The SARS-CoV-2 Coronavirus pandemic and the rise in climate disasters have fueled a surge in disposable mask production, exacerbating waste challenges. The study proposes a sustainable pathway for recycling Non-Woven Fabric (NWF) originating from masks made of Polypropylene (PP) used as Personal Protective Equipment (PPE). Eco-friendly blends of virgin polypropylene (vPP) and recycled non-woven fabric (NWF) were produced through extrusion, and the physicochemical and mechanical properties of the blends were evaluated. The addition of NWF resulted in lower tensile and flexural strengths than vPP. However, from 50%wt of recycled NWF, the blends proved to be as stiff as, or even stiffer than, the virgin polymer. While slightly lower, the 50%wt NWF blend achieved properties close to those of vPP, making it the ideal composition for replacing PP in conventional applications. This approach offers a sustainable solution for mask recycling, reducing disposal impacts and supporting a circular economy.

Banknotes often have a short lifespan and are frequently removed from circulation due to wear and tear, leading to a significant disposal challenge given the millions of banknotes discarded annually. This study evaluated the utilization of these waste banknotes, primarily composed of cotton fibers, in producing polymer composites. The mechanical and thermal properties, hydrophilicity, and degradation through accelerated aging of composites made from recycled polypropylene (PPR) and banknote residues were evaluated. The results indicated that including banknote waste increased the hydrophilicity of the composites relative to pure PPR and improved mechanical properties against weathering. Notably, composites with 10 wt% banknote content enhanced Young’s modulus and tensile strength, both in weathered and non-weathered conditions. This approach not only offers a potential solution for the disposal of waste banknotes but also aligns with the broader goal of reducing ecological impact and promoting the development of sustainable composite materials.

Citric acid can modify thermoplastic starch (TPS) through competing mechanisms involving intermolecular interactions, acid-catalyzed hydrolysis, and esterification. However, the products formed and their effects on TPS properties depend on the conditions under which citric acid is incorporated. This work aimed to investigate how the sequence of citric acid and glycerol incorporation affects the molecular transformations and structure–property relationships of cassava starch-based materials. Two pretreatment routes with different citric acid concentrations were compared. In Route 1, citric acid was incorporated directly into cassava starch before adding glycerol, whereas in Route 2, citric acid was thermally pretreated with glycerol before adding it to the starch. The resulting materials were subsequently processed by extrusion and compression molding. FTIR spectra showed carbonyl bands at approximately 1722–1728 cm⁻¹ in citric-acid-containing materials, supporting the formation of ester-containing species. Route 1 showed more pronounced changes in the apparent molecular-weight distribution in the presence of citric acid, including low-molecular-weight fractions consistent with acid-catalyzed starch chain cleavage. These changes were accompanied by distinct intermediate thermal degradation events and increasing susceptibility to water-induced structural damage at higher citric acid concentrations. In contrast, Route 2 preserved the apparent molecular-weight distribution more effectively and produced materials with substantially greater elongation at break. Citric-acid-containing materials prepared by this route also exhibited greater dimensional stability during water immersion, despite their lower stiffness. Overall, the results demonstrate that the sequence of citric acid and glycerol incorporation directs distinct chemical and molecular transformations during processing, providing a practical strategy for tailoring the mechanical and water-response properties of TPS.