Recent Advances in Polymer Rheology

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Processing and Engineering".

Deadline for manuscript submissions: closed (15 January 2024) | Viewed by 10598

Special Issue Editors


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Guest Editor
Department of Chemical and Materials Engineering, Tamkang University, New Taipei City 251, Taiwan
Interests: polymer processing and simulation; polymer rheology; lightweight technology; fiber microstructure characterization and validation; precision injection molding; special injection molding technologies

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Guest Editor
Department of Mechanical Engineering, National Cheng Kung University, Tainan City 701, Taiwan
Interests: polymer processing; composite processing; CAD/CAM; IC packaging

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Guest Editor
Department of Mechanical and Computer Aided Engineering, Feng Chia University, Taichung City 407, Taiwan
Interests: intelligent injection molding technology; foam injection molding; gas-assisted injection molding; short/long fiber reinforced thermoplastics injection molding; mold design & mold flow analysis; dynamic mold temperature control technology
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Special Issue Information

Dear Colleagues, 

In the recent years, various advanced polymer applications have been proposed continuously, such as in lightweight, environmental sustainability, electrical and optical devices, or even in integrated circuit (IC) encapsulation applications. However, not all the proposals are so succeeded due to their complexity in the integration from polymer materials to processing, and to products.  To overcome the related complexity, rheology is a well-known science to help discover the related physical and chemical mechanisms.  Specifically, polymer rheology is the knowledge about the flow behaviour and the deformation of polymer materials to connect the polymer structures, to the processing, and to the application.  Even so, regarding to different applications’ targets, the rheological techniques needed to be enhanced to decouple the complicated mechanism during polymer processing. 

Hence, in this Special Issue, we would like to invite contributions which utilize advanced rheological concepts or techniques in polymer material characterization, polymer processing enhancement or optimization, or in polymer applications.  Moreover, the understanding the physical or chemical mechanisms from polymer molecular structures to polymer processing, and to the product properties is very important in advanced polymer applications.  The related rheology concepts and techniques to connect the relation from polymer materials to processing and to applications using simulation or experimental studies both in academia or industry are highly welcomed.

Prof. Dr. Chao-Tsai Huang
Prof. Dr. Sheng-Jye Hwang
Dr. Hsinshu Peng
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • polymer rheology
  • polymer characterization
  • polymer processing and simulation
  • suspension rheology
  • chemo-rheology
  • advanced rheological technology
  • shear thinning
  • stress relaxation
  • viscous flow modeling
  • viscoelastic modeling
  • viscosity index
  • process monitoring
  • process control
  • process qualification
  • material testing and characterization
  • materials reliability

Published Papers (4 papers)

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Research

16 pages, 5922 KiB  
Article
Investigation of Parameter Sensitivity and the Physical Mechanism for the Formation of a Core-Skin-Core (CSC) Structure in Two-Stage Co-Injection Molding
by Chao-Tsai Huang, You-Ti Rao, Kuan-Yu Ko, Chih-Chung Hsu, You-Sheng Zhou, Chia-Hsiang Hsu, Rong-Yue Chang, Shi-Chang Tseng and Likey Chen
Polymers 2022, 14(21), 4747; https://doi.org/10.3390/polym14214747 - 05 Nov 2022
Viewed by 1420
Abstract
One of the main challenges in co-injection molding is how to predict the skin to core morphology accurately and then manage it properly, especially after skin material has been broken through. In this study, the formation of the Core-Skin-Core (CSC) structure and its [...] Read more.
One of the main challenges in co-injection molding is how to predict the skin to core morphology accurately and then manage it properly, especially after skin material has been broken through. In this study, the formation of the Core-Skin-Core (CSC) structure and its physical mechanism in a two-stage co-injection molding has been studied based on the ASTM D638 TYPE V system by using both numerical simulation and experimental observation. Results showed that when the skin to core ratio is selected properly (say 30/70), the CSC structure can be observed clearly at central location for 30SFPP/30SFPP system. When the skin to core ratio and operation conditions are fixed, regardless of material arrangement (including 30SFPP/30SFPP; PP/PP; 30SFPP/PP; and PP/30SFPP systems), the morphologies of the CSC structures are very close for all systems. This CSC structure can be further validated by using μ-CT scan and image analysis technologies perfectly. Furthermore, the influences of various operation parameters on the CSC structure variation have been investigated. Results exhibited that the CSC structure does not change significantly irrespective of the flow rate changing, melt temperature varying, or even mold temperature being modified. Moreover, the mechanism to generate the CSC structure can be derived using the melt front movement of the numerical simulation. It is worth noting that after the skin material was broken through, the core material travelled ahead with fountain flow to occupy the flow front. In the same period, the proper amount of skin material with certain inertia of enough kinetic energy will keep going to penetrate the new coming core material to travel until the end of filling. It ends up with this special CSC structure. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Rheology)
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13 pages, 6098 KiB  
Article
Determining the Rheological Parameters of Polymers Using Artificial Neural Networks
by Anton Chepurnenko
Polymers 2022, 14(19), 3977; https://doi.org/10.3390/polym14193977 - 23 Sep 2022
Cited by 4 | Viewed by 1890
Abstract
Artificial neural networks have great prospects in solving the problems of predicting the properties of polymers. The purpose of this work was to study the possibility of using artificial neural networks to determine the rheological parameters of polymers from stress relaxation curves. The [...] Read more.
Artificial neural networks have great prospects in solving the problems of predicting the properties of polymers. The purpose of this work was to study the possibility of using artificial neural networks to determine the rheological parameters of polymers from stress relaxation curves. The nonlinear Maxwell–Gurevich equation was used as the deformation law. The problem was solved in the MATLAB environment. The substantiation for the choice of the neural network input and output parameters was made. An algorithm for obtaining the data for neural network training was also proposed. Neural networks were trained on theoretical stress relaxation curves constructed with the Euler method. The value of the mean square error (MSE) was used as a criterion for the performance of the training. The constructed model of the artificial neural network was tested on the experimental relaxation curves of recycled polyvinyl chloride. The quality of the experimental curve approximation was quite good and was comparable with the standard methods for processing stress relaxation curves. Unlike the standard methods, when using artificial neural networks, no preliminary data smoothing was required. It is possible to use the proposed technique for processing not only relaxation curves, but also creep curves as well as processing creep tests not only in central tension, but also in bending, torsion and shear. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Rheology)
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19 pages, 8555 KiB  
Article
Development of an Online Quality Control System for Injection Molding Process
by Ming-Hong Tsai, Jia-Chen Fan-Jiang, Guan-Yan Liou, Feng-Jung Cheng, Sheng-Jye Hwang, Hsin-Shu Peng and Hsiao-Yeh Chu
Polymers 2022, 14(8), 1607; https://doi.org/10.3390/polym14081607 - 15 Apr 2022
Cited by 7 | Viewed by 2503
Abstract
This research developed an adaptive control system for injection molding process. The purpose of this control system is to adaptively maintain the consistency of product quality by minimize the mass variation of injection molded parts. The adaptive control system works with the information [...] Read more.
This research developed an adaptive control system for injection molding process. The purpose of this control system is to adaptively maintain the consistency of product quality by minimize the mass variation of injection molded parts. The adaptive control system works with the information collected through two sensors installed in the machine only—the injection nozzle pressure sensor and the temperature sensor. In this research, preliminary experiments are purposed to find master pressure curve that relates to product quality. Viscosity index, peak pressure, and timing of the peak pressure are used to characterize the pressure curve. The correlation between product quality and parameters such as switchover position and injection speed were used to produce a training data for back propagation neural network (BPNN) to compute weight and bias which are applied on the adaptive control system. By using this system, the variation of part weight is maintained to be as low as 0.14%. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Rheology)
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21 pages, 6071 KiB  
Article
Retrieving Equivalent Shear Viscosity for Molten Polymers from 3-D Nonisothermal Capillary Flow Simulation
by Yu-Ho Wen, Chen-Chieh Wang, Guo-Sian Cyue, Rong-Hao Kuo, Chia-Hsiang Hsu and Rong-Yeu Chang
Polymers 2021, 13(23), 4094; https://doi.org/10.3390/polym13234094 - 24 Nov 2021
Cited by 3 | Viewed by 2864
Abstract
For highly viscous polymer melts, considerable fluid temperature rises produced by viscous heating can be a disturbing factor in viscosity measurements. By scrutinizing the experimental and simulated capillary pressure losses for polymeric liquids, we demonstrate the importance of applying a viscous heating correction [...] Read more.
For highly viscous polymer melts, considerable fluid temperature rises produced by viscous heating can be a disturbing factor in viscosity measurements. By scrutinizing the experimental and simulated capillary pressure losses for polymeric liquids, we demonstrate the importance of applying a viscous heating correction to the shear viscosity, so as to correct for large errors introduced by the undesirable temperature rises. Specifically, on the basis of a theoretical derivation and 3-D nonisothermal flow simulation, an approach is developed for retrieving the equivalent shear viscosity in capillary rheometry, and we show that the shear viscosity can be evaluated by using the average fluid temperature at the wall, instead of the bulk temperature, as previously assumed. With the help of a viscous Cross model in analyzing the shear-dominated capillary flow, it is possible to extract the viscous heating contribution to capillary pressure loss, and the general validity of the methodology is assessed using the experiments on a series of thermoplastic melts, including polymers of amorphous, crystalline, and filler-reinforced types. The predictions of the viscous model based on the equivalent viscosity are found to be in good to excellent agreement with experimental pressure drops. For all the materials studied, a near material-independent scaling relation between the dimensionless temperature rise (Θ) and the Nahme number (Na) is found, Θ ~ Na0.72, from which the fluid temperature rise due to viscous heating as well as the resultant viscosity change can be predicted. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Rheology)
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