Advances in Polymer Technology最新文献

Interpolyelectrolyte complexes (IPECs) of polysaccharides are multifunctional polymer materials that improve the mechanical and physicochemical properties of individual polysaccharides. In this study, highly porous (>90%) materials based on IPECs of versatile natural polysaccharides, chitosan (30 and 1,200 kDa) and pectin, are obtained by freeze-drying technique. To enhance the interaction between chitosan and pectin macromolecules, the latter are chemically functionalized with dialdehyde groups. The chitosan-/aldehyde-functionalized pectin (Chit/AF-Pect) polyelectrolyte complex sponges obtained are characterized using SEM, FTIR spectroscopy, and TGA. The swelling capacity study reveals a higher swelling ratio of IPEC sponges with an increase in both the molecular weight and content of chitosan: for Chit30/AF-Pect, the swelling ratio rises from 327% to 480%, while for Chit1200/AF-Pect, from 681% to 1,066%. Additionally, the in vitro degradation test demonstrates higher stability of Chit1200/AF-Pect sponges in comparison with those of Chit30/AF-Pect: after 4 days of incubation, the weight losses are found to be 9%–16% and 18%–41%, respectively. The cytotoxicity study shows that Chit30/AF-Pect sponges are noncytotoxic, with cell viability values >70%. Furthermore, the Chit30/AF-Pect sponges, obtained at chitosan:pectin weight ratio of 5:1, exhibit bactericidal activity against Escherichia coli BIM B-984 G, Pseudomonas aeruginosa BIM B-807 G, Staphylococcus aureus BIM B-1841, and slightly inhibit the growth of Enterococcus faecalis BIM B-1530 G. These findings indicate that the obtained Chit30/AF-Pect sponges can be used to create wound dressings for wound healing applications.

The blend matrix composed of polyvinyl alcohol and carboxymethylcellulose (PVA/CMC) was prepared via the casting method. SiO₂ nanoparticles were added as reinforcement in different amounts (SiO₂ = 1, 2, 3, and 4 wt.%). The study utilized FTIR to examine the alterations in composition and the interplay between the blend matrix and the inclusion of SiO₂. Also, for the first time, the surface roughness and surface wettability of the PVA/CMC blend matrix were investigated with the addition of SiO₂ using measurements of contact angle and surface roughness parameters. The surface roughness and wettability of the blend matrix increased as the SiO₂ content increased. In addition, the blend matrix optical features were determined by the UV–visible spectrophotometer. Based on the analysis using Tauc’s relation, it was found that the energy bandgap decreases from 5.52 to 5.17 eV (direct transition) and from 4.79 to 4.32 eV (indirect transition) for the PVA/CMC and PVA/CMC/4%SiO₂ blend films, respectively. The refractive index increases from 2.009 to about 2.144 for the PVA/CMC and PVA/CMC/4%SiO₂ blend films, respectively. Furthermore, optical conductivity and dielectric constants were improved for the PVA/CMC blend film after the addition of SiO₂ nanoparticles.

Vegan leather derived from mushroom mycelium is a revolutionary technology that addresses the issues raised by bovine and synthetic leather. Jute–mycelium-based vegan leather was constructed using hessian jute fabric, natural rubber solution, and extracted polyhydroxyalkanoate (PHA) biopolymer from Bacillus subtilis strain FPP-K isolated from fermented herbal black tea liquor waste. The bacterial strain was confirmed using 16S rRNA genomic sequencing. The structural characteristics of sustainable mycelium vegan leather were identified using FTIR, SEM, and TGA methods. To address the functional features of the developed vegan leather, solubility, swelling degree, WVP, WCA, and mechanical strength were also evaluated. Mycelium networking was further validated by micromorphological examination (SEM) of the leather sample’s cross-sectional area. Jute–mycelium leather demonstrated a tensile strength of 8.62 MPa and a % elongation of 8.34, which were significantly greater than the control sample. Vegan leather displayed a strong peak in the O ═ H group of carbohydrates in the examination of chemical bonds. A high-frequency infrared wavelength of 1,462 cm⁻¹ revealed the amide group of protein due to the presence of mycelium, while the absorption peak at 1,703 cm⁻¹ in leather indicated the crosslinking of PHA. Moreover, the TGA study finalized the thermal stability of leather. The enhanced hydrophobicity and reduced swelling degree and solubility also endorsed the water resistance properties of the leather. The results of the investigation substantiated the potential properties of mycelium vegan leather as animal- and environment-free leather.

Keratin extracted (KE) from chicken feathers was used for the production of composite films comprising poly(ε-caprolactone) (PCL) and keratin (PCL/KE films). The process involved the extraction of keratin from chicken feathers using a 0.1 M NaOH solution, followed by characterization via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The PCL was synthesized through the ring-opening polymerization (ROP) of ε-caprolactone (ԑ-CL) with Sn(Oct)₂ as a catalyst. Films were prepared via solvent casting, including pure PCL films and those enriched with different weight percentages of KE (10%, 15%, 25%, and 30%). The films were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and scanning electron microscopy (SEM). SEM analysis revealed a more uniform incorporation of KE within the PCL matrix in the case of the 15% keratin-enriched film (PCL/KE15) as compared to other keratin percentages. The thermal analysis showed a positive influence of keratin on the thermal stability of the films. Keratinocytes viability and proliferation tests on the PCL/KE15 film demonstrated compatibility with cells. Collectively, these results hold relevance for potential biomedical applications of PCL/KE films.

Polystyrene and silica gel polymer hybrids derived from polystyrene and phenyltrimethoxysilane via π–π interactions were synthesized by a slight modification of the previous method. Spectroscopic evidence of the π–π interaction is provided. The obtained polymer hybrids were optically transparent, and no phase separation was observed by scanning electron microscopy measurements. In the FT-IR spectrum of the resulting polymer hybrids, the absorption peaks corresponding to C–H wagging vibration shifted to a lower wavenumber range as the content of silica in the hybrids increased. A UV–vis spectrum of the polystyrene and silica gel polymer hybrids showed a shoulder peak at around 260 nm that shifted toward longer wavenumbers side as the content of silica increased. These results clearly indicate that π–π interactions contribute to the formation of these transparent hybrids.

The widespread discourse on the circular economy has fueled a growing demand for polymeric materials characterized by mechanical robustness, sustainability, renewability, and the ability to mend defects. Such materials can be crafted using dynamic covalent bonds, albeit rarely or more efficiently through noncovalent interactions. Metal–ligand interactions, commonly employed by living organisms to adapt to environmental changes, play a pivotal role in this endeavor. Metallosupramolecular polymers (MSPs), formed through the incorporation of metal–ligand interactions, present a versatile platform for tailoring physicochemical properties. This review explores recent advancements in MSPs achieved through the assembly of (macro)monomers via reversible metal–ligand interactions. Various strategies and pathways for synthesizing these materials are discussed, along with their resulting properties. The review delves into the stimuli-responsive behavior of coordination metal–ligand polymers, shedding light on the impact of the core employed in MSPs. Additionally, it examines the influence of parameters such as solvent choice and counter-ions on the supramolecular assemblies. The ability of these materials to adapt their properties in response to changing environmental conditions challenges the traditional goal of creating stable materials, marking a paradigm shift in material design.

Wheat stalk (W), Fosro (F), Nigalo with waxy layer (NW), and Nigalo without waxy layer (NWo) were used to extract microcrystalline cellulose (MCC), the xMCC (where x represents origin such as W, F, NW, and NWo) by thermochemical and mechanical treatments. About 10 wt% of xMCC and commercial MCC (C-MCC) were solution casted with ethylene oxide-epichlorohydrin (EO-EPI) to prepare microcomposites. The xMCC and cryo-fractured composites were observed by scanning electron microscopy, and the mechanical properties of the composites were measured by dynamic mechanical analysis to observe the effect of fillers on viscoelastic properties. The results concluded that the xMCCs are homogeneously dispersed in the EO-EPI polymer matrix, which reinforced the viscoelastic and mechanical properties in EO-EPI composites, and reinforcement is dramatically high with NWoMCC compared to NWMCC, WMCC, FMCC, and C-MCC.

Currently, petrochemical plastics dominate the food service industry due to their good mechanical properties and barrier against heat, water vapor, carbon dioxide, and oxygen. This widespread use is not only harmful to humans but also to the ecosystem as synthetic plastics disrupt ecological balance and deplete petroleum-based oil resources. Researchers and manufacturers are continuously addressing this problem by developing bio-based alternatives that provide numerous advantages including structural flexibility, biodegradability, and effective barrier properties. However, the high cost of production and unavailability of equipment for batch processing impede the potential for widespread manufacturing. Natural fibers mixed with bio-based adhesives derived from plants provide one of the biggest potential sources of bio-based materials for the food container industry. Not only does this address the issue of high raw material cost but it also has the potential to become sustainable once processing steps have been optimized. In this review, the current findings of several research related to the production of bio-based disposable food containers, packaging, and composites made from bio-based materials and bio-based adhesives are critically discussed. Several properties and characteristics important to the production of food service containers and primary packaging, as well as the existing challenges and future perspectives, are also highlighted.

Automatic detection of fabric defects is important in textile quality control, particularly in detecting fabrics with multifarious patterns and colors. This study proposes a fabric defect detection system for fabrics with complex patterns and colors. The proposed system comprises five convolutional layers designed to extract features from the original images effectively. In addition, three fully connected layers are designed to classify the fabric defects into four categories. Using this system, the detection accuracy is improved, and the depth of the model is shortened simultaneously. Optimal detection rates for testing dirty marks, clip marks, broken yams, and defect-free were 88.01%, 90.15%, 98.01%, and 97.73%, respectively. The experimental results show that the proposed method is effective, feasible, and has significant potential for fabric defect detection.

In the field of lighter substitute materials, sandwich plate models of composite and hybrid foam cores are used in this study. Three core structures: composite core structure and then the core is replaced by a structure of a closed and open repeating cellular pattern manufactured with 3D printing technology. It finally integrated both into one hybrid open-cell core filled with foam and employed the same device (WBW-100E) to conduct the three-point bending experiment. The test was conducted based on the international standard (ASTM-C 393-00) to perform the three-point bending investigation on the sandwich structure. Flexural test finding, with the hybrid polyurethane/polytropic acid (PUR/PLA) core, the ultimate bending load is increased by 127.7% compared to the open-cell structure core. In addition, the maximum deflection increased by 163.3%. The simulation results of three-point bending indicate that employing a hybrid combination of PUR-PLA led to an increase of 382.3%, and for PUR–TPU by 111.8%; however, the highest value recorded with PUR/PLA, which has the slightest stress error among the tests. Also, it is reported that when the volume fraction of reinforced aluminum particles is increased, the overall deformation becomes more sufficient, and the test accuracy improves; for example, rising from 0.5% to 3%, the midspan deflection of composite (foam-Al) is increased by 40.34%. There were noticeable improvements in mechanical properties in the 2.5% composite foam-Al.