摘要
竹束施胶前和施胶后的干燥和施胶工艺是重组竹制备过程中的关键工序。目前,企业主要采用间歇式吊笼浸胶法,但此施胶工艺存在施胶不均匀、干燥能耗高的问题。为解决上述问题,研发了辊压树脂定向渗透技术,研究了辊压树脂定向渗透技术对竹束干燥和重组竹物理力学性能的影响。试验结果表明:在相同干燥条件下,采用辊压树脂定向渗透技术时竹束施胶前、后的干燥时间比间歇式吊笼浸胶法的干燥时间缩短幅度分别约为65%和48%。由此可知,辊压树脂定向渗透技术可大大缩短竹束施胶前、后的干燥时间,提高干燥效率和降低干燥能耗。通过扫描电镜观察可知:采用辊压树脂定向渗透技术施胶过程中,压辊对竹束进行辊压,使得竹束的宽度增大,表面的裂隙增多,增加了胶液在竹束中的渗透通道;同时,胶液在辊压压力的作用下向竹材细胞壁内渗透,使得胶液在竹束中的分布更加均匀。采用两种施胶方法制备的重组竹力学性能和耐水性能测试结果显示:相对于间歇式吊笼浸胶法制备的重组竹,采用辊压树脂定向渗透技术制备的重组竹静曲强度变化不大,而弹性模量和水平剪切强度显著增大,增大幅度分别达到17.85%和59.25%;吸水宽度膨胀率和吸水厚度膨胀率均显著降低,降低幅度分别达到36.48%和22.67%。因此,采用辊压树脂定向渗透技术制备的重组竹刚度增大,耐水性能提高,尺寸稳定性得到改善。辊压树脂定向渗透技术的开发,解决了间歇式吊笼施胶过程中施胶量难以精确控制、干燥成本高的技术瓶颈问题,对降低竹束的干燥能耗和提高重组竹的产品质量具有重要的意义。
The drying process and impregnation technology of bamboo bundles are the key procedures during the manufacturing process of bamboo scrimbers.Currently,the intermittent cage immersion method has been widely used in the bamboo enterprises.However,there are some drawbacks of the intermittent cage immersion method,such as the uneven distribution of phenol formaldehyde(PF)resins in the bamboo bundles and the difficulty of manufacturing bamboo scrimbers continuously.Additionally,the energy consumption of the method is high in the drying process after the dipping process.To solve these problems,the resin directional penetration by the rolling technology was developed by the Research Institute of Wood Industry,Chinese Academy of Forestry.The effects of the resin directional penetration by the rolling technology on the drying process of bamboo bundles and the physical and mechanical properties of bamboo scrimbers were studied.The results showed that the absolute moisture content of bamboo bundles increased to 35%before the dipping process and decreased to about 55%after the dipping process in the resin directional penetration by the rolling technology.Compared with the intermittent cage immersion method,the drying time of bamboo bundles and energy consumption were reduced due to the use of the resin directional penetration by the rolling technology,and the drying efficiency was improved.As shown by the results of the scanning electron microscope(SEM),the cracks on the bamboo surface increased after the dipping process using the resin directional penetration by the rolling technology,which was due to the pressure of rollers,and consequently the PF resin penetrated into the bamboo cell walls under the pressure.Therefore,much more uniform distribution of PF resin in the bamboo bundles were observed by the ultra-depth three-dimensional microscope(UTDM).Meanwhile,the modulus of rupture(MOR)of bamboo scrimbers changed slightly,while the modulus of elasticity(MOE)and horizontal shear strength(HSS)increased by 17.85%and 59.25%,respectively,for the resin directional penetration by the rolling technology.Additionally,the width swelling rate(WSR)and thickness swelling rate(TSR)of bamboo scrimbers decreased by 36.48%and 22.67%,respectively.The results indicated that the bamboo scrimbers produced by the resin directional penetration by the rolling technology showed enhanced stiffness and improved water resistance,and improved dimensional stability.Therefore,it is important to develop the resin directional penetration by the rolling technology,which can reduce the drying time and energy consumption of bamboo bundles,enhance the productivity,and improve the product quality of bamboo scrimbers.
作者
张亚梅
祝荣先
余养伦
于文吉
ZHANG Yamei;ZHU Rongxian;YU Yanglun;YU Wenji(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091,China)
出处
《林业工程学报》
CSCD
北大核心
2022年第5期44-49,共6页
Journal of Forestry Engineering
基金
浙江省省院合作林业科技项目(2021SY06)。
关键词
重组竹
间歇式吊笼浸胶法
辊压树脂定向渗透技术
干燥时间
力学性能
耐水性能
bamboo scrimber
the intermittent cage immersion method
the resin directional penetration by rolling technology
drying time
mechanical property
water resistance
作者简介
张亚梅,女,副研究员,研究方向为竹/木基复合材料。;通信作者:于文吉,男,研究员。E-mail:yuwenji@caf.ac.cn。
