 |
 |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Differential Scanning Calorimetric Studies of Non-isothermal Crystallization of HDPE and HDPE/CaCO3 Composites) ผู้เขียน: ดร.ณัฐณรัณ (สุปรียา) ตรีวิจิตรเกษม, รองศาสตราจารย์ ,  Thanate Sukkamart, พนม กาศรุณ สื่อสิ่งพิมพ์:pdf AbstractCrystallization of high density polyethylene (HDPE) and HDPE/CaCO3 composites (10, 20 and 30% wt, CaCO3) was investigated by differential scanning calorimetry (DSC) under non-isothermal conditions. The Avrami method modified by Jeziorny and a method developed by Liu et al. were employed to describe the non-isothermal crystallization process of the samples. The results showed that the Avrami exponent n decreased from 3.0 to 2.4 with an increase in the cooling rate from 5?C/min to 40?C/min, while the crystal growth constant Zc was nearly constant (~1.1) at a 10?C /min – 40?C/min cooling rate for all systems. The value of F(T) showed that the crystallization rate of the HDPE/10% CaCO3 composite was the slowest at a given cooling rate. Moreover, the activation energy determined from the Kissinger method indicated little difference in the values of the activation energy for all systems, except the 30% CaCO3 system which showed a slightly higher activation energy. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Isothermal Crystallization Kinetics of Polypropylene/CaCO3 Blends) ผู้เขียน:ดร.ณัฐณรัณ (สุปรียา) ตรีวิจิตรเกษม, รองศาสตราจารย์, Kriengkri Timsorn สื่อสิ่งพิมพ์:pdf AbstractCrystallization of polypropylene (PP) and PP blended with 10, 15, and 20 wt% CaCO3 was investigated using Differential Scanning Calorimetry (DSC) under isothermal conditions at four different crystallization temperatures of 110, 115, 120 and 125?C. The kinetic parameters were analyzed using the Avrami equation. The results show that the Avrami exponent, n, decreased with increasing crystallization temperature, except for a crystallization temperature TC of 125?C where the opposite effect was observed. At the same crystallization temperature, the values of n for PP/CaCO3 blends were slightly lower than for PP, which suggests that the addition of CaCO3 to PP caused a slight decrease in heterogeneous nucleation. Both PP and PP/CaCO3 blends followed three-dimensional crystallization growth. The value of the crystallization rate constant, k, strongly depended on the crystallization temperature, which decreasing with increasing crystallization temperature and CaCO3 content. The rate of the three-dimensional crystallization growth was reduced by increasing the crystallization temperature and CaCO3 content. |
 ที่มา:มหาวิทยาลัยเกษตรศาสตร์หัวเรื่อง:Stochastic Simulation for Morphological Development During the Isothermal Crystallization of Semicrystalline Polymers: A Case Study of Syndiotactic Polypropylene |