کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5191453 1381232 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Single crystal morphology of star-branched polyesters with crystallisable poly(ε-caprolactone) arms
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Single crystal morphology of star-branched polyesters with crystallisable poly(ε-caprolactone) arms
چکیده انگلیسی
Star-branched polymers consisting of poly(ε-caprolactone) (PCL) attached to third generation dendrimer, hyperbranched and dendron cores have been studied together with linear PCL analogues. The degree of polymerisation of the PCL arms of the star-branched polymers ranged from 14 to 81. Single crystals were grown from dilute solution and studied by transmission electron microscopy. Single crystals of linear PCL were multilayer hexagons with flat or slightly curved {110} and {100} faces. These single crystals were larger along [010] than along [100]. Single crystals of star-branched PCL showed the same basic shape, but with many crystallographic and irregular steps on the lateral crystal faces. The width of the micro-faces was typically 100-300 nm. These single crystals were more extended along [100] than along [010]. It is proposed that the high fold surface free energy and the constrained character of the star-branched polymers favour the formation of steps on the growth faces. Globular polycrystalline aggregates were also observed. They originated from a more concentrated polymer phase following phase separation of the solution. In the case of the star-branched polymers, lamellar branching was observed with a 30° angle between the crystals arms.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 16, 25 July 2005, Pages 5992-6000
نویسندگان
, ,