芦苇茎秆表皮特性及防水剂用量对刨花板性能的影响

Characteristics of reed stem epidermis and effects of waterproofing agent on reed particleboard

芦苇Phragmites australis作为一种天然的生物质材料在木质复合材料的应用方面具有很大潜力。运用扫描电子显微镜、红外吸收光谱仪对芦苇茎秆表皮的微观构造及化学成分进行了分析,并测试了芦苇茎秆硅的质量分数及表面接触角。在此基础上研究防水剂用量对板材性能的影响,以解决芦苇刨花板胶合强度差的问题。结果表明:芦苇茎秆表皮含有蜡质层和硅物质,茎秆硅的质量分数达到20.9 g.kg-1;当不添加防水剂时,制得刨花板的物理力学性能达到了国家标准GB/T4897.3-2003中的技术指标要求,添加防水剂使刨花板的物理力学性能下降,其中内结合强度的降幅最大。经机械粉碎后的芦苇刨花均匀地分散在板坯中,刨花表皮中的硅物质可以起到防水作用,因此,在不添加防水剂的条件下采用脲醛树脂胶黏剂可以制造出合格的芦苇刨花板。

Reed is a natural biological material and has great potential as reinforced material in wood-based composites.To resolve the problem of low bond strength with reed particleboard,the reed（Phragmites australis） stem epidermis was analyzed with a scanning electron microscope（SEM） and infrared spectrometer.Microstructure and chemical composition were determined,and then the silicon mass fraction and the surface contact angle of the reed stem were tested.Finally,the effect of waterproofing agent on the physical and mechanical properties of reed particleboard was studied.Results showed that the reed stem epidermis contained a wax layer and silicon with the mass fraction of the silicon reaching 20.9 g·kg-1.The physical and mechanical properties met the demands of National Standards（GB/T 4897.3-2003） without adding waterproofing agent.When waterproofing agent was added,the physical and mechanical properties,especially internal bond strength,decreased greatly.Thus,silicon from the reed stem epidermis produced by reed particles dispersed in plate slap after mechanical shattering could be used as water repellent meaning it was possible to manufacture qualified particleboard using urea-formaldehyde resin adhesive without adding waterproofing agent.