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 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 : Non-Isothermal Crystallization and Thermal Degradation Kinetics of Biodegradable Poly(butylene adipate-co-terephthalate)/Starch Blends) ผู้เขียน:ดร.สุรศักดิ์ เชียงกา, รองศาสตราจารย์ , Satayu Suwannasopon, Nutnarun (Supreya) Trivijitkasem สื่อสิ่งพิมพ์:pdf AbstractThe non-isothermal crystallization behavior of biodegradable poly (butylene adipate-coterephthalate)/ starch (PBAT/S) blends was studied using differential scanning calorimetry under a nitrogen atmosphere from 25 to 225 ?C at four constant cooling rates of 5, 10, 15 and 20 ?C.min-1. There was only one crystallization peak in the exothermic curve which shifted to a lower temperature as the cooling rate was increased. The crystallization temperature decreased from 98 to 84 ?C, but the crystallization enthalpy increased from 11 to 12 J.g-1 as the heating rate was increased. The thermal degradation(TG) of the PBAT/S blends was studied using thermogravimetric analysis under a nitrogen atmosphere from 100 to 800 ?C at five constant heating rates of 1, 2, 5, 10, and 15 ?C.min-1. The TG curves showed two degradation stages occurring at 309–342 ?C and 375–420 ?C, which were the degradation of corn starch and PBAT, respectively. The thermal degradation kinetics of the PBAT/S were analyzed using the isoconversion Flynn- Wall-Ozawa model-free method. The results showed that both the apparent activation energy and the logarithm pre-exponent factor increased with increasing conversion ?. The average apparent activation energy and the average logarithm apparent pre-exponent factor for ? = 0.1 – 0.9 were 266 kJ.mol-1 and 37 min-1, respectively. The reaction model g(?) determined from the master plot method for PBAT/S was a phase-boundary controlled reaction, where g(?) = [1– (1– ?)1/2] |
 ที่มา:มหาวิทยาลัยเกษตรศาสตร์หัวเรื่อง:การจำลองการเปลี่ยนแปลงทางสัณฐานวิทยาของพอลิเมอร์ที่ตกผลึกภายใต้สภาวะอุณหภูมิไม่คงที่ |
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ที่มา:Siam Physics Congress 2011หัวเรื่อง:- |
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