and damage upon stretching of degradable polymers (PLA and PCL)
چکیده انگلیسی
Microstructure and plastic behavior of poly(lactic acid), PLA, and poly(ε-caprolactone), PCL, are investigated. The injected molded specimens are analyzed as received. Thermomechanical properties are characterized by DSC and DMA and crystalline structure by WAXS. The results show that PLA samples are weakly crystalline (14 wt%) and that amorphous phase is glassy at room temperature. The PCL samples exhibit higher crystallinity (53 wt%) and contain a rubber-like amorphous phase. Mechanical behavior is investigated by means of novel video-controlled materials testing system specially developed to assess true stress vs. true strain curves and to record the volume changes upon stretching. While tested at 50 °C, PLA undergoes extensive plastic deformation with a dramatic yield softening followed by a progressively increasing strain hardening. Volume strain, which characterizes deformation damage, increases steadily over the whole plastic stage until reaching 0.27 for an axial strain of 1, 4. For its part, PCL exhibits at 23 °C a much progressive plastic response with a soft yield point, no softening, and moderate strain hardening at large strain. Volume change is delayed until axial strain reaches 0.4. Subsequent damage grows very quickly, eventually reaching 0.2 for an ultimate strain of 1, 3. Results are discussed on the basis of microscopic damage mechanisms observed in the stretched state.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 18, 23 August 2005, Pages 7370-7385
نویسندگان
, , , , ,