Melt Crystallization Behavior of Injection-Molded High-Density Polyethylene Based Upon a Solidification Kinetic Analysis

Yang, Bin; Ding, Mengya; Hu, Lei; Li, Guijing; Miao, Jibin; Gao, Xuan; Li, Xiaobao; Zhang, Bin; Su, Lifen; Chen, Peng; Qian, Jiasheng

doi:10.1080/00222348.2018.1476429

Cited by 9 publications

(2 citation statements)

References 42 publications

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“…However, excessively high melt temperatures can cause increased shrinkage due to accelerated cooling rates and potential thermal degradation of the material. The different cooling behavior driven by varying melting temperatures can alter the amount of volumetric shrinkage experienced 48–50 . In this study, the melt temperature in the first level was set at 365°C, considering that the melting point temperature of PFA material is around 305°C.…”

Section: Resultsmentioning

confidence: 99%

“…The different cooling behavior driven by varying melting temperatures can alter the amount of volumetric shrinkage experienced. [48][49][50] In this study, the melt temperature in the first level was set at 365 C, considering that the melting point temperature of PFA material is around 305 C. It was observed that the outside diameters decreased as the melt temperature increased, indicating that higher temperatures resulted in greater product shrinkage. Therefore, the lowest temperature was chosen as the optimal level for later experiments.…”

Section: Outside Diametermentioning

confidence: 99%

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The influence of mold design and process parameters on dimensional shrinkage of perfluoroalkoxy alkane injection molding parts

Li,

Liu,

Zhang

et al. 2024

J of Applied Polymer Sci

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In mass production, injection molding plays a vital role in manufacturing various parts with complex settings. As perfluoroalkoxy alkane (PFA) injection‐molded products are widely used in immersion system, dimensional quality needs more attention. However, there is limited research on the dimension defects of PFA injection‐molded products. This study focused on the influence of mold design and process parameters on PFA part shrinkage, using mold flow simulation and orthogonal testing separately. Several gate locations and sizes were simulated to minimize shrinkage in mold design. Displacements varied with gate locations, and shrinkage decreased with larger gate sizes. The Taguchi method analyzed process parameters' impact on shrinkage. The results indicated that the injection rate had the most significant effect on the shrinkage of tube length, while melt temperature, holding pressure, and screw speed affected the shrinkage of tubes' outside diameter. Different flow directions exhibited variance in shrinkage. Using max–min normalization, the two shrinkage values reached 0.00972, whereas the smallest value obtained in the orthogonal experiment was 0.1545 in run 3. Thus, optimizing mold design and process parameters were two effective methods to reduce shrinkage. This study reduced shrinkage and improved the quality of PFA injection molding parts for semiconductor systems.

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Section: Resultsmentioning

confidence: 99%

Section: Outside Diametermentioning

confidence: 99%

The influence of mold design and process parameters on dimensional shrinkage of perfluoroalkoxy alkane injection molding parts

Li,

Liu,

Zhang

et al. 2024

J of Applied Polymer Sci

View full text Add to dashboard Cite

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Facile way of dynamically tailoring microporous structures in polyvinylidene fluoride films prepared by thermally induced phase separation

Yang

Chen

Ding

et al. 2021

Journal of Polymer Science

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Polyvinylidene fluoride (PVDF) films were prepared via thermally induced phase separation (TIPS) using diphenyl carbonate as the diluter in an attempt to disclose the competitive relationship between crystal growth and droplet growth during phase separation process. By varying the quenching temperature different temperature gradient fields were established, which were theoretically evaluated via enthalpy transformation method. The effects of polymer concentration and quenching temperature on evolution of hierarchical morphologies in TIPS films were systematically investigated. According to the morphological characteristics, the cross‐sectional morphology of the films with lower polymer concentration (ΦP = 25%) could be divided into three layers; while that of higher polymer concentration counterpart (ΦP = 55%) only presented a bi‐layered structure. The reason for this could be ascribed to the effect of cooling rate on both crystal growth and droplet growth during TIPS process, which further determined the formation of the hierarchical structure in microporous films. With an increasing quenching temperature, both pore size and porosity of PVDF films increased, accompanied by an improvement on both thermal stability and dynamic mechanical thermal property. The present study could insightfully supply a facile route to fabricate structure‐controllable microporous films of crystalline polymers via an appropriate regulation of the TIPS quenching parameters.

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Recent progress in flow‐induced polymer crystallization

Nie

Fan

Cao

et al. 2022

Journal of Polymer Science

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During industrial processing, such as film blowing and injection molding, semicrystalline polymers have to be subjected to external flow. Flow changes the nucleation rate, crystal morphology and polymorphism of polymers. As flow can be tunable, polymeric products with different macroscopic performance and versatile applications can be obtained. Understanding polymer crystallization with the presence of flow, or namely flow-induced crystallization (FIC), is crucial to optimize polymer processing parameters and to understand phase transition under far-from equilibrium conditions, as FIC is essentially a typical nonequilibrium process. Current review aims to summarizes recent achievements of FIC during last five years from three aspects: theory, experiment and simulation. First, we present the FIC model and theory, including the classical conformational entropy reduction model, the newly developed POLYdisperse STRain Accelerated Nucleation Dynamics (PolySTRAND) Model and uFIC Model. Then we discuss the FIC experiments under both well-controlled flow and complex processing conditions. Finally, we show the recent advance of FIC in computer simulation. With the fast development in modeling efficiency, more detailed nucleation and structure transition processes during FIC can be obtained, which promote the study of molecular mechanisms of FIC.

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Melt Crystallization Behavior of Injection-Molded High-Density Polyethylene Based Upon a Solidification Kinetic Analysis

Cited by 9 publications

References 42 publications

The influence of mold design and process parameters on dimensional shrinkage of perfluoroalkoxy alkane injection molding parts

The influence of mold design and process parameters on dimensional shrinkage of perfluoroalkoxy alkane injection molding parts

Facile way of dynamically tailoring microporous structures in polyvinylidene fluoride films prepared by thermally induced phase separation

Recent progress in flow‐induced polymer crystallization

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