Curing studies of bisphenol a based bismaleimide and cloisite 15a nanoclay blends using differential scanning calorimetry and model-free kinetics

2012 ◽  
Vol 128 (1) ◽  
pp. 712-724 ◽  
Author(s):  
R. Surender ◽  
A. Mahendran ◽  
A. Thamaraichelvan ◽  
S. Alam ◽  
C. T. Vijayakumar
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bisphenol A ◽  
Scanning Calorimetry ◽  
Model Free ◽  
Model Free Kinetics ◽  
Cloisite 15A

Model free kinetics—Thermal degradation of bisphenol A based polybismaleimide–cloisite 15a nanocomposites

2013 ◽  
Vol 562 ◽  
pp. 11-21 ◽  
Author(s):  
R. Surender ◽  
A. Mahendran ◽  
A. Thamaraichelvan ◽  
S. Alam ◽  
C.T. Vijayakumar
Keyword(s):  
Thermal Degradation ◽  
Bisphenol A ◽  
Model Free ◽  
Model Free Kinetics ◽  
Cloisite 15A

Crystallization kinetics mechanism investigation of sol–gel-derived NaYF4:(Yb,Er) up-converting phosphors

CrystEngComm ◽  
2017 ◽  
Vol 19 (34) ◽  
pp. 4992-5000 ◽  
Author(s):  
C. Bartha ◽  
C. E. Secu ◽  
E. Matei ◽  
M. Secu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystallization Kinetics ◽  
Sol Gel ◽  
Model Fitting ◽  
Crystallization Mechanism ◽  
Differential Scanning Calorimetry Analysis ◽  
Scanning Calorimetry ◽  
Model Free

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.

Chemical Exchange Reactions in Blends of the Biodegradable Polyester with poly(hydroxy ether of bisphenol-A)

2014 ◽  
Vol 953-954 ◽  
pp. 1246-1249 ◽  
Author(s):  
Chean Cheng Su ◽  
Chern Hwa Chen ◽  
Neng Lang Shih ◽  
Yin Shuo Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Bisphenol A ◽  
Chemical Exchange ◽  
Exchange Reactions ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Butylene Terephthalate ◽  
Before And After ◽  
Hydroxy Ether

Compatibilization via transreactions in blends of poly (butylene succinate-co-butylene terephthalate) [P(BS-co-BT)] with poly (hydroxy ether of bisphenol-A) (phenoxy) were investigated. Analyses were based on characterization using differential scanning calorimetry (DSC) and solid-state nuclear magnetic resonance (NMR). They revealed that the P(BS-co-BT)/phenoxy blend had a phase morphology that could be homogenized only following annealing at high temperatures. As-blended P(BS-co-BT)/phenoxy (50/50 composition) exhibited immiscible phases with two distinct Tgs, but the initially phase separated blends finally merged to form a homogeneous phase with a single Tgupon heating and annealing for 60 min at 280 °C. Chemical exchange reactions upon heat-annealing were likely to have caused the phase homogenization in the P(BS-co-BT)/phenoxy blend. NMR was performed on blend samples before and after they were heated to 280 °C, but the similarity of bonds made obtaining straight results difficult. Results of this study demonstrate phase homogenization can be brought only upon heat-annealing in the P(BS-co-BT)/phenoxy blend.

Complementarity of Atom Probe, Small Angle Scattering and Differential Scanning Calorimetry for the Study of Precipitation in Aluminium Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 926-932 ◽  
Author(s):  
Frédéric de Geuser ◽  
Thomas Dorin ◽  
Williams Lefebvre ◽  
Baptiste Gault ◽  
Alexis Deschamps
Keyword(s):  
Differential Scanning Calorimetry ◽  
Small Angle ◽  
Atom Probe Tomography ◽  
Aluminium Alloys ◽  
Atom Probe ◽  
Small Angle Scattering ◽  
Precipitation Behavior ◽  
Scanning Calorimetry ◽  
Model Free ◽  
Angle Scattering

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.

SOĞUK HADDELENMİŞ AA3105 VE AA5005 LEVHALARIN DSC ANALİZİ İLE YENİDEN KRİSTALLENME KİNETİĞİ

2021 ◽  
Vol 8 (17) ◽  
pp. 80-85
Author(s):  
Atae RAOUGUI ◽  
Ion GRECU ◽  
Volkan Murat YILMAZ ◽  
Kenan YILDIZ
Keyword(s):  
Differential Scanning Calorimetry ◽  
Aluminum Alloy ◽  
Activation Energies ◽  
Isothermal Kinetics ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Recrystallization Kinetics ◽  
Model Free ◽  
Cold Rolled ◽  
Kinetics Of

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.

scholarly journals Flexible Nanocomposites Based on Polydimethylsiloxane Matrices with DNA-Modified Graphene Filler: Curing Behavior by Differential Scanning Calorimetry

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2301 ◽  
Author(s):  
Elisa Toto ◽  
Susanna Laurenzi ◽  
Maria Gabriella Santonicola
Keyword(s):  
Differential Scanning Calorimetry ◽  
Deoxyribonucleic Acid ◽  
Isoconversional Methods ◽  
Activation Energies ◽  
Scanning Calorimetry ◽  
Curing Behavior ◽  
Model Free ◽  
Lower Viscosity ◽  
Modified Graphene

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.

scholarly journals Novel Bio-Based Epoxy Thermosets Based on Triglycidyl Phloroglucinol Prepared by Thiol-Epoxy Reaction

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 337 ◽  
Author(s):  
Dailyn Guzmán ◽  
David Santiago ◽  
Àngels Serra ◽  
Francesc Ferrando
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Bisphenol A ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
High Transparency ◽  
Epoxy Curing ◽  
Curing Agents

The pure trifunctional glycidyl monomer from phloroglucinol (3EPO-Ph) was synthesized and used as feedstock in the preparation of novel bio-based thermosets by thiol-epoxy curing. The monomer was crosslinked with different commercially available thiols: tetrafunctional thiol (PETMP), trifunctional thiol (TTMP) and an aromatic dithiol (TBBT) as curing agents in the presence of a base. As catalyst, two different commercial catalysts: LC-80 and 4-(N,N-dimethylamino) pyridine (DMAP) and a synthetic catalyst, imidazolium tetraphenylborate (base generator, BG) were employed. The curing of the reactive mixtures was studied by using DSC and the obtained materials by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results revealed that only the formulations catalyzed by BG showed a latent character. Already prepared thermosetting materials showed excellent thermal, thermomechanical and mechanical properties, with a high transparency. In addition to that, when compared with the diglycidyl ether of bisphenol A (DGEBA)/PETMP material, the thermosets prepared from the triglycidyl derivative of phloroglucinol have better final characteristics and therefore this derivative can be considered as a partial or total renewable substitute of DGEBA in technological applications.

scholarly journals Kinetic Analysis of the Curing of a Partially Biobased Epoxy Resin Using Dynamic Differential Scanning Calorimetry

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 391 ◽  
Author(s):  
Diego Lascano ◽  
Luis Quiles-Carrillo ◽  
Rafael Balart ◽  
Teodomiro Boronat ◽  
Nestor Montanes
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
Curing Kinetics ◽  
Reaction Model ◽  
Diglycidyl Ether ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Model Free

This research presents a cure kinetics study of an epoxy system consisting of a partially bio-sourced resin based on diglycidyl ether of bisphenol A (DGEBA) with amine hardener and a biobased reactive diluent from plants representing 31 wt %. The kinetic study has been carried out using differential scanning calorimetry (DSC) under non-isothermal conditions at different heating rates. Integral and derivative isoconversional methods or model free kinetics (MFK) have been applied to the experimental data in order to evaluate the apparent activation energy, Ea, followed by the application of the appropriate reaction model. The bio-sourced system showed activation energy that is independent of the extent of conversion, with Ea values between 57 and 62 kJ·mol−1, corresponding to typical activation energies of conventional epoxy resins. The reaction model was studied by comparing the calculated y(α) and z(α) functions with standard master plot curves. A two-parameter autocatalytic kinetic model of Šesták–Berggren [SB(m,n)] was assessed as the most suitable reaction model to describe the curing kinetics of the epoxy resins studied since it showed an excellent agreement with the experimental data.

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