Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
6.6
5.0
Journals
Polymers
Special Issues
Extensional Rheology and Processing of Polymeric Materials
share announcement

Extensional Rheology and Processing of Polymeric Materials

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

Deadline for manuscript submissions: closed (30 June 2020) | Viewed by 11913

Special Issue Editor

Prof. Dr. Helmut Münstedt

E-Mail Website1 Website2
Guest Editor
Department of Materials Science and Engineering, Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nürnberg, Martensstr. 7, D-91058 Erlangen, Germany
Interests: general aspects of rheology; flow analysis of polymer melts; rheology and processing; polymer rheology and molecular structure; modification of polymers by physical means; particle-filled polymeric materials; polymer blends
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Processing operations are essentially governed by rheological properties. While shear rheology has widely been used for a better understanding and the modeling of processes, extensional properties of polymer melts are very sparsely discussed in these fields. This Special Issue intends to compile and assess the role of elongational flow in processing operations, such as fiber spinning, film blowing, film extrusion, blow molding, thermoforming, and foaming. Experimental results are welcome, as well as quantitative descriptions making use of models and finite element methods.

To attain a broadly-based understanding, different experimental methods should be compared and results on the time and stress dependences of elongational flow should be discussed with respect to the conditions of the various processes. Fundamental experiments with respect to the influence of the molecular structure on the extensional behavior and, in particular, to the role of long-chain branches are seen as a base for a better understanding of the processing performance of various materials.

More general investigations on elongational flow and processing-related phenomena, such as entrance flow, extrudate swell, failure, and the various kinds of melt fracture are also of interest for this Special Issue.

Contributions in the form of original research as well as review articles are welcome.

Prof. Dr. Helmut Münstedt
Guest Editor

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

  • methods
  • failure behavior
  • elastic properties
  • modeling
  • molecular structure
  • fiber spinning
  • film blowing
  • film extrusion
  • blow molding
  • thermoforming
  • foaming
  • extrudate swell
  • melt fracture

Published Papers (3 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

14 pages, 2389 KiB  
Article
Film Blowing of Linear and Long-Chain Branched Poly(ethylene terephthalate)
by Michael Härth and Andrea Dörnhöfer
Polymers 2020, 12(7), 1605; https://doi.org/10.3390/polym12071605 - 19 Jul 2020
Cited by 16 | Viewed by 5442
Abstract
Film blowing of Poly(ethylene terephthalate) (PET) is challenging due its inherently low melt viscosity and poor melt strength. In this study, it is shown how the rheological properties of a commercial PET can be altered by reactive extrusion using either pyromellitic dianhydride (PMDA) [...] Read more.
Film blowing of Poly(ethylene terephthalate) (PET) is challenging due its inherently low melt viscosity and poor melt strength. In this study, it is shown how the rheological properties of a commercial PET can be altered by reactive extrusion using either pyromellitic dianhydride (PMDA) or a multifunctional epoxy (Joncryl® ADR 4368) as chain extender, in order to improve the processing behavior during film blowing. The modified materials were characterized by shear and elongation rheometry and relevant processing characteristics, like melt pressure, bubble stability, and film thickness uniformity, were used to assess the influence of the type of modifier on processing and product performance. It is shown that PMDA is useful to increase the melt strength which leads to an improved bubble stability, while epoxy modified PET shows a reduced drawability that can cause problems at high take-up ratios. On the other hand, the epoxy modifier indicates a pronounced strain hardening during elongational deformation, and therefore leads to a better film thickness uniformity compared to the neat PET and the PET modified with PMDA. The differences with respect to processing performance are discussed and ascribed to the molecular structure of the materials. Full article
(This article belongs to the Special Issue Extensional Rheology and Processing of Polymeric Materials)
►▼ Show Figures

Graphical abstract

20 pages, 7830 KiB  
Article
Recoverable Extensional Flow of Polymer Melts and Its Relevance for Processing
by Helmut Münstedt
Polymers 2020, 12(7), 1512; https://doi.org/10.3390/polym12071512 - 8 Jul 2020
Cited by 5 | Viewed by 2475
Abstract
While the uniaxial elongational viscosity is widely investigated, and its relevance for processing is described in the literature, much less has been published on the recoverable extensional flow of polymer melts. This paper presents a short overview of the dependencies of the recoverable [...] Read more.
While the uniaxial elongational viscosity is widely investigated, and its relevance for processing is described in the literature, much less has been published on the recoverable extensional flow of polymer melts. This paper presents a short overview of the dependencies of the recoverable elongation on the molecular structure of a polymer, and on some experimental parameters. Its main focus lies on the discussion of processing operations and applications that are largely affected by the elastic components of elongational flow. The recoverable portions of stretched films are considered, and the exploitation of the shrinkage of films, due to the recovery of frozen recoverable deformations, and its role for applications are addressed. The analysis of measurements of velocity fields in the entry region of a slit die and results on the determination of the recoverable elongation from uniaxial experiments, according to the literature, lead to the conclusion of dominant elastic extensions. Considering these facts, the assumptions for Cogswell’s widely used method of determining elongational viscosities under processing conditions from entrance flow are not realistic. As examples of a direct application of extrudate swell from short dies for processing, pelletizing and fused deposition modelling within additive manufacturing are addressed. The special features of extrudate swell from short dies, and uniaxial recoverable elongation for a polymer filled with rigid particles in comparison to an immiscible polymer blend, are presented and discussed. Full article
(This article belongs to the Special Issue Extensional Rheology and Processing of Polymeric Materials)
►▼ Show Figures

Figure 1

13 pages, 7033 KiB  
Article
Correlation Between the Structure and Compressive Property of PMMA Microcellular Foams Fabricated by Supercritical CO2 Foaming Method
by Ruizhi Zhang, Ju Chen, Yuxuan Zhu, Jian Zhang, Guoqiang Luo, Peng Cao, Qiang Shen and Lianmeng Zhang
Polymers 2020, 12(2), 315; https://doi.org/10.3390/polym12020315 - 3 Feb 2020
Cited by 19 | Viewed by 3287
Abstract
In this study, we fabricated poly (methyl methacrylate) (PMMA) microcellular foams featuring tunable cellular structures and porosity, through adjusting the supercritical CO2 foaming conditions. Experimental testing and finite element model (FEM) simulations were conducted to systematically elucidate the influence of the foaming [...] Read more.
In this study, we fabricated poly (methyl methacrylate) (PMMA) microcellular foams featuring tunable cellular structures and porosity, through adjusting the supercritical CO2 foaming conditions. Experimental testing and finite element model (FEM) simulations were conducted to systematically elucidate the influence of the foaming parameters and structure on compressive properties of the foam. The correlation between the cellular structure and mechanical properties was acquired by separating the effects of the cell size and foam porosity. It was found that cell size reduction contributes to improved mechanical properties, which can be attributed to the dispersion of stress and decreasing stress concentration. Full article
(This article belongs to the Special Issue Extensional Rheology and Processing of Polymeric Materials)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-3
Back to TopTop