毛竹及其组成单元的水分吸着特性

通过测量不同相对湿度下毛竹竹块、竹粉、竹纤维、薄壁细胞的吸湿平衡含水率,建立了相应的水分吸着等温线,并探讨了它们水分吸着特性的差异及原因。结果表明:毛竹竹块、竹粉、竹纤维、薄壁细胞的水分吸着等温线与木材类似,均呈反"S"形;竹粉的水分吸着等温线整体高于竹块,但两者的纤维饱和点含水率相差很小,约为0.37%;化学离析得到的毛竹薄壁组织细胞的纤维饱和点含水率为44.24%,显著大于竹纤维的纤维饱和点含水率(34.07%);毛竹薄壁细胞及竹纤维的纤维饱和点含水率均显著大于竹块和竹粉,原因是化学离析使竹材细胞壁壁内产生较多的微毛细管系统,有利于水分子的多分子层吸附和凝结水的产生。

Hygroscopic behavior of bamboo and its blocking units

In this paper,the moisture sorption isotherms of bamboo power,bamboo blocks,chemically macerated bamboo fibers and parenchymal cells were respectively established by measuring their corresponding adsorption equilibrium moisture content(EMC) at different relative humidity(RH) levels.The results indicate that all the established moisture sorption isotherms of bamboo are characterized with anti-S shaped curves,which is normally found in wood and wood composites.The moisture sorption isotherm of bamboo powder is as a whole located above that of bamboo blocks with a maxim value of 1.5 % at 46 % RH,however the difference at fiber saturation point(FSP) is only about 0.37 %.The moisture content at FSP of bamboo fibers and parenchyma cells is 34.07 % and 44.24 % respectively,significantly higher than that of bamboo blocks and bamboo powders.It was explained that the chemical maceration facilitated the formation of multi-layer water adsorption and condensed water in the bamboo cell wall.