An enhanced phase field model for the numerical simulation of polymer crystallization (original) (raw)
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International Journal of Technology, 2017
A phase field model has been successfully constructed to simulate the behavior of the semicrystalline polymer solidification phenomenon. It is a model that has been widely and successfully utilized to simulate solidification phenomena in metals. However, the non-conserved phase field equation can be extended to include unique polymer parameters that do not exist in metals; for example, polymer melt viscosity and the diffusion coefficient. In order to extend this model, we incorporate free energy density and non-local free energy density based on the Harrowell-Oxtoby and Ginzburg-Landau theorems for polymer. By using the expansion principle for the higher order of binary phase field parameter, a full modified phase field equation can be obtained. The solidification phenomenon in polymer is very important to optimize the final properties of the products. Here, we use our modified equation to investigate the effect of melting temperature on the rate of solidification. It was found that the rate of solidification is correlated with melting temperature in a non-straightforward manner.
Simulations on crystallization in polymers
1997
Strain-induced crystallization has always been important in the area of elastomers (since the crystallites thus generated provide substantial in situ reinforcement) and can be simulated using Monte Carlo methods to generate chains having representative sequence distributions for different polymerization conditions. The chains are then placed alongside one another to determine matched-sequence runs that could lead to the formation of crystallites.
Modeling of polymer crystallization in a temperature gradient
Journal of Applied Polymer Science, 2002
The crystallization of polymer films in a temperature gradient was simulated. The curvature of lamella growth directions observed experimentally was taken into account. The computer simulation permitted the visualization of the evolution of the spherulitic pattern and also the calculation of the conversion of the melt into spherulites. The mathematical model was also elaborated and allowed the prediction of the kinetics of conversion during the crystallization of polymers in the temperature gradient. A good agreement between the computer simulation results, the mathematical model predictions, and the experimental data for isotactic polypropylene crystallized in a temperature gradient was obtained.
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Polymer, 2009
Crystalline polymers are very interesting and useful materials with great versatility through their potential morphology control. Recent surge in computer modeling studies has its origin both in increasing need for efficient methods of materials' design and in tremendous developments in computer power that is expected to meet the need. In this paper, we briefly survey the present state of computer modeling of polymer crystallization with the aim to foresee future developments. We first review simulations of crystallization in simple polymers under quiescent conditions where most of the efforts have hitherto been devoted. We also examine recent studies on crystallization under flow or large deformation. Then we present our ambitious plans to extend the simulation methods to polymers having complex chemical structures, though it is still an uncultivated field of research. We also refer to the new modeling strategies which integrate macroscopic and microscopic methods, and to the possibilities of molecular modeling in polymer nanotechnologies. Though our goal seems very far, there are obviously very fertile lands for the computer simulation studies.
Interfaces and Free Boundaries, 2000
Crystallization and solidification in polymers is a problem of great importance to the polymer processing industry. In these processes, the melt is subjected to deformation while being cooled into the desired shape. The properties of the final product are strongly influenced by the deformation and thermal histories and the final solid is invariably anisotropic. In this work we present a model to capture the effects during solidification and crystallization in polymers within a purely mechanical setting, using the framework of multiple natural configurations that was introduced recently to study a variety of non-linear dissipative responses of materials undergoing phase transitions. Using this framework we present a consistent method to model the transition from a fluid-like behaviour to a solid-like behaviour. We also present a novel way of incorporating the formation of an anisotropic crystalline phase in the melt. The anisotropy of the crystalline phase, and consequently that of the final solid, depends on the deformation in the melt at the instant of crystallization, a fact that has been known for a long time and has been exploited in polymer processing. The proposed model is tested by solving three homogenous deformations.
Numerical simulation of phase separation coupled with crystallization
The Journal of Chemical Physics, 2008
The kinetics of liquid-liquid phase separation and polymer crystallization observed in double-quench experiments with blends of poly͑ethylene-co-hexene͒ and poly͑ethylene-co-butene͒ are studied using time-dependent Ginzburg-Landau Model. Numerical simulations demonstrate that our model can successfully reproduce three experimental phenomena: The decrease in number and size of crystallized spherulites with increasing time in phase separation, the preponderance of nuclei near the domain interface, and the subphase separation and subcrystallization occurring when the second quench is very deep. Moreover, the simulations are consistent with the recently proposed mechanism of "phase separation fluctuation assisted nucleation" in the crystallization process.
Phase-Field Simulation during Spherulite Formation of Polymer
Key Engineering Materials, 2007
The establishment of the coupled numerical model which enable to simulate the spherulite formation and its mechanical behavior continuously is our final goal. In this paper, we have developed Phase-field model for spherulte growth of polymer by generalizing the model proposed by Granasy et. al.. The numerical simulations for single spherulite and multi-sperulites have been performed with isotropic interface energy.
Simulation of Melt Viscosity Effect on the Rate of Solidification in Polymer
Indonesian Journal of Chemistry
Phase field model has been successfully derived from ordinary metal phase field equation to simulate the behavior of semi-crystalline polymer solidification phenomenon. To obtain the polymer phase field model, a non-conserved phase field equation can be expanded to include the unique polymer parameters, which do not exist in metals, for example, polymer melt viscosity and diffusion coefficient. In order to expand this model, we include free energy density and non-local free energy density based on Harrowel-Oxtoby and Ginzburg-Landau theorem for polymers. The expansion principle for a higher order of binary phase field parameter was employed to obtain fully modified phase field equation. To optimize the final properties of the products, the solidification phenomenon in polymers is very important. Here, we use our modified equation to investigate the effect of melt viscosity on the rate of solidification by employing ordinary differential equation numerical methods. It was found that ...