Macromolecular Materials and Engineering最新文献

Front Cover: Single processing methods hardly cover the vast range of parameters needed to obtain polymer materials with integrated functionalities for increasingly complex applications. This study combines injection molding with precision additive manufacturing to produce customized hybrid materials, in particular to achieve selective mechanical reinforcement of injection molded objects by overprinting with microstructures. More details can be found in article 2400210 by Julian Thiele, Ines Kühnert, and co-workers. Cover art designed by Martin Schumann and Marie Zeil.

In this study, a thermoresponsive double-network (DN) nanocomposite hydrogel is developed. The primary hydrogel network comprises Pluronic P123, while the secondary network comprises gelatinmethacrylate (GELMA) and polyacrylamide (PAM). A systematic approach is adopted to develop DN hydrogels. Initially, the impact of Pluronic P123 concentrationon the mechanical properties of PAM-GELMA hydrogel is investigated. Results from the tensile strength and the oscillatory shear tests reveal that an increasing P123 concentration has a marginal effect on the storage modulus while significantly reducing the loss modulus of the PAM-GELMA hydrogel, thereby improving mechanical properties. Notably, DN3 hydrogel containing 7.5w/v% P123 in PAM-GELMA exhibits osteoid matrix-like mechanical properties. To further enhance the mechanical properties, citrate-containing amorphous calcium phosphate (ACP_CIT) is incorporated in DN3 hydrogel at varying concentrations. At a lower concentration of ACP_CIT (0.75 w/v%), the mechanical properties of DN3-ACP0.75 hydrogel are notably enhanced. Incorporating ACP_CIT in DN3 hydrogel (DN3-ACP0.75) decreases creep strain, rapid stress relaxation, and reduced water uptake capacity while maintaining the thermoresponsive behavior. Finally, an in vitro analysis confirms the cytocompatibility of the hydrogels with MC3T3-E1 cells, indicating the potential use in bone tissue engineering.

“Thermoreversible Structurally Recoverable Dual-Network Elastomer Hydrogel,” Macromolecular Materials and Engineering 305, no. 1 (2020): 1900633, https://doi.org/10.1002/mame.201900633.

The above article, published online on 03 December 2019 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editor-in-Chief, David Huesmann; and Wiley-VCH GmbH. The retraction has been agreed after an investigation took place when the authors requested a correction to the article, admitting they-had accidentally reused an image they previously published. Upon further review, the Editor-In-Chief saw that this reused image was-also clearly manipulated by the authors to create Figure 7b by rotation plus the removal of cells from the original image seen both in Figure 7a and also in the previous journal article figure. Upon questioning, the authors acknowledged they-had edited the previously published image. As a result, the figures, data, and conclusions are considered unreliable and therefore the article must be retracted.

Pollution from plastics is a major issue in the current context, prompting the scientific community to focus its efforts on recycling these materials. Mechanical recycling emerges as the most popular due to its practicality and cost-effectiveness. In fact, with the increase in environmental awareness, the adoption of new circular economy models, stricter regulations mandating disposal and recycling, and lower costs compared to other recycling techniques, this type of recycling is taking a predominant role over other method. However, the presence of a variety of products of different polymeric nature, the introduction of new biodegradable products, and the complexity of multilayer packaging combining different polymers, without concrete solutions for recycling create a heterogeneous range of materials that leaks into the environment. The scientific literature is actively addressing these challenges, and this review aims to explore the latest strategies for enhancing the mechanical recycling of new and challenging polymer systems. Specifically, it explores the recycling of materials originally designated for landfill, incineration or composting, focusing on advancements in management of these previously overlooked and problematic system. This underexplored perspective seeks to offer new insights and innovative solutions that can transform polymer waste management and advance more sustainable recycling practices.

Bone pathologies are still among the most challenging issues for orthopedics. Over the past decade, different methods are developed for bone repair. In addition to advanced surgical and graft techniques, polymer-based biomaterials, bioactive glass, chitosan, hydrogels, nanoparticles, and cell-derived exosomes are used for bone healing strategies. Owing to their variation and promising advantages, most of these methods are not translated into clinical practice. Three dimensonal (3D) bioprinting is an additive manufacturing technique that has become a next-generation biomaterial technique adapted for anatomic modeling, artificial tissue or organs, grafting, and bridging tissues. Polymer-based biomaterials are mostly used for the controlled release of various drugs, therapeutic agents, mesenchymal stem cells, ions, and growth factors. Polymers are now among the most preferable materials for 3D bioprinting. Melatonin is a well-known antioxidant with many osteoinductive properties and is one of the key hormones in the brain–bone axis. 3D bioprinted melatonin-loaded polymers with unique lipophilic, anti-inflammatory, antioxidant, and osteoinductive properties for filling large bone gaps following fractures or congenital bone deformities may be developed in the future. This study summarized the benefits of 3D bioprinted and polymeric materials integrated with melatonin for sustained release in bone regeneration approaches.

The preparation of resistant ultrathin film (utf) hydrogels coated onto different working surfaces (e.g., fabrics) is paying increasing attention as an advantageous strategy for customizing their resultant properties. More specifically, poly(ethylene glycol) (PEG)-based utf-hydrogels are relevant for their superior biocompatibility or antibiofouling properties. However, promoting the generation of poly(ethylene glycol) dimethacrylate (PEGDMA) cross-links ideally without the use of initiators or other cross-link agents, which might compromise the final bioactivity of the system, is complicated. Moreover, the actual synthesis techniques used for the preparation of such utf-hydrogels face important drawbacks like high scale-up costs or important geometrical restrictions, completely hindering its technological transfer. Herein, for the first time and easy and technologically scalable technology is reported for the synthesis and direct deposition of PEGDMA₄₀₀ utf-hydrogels onto different substrates based on atmospheric pressure nanosecond pulsed plasma approach. The advantages of the technology are explored and discussed, reporting the ready-to-use transparent coating of fabrics. After washing the samples using washing programs of a commercial laundry machine, coatings are still well adhered, showing excellent stability. Finally, the resultant properties of PEGDMA₄₀₀ utf-hydrogels are exhaustively characterized using in operando conditions in order to elucidate their potential capabilities in the biomedical field.

This study demonstrates a high-throughput fabrication of fiber interlayers for proton exchange membranes based on poly(pentafluorostyrene) (PPFSt) and its aminated derivatives. The fibers are produced by electrospinning, where the parameters are carefully screened. The controlled parameters are solvent composition, weight percentage, voltage, flow rate, and temperature, controlled with a self-designed heating jacket. The parameters are iterated toward optimized fiber structure and maximum output. The yielded fibers are infiltrated with Nafion and sulfonated polymer from bisphenol AF and decafluorobiphenyl (SFS001) by spray-coating and doctor blading to obtain the fiber-reinforced proton exchange membranes. Tensile tests reveal a higher Young's modulus and yield stress than pure Nafion. Here, the basicity of the aminated PPFSt fibers correlates with the Young's modulus due to improved acid-base interactions between amine groups and sulfonic acid. The acid-base interactions influence the composite membrane's proton conductivity, varying from 23 mS cm⁻¹ for strongly alkaline fibers to 69 mS cm⁻¹ for non-basic fibers. These findings can be transferred to fabricating fiber reinforcements beyond routinely used poly(benzimidazoles).

With the issue of plastic waste persisting and the need for more sustainable solutions to the ever-increasing demand for lightweight and durable plastic products, this review has become imminent and compelling. Poly (butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer with exceptional film-forming ability resembling those of low-density polyethylene. PBAT has a huge advantage for packaging applications due to its remarkably high elongation at break, giving it a good processing window for its application in packaging. However, certain defiant intrinsic properties stand in the way of its full commercialization. The development of blends and biocomposites of PBAT has, therefore, become imperative for complementing its properties and producing a superior material. This paper focuses on the recent developments in preparing PBAT-based blends and biocomposites with superior mechanical, barrier, and antimicrobial properties and, most importantly, has also investigated how the development of these blends and biocomposites impacts the biodegradation rate of PBAT. It also highlights the possible synthesis of bio-based PBAT and the commercialization, market trends, and prospects of PBAT-based materials for flexible, rigid packaging, and other industrial applications compared with biodegradable alternatives.

This study explores the impact of a graphene oxide (GO)/nano silica (NS) hybrid (GO/NS) filler on the diffusion characteristics of natural rubber (NR) composites when exposed to toluene, xylene, and hexane solvents. The lowest solvent uptake is observed for NR GO/NS 3 (3 phr), which is attributed to forming a robust filler network within the composite. The calculation of crosslink density using the Flory-Rehner equation reveals significantly higher values for NR GO/NS 3, indicating good crosslinking density in the presence of the hybrid filler. Furthermore, molecular mass between crosslinks (Mc) is calculated, demonstrating a favorable fit with the Affine model. The investigation extends to theoretical modeling, where the Korsemeyer–Peppas and Peppas–Sahlin models are employed to predict solvent uptake behavior. Strikingly, the experimental values exhibit a strong alignment with the Peppas–Sahlin model. This comprehensive analysis provides valuable insights into the diffusion behavior of graphene oxide/nano silica (GO/NS) hybrid-reinforced natural rubber latex in organic solvents, highlighting potential applications in areas such as solvent-resistant coatings, barrier materials for chemical storage, and enhanced performance in protective gloves and seals used in harsh chemical environments.

The present work provides a unique insight to reveal the long chain branching (LCB) influence to the nano-fillers, that is via analyzing the conductivity evolution during the thermal annealing, fast shear flow and melt to solid cooling process. Meanwhile the crystallization behavior is also discussed. A linear polypropylene (PPC) and a long chain branched polypropylene (PPH) are chosen as the two polymer matrices with carbon nanotubes (CNTs) as the nanofillers. During the thermal annealing process, a more obvious growth of electrical conductivity of linear PPC nanocomposites are observed compared with LCB PPH nanocomposites. The harder movement of CNTs inside LCB PPH matrix may be the main reason. This also can be reflected by the conductivity evolution during slow cooling process where a decrease-then-increase (DTI) phenomenon is found for PPC/CNTs systems due to the rebuilding of CNTs conductivity network after crystallization. By contrast, this does not happen for PPH/CNTs systems.