کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5190449 | 1381206 | 2005 | 15 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
From stiff plastic to elastic polypropylene: Polymorphic transformations during plastic deformation of metallocene-made isotactic polypropylene
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: From stiff plastic to elastic polypropylene: Polymorphic transformations during plastic deformation of metallocene-made isotactic polypropylene From stiff plastic to elastic polypropylene: Polymorphic transformations during plastic deformation of metallocene-made isotactic polypropylene](/preview/png/5190449.png)
چکیده انگلیسی
An analysis of the mechanical properties and polymorphic transformations occurring during plastic deformation of isotactic polypropylene with variable stereoregularity, containing only rr stereo-defects, is presented. Thermoplastic materials showing high stiffness, or high flexibility, or elastic properties can be produced depending on the concentration of defects. Relationships between the different mechanical behavior and the different observed polymorphic transformations occurring during tensile deformation are discussed. The elastic behavior of the poorly isotactic samples and the values of the corresponding mechanical parameters are related to the structural transformations occurring during stretching. The γ-form present in the unstretched sample transforms by stretching into the α-form, which in turn, transforms into the mesomorphic form at very high deformations. The mesomorphic form transforms back into the crystalline α-form upon releasing the tension and elastic recovery is observed. The crystallization of the mesomorphic form into the α-form upon releasing the tension is not observed in the case of flexible or stiff-plastic samples, which do not show elastic behavior. This indicates that in the elastomeric samples elasticity is probably partially due to the enthalpic contribution associated with the crystallization of the mesomorphic form into the α-form.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 22, 24 October 2005, Pages 9461-9475
Journal: Polymer - Volume 46, Issue 22, 24 October 2005, Pages 9461-9475
نویسندگان
Claudio De Rosa, Finizia Auriemma, Giordano De Lucia, Luigi Resconi,