Natural fibre-based materials offer various advantages compared to synthetic fibres, however their applications are limited mainly due to their hygroscopic properties, which are affected by their chemical composition, microstructure and the porosity of the plant cells of which the fibre is composed. Therefore, this work investigates the hygroscopic behavior of natural fibres to obtain a better understanding of the relation of the chemical composition of the fibres, their crystallinity, and their equilibrium moisture content. The crystallinity index was determined to include amorphous cellulose into the developed models. Nine biomass samples were selected (flax, hemp, jute, spruce, bamboo, corn stalks, palm leaves, rice husk and wheat straw) to construct models via linear regression to predict the moisture sorption behavior of natural fibres. Thorough statistical (ANOVA, RMSE) analysis showed that the developed models are relevant and descriptive. From all major plant cell wall constituents (lignin, crystalline cellulose, amorphous cellulose and hemicellulose), it is hemicellulose’s hygroscopicity that is largely responsible for the moisture uptake of the fibres, with (amorphous) cellulose and lignin playing a (much) smaller role. This study has improved the understanding of the hygroscopic behavior of natural fibres, and is important for optimal application of these fibres in composite materials.

与合成纤维相比，基于天然纤维的材料具有多种优势，但它们的应用受到限制，主要是由于其吸湿性能受到其化学成分、微观结构和组成纤维的植物细胞的孔隙率的影响。因此，这项工作研究了天然纤维的吸湿行为，以更好地了解纤维的化学成分、结晶度和平衡水分含量之间的关系。确定结晶度指数以将无定形纤维素包括在开发的模型中。选择九个生物质样品（亚麻、大麻、黄麻、云杉、竹子、玉米秸秆、棕榈叶、稻壳和麦秆）通过线性回归构建模型，以预测天然纤维的吸湿行为。全面的统计（ANOVA，RMSE）分析表明，开发的模型具有相关性和描述性。在所有主要的植物细胞壁成分（木质素、结晶纤维素、无定形纤维素和半纤维素）中，半纤维素的吸湿性是纤维吸收水分的主要原因，而（无定形）纤维素和木质素的作用（小得多）。这项研究提高了对天然纤维吸湿行为的理解，对于这些纤维在复合材料中的最佳应用具有重要意义。半纤维素的吸湿性是纤维吸收水分的主要原因，而（无定形）纤维素和木质素的作用（小得多）。这项研究提高了对天然纤维吸湿行为的理解，对于这些纤维在复合材料中的最佳应用具有重要意义。半纤维素的吸湿性是纤维吸收水分的主要原因，而（无定形）纤维素和木质素的作用（小得多）。这项研究提高了对天然纤维吸湿行为的理解，对于这些纤维在复合材料中的最佳应用具有重要意义。