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Polymers
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Processing of High Performance Polymeric Materials: Modeling and Characterization
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Processing of High Performance Polymeric Materials: Modeling and Characterization

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

Deadline for manuscript submissions: closed (25 December 2023) | Viewed by 31721

Special Issue Editors

Prof. Dr. Gernot Zitzenbacher

E-Mail Website
Guest Editor
School of Engineering, University of Applied Sciences Upper Austria, Stelzhamerstr. 23, 4600 Wels, Austria
Interests: determination of material properties for polymer extrusion; tribology in polymer processing; development and modeling of extrusion processes; polymer rheology; wetting and adhesion in polymer processing; thermoforming; liquid crystal polymers
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Christoph Burgstaller

E-Mail Website
Guest Editor
1. Transfercenter für Kunststofftechnik GmbH, Franz-Fritsch-Strasse 11, 4600 Wels, Austria
2. School of Engineering, University of Applied Sciences Upper Austria, Stelzhamerstr. 23, 4600 Wels, Austria
Interests: structure–processing–property relationships of polymer-based systems; polymer matrix composites; simple models for predicting polymer matrix composite properties; mechanical recycling of plastics; natural fiber reinforcement
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues, 

High-performance polymers are characterized by outstanding thermal stability, chemical resistivity, and mechanical properties. In addition, they are suited for a variety of applications in many different areas, including automotive, aerospace, defense, electronics, medical, and sport and safety equipment. This Special Issue of Polymers is dedicated to the Process Modeling and Characterization of high-performance polymers. Computational modeling and simulation have been emerging as an indispensable tool, nowadays, to complement and/or guide experiments in every field. The complex and intriguing mechanical/physical properties of polymeric materials, originating from the multiple spatial and temporal scales, call for advanced multiscale computational techniques in order to account for all-important mechanisms in polymers. Using these to understand the complex structure–processing–property relationships in polymer-based composites and blends helps to further develop polymeric materials.

This Special Issue aims to compile original and cutting-edge research works in the field of characterization, manufacturing, and applications of high-performance polymers.

Prof. Dr. Gernot Zitzenbacher
Dr. Christoph Burgstaller
Guest Editors

Manuscript Submission Information

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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

  • functional
  • manufacturing
  • characterization
  • modeling

Published Papers (16 papers)

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18 pages, 21111 KiB  
Article
Characterization of PPS Piston and Packing Ring Materials for High-Pressure Hydrogen Applications
by Alexander Pöllinger, Julia Maurer, Thomas Koch, Stefan Krenn, Bernhard Plank, Sabine Schwarz, Michael Stöger-Pollach, Eleni Siakkou, Karolina Smrczkova and Michael Schöbel
Polymers 2024, 16(3), 412; https://doi.org/10.3390/polym16030412 - 01 Feb 2024
Cited by 1 | Viewed by 1013
Abstract
The widespread adoption of renewable energy hinges on the efficient transportation of hydrogen. Reciprocating piston compressor technology in non-lubricated operation will play a key role, ensuring high flow rates and compression ratios. These systems rely on advanced high-strength sealing solutions for piston and [...] Read more.
The widespread adoption of renewable energy hinges on the efficient transportation of hydrogen. Reciprocating piston compressor technology in non-lubricated operation will play a key role, ensuring high flow rates and compression ratios. These systems rely on advanced high-strength sealing solutions for piston and rod packing rings utilizing advanced fiber-reinforced polymers. Polyphenylene sulfide (PPS) polymer matrix composites have seen use in tribological applications and promise high mechanical strength and wear resistance. The presented work describes carbon and glass fiber-reinforced PPS matrix polymers in comparison, which are characterized by complementary methods to investigate their properties and potential for application in reciprocating compressor under non-lubricated operation. Thermo-mechanical and tribological testing was supported by microstructure analysis utilizing advanced X-ray and electron imaging techniques. New insights in micromechanical deformation behavior in regard to fiber materials, interface strength and orientation in fiber-reinforced polymers are given. Conclusions on the suitability of different PPS matrix composites for high-pressure hydrogen compression applications were obtained. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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15 pages, 3088 KiB  
Article
A New Approach to Estimating the Parameters of Structural Formations in HDPE Reactor Powder
by Artem Borisov, Yuri Boiko, Svetlana Gureva, Ksenia Danilova, Victor Egorov, Elena Ivan’kova, Vyacheslav Marikhin, Liubov Myasnikova, Ludmila Novokshonova, Elena Radovanova, Elena Starchak, Tatiana Ushakova and Maria Yagovkina
Polymers 2023, 15(18), 3742; https://doi.org/10.3390/polym15183742 - 13 Sep 2023
Viewed by 756
Abstract
The morphology of virgin reactor powder (RP) of high-density polyethylene (HDPE) with MW = 160,000 g/mol was investigated using DSC, SEM, SAXS, and WAXS methods. The morphological SEM analysis showed that the main morphological units of RP are macro- and micro-shish-kebab structures [...] Read more.
The morphology of virgin reactor powder (RP) of high-density polyethylene (HDPE) with MW = 160,000 g/mol was investigated using DSC, SEM, SAXS, and WAXS methods. The morphological SEM analysis showed that the main morphological units of RP are macro- and micro-shish-kebab structures with significantly different geometric dimensions, as well as individual lamellae of folded chain crystals. A quantitative analysis of an asymmetric SAXS reflection made it possible to reveal the presence of several periodic morphoses in the RP with long periods ranging from 20 nm to 60 nm, and to correlate them with the observed powder morphology. According to the DSC crystallinity data, the thickness of the lamellae in each long period was estimated. Their surface energy was calculated in the framework of the Gibbs—Thompson theory. The presence of regular and irregular folds on the surface of different shish-kebab lamellae was discussed. The percentage of identified morphoses in the RP was calculated. It has been suggested that the specific structure of HDPE RP is due to the peculiarity of polymer crystallization during suspension synthesis in a quasi-stationary regime, in which local overheating and inhomogeneous distribution of shear stresses in a chemical reactor are possible. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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11 pages, 4030 KiB  
Article
Aqueous-Cellulose-Solvent-Derived Changes in Cellulose Nanocrystal Structure and Reinforcing Effects
by Yuqi Tong, Shuting Huang, Xianjun Meng and Yixiang Wang
Polymers 2023, 15(14), 3030; https://doi.org/10.3390/polym15143030 - 13 Jul 2023
Cited by 3 | Viewed by 1143
Abstract
Cellulose nanocrystals as reinforcing agents have received considerable interest, and their dimension mainly depends on the original sources of cellulose. We intend to manually modulate the morphology of cellulose nanocrystals by treating them with cellulose solvents so that we can explore their reinforcing [...] Read more.
Cellulose nanocrystals as reinforcing agents have received considerable interest, and their dimension mainly depends on the original sources of cellulose. We intend to manually modulate the morphology of cellulose nanocrystals by treating them with cellulose solvents so that we can explore their reinforcing capacity. In this work, waste cotton fabric was processed in two aqueous solvents (a sulfuric acid aqueous solution and a NaOH/urea aqueous solution), and the regenerated cellulose was used to produce cellulose nanocrystals using acid hydrolysis. The results revealed that the nanocrystals (RCNC-H) obtained after the treatment in sulfuric acid had a hybrid crystalline structure and a needle-like shape with an aspect ratio of about 15.2, while cotton fabric was completely dissolved in the NaOH/urea aqueous solution, and the regenerated nanocrystals (RCNC-N) displayed a typical crystalline form of cellulose II with a higher crystallinity and a shorter rod-like shape with an aspect ratio of about 6.3. The reinforcing effects of RCNC-H and RCNC-N were evaluated using polyvinyl alcohol (PVA) films as a model, where the addition of RCNC-H resulted in a relatively better tensile strength and oxygen barrier property, and the PVA/RCNC-N films had a slightly lower water vapor permeability. Therefore, this work suggests a new possibility for altering the naturally formed nanostructure of cellulose for different applications. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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14 pages, 5063 KiB  
Article
Novel Airflow-Field-Driven Melt Spinning 3D Printing of Tubular Scaffolds Based on Polycaprolactone Blends
by Junyuan Zhang, Zilong Peng, Mengjie Wang, Yinan Li, Jinyin Wu, Yifan Jiang, Chaolong Liu, Guqiang Li, Lin Xu and Hongbo Lan
Polymers 2023, 15(7), 1755; https://doi.org/10.3390/polym15071755 - 31 Mar 2023
Viewed by 1188
Abstract
The fabrication of various 3D tissue engineering tubular scaffolds with fibrous structures, to assist the human body in rapidly repairing a variety of ailments, is receiving more and more attention. Due to the inefficiency of the majority of fibrous preparation techniques, the question [...] Read more.
The fabrication of various 3D tissue engineering tubular scaffolds with fibrous structures, to assist the human body in rapidly repairing a variety of ailments, is receiving more and more attention. Due to the inefficiency of the majority of fibrous preparation techniques, the question of how to rapidly produce the requisite three-dimensional tubular microfiber scaffold structures has become an urgent problem. In this study, an efficient polymer fiber preparation method was developed, using a high-speed airflow drive. Melt blending of polycaprolactone (PCL), polylactic acid (PLA), and tributyl citrate (TBC), was used for the printing material, to achieve the efficient preparation of tubular microfiber scaffolds with different structures. The scaffold diameter was as small as 2 mm, the wall thickness was up to 100 μm, and the fiber injection efficiency reached 15.48 g/h. By utilizing simulations to optimize the printing parameters and by adjusting the printing settings, it was possible to achieve a controlled fiber diameter in the range of 3 μm to 15 μm. In addition, plasma treatment was applied to the microfibers’ surface, to increase their wettability, and the efficiency of the hydrophilic modification was demonstrated. Furthermore, the mechanical property test demonstrated that the fibers have a tensile strength of 1.36 ± 0.16 MPa and a tensile strain of 30.8 ± 3.5%. The radial compressive strain of the tubular scaffold could reach 60% of the original scaffold’s diameter. Finally, the in vitro degradation of the fibers at various pH values was tested. The results showed that, under alkaline conditions, the surface of the fibers would be severely crushed and the rate of deterioration would increase. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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20 pages, 5522 KiB  
Article
Accelerated Simple Preparation of Curcumin-Loaded Silk Fibroin/Hyaluronic Acid Hydrogels for Biomedical Applications
by Mohamed Chaala, Fatima Zohra Sebba, Marta G. Fuster, Imane Moulefera, Mercedes G. Montalbán, Guzmán Carissimi and Gloria Víllora
Polymers 2023, 15(3), 504; https://doi.org/10.3390/polym15030504 - 18 Jan 2023
Cited by 7 | Viewed by 1770
Abstract
The development of new biomaterials from natural fibres in the field of biomedicine have attracted great interest in recent years. One of the most studied fibres has been silk fibroin produced by the Bombyx mori worm, due to its excellent mechanical properties and [...] Read more.
The development of new biomaterials from natural fibres in the field of biomedicine have attracted great interest in recent years. One of the most studied fibres has been silk fibroin produced by the Bombyx mori worm, due to its excellent mechanical properties and its biodegradability and bioavailability. Among the different biomaterials that can be prepared from silk fibroin, hydrogels have attracted considerable attention due to their potential use in different fields, such as scaffolding, cell therapy and biomedical application. Hydrogels are essentially a three-dimensional network of flexible polymer chains that absorb considerable amounts of water and can be loaded with drugs and/or cells inside to be used in a wide variety of applications. Here we present a simple sonication process for the preparation of curcumin-hyaluronic acid-silk fibroin hydrogels. Different grades of hydrogels were prepared by controlling the relative amounts of their components. The hydrogels were physically and morphologically characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM) and their biological activity was tested in terms of cell viability in a fibroblast cell line. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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10 pages, 1612 KiB  
Article
Influence of Fiber Content and Dosing Position on the the Mechanical Properties of Short-Carbon-Fiber Polypropylene Compounds
by Thomas Höftberger, Florian Dietrich, Gernot Zitzenbacher and Christoph Burgstaller
Polymers 2022, 14(22), 4877; https://doi.org/10.3390/polym14224877 - 12 Nov 2022
Cited by 1 | Viewed by 1161
Abstract
The properties of short-fiber-reinforced composites depend on the fiber length of the reinforcing fibers. This fiber length is typically influenced by processing to different extents. In this work, we investigate the influence of processing, i.e., the influence of residence time achieved via different [...] Read more.
The properties of short-fiber-reinforced composites depend on the fiber length of the reinforcing fibers. This fiber length is typically influenced by processing to different extents. In this work, we investigate the influence of processing, i.e., the influence of residence time achieved via different dosing points in compounding, and the fiber content on the fiber length and mechanical properties of short-carbon-fiber-reinforced polypropylene. We found that, with increasing fiber content, the fiber length decreases from 900 to 300 µm after compounding and from 500 to 250 µm after injection molding. Additionally, a decrease in residence time in the compounder leads to an increase in the fiber length of approx. 300 µm compared to the longer residence time. This is later reduced by the injection molding step, but the longer fibers are still longer in the final molded test specimen, thus resulting in a 5–10% increased tensile strength and elastic modulus as well as an some increase in impact strength. As the injection molding step showed considerable fiber length reduction (down to 250 µm), further investigations of injection molding should be undertaken to preserve fiber length better for the increased performance of these composites. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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18 pages, 6298 KiB  
Article
Impact of Micro Silica Filler Particle Size on Mechanical Properties of Polymeric Based Composite Material
by Sidra Siraj, Ali H. Al-Marzouqi, Muhammad Z. Iqbal and Waleed Ahmed
Polymers 2022, 14(22), 4830; https://doi.org/10.3390/polym14224830 - 09 Nov 2022
Cited by 26 | Viewed by 2139
Abstract
In this study, silica in the form of raw local natural sand was added to high-density-polyethylene (HDPE) in order to develop a composite material in the form of sheets that could have potential applications in thin film industries, such as packaging, or recycling [...] Read more.
In this study, silica in the form of raw local natural sand was added to high-density-polyethylene (HDPE) in order to develop a composite material in the form of sheets that could have potential applications in thin film industries, such as packaging, or recycling industries, such as in 3D printing. The silica/HDPE composite sheets were developed using a melt extruder followed by using a hot press for compression molding. The impact of two different particle sizes (25 µm and 5 µm) of the silica particles on selected properties such as toughness, elastic modulus, ductility, and composite density were analyzed. A considerable increase in the toughness and elastic modulus was observed from 0 wt% to 20 wt% with a 25 µm filler size. However, a general decreasing trend was observed in the material’s toughness and elastic modulus with decreasing particle size. A similar trend was observed for the ductility and the tensile strength of the sheets prepared from both filler particle sizes. In terms of the composite density, as the filler was increased from 20 wt% to 50 wt%, an increase in the composite densities was noticed for both particle sizes. Additionally, the sheets developed with 25 µm particle size had a slightly higher density than the 5 µm particle size, which is expected as the size can account for the higher weight. Results from this work aim to analyze the use of local sand as a filler material that can contribute towards maximizing the potential of such composite materials developed in extrusion industries. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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15 pages, 1906 KiB  
Article
Adhesion Improvement of Solvent-Free Pressure-Sensitive Adhesives by Semi-IPN Using Polyurethanes and Acrylic Polymers
by Kwang Hun Park, Dong Yeob Lee, Sung Ha Yoon, Seong Hun Kim, Min Su Han, Seungju Jeon, Yejin Kim, Yong Kwan Lim, Do-Hoon Hwang, Seo-Hyun Jung and Bogyu Lim
Polymers 2022, 14(19), 3963; https://doi.org/10.3390/polym14193963 - 22 Sep 2022
Cited by 9 | Viewed by 2629
Abstract
To improve the peel strength and holding time of polypropylene glycol (PPG)-based pressure-sensitive adhesives (PSAs), a semi-interpenetrating polymer network (semi-IPN) was prepared using acrylic polymers. In addition, to prevent air pollution due to volatile organic compound emissions and avoid the degradation of physical [...] Read more.
To improve the peel strength and holding time of polypropylene glycol (PPG)-based pressure-sensitive adhesives (PSAs), a semi-interpenetrating polymer network (semi-IPN) was prepared using acrylic polymers. In addition, to prevent air pollution due to volatile organic compound emissions and avoid the degradation of physical properties due to a residual solvent, the PPG-based semi-IPN PSAs were fabricated by an eco-friendly solvent-free method using an acrylic monomer instead of an organic solvent. PPG-based semi-IPN PSAs with different hard segment contents (2.9–17.2%) were synthesized; their holding time was found to depend on the hard segment contents. The peel strength was improved because of the formation of the semi-IPN structure. Moreover, the high degree of hard domain formation in the semi-IPN PSA, derived from the increase in the hard segment content using a chain extender, resulted in a holding time improvement. We believe that the as-prepared PSAs can be used in various applications that require high creep resistance. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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15 pages, 3594 KiB  
Article
Inverse Finite Element Approach to Identify the Post-Necking Hardening Behavior of Polyamide 12 under Uniaxial Tension
by Cornelia Amstutz, Bernhard Weisse, Andreas Haeberlin, Jürgen Burger and Adrian Zurbuchen
Polymers 2022, 14(17), 3476; https://doi.org/10.3390/polym14173476 - 25 Aug 2022
Cited by 2 | Viewed by 1793
Abstract
Finite-element (FE) simulations that go beyond the linear elastic limit of materials can aid the development of polymeric products such as stretch blow molded angioplasty balloons. The FE model requires the input of an appropriate elastoplastic material model. Up to the onset of [...] Read more.
Finite-element (FE) simulations that go beyond the linear elastic limit of materials can aid the development of polymeric products such as stretch blow molded angioplasty balloons. The FE model requires the input of an appropriate elastoplastic material model. Up to the onset of necking, the identification of the hardening curve is well established. Subsequently, additional information such as the cross-section and the triaxial stress state inside the specimen is required. The present study aims to inversely identify the post-necking hardening behavior of the semi-crystalline polymer polyamide 12 (PA12) at different temperatures. Our approach uses structural FE simulations of a dog-bone tensile specimen in LS-DYNA with mesh sizes of 1 mm and 2 mm, respectively. The FE simulations are coupled with an optimization routine defined in LS-OPT to identify material properties matching the experimental behavior. A Von Mises yield criterion coupled with a user-defined hardening curve (HC) were considered. Up to the beginning of necking, the Hockett–Sherby hardening law achieved the best fit to the experimental HC. To fit the entire HC until fracture, an extension of the Hockett–Sherby law with power-law functions achieved an excellent fit. Comparing the simulation and the experiment, the following coefficient of determination R2 could be achieved: Group I: R2 > 0.9743; Group II: R2 > 0.9653; Group III: R2 > 0.9927. Using an inverse approach, we were able to determine the deformation behavior of PA12 under uniaxial tension for different temperatures and mathematically describe the HC. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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17 pages, 3279 KiB  
Article
Homogenisation of the Local Thermal Conductivity in Injection-Moulded Short Fibre Reinforced Composites
by Majid Mokarizadehhaghighishirazi, Bart Buffel, Stepan V. Lomov and Frederik Desplentere
Polymers 2022, 14(16), 3360; https://doi.org/10.3390/polym14163360 - 17 Aug 2022
Cited by 2 | Viewed by 1559
Abstract
This paper deals with predicting the effective thermal conductivity (ETC) of injection-moulded short fibre reinforced polymers (SFRPs) using two different homogenisation schemes: a scheme based on the dielectric theory for pseudo-oriented inclusions and a two-step homogenisation model based on the mean-field homogenisation approach. [...] Read more.
This paper deals with predicting the effective thermal conductivity (ETC) of injection-moulded short fibre reinforced polymers (SFRPs) using two different homogenisation schemes: a scheme based on the dielectric theory for pseudo-oriented inclusions and a two-step homogenisation model based on the mean-field homogenisation approach. In both cases, the fibre orientation tensor (FOT) obtained from Autodesk Moldflow® simulation was used. The Moldflow FOT predictions were validated via structure tensor analysis of micro-computed X-ray tomography (micro-CT) scans of the part. In the dielectric-wise approach, the orientation of fibres was originally defined by a scalar parameter, which is related to the diagonal components of the FOT. In the two-step homogenisation approach, an interpolative model based on the Mori–Tanaka theory is used in the first step for calculating the ETC for the ideal case of unidirectional fibre alignment, followed by a second step in which orientation averaging based on the FOT inside each element is applied. The ETC was calculated using both schemes for the specific case of uniform fibre orientation distribution and at three different locations with non-identical FOTs of an injection-moulded SFRP part. The results are compared with each other and evaluated against the direct numerical simulation for the uniform fibre orientation and experimental measurements for the injection-moulded SFRP. This shows that while the two-step homogenisation can predict the ETC in the full range of orientations between the perfectly aligned and uniformly distributed fibres, the dielectric-wise approach is only capable of modelling the ETC when distributions are close to the two extreme ends of the orientation spectrum. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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18 pages, 6035 KiB  
Article
Enhanced Simulation of Infrared Heating of Thermoplastic Composites Prior to Forming under Consideration of Anisotropic Thermal Conductivity and Deconsolidation by Means of Novel Physical Material Models
by Manuel Längauer, Gernot Zitzenbacher, Hannes Stadler and Christoph Hochenauer
Polymers 2022, 14(16), 3331; https://doi.org/10.3390/polym14163331 - 16 Aug 2022
Viewed by 1457
Abstract
In recent years, thermoplastic composites have found their place in large business sectors and are in direct rivalry to thermoset matrix composites. In order to ensure efficient and lean processes, process modeling gains ever-growing attention. This work shows the computational fluid dynamics (CFD)-modeling [...] Read more.
In recent years, thermoplastic composites have found their place in large business sectors and are in direct rivalry to thermoset matrix composites. In order to ensure efficient and lean processes, process modeling gains ever-growing attention. This work shows the computational fluid dynamics (CFD)-modeling of a typical heating step in a thermoforming process of a thermoplastic composite sheet. When heating thermoplastic composites, the heat conduction proceeds anisotropic, and the sheets are subject to thermal deconsolidation when heated above the melting temperature of the polymer matrix adding to the anisotropic effect. These effects are neglected in known process models and this study shows the first successful attempt at introducing them into CFD-modeling of the heating of thermoplastic composite sheets. Thus, the simulation requires temperature dependent values for the anisotropic thermal conductivity and the coefficient of linear thermal expansion, which are calculated with novel physical models which were developed solely for this cause. This alters the behavior of an isotropic CFD-model and allows the successful validation via laboratory experiments using glass fiber reinforced polypropylene (PP/GF) sheets with embedded thermocouples to check the internal temperature distribution when the sheet is heated to the designated forming temperature in a composite thermoforming press. The incorporation of this newly developed process model reduces the error in the core temperature prediction from close to 70 °C to 3 °C at the forming temperature. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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14 pages, 6237 KiB  
Article
Statistical Analysis of the Mechanical Behavior of High-Performance Polymers: Weibull’s or Gaussian Distributions?
by Yuri Boiko, Vyacheslav Marikhin and Lyubov’ Myasnikova
Polymers 2022, 14(14), 2841; https://doi.org/10.3390/polym14142841 - 12 Jul 2022
Cited by 5 | Viewed by 1540
Abstract
This work addresses the following problem: which of the statistical approaches, Weibull’s or Gaussian, is more appropriate to correctly describe the statistical distributions of the mechanical properties of the high-performance polymer materials of different sample types (single or multifilament oriented fibers) and chain [...] Read more.
This work addresses the following problem: which of the statistical approaches, Weibull’s or Gaussian, is more appropriate to correctly describe the statistical distributions of the mechanical properties of the high-performance polymer materials of different sample types (single or multifilament oriented fibers) and chain architectures (ultra-high-molecular-weight polyethylene, polyamide 6, or polypropylene)? Along with the routine mechanical properties such as strength, strain at break, and Young’s modulus, an apparent viscoelastic modulus and an apparent strain at break found when differentiating the stress–strain curves have been considered for the first time. For this purpose, a large sample number (50 in each series) has been tested. It has been shown that the values of the Weibull’s modulus (m) characterizing the data scatter were dependent both on the chain architecture and the sample type for the five elastic, viscoelastic and fracture characteristics analyzed. The Weibull’s model has been found to be more correct as compared to the Gaussian one. The different statistical approaches used for the analysis of the large arrays of the data are important for a better understanding of the deformation and fracture mechanisms of quasi-brittle and quasi-ductile high-performance polymer materials. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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17 pages, 3810 KiB  
Article
Metal Oxide Nanoparticles: An Effective Tool to Modify the Functional Properties of Thermally Stable Polyimide Films
by Alexandra L. Nikolaeva, Alexander N. Bugrov, Maria P. Sokolova, Elena M. Ivan’kova, Ivan V. Abalov, Elena N. Vlasova and Iosif V. Gofman
Polymers 2022, 14(13), 2580; https://doi.org/10.3390/polym14132580 - 25 Jun 2022
Cited by 3 | Viewed by 1800
Abstract
A series of polyimide/metal oxide (either ZrO2 or TiO2) nanocomposite films were fabricated based on two polymer matrices. The prepared films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction analysis (XRD), and their thermal [...] Read more.
A series of polyimide/metal oxide (either ZrO2 or TiO2) nanocomposite films were fabricated based on two polymer matrices. The prepared films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction analysis (XRD), and their thermal and mechanical properties were investigated with the use of thermogravimetric (TGA), differential thermal analysis (DTA), and thermomechanical analysis (TMA). We have found out that functional properties of the obtained materials are determined by a number of factors, not only the type, size, surface functionality, and concentration of the nanofiller, but also the chemical structure of the matrix polyimide. We have demonstrated some trends in the thermal and mechanical behavior of the materials depending on these features. The data could be of great interest in the areas where new materials with improved functional characteristics are needed. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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12 pages, 2961 KiB  
Article
Research on the Influence of Processing Parameters on the Specific Tensile Strength of FDM Additive Manufactured PET-G and PLA Materials
by Michał Bembenek, Łukasz Kowalski and Agnieszka Kosoń-Schab
Polymers 2022, 14(12), 2446; https://doi.org/10.3390/polym14122446 - 16 Jun 2022
Cited by 16 | Viewed by 2818
Abstract
Fused deposition modeling (FDM) is one of the most accessible additive manufacturing (AM) technologies for processing polymeric materials. It allows processing most of thermoplastic polymers, with polyethylene terephthalate glycol-modified (PET-G) and polylactic acid (PLA). AM parts tend to display anisotropic behavior because of [...] Read more.
Fused deposition modeling (FDM) is one of the most accessible additive manufacturing (AM) technologies for processing polymeric materials. It allows processing most of thermoplastic polymers, with polyethylene terephthalate glycol-modified (PET-G) and polylactic acid (PLA). AM parts tend to display anisotropic behavior because of layer-by-layer fabrication and various technological parameters that can be set for 3D print, so it is hard to predict and analyze how the manufactured parts would behave under load. This research presents results of classic tensile strength tests performed on 57 PET-G specimens and 57 PLA specimens manufactured with varying technological parameters such as: printing temperature, print orientation, layer height, and infill percentage. Afterward, a comparative analysis is performed, proposing specific tensile strength (STS) as a benchmark to determine how 3D printed parts strength is varying due to beforementioned parameters, eliminating bias induced by varying weight of specimens. The biggest relative increase of UTS and the biggest relative decrease of STS was noted for variable infill percentage (increasing infill—PLA: 37.27% UTS increase and 30.41% STS decrease; PET-G: 24.42% UTS increase and 37.69% STS decrease). The biggest relative increase of STS between examined parameters was observed for both materials as the printing temperature was increased (27.53% for PLA and 12.69% for PET-G). Similar trends in STS changes were observed for both materials. Obtained data shows which FDM AM parameters are the most important to obtain the biggest UTS of manufactured parts, and those do not overlap with parameters needed to obtain optimal strength-to-weight ratio. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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19 pages, 10443 KiB  
Article
Fabrication of Bipolar Plates from Thermoplastic Elastomer Composites for Vanadium Redox Flow Battery
by Kannika Onyu, Rungsima Yeetsorn and Jeff Gostick
Polymers 2022, 14(11), 2143; https://doi.org/10.3390/polym14112143 - 25 May 2022
Cited by 4 | Viewed by 3009
Abstract
A vanadium redox flow battery (VRFB) is a promising large-scale energy storage device, due to its safety, durability, and scalability. The utilization of bipolar plates (BPs), made of thermoplastic vulcanizates (TPVs), synthetic graphite, woven-carbon-fiber fabric (WCFF), and a very thin pyrolytic graphite sheet [...] Read more.
A vanadium redox flow battery (VRFB) is a promising large-scale energy storage device, due to its safety, durability, and scalability. The utilization of bipolar plates (BPs), made of thermoplastic vulcanizates (TPVs), synthetic graphite, woven-carbon-fiber fabric (WCFF), and a very thin pyrolytic graphite sheet (GS), is investigated in this study. To boost volumetric electrical conductivity, WCFF was introduced into the TPV composite, and the plate was covered with GS to increase surface electrical conductivity. Created composite BPs acquire the desired electrical conductivity, mechanical strength, and deformation characteristics. Those properties were assessed by a series of characterization experiments, and the morphology was examined using an optical microscope, a scanning electron microscope, and atomic force microscopy. Electrochemical testing was used to confirm the possibility of using the suggested BP in a working VRFB. The laminated BP was utilized in a flow cell to electrolytically convert V(IV) to V(V) and V(II), which achieved comparable results to a commercial graphite bipolar plate. Following these experiments, the laminated bipolar plates’ surfaces were examined using X-ray photoelectron spectroscopy, and no evidence of corrosion was found, indicating good durability in the hostile acidic environment. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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Review

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38 pages, 45709 KiB  
Review
Surface Modifications of High-Performance Polymer Polyetheretherketone (PEEK) to Improve Its Biological Performance in Dentistry
by Bidhari Pidhatika, Vania Tanda Widyaya, Prathima C. Nalam, Yogi Angga Swasono and Retno Ardhani
Polymers 2022, 14(24), 5526; https://doi.org/10.3390/polym14245526 - 16 Dec 2022
Cited by 14 | Viewed by 3777
Abstract
This comprehensive review focuses on polyetheretherketone (PEEK), a synthetic thermoplastic polymer, for applications in dentistry. As a high-performance polymer, PEEK is intrinsically robust yet biocompatible, making it an ideal substitute for titanium—the current gold standard in dentistry. PEEK, however, is also inert due [...] Read more.
This comprehensive review focuses on polyetheretherketone (PEEK), a synthetic thermoplastic polymer, for applications in dentistry. As a high-performance polymer, PEEK is intrinsically robust yet biocompatible, making it an ideal substitute for titanium—the current gold standard in dentistry. PEEK, however, is also inert due to its low surface energy and brings challenges when employed in dentistry. Inert PEEK often falls short of achieving a few critical requirements of clinical dental materials, such as adhesiveness, osseoconductivity, antibacterial properties, and resistance to tribocorrosion. This study aims to review these properties and explore the various surface modification strategies that enhance the performance of PEEK. Literatures searches were conducted on Google Scholar, Research Gate, and PubMed databases using PEEK, polyetheretherketone, osseointegration of PEEK, PEEK in dentistry, tribology of PEEK, surface modifications, dental applications, bonding strength, surface topography, adhesive in dentistry, and dental implant as keywords. Literature on the topics of surface modification to increase adhesiveness, tribology, and osseointegration of PEEK were included in the review. The unavailability of full texts was considered when excluding literature. Surface modifications via chemical strategies (such as sulfonation, plasma treatment, UV treatment, surface coating, surface polymerization, etc.) and/or physical approaches (such as sandblasting, laser treatment, accelerated neutral atom beam, layer-by-layer assembly, particle leaching, etc.) discussed in the literature are summarized and compared. Further, approaches such as the incorporation of bioactive materials, e.g., osteogenic agents, antibacterial agents, etc., to enhance the abovementioned desired properties are explored. This review presents surface modification as a critical and essential approach to enhance the biological performance of PEEK in dentistry by retaining its mechanical robustness. Full article
(This article belongs to the Special Issue Processing of High Performance Polymeric Materials: Modeling and Characterization)
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