Polymers

Research

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10 pages, 3414 KiB

Open AccessArticle

Pressing of Functionalized Polymer Composite Materials to Improve Mössbauer Measurement Signals

by Justus Pawlak, Jules Brehme, Maximilian Seydi Kilic, Kevin Tran, Justin Koch, Mohammad Beyki, Ralf Sindelar, Robert Patzke and Franz Renz

Polymers 2024, 16(10), 1311; https://doi.org/10.3390/polym16101311 - 7 May 2024

Viewed by 189

Abstract

Coordination compounds, like iron(II) triazole complexes, exhibit spin crossover (SCO) behavior at around room temperature. Therefore, they are interesting for a variety of possible applications, and it is convenient to integrate them into polymers. Due to a reduction of the iron content and [...] Read more.

Coordination compounds, like iron(II) triazole complexes, exhibit spin crossover (SCO) behavior at around room temperature. Therefore, they are interesting for a variety of possible applications, and it is convenient to integrate them into polymers. Due to a reduction of the iron content and thus also ⁵⁷Fe content in the sample through integration in polymers, Mössbauer measurements are only possible with greater difficulty or very long measurement times without expensive enrichment of the samples with ⁵⁷Fe. So, other ways of improving the Mössbauer signal for these composite materials are necessary. Therefore, we pressed these composite materials to improve the Mössbauer spectra. In this study, we synthesized an iron(II) triazole spin crossover complex and an electrospun polymer complex composite nanofiber material including the same complex. For both products, Mössbauer measurements were performed at room temperature before and after using a press to show that the complex composite is not harmed through pressing. We investigate the influence of the pressing impact on the Mössbauer measurements in the context of measurement statistics and the measured signals. We show that pressing is not connected to any changes in the sample regarding the spin and oxidation state. We present that pressing improves the statistics of the Mössbauer measurements significantly. Furthermore, we use SEM measurements and PXRD to investigate whether or not the obtained fiber mats are destroyed in the pressing process. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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13 pages, 31884 KiB

Open AccessArticle

Preparation of Thermoplastic Polyurethane/Multi-Walled Carbon Nanotubes Composite Foam with High Resilience Performance via Fused Filament Fabrication and CO₂ Foaming Technique

by Huijing Guo, Naveen Thirunavukkarasu, Suhail Mubarak, Huang Lin, Chen Zhang, Yonggui Li and Lixin Wu

Polymers 2023, 15(6), 1535; https://doi.org/10.3390/polym15061535 - 20 Mar 2023

Cited by 4 | Viewed by 2181

Abstract

Wearable flexible sensors with high sensitivity and wide detection range are applied in motion detection, medical diagnostic result and other fields, but poor resilience and hysteresis remain a challenge. In this study, a high-resilience foam sensor was prepared through a combination of additive [...] Read more.

Wearable flexible sensors with high sensitivity and wide detection range are applied in motion detection, medical diagnostic result and other fields, but poor resilience and hysteresis remain a challenge. In this study, a high-resilience foam sensor was prepared through a combination of additive manufacturing and green physical foaming method. The conductive filaments were prepared by using MWCNTs-modified TPU by the physical method of melt blending. Samples were prefabricated using the FFF printer and then saturated with CO₂ in an autoclave before being removed and heated to foam. The composite foam effectively reduced residual strain, demonstrating the high resilience of the 3D-printed composite materials with a foam porous structure. The residual strain of the sample before foaming was >6% after a single cycle, and then gradually increased. The residual strain of the foamed samples is less than 5%. In addition, composite foam has high sensitivity and can monitor subtle pressure changes (0~40 kPa). The sensing performance of the composite foam was evaluated, and the current signal remained stable under different loading rates and small compression strains (2~5%). By using this highly resilient conductive composite material, a hierarchical shoe insole was designed that successfully detected human walking and running movements. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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14 pages, 8685 KiB

Open AccessArticle

Oscillating Laser Conduction Joining of Dissimilar PET to Stainless Steel

by Wei Liao, Suning Zhao and Ming Gao

Polymers 2022, 14(22), 4956; https://doi.org/10.3390/polym14224956 - 16 Nov 2022

Cited by 3 | Viewed by 1234

Abstract

How to improve the bonding strength of polymers to metals has been one of the challenges in joining fields. It is generally assumed that laser transmission joining is better than laser conduction joining (LCJ) for transparent polymers, and few studies have been focused [...] Read more.

How to improve the bonding strength of polymers to metals has been one of the challenges in joining fields. It is generally assumed that laser transmission joining is better than laser conduction joining (LCJ) for transparent polymers, and few studies have been focused on LCJ. However, by introducing beam oscillation, an excellent result was obtained in the LCJ of transparent polyethylene terephthalate (PET) to 304 stainless steel. The interface defects of thermal decomposition and bubbles could be eliminated or reduced more efficiently in oscillating laser conduction joining (O-LCJ) rather than transmission joining. Correspondingly, the tensile shear force of joint O-LCJ could be increased by 23.8%, and the plasticity characterized by tensile displacement could be increased by seven times. The improvement mechanism was attributed to two factors by calculating the interface energy distribution and analyzing the force state at the interface. One is the homogenization of interface energy distribution caused by beam oscillation, which decreases the degradation and destruction of polymer macromolecular chains induced by high temperature. The other is the formation of interface bi-directional forces that both inhibit the porosity formation and intensify the chemical reactions. The results bring new insights and provide a new pathway to improve the joining performances of dissimilar polymers to metals. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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10 pages, 2550 KiB

Open AccessArticle

Phosphorylated Metal–Organic Framework for Reducing Fire Hazards of Poly(Methyl Methacrylate)

by Lei Wang, Ximiao Hu, Zhelin Mao, Jianlei Wang and Xin Wang

Polymers 2022, 14(22), 4871; https://doi.org/10.3390/polym14224871 - 11 Nov 2022

Cited by 5 | Viewed by 1625

Abstract

The low fire safety performance (flame retardant and antistatic properties) of poly(methyl methacrylate) (PMMA) has severely limited practical applications. Here, a phosphorylated Zn-based metal–organic framework (ZIF-8-P) is employed as an effective flame retardant and antistatic agent to reduce the fire risk of PMMA. [...] Read more.

The low fire safety performance (flame retardant and antistatic properties) of poly(methyl methacrylate) (PMMA) has severely limited practical applications. Here, a phosphorylated Zn-based metal–organic framework (ZIF-8-P) is employed as an effective flame retardant and antistatic agent to reduce the fire risk of PMMA. Encouragingly, the as-prepared PMMA/ZIF-8-P composite demonstrated not merely better mechanical properties (e.g., a rise of ca. 136.9% and 175.0% in the reduced modulus and hardness; a higher storage modulus), but also efficient fire safety properties (e.g., lower surface resistance; a decrease of ca. 73.1% in the peak heat release rate; a lower amount of total pyrolysis products), surpassing those of pure PMMA and a PMMA/ZIF-8 composite without phytic acid modification. Mechanism analysis is conducted to reveal the critical role of catalytic charring, char reinforcing, and the dilution of nonflammable gases from ZIF-8 additives during the combustion and pyrolysis process. Our study paves a promising way to achieve high performance PMMA composites. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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15 pages, 3199 KiB

Open AccessArticle

Influence of Ambient Temperature on Part Distortion: A Simulation Study on Amorphous and Semi-Crystalline Polymer

by Anto Antony Samy, Atefeh Golbang, Eileen Harkin-Jones, Edward Archer, Monali Dahale and Alistair McIlhagger

Polymers 2022, 14(5), 879; https://doi.org/10.3390/polym14050879 - 23 Feb 2022

Cited by 10 | Viewed by 2026

Abstract

Semi-crystalline polymers develop higher amounts of residual stress and part distortion (warpage) compared to amorphous polymers due to their crystalline nature. Additionally, the FDM processing parameters such as ambient temperature play an important role in the resulting residual stresses and part distortion of [...] Read more.

Semi-crystalline polymers develop higher amounts of residual stress and part distortion (warpage) compared to amorphous polymers due to their crystalline nature. Additionally, the FDM processing parameters such as ambient temperature play an important role in the resulting residual stresses and part distortion of the printed part. Hence, in this study, the effect of ambient temperature on the in-built residual stresses and warpage of amorphous acrylonitrile-butadiene-styrene (ABS) and semi-crystalline polypropylene (PP) polymers was investigated. From the results, it was observed that increasing the ambient temperature from 50 °C to 75 °C and further to 120 °C resulted in 0.22-KPa and 0.37-KPa decreases in residual stress of ABS, but no significant change in the amount of warpage. For PP, increasing ambient temperature from 50 °C to 75 °C led to a more considerable decrease in residual stress (0.5 MPa) and about 3% increase in warpage. Further increasing to 120 °C resulted in a noticeable 2 MPa decrease in residual stress and a 3.4% increase in warpage. Reduction in residual stress in both ABS and PP as a result of increasing ambient temperature was due to the reduced thermal gradients. The enhanced warpage in PP with increase in ambient temperature, despite the reduction in residual stress, was ascribed to crystallization and shrinkage. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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13 pages, 2597 KiB

Open AccessArticle

Resistance and Strength of Conductive PLA Processed by FDM Additive Manufacturing

by Juraj Beniak, Ľubomír Šooš, Peter Križan, Miloš Matúš and Vít Ruprich

Polymers 2022, 14(4), 678; https://doi.org/10.3390/polym14040678 - 10 Feb 2022

Cited by 22 | Viewed by 2244

Abstract

There is a large number of materials that can be used for FDM additive manufacturing technology. These materials have different strength properties, they are designed for different purposes. They can be highly strong or flexible, abrasion-resistant, or designed for example for environments with [...] Read more.

There is a large number of materials that can be used for FDM additive manufacturing technology. These materials have different strength properties, they are designed for different purposes. They can be highly strong or flexible, abrasion-resistant, or designed for example for environments with higher thermal loads. However recently new innovative and progressive materials have come to the practice, which include nano-composite particles, bringing new added value. One such material is the Conductive PLA material, which is capable of conducting electric current. The aim of this article is to present the material properties of this material. The article describes the design of the experiment, the process of measuring the resistance of samples printed by FDM device, measuring the maximum tensile strength of samples. The article includes a statistical evaluation of the measured data, with the determination of the significance of individual factors of the experiment as well as the evaluation of the overall result of the experiments. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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12 pages, 2424 KiB

Open AccessArticle

Facile Preparation of Tunicate-Inspired Chitosan Hydrogel Adhesive with Self-Healing and Antibacterial Properties

by Xiang He, Ruyue Liu, Huiqing Liu, Ruixiao Wang, Zhenhao Xi, Yixiang Lin and Jie Wang

Polymers 2021, 13(24), 4322; https://doi.org/10.3390/polym13244322 - 10 Dec 2021

Cited by 12 | Viewed by 3481

Abstract

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels [...] Read more.

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels (CS-TBA-Fe) were prepared by easily mixing the solutions of chitosan-FeCl₃ and TBA via the Schiff-base reaction and the coordination between Fe³⁺ and pyrogallol groups. The gelation time was greatly shortened to only several seconds after induced even trace Fe³⁺. The hydrogel (CS-TBA-Fe) exhibited ~12-fold enhanced wet tissue adhesion strength (60.3 kPa) over the commercial fibrin glue. Meanwhile, the hydrogel also showed robust adhesion to various substrates such as wood, PMMA, and aluminum. The swelling ratio and rheological property can be simply controlled by changing the concentrations of chitosan, TBA, and Fe³⁺. Moreover, the hydrogel displayed a rapid and highly efficient self-healing ability and an excellent antibacterial activity against E. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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Review

Jump to: Research

27 pages, 5031 KiB

Open AccessReview

Progress in the Preparation, Properties, and Applications of PLA and Its Composite Microporous Materials by Supercritical CO₂: A Review from 2020 to 2022

by Kangming Peng, Suhail Mubarak, Xuefeng Diao, Zewei Cai, Chen Zhang, Jianlei Wang and Lixin Wu

Polymers 2022, 14(20), 4320; https://doi.org/10.3390/polym14204320 - 14 Oct 2022

Cited by 15 | Viewed by 2957

Abstract

The development of degradable plastic foams is in line with the current development concept of being pollution free and sustainable. Poly(lactic acid) (PLA) microporous foam with biodegradability, good heat resistance, biocompatibility, and mechanical properties can be successfully applied in cushioning packaging, heat insulation, [...] Read more.

The development of degradable plastic foams is in line with the current development concept of being pollution free and sustainable. Poly(lactic acid) (PLA) microporous foam with biodegradability, good heat resistance, biocompatibility, and mechanical properties can be successfully applied in cushioning packaging, heat insulation, noise reduction, filtration and adsorption, tissue engineering, and other fields. This paper summarizes and critically evaluates the latest research on preparing PLA microporous materials by supercritical carbon dioxide (scCO₂) physical foaming since 2020. This paper first introduces the scCO₂ foaming technologies for PLA and its composite foams, discusses the CO₂-assisted foaming processes, and analyzes the effects of process parameters on PLA foaming. After that, the paper reviews the effects of modification methods such as chemical modification, filler filling, and mixing on the rheological and crystallization behaviors of PLA and provides an in-depth analysis of the mechanism of PLA foaming behavior to provide theoretical guidance for future research on PLA foaming. Lastly, the development and applications of PLA microporous materials based on scCO₂ foaming technologies are prospected. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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35 pages, 6850 KiB

Open AccessReview

Recent Advances in Functional Polymer Materials for Energy, Water, and Biomedical Applications: A Review

by Yassine EL-Ghoul, Fahad M. Alminderej, Fehaid M. Alsubaie, Radwan Alrasheed and Norah H. Almousa

Polymers 2021, 13(24), 4327; https://doi.org/10.3390/polym13244327 - 10 Dec 2021

Cited by 22 | Viewed by 8184

Abstract

Academic research regarding polymeric materials has been of great interest. Likewise, polymer industries are considered as the most familiar petrochemical industries. Despite the valuable and continuous advancements in various polymeric material technologies over the last century, many varieties and advances related to the [...] Read more.

Academic research regarding polymeric materials has been of great interest. Likewise, polymer industries are considered as the most familiar petrochemical industries. Despite the valuable and continuous advancements in various polymeric material technologies over the last century, many varieties and advances related to the field of polymer science and engineering still promise a great potential for exciting new applications. Research, development, and industrial support have been the key factors behind the great progress in the field of polymer applications. This work provides insight into the recent energy applications of polymers, including energy storage and production. The study of polymeric materials in the field of enhanced oil recovery and water treatment technologies will be presented and evaluated. In addition, in this review, we wish to emphasize the great importance of various functional polymers as effective adsorbents of organic pollutants from industrial wastewater. Furthermore, recent advances in biomedical applications are reviewed and discussed. Full article

(This article belongs to the Special Issue Functional Polymer Materials and Advanced Processing Technology)

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