Computer modeling of non-isothermal crystallization Download PDF EPUB FB2
A realistic computer model for simulating isothermal and non-isothermal phase transformations proceeding by homogeneous and heterogeneous nucleation and interface-limited growth is presented. A new treatment for particle size effects on the crystallization kinetics is developed and is incorporated into the numerical by: Non-isothermal differential scanning calorimetry (DSC) data of electroless nickel–phosphorus (EN) samples with three different phosphorus contents (9, 12 and 16 wt%) has been used in the computer modelling of crystallization kinetics based upon the Johnson–Mehl–Avrami (JMA) by: A realistic computer model for simulating isothermal and non-isothermal phase transformations proceeding by homogeneous and heterogeneous nucleation and interface-limited growth is presented.
A new treatment for particle size effects on the crystallization kinetics is developed and is incorporated into the numerical model. Non-isothermal differential scanning calorimetry (DSC) data of electroless nickel–phosphorus (EN) samples with three different phosphorus contents (9, 12 and 16 wt%) has been used in the computer.
A 3D computer modeling and simulation has been used to predict crystallization kinetics and crystal morphology in polymers under the non-isothermal condition.
A parametric study is used to explore the influences of thermal conditions on the by: 7. This paper is devoted to the study of mathematical problems arising in the modelling of nonisothermal polymer crystallization under industrial conditions. A review of the hybrid stochastic-deterministic modelling procedure, which yields an averaged model, 5,8 is given and supplied by the study of mathematical problems arising from by: This paper is devoted to the study of mathematical problems arising in the modelling of nonisothermal polymer crystallization under industrial conditions.
A review of the hybrid. Unified isothermal and non-isothermal modelling of neat PEEK crystallization Article (PDF Available) in Journal of Thermal Analysis and Calorimetry (2) February with Reads. A numerical model able to simulate polymer crystallization under nonisothermal flows is developed.
It is based on the assumption that the trace of the extra-stress tensor, calculated according to a. Summary. Recently, Burger and Capasso [M 3 AS 11 () –] derived a coupled system of partial differential equations to describe non-isothermal crystallization of polymers.
The system is based on a spatial averaging of the underlying stochastic birth-and-growth process describing the nucleation and growth of single by: 2. This paper is devoted to the study of mathematical problems arising in the modelling of nonisothermal polymer crystallization under industrial conditions.
A review of the hybrid stochastic-deterministic modelling procedure, which yields an averaged model 5;8, is given and supplied by the study of mathematical problems arising from it. A differential generalized Avrami’s law is used to model crystallization kinetic of PEEK in considering that PEEK crystallization results from the contribution of two distinct mechanisms.
The form of this equation allows to predict with good accuracy both isothermal and non-isothermal crystallization kinetics. Nevertheless, isothermal model parameters are not Cited by: 9. This chapter discusses recent experimental and model developments concerning the influence of industrially relevant cooling rates and pressures on the non-isothermal crystallization of both an isotactic polypropylene and a linear low-density polyethylene by: 1.
Non Isothermal Global Model and Operating Maps 79 Stochastic Global Model 80 PBM comparison 87 Operational Map 93 Solvent-Antisolvent Interactions and Hydrogen Bonding Chapter 6. Conclusions and Future Research Conclusions Future Research Appendix A. Nomenclature References Non-isothermal crystallization during cooling The main focus of this report is the analysis of heating curves after defined crystallization.
But for a better comparison we first mention here additional experimental results measured from cooling at various cooling by: An equation expressing the volume fraction,x, of crystals precipitating in a glass heated at a constant rate, α, was derived. When crystal particles grow m-dimensionally,x is expressed as In [- ln(1 -x)] = -n (nα - mE/RT + Constant whereE is the activation energy for crystal growth andn is a numerical factor depending on the nucleation process.
When the Cited by: A computer model that al- lows a realistic analysis of these non-isothermal DTA data and an exploration of finite size effects is presented in a companion paper . Conclusions Acknowledgements In summary, we have demonstrated that glasses heated through a temperature range where there is significant nucleation can develop widely different.
COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle.
Modeling of non-isothermal annealing: Interaction of recrystallization, recovery, and precipitation Article in Acta Materialia 59(17) October with 56. Two nonisothermal crystallization models, the Ozawa model and the modified Avrami model, have been evaluated using computer simulation data of nonisothermal crystallization .
In this short communication, the Kissinger model is evaluated using the nonisothermal crystallization data derived from computer simulation.
The only comprehensive reference on polymer crystallization, Handbook of Polymer Crystallization provides readers with a broad, in-depth guide on the subject, covering the numerous problems encountered during crystallization as well as solutions to resolve those problems to achieve the desired result.
Edited by leading authorities in the field. isothermal crystallization, is based on rapidly cooling the sample from the melt to the crystallization temperature and then measuring the heat evolved while the sample is held isothermal.
The model most often applied to isothermal crystallization data is the Avrami model. This model, while possessing physically significant parameters, is somewhatFile Size: KB. (Fe40Ni40B19Cu1)97Nb3 magnetic amorphous alloys have been prepared by a melt-spun method, and their crystallization behavior and kinetics have been investigated.
The results showed that under non-isothermal conditions, the growth process is easier than the nucleation process for both precipitated phases ((Fe,Ni)23B6 and γ(Fe,Ni)), and the activation energy Author: Zhe Chen, Qianke Zhu, Kewei Zhang, Yong Jiang.
The isoconversional method, a model-free analysis of the kinetics of liquid−solid transformations, was used to determine the effective activation energy of the nonisothermal crystallization of melts of pure and complex systems of triacylglycerols (TAGs). The method was applied to data from differential scanning calorimetry (DSC) measurements of the heat of crystallization Cited by: Researchers have sought to study the non-isothermal crystallization of polymers because actual processing conditions in this process are closer to non-isothermal cycles than to isothermal cycles.
Based on Avrami’s model, Jeziorny [ 13 ] established a model that may be applied in the crystallization behavior of polymers at a constant cooling : Jianqiang Fang, Minghua Lang, Xuchu Ye, Wei Zhang, Kongjun Zhu.
Isothermal and Non-Isothermal Crystallization Kinetics of Conductive Polyvinylidene Fluoride/Poly(Ethylene Terephthalate) Based Composites. Nafaa Athmouni, Jianbin Song, Frej Mighri, Saïd Elkoun. Materials Sciences and Applications Vol.7 No Full-Text HTML XML Pub.
Date: Janu Nonisothermal crystallization behaviors of nanocomposites prepared by in situ polymerization of high-density polyethylene on tungsten oxide particles. Macromolecular Research23, DOI: /s Freddy A.
Cited by: A non-isothermal Taylor vortex fluid motion was applied for effective control of the crystal size distribution (CSD) in batch cooling crystallization without seed crystals.
The non-isothermal Taylor vortex fluid motion was generated using different cylinder temperatures, i.e., a hot inner cylinder and cold outer cylinder, in a Couette–Taylor (CT) by: 1.
Equation  should be a straight line if this model is valid, Z t and n can be determined from the antilogarithmic value of the y-intercept and from the slope, should be noted that Z t and n do not have the same physical meaning as in the original Avrami analysis for isothermal crystallization, because the temperature changes instantly in the non-isothermal process.
A numerical model simulating the crystallization of polymers under nonisothermal flow conditions is presented. Crystallization is described as a spherulitical nucleation and growth process. Two distinct nucleation rates are considered. The modified Avrami model was found to accurately predict the induction time, maximum phase volume and dimensionality of crystal growth for stearic acid containing molecules when the experimental method employed measures as a function of phase volume.
Four methods were examined to validate the model includinCited by: The crystallization of a model compound, sucrose, from the amorphous solid state has been studied non-isothermally using differential scanning calorimetry to determine crystallization temperature, Tc, and isothermally at 30°C by subjecting samples to % relative humidity and gravimetrically monitoring water vapor uptake and subsequent loss with time due to by: The isothermal and nonisothermal crystallization kinetics of monoglyceride (MAG) organogels were studied by pulsed nuclear magnetic resonance (pNMR) and differential scanning calorimetry (DSC), Avrami equation was used to describe the isothermal crystallization kinetics and experimental data fitted the equation fairly by: 7.