Chitosan–Antimony Trioxide Nanocomposites: New Perspectives for Heat-Resistant and Antimicrobial Materials
An innovative approach for multifunctional high-performance materials
Chitosan has gained increasing attention as a versatile biopolymer due to its biocompatibility, environmental friendliness, and outstanding mechanical and chemical versatility.
A recent study by Venkatesh et al. (2025) presents a novel chitosan–antimony trioxide (Sb₂O₃) nanocomposite that combines thermal stability, flame retardancy, and antimicrobial activity within a sustainable hybrid material.
Simple synthesis through modified ionotropic gelation
The nanocomposite was synthesized via a modified ionotropic gelation method. Chitosan dissolved in acetic acid served as the polymer matrix. The addition of antimony trioxide nanoparticles (0.05 mg/mL) and tripolyphosphate (TPP) as a crosslinker resulted in a stable nanostructure with uniformly distributed spherical particles between 100 and 190 nanometers.
For this purpose, chitosan with a high degree of deacetylation and medium to high molecular weight is recommended, as it provides enhanced intermolecular bonding and higher heat resistance.
Enhanced thermal and mechanical performance
Thermogravimetric analysis (TGA) revealed a significant increase in glass transition temperature (Tg) and an improvement in thermal stability by up to 40 °C. The decomposition temperature shifted from 215 °C to 259 °C, indicating strong polymer–metal interactions.
Mechanically, the composite showed higher hardness, tensile strength, and flexural strength than pure chitosan or Sb₂O₃. The surface hardness reached 7.6 g, and the maximum tensile stress was 39 N/mm², demonstrating a well-balanced combination of strength and flexibility.
Optimal flame retardancy at 3 wt% composite concentration
Flame resistance tests showed a marked reduction in burning rate at 3 wt% nanocomposite concentration, reaching about 10.8 mm/min in vertical tests. This effect is attributed to the formation of a protective char layer that limits oxygen diffusion and heat transfer.
Such properties make the material a promising alternative to traditional halogen-based flame retardants, particularly in textiles, composites, and coatings.
Antimicrobial efficiency against diverse bacteria
The material also exhibited strong antimicrobial effects. The combination of chitosan’s polycationic properties with Sb₂O₃’s oxidative mechanisms resulted in a synergistic antibacterial action.
Tests against Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa demonstrated a dose-dependent inhibition, with almost complete bacterial reduction at 0.25 mg/mL. This highlights the material’s potential for biomedical coatings, wound dressings, and hygiene applications.
Versatile application potential
The thermal stability, mechanical robustness, and antimicrobial functionality of the chitosan–Sb₂O₃ nanocomposite open pathways for applications such as:
- flame-retardant and antibacterial textiles
- aerospace and protective surface coatings
- biomedical devices and wound care materials
- sustainable and durable composites
For large-scale production, high-molecular-weight, highly deacetylated chitosan derived from crustacean shells is recommended due to its excellent film-forming and dispersion properties.
Conclusion
The study by Venkatesh and colleagues highlights the potential of biopolymer–metal oxide nanocomposites for next-generation high-performance materials. The chitosan–antimony trioxide nanocomposite successfully merges sustainability, stability, and functionality, offering a promising path toward safer, more durable, and environmentally responsible materials.
Source
Venkatesh R., Vairamuthu G., Kanagasabapathy H. (2025). Facile synthesis and characterization of chitosan-antimony trioxide nanocomposite and its thermal properties. Materials Research Express (IOP Publishing). DOI: 10.1088/2053-1591/ae1d25
First published on 14th of November 2025
Revised on 14th of November 2025