01.Nov.2011
This article highlights the melt crystallization behavior of different grades of isotactic polypropylene (iPP) using a hot-stage polarizing optical microscopy. iPP samples were heated up at a heating rate of 10°C/min passing the melting temperature and then kept for 3 min at a temperature range of 175–200°C before they cooled rapidly at 40°C/min to crystallize isothermally at a range of 130–145°C. It has been found that the temperature at which the samples were kept has a strong effect on the crystallization mode; for samples heated up and kept at temperatures below 190°C, the crystallization started with thin and long rods or nodules, which grew in the circumferential direction only while their lengths remain unchanged as the time passed. The shape of the nodules can be straight, circular, branched, or entangled, and they can grow parallel to each other or they can be crossed or in a random way. This phenomenon disappeared completely for samples melted and kept at temperatures above 195°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 https://www.researchgate.net/publication/264681783_Nodular_Structure_of_Isotactic_Polypropylene_Crystallizes_from_the_Melt
This article highlights the melt crystallization behavior of different grades of isotactic polypropylene (iPP) using a hot-stage polarizing optical microscopy. iPP samples were heated up at a heating rate of 10°C/min passing the melting temperature and then kept for 3 min at a temperature range of 175–200°C before they cooled rapidly at 40°C/min to crystallize isothermally at a range of 130–145°C. It has been found that the temperature at which the samples were kept has a strong effect on the crystallization mode; for samples heated up and kept at temperatures below 190°C, the crystallization started with thin and long rods or nodules, which grew in the circumferential direction only while their lengths remain unchanged as the time passed. The shape of the nodules can be straight, circular, branched, or entangled, and they can grow parallel to each other or they can be crossed or in a random way. This phenomenon disappeared completely for samples melted and kept at temperatures above 195°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
https://www.researchgate.net/publication/264681783_Nodular_Structure_of_Isotactic_Polypropylene_Crystallizes_from_the_Melt
17.Apr.2024
16.Jan.2024
20.Sep.2023
أنا طالبة في الهندسة الصناعية, اختياري لهذا التخصص كان بناءً على أهميته الكبيرة كمهنة في الحاضر والمستقبل ... رغد بركات
الهندسة الصناعية تساعدك على اتخاذ قرارات أفضل، وتعطي أشكالا أخرى من مبادئ الهندسة بشكل عملي وعلمي في آن. ... محمود صلاح
قسم الهندسة الكيميائية قسم جميل جدا تعلمت فيه الكثير ومما تعلمته فيه جدية العمل وروح الفريق الواحد .. ... رغد الشويكي