Macromol, Volume 5, Issue 2 (June 2025) – 5 articles

As the global plastic pollution crisis intensifies, the development of sustainable food packaging materials has become a priority. Starch-based films present a viable, biodegradable alternative to petroleum-derived plastics but face challenges such as poor moisture resistance and mechanical fragility. This review comprehensively examines state-of-the-art advancements in starch-based packaging, including polymer modifications, bio-nanocomposite incorporation, and innovative processing techniques that enhance functionality. Furthermore, the role of advanced analytical tools in elucidating the structure–performance relationships of starch films is highlighted. In particular, we provide an in-depth exploration of advanced characterization techniques, not only to assess starch-based food packaging but also to monitor starch retrogradation, including Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and iodine binding (Blue Value). We also explore cutting-edge developments in active and intelligent packaging, where starch films are functionalized with bioactive compounds for antimicrobial protection and freshness monitoring. While substantial progress has been made, critical challenges remain in upscaling these technologies for industrial production. This review provides a roadmap for future research and the industrial adoption of starch-derived packaging solutions. Full article

Unexpected mutations in SARS-CoV-2 produce unique variations. While numerous vaccines and antiviral medications are available for SARS-CoV-2, their use in controlling and preventing COVID-19 is restricted in some areas and countries due to accessibility and cost issues. This study investigated polysaccharides produced from two brown seaweed (Padina boergesenii and Sargassum euryphyllum) for their capacity to inhibit SARS-CoV-2. The seaweed polysaccharides were characterized and identified using ultraviolet and visible (UV/VIS) and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectra. The polysaccharides inhibited SARS-CoV-2 propagation with inhibitory concentration 50% (IC₅₀) values ranging from 24.2 to 29.3 µg/mL and cytotoxicity concentration 50% (CC₅₀) values for Vero-E6 cells ranging from 587.7 to 396.4 µg/mL for P. boergesenii and S. euryphyllum, respectively. P. boergesenii polysaccharide had a more substantial antiviral potential than S. euryphyllum against SARS-CoV-2 and appeared more promising. At a concentration of 575 µL/mL of P. boergesenii polysaccharide, the virucidal mechanism was found to be the most effective, followed by viral adsorption and replication, with viral inhibition percentages of 68.6% ± 0.8, 57.1% ± 1.4, and 37.2 ± 3, respectively, compared to remdesivir as an antiviral drug. Thus, we concluded that brown seaweed alginate polysaccharides efficiently inhibit SARS-CoV-2 from spreading by preventing viral entry. Finally, P. boergesenii polysaccharide looked promising as a potential therapeutic candidate for the treatment of COVID-19. Full article

Many modern technologies rely on materials that harm the environment. Glass manufacturing, for instance, is both expensive and environmentally damaging. In response, scientists have developed a technique to replace glass with transparent wood, an innovative, versatile, and sustainable alternative. Wood naturally retains heat, is durable, and remains cost-effective, making it promising substitute for glass and plastic in window production. This innovation highlights the urgent need for eco-friendly technologies to replace or improve existing materials. This work explores cork as a sustainable alternative for producing transparent materials, potentially replacing transparent wood. Unlike wood, cork can be harvested from the same tree for up to 300 years. The process followed a method like transparent wood production, involving delignification, bleaching, and forced polymer impregnation. The choice of bleaching agent significantly impacted results—samples treated with sodium hypochlorite solution appeared whiter but became extremely fragile, whereas hydrogen peroxide preserved mechanical properties better. The resin-to-hardener ratio was crucial, with higher resin content improving polymer infiltration and transparency. While fully transparent cork was not achieved, the resulting translucent material lays the groundwork for future research in this field. Full article

Poly(lactic acid) (PLA) is derived from sugar-based materials. While it is a leading sustainable biopolymer, PLA has been integrated with other agricultural coproducts (e.g., lignin, protein, and starch) to reduce its cost and enhance its modulus and biodegradability. Cottonseed oil and meal are the byproducts of the cotton fiber industry. In this work, four biocomposites were formulated with PLA, cottonseed oil, washed cottonseed meal, and plasticizing reagent glycerol with different formulation ratios. The thermal degradation behaviors were examined via thermogravimetric (TG) analysis under air and nitrogen conditions with the neat PLA sample as a control. The thermal decomposition characteristic values were impacted by both the biocomposite formulation and the heating rates of 1, 2, 5, and 10 °C min⁻¹. Results from two kinetic modeling methods that were examined indicated that the activation energy was relatively steady for the neat PLA in the whole degradation process. Generally, the low activation energy values of biocomposites other than PLA under nitrogen conditions implied that these cottonseed byproduct constituents promote the thermal decomposition of these biocomposites. However, the presence of oxygen would confound the thermal decomposition of the biocomposites, as shown by variable activation energy curves with higher values under air conditions. TG-FTIR analysis revealed that the major gaseous compounds were carbonyl, carbon dioxide, carbon monoxide, methane, and water, which were derived from the thermal decomposition of the biocomposites. Full article

Antimicrobial resistance (AMR) is a major global health problem, exacerbated by the excessive and inappropriate use of antibiotics in human medicine, animal care and agriculture. Therefore, new strategies and compounds are needed to overcome this issue. In this view, it may be appropriate to reconsider existing biomaterials to alleviate antibiotic overuse. Chitin, a naturally abundant amino mucopolysaccharide, is a poly-β-1, 4-N-acetylglucosamine (GlcNAc). It is a white, hard, inelastic, nitrogenous polysaccharide and the major source of surface pollution in coastal areas. Chitosan derives from the partial N-deacetylation of chitin and originates from the shells of crustaceans and the fungi cell walls. It is a nontoxic natural antimicrobial polymer approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitin and chitosan, as non-toxic biopolymers, are useful compounds for wastewater treatment to remove pollutants, such as pharmaceuticals, heavy metals and dyes. The described features make these biopolymers intriguing compounds to be investigated for their application as antibacterials. Full article