Novel hybrid panel composites based on wood, fungal mycelium, and cellulose nanofibrils (CNF) were developed and investigated in the present study. In one set of experiments, mycelium was grown on softwood particles to produce mycelium-modified wood which was then hybridized with various levels of CNF as binder. The other set of experiments were conducted on unmodified wood particles mixed with CNF and pure mycelium tissue. It was found that the composites made of mycelium-modified wood and CNF resulted in enhanced physical and mechanical properties compared to the ones made by physically mixing wood, mycelium, and CNF. Scanning electron microscopy (SEM) images showed that mycelium modification covered wood particles with a network of fungal hyphae whereas CNF formed a uniform mycelial film over wood particles. Mycelium modification had a significant effect on reducing water absorption and thickness swelling of the hybrid composites and CNF increased the modulus of rupture and modulus of elasticity, optimally at 2.5% addition. We also present results and analysis pertaining to the development of unique lightweight composite systems with physical and mechanical properties optimized at 5% CNF addition with potential to be used in packaging and furniture applications.

This study investigated the effect of Kraft lignin as natural compatibilizer on the water absorption, thermal, mechanical, and interfacial properties of poplar wood flour (WF)/polypropylene (PP) composites. Varying contents (0.5, 1, 2, 4, and 8 wt%) of lignin were added to WF and PP by direct mixing, then the composites were prepared by two‐screw extrusion and compression moulding. Results showed that lignin incorporation reduced the water absorption and postponed the thermal decomposition of the composites. Composites with lower lignin contents (0.5% and 1%) could get the optimal properties, and the excess lignin contents (4% and 8%) resulted in slight decrease in the mechanical properties. DMA and calculation of adhesion factor showed that the composites with 0.5% lignin had the best interaction between WF and PP. The morphologies of fractured surface also indicated improved interfacial adhesion between WF and PP from the addition of 0.5% and 1% lignin. POLYM. COMPOS., 38:2387–2394, 2017. © 2015 Society of Plastics Engineers

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Filamentous fungi have been considered as candidates to replace petroleum-based adhesives and plastics in novel composite material production, particularly those containing lignocellulosic materials. However, the nature of the role of surface mycelium in the adhesion between lignocellulosic composite components is not well-known. The current study investigated the functionality of surface mycelium for wood bonding by incubating Trametes versicolor on yellow birch veneers and compared the lap-shear strengths after hot-pressing to evaluate if the presence of surface mycelium can improve the interface between two wood layers and consequently improve bonding. We found that the lap-shear strength of the samples was enhanced by the increase of surface mycelium coverage up to 8 days of incubation (up to 1.74 MPa) without a significant wood weight loss. We provide evidence that the bottom surface of the mycelium layer is more hydrophilic, contains more small-scale filamentous structure and contains more functional groups, resulting in better bonding with wood than the top surface. These observations confirm and highlight the functionality of the surface mycelium layer for wood bonding and provide useful information for future developments in fully biobased composites manufacturing.

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