Advances in Polymer Technology

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.