In the reported work, coarse wool fibre was mixed with natural rubber (NR) at equal proportion in two roll mixing machine and subsequently wool- NR composite was prepared using a compression moulding machine. The physico-mechanical properties of the developed composites such as tensile strength, areal density, hardness, thermal stability, water diffusion, moisture absorption, etc were analyzed. The composites were further characterized for its surface morphology, curing characteristics, accelerated aging properties, ultraviolet resistance,, and Fourier Transform Infrared Spectroscopy (FTIR). The results were compared with bare vulcanized rubber (VR). It is inferred that, while adding wool in the NR matrix, the time taken for the vulcanization got considerably reduced. Though the wool - NR composite showed reduction in tensile strength in comparison with VR, the tear strength, hardness, areal density, and Young's modulus were found to be improved. Thermal analysis of the composite depicted that the incorporation of wool fibre caused an improvement in the thermal stability of the composite in comparison with the vulcanized rubber.

Inverse vulcanized polymers have demonstrated significant potential as alternatives to conventional petrochemical polymers in various applications, including environmental remediation, where they are used to absorb heavy metals and pollutants from water and soil, and energy devices, such as in the development of high-capacity lithium-sulfur batteries. Despite their promise in these areas, the full application scope of these sulfur-based polymers remains unexplored. There is substantial potential for their use in other fields, such as advanced material coatings, medical devices, and as additives to improve the properties of existing polymers, yet these possibilities have not been thoroughly investigated. This study presents a sulfur-based polymer, synthesized via the inverse vulcanization of sulfur and styrene and partially crosslinked with divinylbenzene, as a novel plasticizer for polystyrene (PS). This polymer blend was prepared using an internal mixer to replace conventional organic-based plasticizers. The selected system was designed to maximize miscibility. Both virgin and plasticized PS were injection molded for comprehensive characterization. Differential Scanning Calorimetry (DSC) confirmed the complete consumption of sulfur, revealing a significant reduction in the glass transition temperature of PS upon the addition of the sulfur-based plasticizer. Morphological analysis showed a homogeneous surface with uniform single-phase morphology, indicating full miscibility of the blend. Tensile tests demonstrated enhanced ductility and reduced stiffness in plasticized PS, with strain at maximum tensile strength and elongation at break increasing by 22.0 % and 28.1 %, respectively. The plasticizer also improved the toughness of PS by 25.2 %. Rheological assessments corroborated the plasticization effect and confirmed the blend's full miscibility. Contact angle measurements indicated increased hydrophilicity of the plasticized PS samples. This newly developed sulfur-based plasticizer proved to be highly effective for PS, showcasing competitive efficiency comparable to commercial plasticizers. This advancement paves the way for new applications in the expanding field of sulfur-based polymers.

Bio-oxidation has been perceived as a promising treatment for the solidification/stabilization (S/S) of heavy metals (HMs) in mining soils. Nonetheless, no research exists on the integration of the iron-sulfur oxidizing bacterium Acidithiobacillus ferrooxidans as a microbial agent into the treatment of municipal solid waste incineration-fly ash (MSWI-FA). The effect of vulcanization (Stage I), precipitation (Stage II) and bio-oxidation (Stage III) on the stabilization of HMs in MSWI-FA was unexplored. This study investigated the stabilization effects of Stage I and Stage II by utilizing Na2S and FeSO4 to adjust the Fe/S ratio. The findings contributed to identifying suitable methods to enhance the stabilization effect of the microbial agent on MSWI-FA (Stage III). The results indicated that the vulcanization (Stage I) increased the compressive strength of MSWI-FA to 1.87 MPa when the concentration of Na2S reached 0.03 mM. The leaching toxicity of Cd, Pb, and Zn at 28 days after Stage II was 0.12 mg/L, 0.99 mg/L, and 356 mg/L, respectively, which improved by 96.3%, 94.8%, and 26.9% compared to the untreated samples. The compressive strength of the samples peaked at 1.97 MPa when the Fe/S ratio was 0.25 (precipitation (Stage II)). Despite the inhibitory effect of MSWI-FA on microbial activity, the leaching toxicity of Cd, Pb, and Zn in the presence of Acidithiobacillus ferrooxidans decreased to 0.07 mg/L, 0.17 mg/L and 97.3 mg/L at 28 days after Stage III, with no significant further increase in compressive strength. This study suggested that bio-oxidation utilizing iron sources may change the formation of iron oxides, thereby impacting the mechanical and chemical properties of MSWI-FA-based materials. The treatment sequence of vulcanization, precipitation and bio-oxidation proved effective in immobilizing HMs, particularly Pb, Cd, and Zn in MSWI FA. This research highlighted the potential of employing this technique to treat MSWI FA, yet it is essential to identify suitable reaction systems with appropriate additives to further enhance the long-term effectiveness and mechanical properties of MSWI-FA-based materials.