scholarly journals The Effect of a Secondary Process on the Analysis of Isothermal Crystallisation Kinetics by Differential Scanning Calorimetry

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Catherine A. Kelly ◽  
James N. Hay ◽  
Richard P. Turner ◽  
Mike J. Jenkins
Keyword(s):  
Differential Scanning Calorimetry ◽  
Time Dependence ◽  
Laser Flash ◽  
Avrami Equation ◽  
Secondary Process ◽  
Square Root ◽  
Scanning Calorimetry ◽  
Crystallisation Kinetics ◽  
Long Duration ◽  
Laser Flash Analysis

This paper demonstrates the application of a modified Avrami equation in the analysis of crystallisation curves obtained using differential scanning calorimetry (DSC). The model incorporates a square root of time dependence of the secondary process into the conventional Avrami equation and, although previously validated using laser flash analysis and infrared spectroscopy, is not currently transferable to DSC. Application of the model to calorimetric data required long-duration isotherms and a series of data treatments. Once implemented, the square root of time dependence of the secondary process was once again observed. After separation of the secondary process from the primary, a mechanistic n value of 3 was obtained for the primary process. Kinetic parameters obtained from the analysis were used in the model to regenerate the fractional crystallinity curves. Comparison of the model with experimental data generated R2 values in excess of 0.995. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was used as model polymer due to the prominent secondary crystallisation behaviour that this polymer is known to display.

Non-Isothermal Crystallisation Kinetics of Polyamide 6/Mesoporous Silica Nanocomposites

2007 ◽  
Vol 15 (7) ◽  
pp. 561-567
Author(s):  
Qingyuan Hu ◽  
Xiangling Ji ◽  
Yunfeng Lu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Mesoporous Silica ◽  
Polyamide 6 ◽  
Nucleating Agents ◽  
Scanning Calorimetry ◽  
Crystallisation Kinetics ◽  
Silica Nanocomposites ◽  
Crystallisation Process ◽  
Isothermal Crystallisation ◽  
Kinetics Of

Non-isothermal crystallisation kinetics of a polyamide 6/mesoporous silica nanocomposite (PA6-MS) has been investigated by differential scanning calorimetry (DSC) at different cooling rates. Mandelkern, Jeziorny-Ziabicki and Ozawa methods were applied to describe this crystallisation process. The analyses show that the mesoporous silica particles act as nucleating agents in the composite and that the Avrami exponent n varies from 3.0 to 4.6. The addition of mesoporous silica influenced the mechanism of nucleation and the growth of polyamide 6 (PA 6) crystallites.

Polyethylene Glycol (PEG) - Polyvinyl Alcohol Graft Copolymer System of Non-Isothermal Crystallization Kinetics

2011 ◽  
Vol 332-334 ◽  
pp. 1485-1489
Author(s):  
Mei Zhang ◽  
Tian Yu Xu ◽  
Yong Jia Liu ◽  
Da Hui Sun
Keyword(s):  
Differential Scanning Calorimetry ◽  
Polyethylene Glycol ◽  
Crystallization Kinetics ◽  
Graft Copolymers ◽  
Avrami Equation ◽  
Temperature Peak ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Peak Intensity ◽  
Lower Temperature

The confined of PEG in PVA-g-PEG graft copolymers was investigated by differential scanning calorimetry. The crystallization kinetics was discussed by several methods. The results showed that the lower temperature peak (Tp) shifted to the lower temperature and its peak intensity also decreased with increasing the cooling rates, t1/2 decreased and G increased. The Tp of graft copolymers were lower than pure PEG and t1/2 of which were higher than pure PEG. The graft ratio had litter influence on t1/2. The results also showed that both Jeziorny method and the new method combing the Avrami equation described this system very well.

Induced Smectic-G Phase through Intermolecular Hydrogen Bonding Part VIII: Phase and Crystallization Behaviours of 2-(p-n-heptyloxybenzyIidene imino)-5-chIoro-pyridine: p-n-alkoxybenzoic acid (HICP:n ABA) Complexes

2001 ◽  
Vol 56 (9-10) ◽  
pp. 685-691 ◽  
Author(s):  
M. Srinivasulu ◽  
P. V. V. Satyanarayana ◽  
P. A. Kumar ◽  
V. G. K. M. Pisipatia
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystalline ◽  
Phase Behaviour ◽  
Avrami Equation ◽  
Cooh Group ◽  
Intermolecular Hydrogen Bonding ◽  
Acid Moiety ◽  
Scanning Calorimetry ◽  
Reported Data ◽  
Kinetics Of

Abstract New intermolecular H-bonded liquid crystalline complexes, viz., 2-(p-n-heptyloxybenzylidene imi-no)-5-chloro-pyridine:p-/z-alkoxybenzoic acid; (HICP:nABA) (where n denotes the alkoxy carbon num­ bers 3 to 10 and 12) exhibiting smectic-F (n = 12) and smectic-G phases have been synthesized and char­ acterized by Thermal Microscopy and Differential Scanning Calorimetry (DSC). Detailed IR (solid and solution states) analysis confirms the existence of intermolecular H-bonding between the pyridyl nitro­ gen and the COOH group of the p-n-alkoxybenzoic acid moiety. The phase behaviour of the series is discussed in the light of reported data on free p-n-alkoxybenzoic acids. The crystallization kinetics of a representative complex, using the DSC technique, is discussed. The mechanism of the crystal growth of the new crystalline smectic-G phase is computed with the Avrami equation.

DSC and Mössbauer Studies of Fe80B20 Crystallization

1993 ◽  
Vol 321 ◽  
Author(s):  
Federica Malizia ◽  
Franco Ronconi
Keyword(s):  
Differential Scanning Calorimetry ◽  
Growth Process ◽  
Isothermal Annealing ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Avrami Equation ◽  
Thermal Treatments ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Crystalline Component

ABSTRACTDifferential Scanning Calorimetry has been used to investigate the mechanism of the isothermal crystallization kinetics in Fe80B20 Metallic glass. It is shown that the whole crystallization analysis must include, not only a crystal nucleation-and-growth process, but also a grain-growth process and that these two processes are separated in time during isothermal annealing. These processes have been studied directly finding the parameters which characterize their Mechanism. From the theoretical Johnson-Mehl-Avrami equation describing the nucleation-and-growth process, it was possible to calculate the evolution of the transformed fraction of the material as a function of the annealing time. To infer the meaning of the transformed fraction, samples subjected to different thermal treatments have been studied by Mössbauer Spectroscopy. Our results reveal that the transformed fraction is the sum of the crystalline component formed by all atoms located in the lattice of the grains and the interfacial component composed of atoms in the interfacial regions between grains.

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