Advances in Polymer Technology

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.

Infectious diseases caused by microorganisms have gained worldwide attention in recent years. According to data compiled by the World Health Organization, the number of deaths resulting from infectious diseases is on the rise. In light of these dangers, the study of antibacterial materials has become increasingly vital. In this research, an antibacterial polymer was developed using poly(vinyl chloride) (PVC) and 4,4-diamminodiphenylmethane (DDM). The produced polymer’s chemical structure and thermal properties were investigated using Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and thermo-gravimetric analysis. The antibacterial activity of the resulting PVC-g-DDM polymer was effective in killing both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The antimicrobial efficacy was tested using a spread plate method, demonstrating its potential utility in a variety of applications like biomedical, coatings, water purification systems, and others. Antimicrobial resistance is increasing, especially among bacteria that have acquired resistance to multiple therapeutics. To fully optimize and explore the polymer’s potential and its usage, more research is needed.