Glass Formation During Room Temperature, Isothermal Drying

2003 ◽  
Author(s):  
Alptekin Aksan ◽  
Mehmet Toner
Keyword(s):  
Glass Transition ◽  
Glassy State ◽  
Glass Transitions ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Glass Transition Kinetics ◽  
The Stability ◽  
Isothermal Drying ◽  
Kinetics Of

Isothermal drying and glass transition of solutions and films have drawn considerable attention from many industries. We here explore the feasibility of modifying the isothermal drying and vitrification kinetics of carbohydrate solutions in order to ensure the stability and quality of their ingredients. Modulated Differential Scanning Calorimetry experiments with isothermally dried trehalose and trehalose/dextran solutions were performed and the glass transition kinetics have been determined. Three distinct drying regimes were observed. With isothermal, isobaric drying at 0%RH, it was indeed possible to reach the glassy state for a trehalose and a trehalosedextran system. With the addition of high molecular weight sugars, the glass transitions of isothermally dried carbohydrate solutions can be accelerated as a function of dextran mass ratio in the sample.

Study of glass transition kinetics of As 2 S 3 and As 2 Se 3 by ultrafast differential scanning calorimetry

2019 ◽  
Vol 28 (4) ◽  
pp. 047802 ◽  
Author(s):  
Fan Zhang ◽  
Yimin Chen ◽  
Rongping Wang ◽  
Xiang Shen ◽  
Junqiang Wang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Scanning Calorimetry ◽  
Glass Transition Kinetics ◽  
Kinetics Of

STUDY OF GLASS TRANSITION KINETICS FOR Co66Si12B16Fe4Mo2 METALLIC GLASS

2013 ◽  
Vol 22 ◽  
pp. 321-326 ◽  
Author(s):  
ASHMI T. PATEL ◽  
ARUN PRATAP
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Glass Forming Ability ◽  
Fragility Index ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Glass Transition Kinetics ◽  
Glass Forming ◽  
The Given ◽  
Kinetics Of

Metallic glasses have received considerable attention in comparison to normal metallic materials due to their superior physical, mechanical, electrical and magnetic properties. Understanding the glass transition kinetics of metallic alloys is of great importance in order to know its thermal stability. In the present paper, kinetics of glass transition of metallic glass Co66Si12B16Fe4Mo2 is studied using thermal analysis technique, i.e. differential scanning calorimetry (DSC), by non-isothermal heating of the sample at four different heating rates. The activation energy (E) of the glass transition region is determined by two most frequently used methods, namely, Moynihan’s method and Kissinger’s equation. The fragility index, m is also calculated using Tg, which is a measure of glass forming ability of the given system. The results show that the fragility index ‘m’ of the given system falls below 16. This clearly indicates that the given system is strong liquid with excellent glass forming ability (GFA).

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

scholarly journals Physical Aging Behavior of a Glassy Polyether

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 954
Author(s):  
Xavier Monnier ◽  
Sara Marina ◽  
Xabier Lopez de Pariza ◽  
Haritz Sardón ◽  
Jaime Martin ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physical Aging ◽  
Glassy State ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Narrow Temperature Range ◽  
Glass Forming ◽  
Fast Scanning Calorimetry

The present work aims to provide insights on recent findings indicating the presence of multiple equilibration mechanisms in physical aging of glasses. To this aim, we have investigated a glass forming polyether, poly(1-4 cyclohexane di-methanol) (PCDM), by following the evolution of the enthalpic state during physical aging by fast scanning calorimetry (FSC). The main results of our study indicate that physical aging persists at temperatures way below the glass transition temperature and, in a narrow temperature range, is characterized by a two steps evolution of the enthalpic state. Altogether, our results indicate that the simple old-standing view of physical aging as triggered by the α relaxation does not hold true when aging is carried out deep in the glassy state.

scholarly journals Manipulation of the Glass Transition Properties of a High-Solid System Made of Acrylic Acid-N,N′-Methylenebisacrylamide Copolymer Grafted on Hydroxypropyl Methyl Cellulose

2021 ◽  
Vol 22 (5) ◽  
pp. 2682
Author(s):  
Nazim Nassar ◽  
Felicity Whitehead ◽  
Taghrid Istivan ◽  
Robert Shanks ◽  
Stefan Kasapis
Keyword(s):  
Glass Transition ◽  
Acrylic Acid ◽  
Methyl Cellulose ◽  
Small Deformation ◽  
Polymerization Reaction ◽  
Solid Matrix ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
High Solid ◽  
Hydroxypropyl Methyl Cellulose

Crosslinking of hydroxypropyl methyl cellulose (HPMC) and acrylic acid (AAc) was carried out at various compositions to develop a high-solid matrix with variable glass transition properties. The matrix was synthesized by the copolymerisation of two monomers, AAc and N,N′-methylenebisacrylamide (MBA) and their grafting onto HMPC. Potassium persulfate (K2S2O8) was used to initiate the free radical polymerization reaction and tetramethylethylenediamine (TEMED) to accelerate radical polymerisation. Structural properties of the network were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), modulated differential scanning calorimetry (MDSC), small-deformation dynamic oscillation in-shear, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results show the formation of a cohesive macromolecular entity that is highly amorphous. There is a considerable manipulation of the rheological and calorimetric glass transition temperatures as a function of the amount of added acrylic acid, which is followed upon heating by an extensive rubbery plateau. Complementary TGA work demonstrates that the initial composition of all the HPMC-AAc networks is maintained up to 200 °C, an outcome that bodes well for applications of targeted bioactive compound delivery.

scholarly journals Thermal Properties and Non-Isothermal Crystallization Kinetics of Poly (δ-Valerolactone) and Poly (δ-Valerolactone)/Titanium Dioxide Nanocomposites

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 452 ◽  
Author(s):  
Waseem Saeed ◽  
Abdel-Basit Al-Odayni ◽  
Abdulaziz Alghamdi ◽  
Ali Alrahlah ◽  
Taieb Aouak
Keyword(s):  
Titanium Dioxide ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Three Dimensional ◽  
Degree Of Crystallinity ◽  
Simultaneous Occurrence ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
The Stability ◽  
Kinetics Of

New poly (δ-valerolactone)/titanium dioxide (PDVL/TiO2) nanocomposites with different TiO2 nanoparticle loadings were prepared by the solvent-casting method and characterized by Fourier transform infra-red, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, and thermogravimetry analyses. The results obtained reveal good dispersion of TiO2 nanoparticles in the polymer matrix and non-formation of new crystalline structures indicating the stability of the crystallinity of TiO2 in the composite. A significant increase in the degree of crystallinity was observed with increasing TiO2 content. The non-isothermal crystallization kinetics of the PDVL/TiO2 system indicate that the crystallization process involves the simultaneous occurrence of two- and three-dimensional spherulitic growths. The thermal degradation analysis of this nanocomposite reveals a significant improvement in the thermal stability with increasing TiO2 loading.

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