Effect of plasma modification on resin efficiency and properties of OSB
To enhance the performance of oriented strand boards(OSBs)using fast-growing wood flakes as raw wooden materials,this study employed a dielectric barrier discharge(DBD)plasma modification method to alter the surface properties of P.radiata flakes.The combined effects of physical etching and chemical modification induced by plasma improved the wettability,distribution,and penetration of phenol-formaldehyde adhesive resin(collectively referred to as resin efficiency).This study also investigated the impact of DBD treatment power and speed on the resin efficiency on P.radiata flake surfaces.Furthermore,the modified flakes were fabricated into OSBs,and their mechanical and swelling properties were subsequently assessed.The modification parameters were optimized to produce OSBs with enhanced load-bearing capacity and dimensional stability,outperforming untreated panels and meeting or exceeding national standard benchmarks.The changes of micro monography and chemical components of the flake surfaces before and after plasma modification with optimized parameters were analyzed and the mechanism of plasma modification was explained.The results showed that,after the DBD plasma modification with different parameters,the resin efficiency,mechanical and swelling properties of OSBs were enhanced to varying degrees and exhibited a trend of increasing firstly then decreasing as the modification power increasing from 1.5 to 6.0 kW and the speed increasing from 4 to 16 m/min.The properties of all DBD plasma enhanced OSBs met the requirements of OSB/4 Type panel in Chinese national standard GB/T 41715-2022"Oriented strand boards".Under the optimized parameters of 4.5 kW and 8 m/min,and compared with untreated samples,the initial and equilibrium contact angles were decreased by 28.06％and 44.46％,respectively.The surface free energy was increased from 41.4 to 47.5 mJ/m2,the average resin droplet size and coverage were increased by 187.32％and 136.45％,respectively.The average and effective penetration depths were increased by 121.33％and 97.01％,respectively.Compared to the untreated OSBs,the bending strength and modulus of elasticity along the major axis,and the internal bond surpassing the benchmark of OSB/4 Type panel benchmarks by 219％,123％and 98％,respectively.The surface roughness values of Ra and Rq were increased from 5.300 to 6.560 nm and from 6.697 to 8.640 nm,respectively.The XPS analysis revealed an increase in the content of various oxygen containing functional groups on flake surfaces to varying extent.This study demonstrated that plasma modification effectively enhances resin efficiency on flake surfaces,leading to the production of high-performance OSBs using fast-growing wood as raw materials.
国家科技期刊平台
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