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Thananchai, Leephakpreeda,

doi:10.2306/scienceasia1513-1874.2001.27.127

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…A number of researchers4–6 have examined the temperature and crystallization behaviors of molten polymers during cooling through both computer simulation and experimental approaches. Hu et al4 investigated the effect of cooling system design, part thickness, mold thermal properties, coolant temperature, and cycle time on the cyclic variation of mold temperatures with the dual reciprocity boundary element method.…”

Section: Introductionmentioning

confidence: 99%

“…The thermal conductivity and coolant temperature were observed to have a considerable effect on the variations in mold temperature values as compared to effects of cycle time and part thickness. Leephakpreeda5 proposed a mathematical model for the solidification of semicrystalline polymers under quiescent nonisothermal crystallization to predict the size of the crystallites. It was suggested that the mean radius of the crystallites was a function of nucleation and growth processes, and the spherulite size increased with increasing cooling rate.…”

Section: Introductionmentioning

confidence: 99%

“…Although the literature has many references4–11 to the temperature and crystallinity profiles of unfilled and synthetic‐fiber‐filled thermoplastics during the cooling process, little attention has been given to natural‐fiber‐filled polymers, especially to research evidence from experiments. Cyras et al14 used a nonisothermal kinetic computational model15 to predict the crystallinity profiles of a sisal‐fiber/polycarprolactone/starch molded part.…”

Section: Introductionmentioning

confidence: 99%

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Experimental analysis of temperature and crystallinity profiles of wood sawdust/polypropylene composites during cooling

Sombatsompop¹,

Kositchaiyong²,

Wimolmala³

2006

J of Applied Polymer Sci

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The temperature profiles of wood sawdust/ polypropylene (PP) composite melts during cooling were experimentally investigated with a cooling jacket apparatus connected to the end of an injection-molding machine. Real-time melting temperature was measured with an unsheathed thermocouple array coupled with a high-speed data-acquisition unit. The crystallinity level of the solidified composites was evaluated with an X-ray diffractometer. Before the crystallization temperature (T c ) was reached, the cooling rate of the melt layer near the wall was greater than that near the center. After T c was reached, the opposite behavior was observed. Wood sawdust content did not affect the general temperature and crystallinity profiles across the duct diameter but led to more nonuniform temperature profiles across the duct diameter. The sawdust particles could act as a nucleating agent during the nucleation stage to increase T c of the PP and as an interfering agent during the crystal growth stage to decrease the overall crystallinity level of the PP. The temperature and crystallinity profiles were not affected by the coolant flow rate. The normalized induction time changed with reduced radius (r/R, where r is the distance between the central duct to any point along the cross-section of the duct and R is the duct radius) positions and coolant flow rate, especially for neat PP and PP composites with a low sawdust content (10 wt %).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental analysis of temperature and crystallinity profiles of wood sawdust/polypropylene composites during cooling

Sombatsompop¹,

Kositchaiyong²,

Wimolmala³

2006

J of Applied Polymer Sci

View full text Add to dashboard Cite

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Simulation of Crystallization Kinetics and Morphological Development During Isothermal Crystallization of Polymers: Effect of Number of Nuclei and Growth Rate

Ketdee

Anantawaraskul

2008

Chemical Engineering Communications

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The effect of number of nuclei and growth rate on crystallization kinetics and detailed morphological development during isothermal crystallization of a polymer was investigated using a stochastic simulation. The results show that number of nuclei significantly affects both crystallization kinetics and polymer morphology. An increase in the number of nuclei hastens the crystallization process by speeding up the impingement phenomenon and increasing the levels of impingement. Growth rate has a stronger impact on crystallization kinetics, but it only helps speed up the impingement phenomenon without increasing the level of impingement. Although growth rate influences an average spherulite size and distribution of spherulite size during crystallization, it has no effect on final morphology. The quantitative understanding of morphological development obtained from this work will be a key element for constructing quantitative morphology-property relationships.

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Morphological Monte Carlo Simulation for Crystallization of Isotactic Polypropylene in a Temperature Gradient

Ruan

2019

Crystals

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Polymers are poor heat conductors, so the cooling of thick-walled shapes results in temperature gradients. Here, isotactic polypropylene (iPP) is chosen as a model polymer for the study of polymer crystallization in a temperature gradient field. The morphological Monte Carlo algorithm is applied, combined with the radius growth model, to predict the growth of spherulites. Through comparison of the two numerical solutions, analytical solution and experimental data, the validity of the morphological Monte Carlo algorithm is demonstrated. In addition, the roles of central temperature, temperature gradient for the evolution of spherulites, and the conversion degree of the melt into spherulites are considered. The results of the study show that increases in central temperature and temperature gradient can increase the anisotropy of spherulites. Isothermal crystallization and crystallization in a temperature gradient field are compared, and the differences are considered. Results show that when the central temperature is below 125 °C, and when the temperature gradients are less than 15 K/mm and 27 K/mm, the differences in the conversion degree of the melt into spherulites are less than 2% and 5%, respectively. Therefore, crystallization under such temperature gradient conditions can be simplified as isothermal crystallization.

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Cited by 4 publications

References 6 publications

Experimental analysis of temperature and crystallinity profiles of wood sawdust/polypropylene composites during cooling

Experimental analysis of temperature and crystallinity profiles of wood sawdust/polypropylene composites during cooling

Simulation of Crystallization Kinetics and Morphological Development During Isothermal Crystallization of Polymers: Effect of Number of Nuclei and Growth Rate

Morphological Monte Carlo Simulation for Crystallization of Isotactic Polypropylene in a Temperature Gradient

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