Model-free kinetics: Curing behavior of phenol formaldehyde resins by differential scanning calorimetry

2002 ◽  
Vol 87 (3) ◽  
pp. 433-440 ◽  
Author(s):  
Guangbo He ◽  
Bernard Riedl ◽  
Abdellatif Aït-Kadi
Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2301 ◽  
Author(s):  
Elisa Toto ◽  
Susanna Laurenzi ◽  
Maria Gabriella Santonicola

Novel silicone-based nanocomposites with varied elastic properties were prepared by blending standard polydimethylsiloxane (PDMS) with a lower viscosity component (hydroxyl-terminated PDMS) and integrating a graphene nanoplatelets (GNP) filler modified by strands of deoxyribonucleic acid (DNA). The curing behavior of these nanocomposites was studied by dynamic and isothermal differential scanning calorimetry. The activation energies of the polymerization reactions were determined using the Kissinger method and two model-free isoconversional approaches, the Ozawa–Flynn–Wall and the Kissinger–Akahira–Sunose methods. Results show that the complex trend of the curing behavior can be described using the isoconversional methods, unveiling lower activation energies for the nanocomposites with standard PDMS matrices. The role of the DNA modification of graphene on the curing behavior is also demonstrated. The curing reactions of the nanocomposites with the PDMS matrix are favored by the presence of the GNP–DNA filler. PDMS/PDMS–OH blends generate softer nanocomposites with hardness and reduced elastic modulus that can be tuned by varying the amount of the filler.


CrystEngComm ◽  
2017 ◽  
Vol 19 (34) ◽  
pp. 4992-5000 ◽  
Author(s):  
C. Bartha ◽  
C. E. Secu ◽  
E. Matei ◽  
M. Secu

The crystallization mechanism of sol–gel-derived NaYF4:(Yb,Er) up-converting phosphors has been studied by differential scanning calorimetry analysis using both model-free and model fitting approaches.


1990 ◽  
Vol 9 (2) ◽  
pp. 153-162,228 ◽  
Author(s):  
Seiji BAN ◽  
Yosifumi TAKAHASHI ◽  
Hiroaki TANASE ◽  
Jiro HASEGAWA

2014 ◽  
Vol 794-796 ◽  
pp. 926-932 ◽  
Author(s):  
Frédéric de Geuser ◽  
Thomas Dorin ◽  
Williams Lefebvre ◽  
Baptiste Gault ◽  
Alexis Deschamps

Two examples of precipitation studies (in Al-Li-Cu and Al-Li-Mg alloys) are shown to demonstrate the complementarity of atom probe tomography, small-angle-scattering and differential scanning calorimetry for precipitation studies. It will be used to unravel an unexpected two-step precipitation behavior of T1in Al-Li-Cu and to ascertain precipitates size in Al-Li-Mg. through a model free comparison between atom probe and SAXS.


2003 ◽  
Vol 90 (6) ◽  
pp. 1678-1682 ◽  
Author(s):  
Eliton S. De Medeiros ◽  
Jos� A. M. Agnelli ◽  
Kuruvilla Joseph ◽  
Laura H. De Carvalho ◽  
Luiz H. C. Mattoso

Author(s):  
Atae RAOUGUI ◽  
Ion GRECU ◽  
Volkan Murat YILMAZ ◽  
Kenan YILDIZ

In this study, the non-isothermal recrystallization kinetics of cold rolled AA3105 and AA5005 aluminum alloy sheets obtained from ASAŞ Aluminum located in Akyazı-Sakarya was studied by using differential scanning calorimetry (DSC). The non – isothermal kinetics was performed by using Kissenger, Boswell, Ozawa and Starink methods known as model – free methods. The recrystallization temperatures on DSC graphics at different heating rates (β) were deduced and the activation energies were calculated from the slopes from Y – 1/T diagrams. Y is ln(β/T2) for Kissenger, ln(β/T) for Boswell, ln(β) for Ozawa and ln(β/T1.92) for Starink. The results showed that the activation energies of recrystallization are in the range of 194 – 206 kJ/mol for cold rolled AA5005 sheet and in the range of 235 – 257 kJ/mol for cold rolled AA3105 sheet, according to four non-isothermal kinetics model.


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