毛竹线性振动摩擦焊接无胶胶合的研究

Study on the bonding strength of the linear-vibration mechanical welded Moso bamboo

研究了毛竹竹黄面间线性振动摩擦焊接的胶合强度;利用扫描电子显微镜观察了焊接界面的微观结合情况,探索了毛竹焊接无胶胶合的形成机理和原因,并利用傅里叶红外变换光谱研究了焊接前后竹材中的化学官能团的变化情况。结果表明:毛竹焊接试件的抗拉剪切胶合强度随焊接压力的增大而增大,随后又有减小趋势。焊接胶合层是由一种新形成的复合材料构成。该复合材料由摩擦热量所熔化的竹材细胞壁物质经过冷却固化与相互缠绕着的竹材纤维所组成。焊接胶合层中的竹材发生了部分降解,而降解成分主要集中于半纤维素,焊接层木质素含量较原竹材有增大的趋势,而纤维素的变化不是很明显。

The technology of wood mechanical welding which has been invented and developed for more than ten years has been proved to be a wood-gluing technology with great potential. The mechanical welding has been employed to glue Moso bamboo,which is also a lignin-cellulose biomaterial. The tensile-shear strength of the bamboo welded joints has been mainly studied. Besides that,scanning electron microscopy and FTIR were used to study the welded joints to understand the bonding line. The results showed that the tensile-shear strength of the welded joints increased and then decreased with the increase of the welding pressure. The gluing layers of the welded joints are composed of entangled bamboo fibers enveloped by the melted and flowed intercellular materials mainly lignin. The hemicelluloses in the welded joints was the main constituent which was thermally degradated by the heat generated by the mechanical vibration welding. The content ratio of the lignin was increased a little; but there was no such big difference between the cellulose of the welded joints and the natural bamboo.