scholarly journals Crystallization Kinetics of Low-Melting Point Vegetable Oils

2021 ◽  
Vol 22 (3) ◽  
pp. 67-75
Author(s):  
Yayoi MIYAGAWA
e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Laura Di Lorenzo ◽  
Pawel Sajkiewicz ◽  
Arkadiusz Gradys ◽  
Paola La Pietra

AbstractStudies of kinetics of polymer crystallization are generally performed by heating the material above the melting point, in order to erase previous thermal and mechanical history, followed by rapid cooling to the desired crystallization temperature or by cooling at a constant rate. For poly(3-hydroxybutyrate) this procedure implies some degradation of the polymer chain, which starts below the onset of melting. In this article the effects of melting conditions on the subsequent crystallization kinetics are discussed. It is shown that in order to sufficiently cancel memories of previous crystalline order of the analyzed PHB, it is necessary to bring the material at a temperature higher than 192 °C. Thermal treatments conducted at lower temperatures are not sufficient to destroy all solid aggregates, and crystallization of PHB has an anticipated onset of crystallization due to nucleation occurring via self-seeding. The chain degradation attained upon exposure at high temperatures has much lesser influence on crystallization kinetics than incomplete melting, with some effects detectable on the spherulitic morphology and on the final degree of crystallinity.


1976 ◽  
Vol 49 (1) ◽  
pp. 170-178 ◽  
Author(s):  
G. Gianotti ◽  
A. Capizzi ◽  
L. Del Giudice

Abstract The thermodynamic parameters of fusion and crystallization kinetics of cis-polyoctenamer were investigated. We adopted the cryoscopic method based on the melting point decrease in the presence of diluents, using toluene as a diluent. It was also possible to determine the equilibrium melting temperature by extrapolating the “kinetic” melting points, measured on polymers crystallized at various temperatures. The dependence of ΔHu and Teq on the cis content allows evaluation of their values for all-cis-polyoctenamer. Conclusions about the elastomeric properties of the polymer are drawn.


2012 ◽  
Vol 61 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Lakmali Samuditha K. Dassanayake ◽  
Dharma R. Kodali ◽  
Satoru Ueno ◽  
Kiyotaka Sato

2020 ◽  
Author(s):  
Liyuan Wang ◽  
Jiaxi Liu ◽  
Nan Lu ◽  
Zengchao Yang ◽  
Gang He ◽  
...  

2000 ◽  
Vol 650 ◽  
Author(s):  
Lance L. Snead ◽  
Martin Balden

ABSTRACTDensification and crystallization kinetics of bulk SiC amorphized by neutron irradiation is studied. The temperature of crystallization onset of this highly pure, fully amorphous bulk SiC was found to be between 875-885°C and crystallization is nearly complete by 950°C. In-situ TEM imaging confirms the onset of crystallization, though thin-film effects apparently alter the kinetics of crystallization above this temperature. It requires >1125°C for complete crystallization of the TEM foil. Annealing at temperatures between the irradiation and crystallization onset temperature is seen to cause significant densification attributed to a relaxation, or reordering, of the as-amorphized structure.


2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.


Author(s):  
Pratim Kumar Patra ◽  
Aanchal Jaisingh ◽  
Vishal Goel ◽  
Gurpreet Singh Kapur ◽  
Leena Nebhani

2021 ◽  
Vol 154 (14) ◽  
pp. 144703
Author(s):  
R. Scott Smith ◽  
M. Tylinski ◽  
Greg A. Kimmel ◽  
Bruce D. Kay

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