Development of mycelium-reinforced dialdehyde cellulose-polyvinyl alcohol composites for emerging high-performance sustainable materials.

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Citation abstract

Dialdehyde cellulose (DAC), featuring reactive carbonyl groups introduced via oxidation of hemp-derived cellulose fibers (confirmed by FTIR spectroscopy), was synthesized to promote strong hydrogen bonding with polyvinyl alcohol (PVA) for composite development. In this study, DAC was incorporated into hydrogel composites reinforced with mycelium from three fungal species: Ganoderma boninense, Pleurotus eryngii, and P. ostreatus, thereby enabling direct comparison of their effects on composite performance. Notably, this work pioneers the use of G. boninense -a phytopathogenic fungus with a dense, hydrophobic mycelial architecture (contact angle 104.1°)-as a novel reinforcing agent in the DAC-PVA matrix. The resulting mycelium-reinforced composites demonstrated enhanced thermal stability, as confirmed by thermogravimetric analysis (TGA), which identified a multi-stage pyrolysis process primarily occurring between 200 and 500 °C. Mechanical characterization further revealed significant improvements in tensile strength and elongation at break: P. eryngii reinforcement yielded the highest tensile strength (18.3 MPa). At the same time, G. boninense imparted exceptional flexibility (elongation at break 93.3%). Furthermore, the composites exhibited significantly reduced swelling ratios- Ganoderma boninense, Pleurotus eryngii, and P. ostreatus recorded swelling ratios of 400.9%, 405.3%, and 319.3%, respectively-accompanied by enhanced dimensional stability and a transition from hydrophilic to hydrophobic surfaces, as confirmed by contact angle measurements. Altogether, these mycelium-reinforced DAC-PVA composites represent promising sustainable materials, suitable for diverse applications that require superior mechanical performance, water resistance, and thermal stability, such as biodegradable packaging, biomedical scaffolds, environmental sensors, and construction.