Effects of Different Treatments on Surface Activity of Rice Straw Particleboard

Abstract

The surface activity of rice straw particleboard (RSP), which has a significant effect on the finishing and bonding performance, is reduced by wax coating and free radicals on the straw fiber. The RSP surface was treated by corona treatment and alkali treatment to reveal the effects of different treatments on the surface activity of RSP. The infiltration height method was applied to evaluate the variation of surface activity. The alkalized samples of RSP with different densities were prepared by using sodium hydroxide solution with pH value of 8∼14. The samples of different densities were then subjected to corona treatment under high purity oxygen conditions with treatment power of 50 W, 100 W, 300 W, and 500 W and with a time of 4 min or 7 min. The surface activity of the treated specimens was evaluated by measuring the absorption properties of three kinds of liquids by infiltration-height method: distilled water, glycerin, and alcohol. The results revealed the following. (1) After alkalization treatment, the surface absorption performance of RSP for these three liquids was improved, and it increased with the increase of pH value of the treatment solution. The suitable pH value of the alkalized solution for RSP is 7∼11, which can improve the surface absorption performance. (2) After corona treatment, the surface absorption performance of RSP increased with the increase of corona treatment power. RSP had the highest surface absorption performance for alcohol. With the density of RSP increased, the surface absorbability slightly decreased. Therefore, it is not suitable to utilize corona treatment in improving absorption for the higher density RSP. At the same time, with the variation of corona treatment time, the absorption of RSP surface changed irregularly because of the polarity of different test liquids. (3) The reasonable parameters of alkalization treatment and corona treatment are beneficial in improving the gluability of RSP. These results have guiding significance for RSP surface decoration process.