A new application of polymer membranes has been developed for the effective removal of toxic chromium(VI) ions from aqueous solutions by modifying poly(vinyl chloride) films. The process involved preparing deep eutectic solvents (DESs) composed of choline chloride and glycerol at molar ratios of 1:1 and 1:2, which were used as active compounds to bind metal ions in a polymer membrane. Adsorption experiments were performed to evaluate the ability of the obtained membranes to adsorb Cr(VI) ions from aqueous solutions. The composition of the obtained deep eutectic solvents and polymer membranes was confirmed with the use of nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), respectively. Contact angle analysis of the membranes indicated their potential to remove metal ions. The use of a polymer membrane with deep eutectic solvents for the separation of toxic metal ions from an aqueous solution allows the development of an optimized membrane formulation.

Cigarette butts (CBs) are among the most abundant forms of anthropogenic litter worldwide and constitute a persistent source of environmental contamination due to their slow degradation and the release of toxic substances into terrestrial and aquatic ecosystems. This review critically evaluates recent advances in the valorisation of CB waste into value-added functional materials. Particular attention is given to conversion strategies including chemical activation, electrospinning, hydrothermal processing, and nanocomposite fabrication. These approaches enable the production of activated carbons, cellulose-derived nanomaterials, and metal-doped composites with promising applications in water purification, energy storage, vector control, and pollutant remediation. The underlying mechanisms, performance, scalability, and sustainability of these technologies are discussed. Finally, current challenges, research gaps, and future opportunities of large-scale implementation are highlighted. Collectively, the findings demonstrate that CBs can be re-envisioned not only as a persistent environmental pollutant but also as valuable secondary resources that support circular economy and sustainable material development strategies.

Conventional sulfur vulcanization in rubber manufacturing depends on elevated curing temperatures and zinc oxide activators, resulting in high energy consumption and increasing environmental concerns associated with zinc release. To overcome these limitations, a novel graphene oxide (GO)-supported rare-earth-containing accelerator (GO–LZC) was designed by coordinating lanthanum(III) and zinc(II) ions with sodium diethyldithiocarbamate (DC). At the same time, the oxygen-containing groups on GO further participated in ligand coordination. The resulting GO-immobilized complex exhibits a well-defined chelating structure and uniform nanoscale dispersion, which together enhance the accessibility and reactivity of active sulfurating species during curing. When incorporated into solution-polymerized styrene–butadiene rubber (SSBR), GO–LZC markedly promotes crosslink formation at reduced thermal input. Kinetic analysis reveals a substantial decrease in the apparent activation energy, and curing and mechanical tests confirm that efficient vulcanization can be achieved at 130 °C, representing a 20–40 °C reduction relative to typical industrial curing conditions. This work demonstrates a viable strategy for developing low-zinc, energy-efficient, and high-performance vulcanization systems. It highlights the potential of rare-earth/GO hybrid catalysts for sustainable rubber processing.

Hydrogenated acrylonitrile–butadiene rubber (HNBR) is widely used in automotive and sealing applications due to its oil resistance and mechanical durability; however, its long-term performance is significantly influenced by the curing chemistry. Sulfur vulcanization offers superior elasticity but restricted thermal stability, while peroxide curing improves heat resistance at the expense of flexibility. In this study, we investigate hybrid sulfur–peroxide curing to integrate these benefits. The hybrid pathway encompasses competitive and sequential processes, such as partial radical quenching and accelerator oxidation, resulting in a dual crosslink network. Dynamic mechanical, thermal, and temperature scanning stress relaxation (TSSR) evaluations demonstrate that hybrid systems provide precise modulation of the operational temperature–frequency range, broaden the glass-transition relaxation, and control stress dissipation. The coexistence of sulfur and C–C crosslinks results in a heterogeneous structure characterized by diverse crosslink densities and bond energies, leading to numerous relaxation modes and an optimal blend of elasticity, strength, and thermal stability. Microscopy confirms the absence of phase separation, indicating that hybrid vulcanization is a viable approach for producing robust, high-performance HNBR elastomers.

The present study has proposed a straightforward method to improve the reprocessability of modified natural rubber (NR) by blending it with gelatin (GT). The reprocessable characteristics of these blends were evaluated based on their remolding capabilities and mechanical recovery performance. In this method, poly(vinylbenzyl chloride) (PVBC) was first grafted onto NR chains to create graft copolymers known as NR-g-PVBC. The benzyl chloride groups in the graft copolymers were subsequently converted into quaternary ammonium groups, referred to as NR-g-QPVBC. This modification enabled ionic crosslinking when NR-g-QPVBC reacted with ethylenediamine tetraacetic acid. Blends were created by incorporating GT powder into the NR-g-QPVBC latex. The optimal loading level of GT was determined to be 30 wt%, as the resulting film exhibited the highest recovery of tensile properties. Initially, the film's tensile strength was measured at 15 MPa. After being remolded at 160 °C, the tensile strength decreased to 9.3 MPa, resulting in a recovery rate of 60.7% and withstanding a tensile strain of 144%. Although the NR-g-QPVBC/GT films could be remolded, their tensile properties declined with increasing remolding cycles. Therefore, this work demonstrated a practical method for producing NR-based films that could be reshaped through hot-pressing after being formed into products, increasing their reusability.