| The proportion of wood-based panels in furniture production and interior decoration applications is increasing,and wood-based panels usually contain formaldehyde,which are harmful to the environment and health.Therefore,the design and development of new formaldehyde-free environmental protection board has become an urgent market demand.Mycelium is a viscous organism and is the nutritional part of edible fungi.China's edible mushroom industry has developed rapidly,resulting in a large number of discarded edible mushroom cultivation substrates.In this study,a fungal mycelium/biomass composite material was prepared using waste mycelium residues as raw materials.The effects of tree species,biomass particle size and fungal cultivation time on the physical and mechanical properties of composite panels were studied by analyzing the lignocellulose degradation degree of the mycelium residue.The results show that:(1)Using black locust(Robinia pseudoacacia L.)and apple wood(Malus spp.),three biomass particle sizes of coarse(2.7-3.0mm),medium(2.1-2.6mm)and fine(1.5-2.0mm),four cultivation times(full of hypha,first harvest,second harvest,and third harvest)as experimental variables,and the mycelium residues were hot-pressed at 160°C for 10 minutes,pressure is 2.2-2.5MPa,then a mycelium/biomass composite board was successfully prepared.Among them,the coarse particles of mycelium residue pressed at the full of hypha period had obvious defects at the edges and did not achieve the expected results,while the composite boards pressed at other conditions of mycelium residue achieved the expected appearance and quality requirements.The density of composite boards in the range of 0.7g/cm~3-1.0g/cm~3,and the surface hardness was in the range of 50-70HD.(2)Biomass granularity and mycelium growth time significantly influenced the physical and mechanical properties of the fungal mycelium/biomass composite boards.The finer the granularity of biomass,the better its adhesion to mycelium;the longer the mycelium incubation time,the higher the lignocellulose degradation rate of biomass particles in the matrix,which was conducive to improving the internal bonding strength of composite panels.Among them,the internal bonding strength of the composite boards pressed with mycelium residues after the second harvests of mushroom production was the highest(0.36MPa for the second harvest of medium size locest and 0.49MPa for the second harvest of fine size apple wood),which reached the national standard GB/T 4897-2015 for the composite boards used in the dry state.The internal bonding strength(?0.28MPa)of ordinary particleboard(P1)used in the dry state has reached the requirement of GB/T 4897-2015.(3)The waterproof performance of mycelium/biomass composite boards was significantly affected by the growth time of mycelium,while the tree species and biomass granularity had no significant effect on the waterproof performance of the boards.The longer the growth time of mycelium,the lower the water absorption thickness swelling rate and water absorption weight increase rate of the pressed boards made of mycelium residue,indicating that the waterproof performance was better.However,the different granularity of the biomass had no significant effect on its water absorption thickness swelling rate and weight increase rate.Among them,the best waterproof performance of the third harvest of medium size apple wood with a water absorption thickness expansion rate of as high as 40%,did not meet the requirements of the national standard GB/T 4897-2015 for the waterproof performance of furniture-type and load-bearing particleboard,and is not suitable for wet environment.(4)By comparing the performance of mycelium composite plates prepared from cultivation substrates of two species,three biomass granularities and four cultivation periods,the best substrate conditions for preparing mycelium/biomass composite plates were apple wood,fine particles(1.5-2.0mm),and the best incubation time of second harvest of mushroom. |
PDF Full Text Request