This work investigates the effects of ageing on autoclaved composites made with unidirectional prepreg epoxy and flax tape in environments with 50% and 100% of relative humidity. A Design of Experiment (DoE) has been used first to determine the effect of the ageing time (0, 2, 4, 6, 8 and 16 days), type of bending (3-point and 4-point bending) and fibre orientation (longitudinal and transverse) on the water absorption and flexural properties of 50% saturated composites. A second experiment at 100% humidity has been also performed to further characterise the composites and to identify the equivalent ageing time that provides the mechanical behaviour of the 50% humidity samples after sixteen days. The water absorption and apparent porosity levels increase progressively with the ageing time, in particular for the case of transverse laminates; these features compromise the flexural properties of the composites. The laminates subjected to 4-point bending showed increased water absorption levels and improved flexural properties compared to the samples under 3-point bending. The flexural properties of flax composites at 50% humidity after 16 days are equivalent to those shown by composites immersed in water for less than one day.

这项工作研究了在相对湿度为50％和100％的环境中，老化对单向预浸料环氧树脂和亚麻胶带制成的高压灭菌复合材料的影响。首先使用实验设计（DoE）确定老化时间（0、2、4、6、8和16天），弯曲类型（3点弯曲和4点弯曲）和纤维取向的影响（纵向和横向）对50％饱和复合材料的吸水率和弯曲性能的影响。还进行了第二个在100％湿度下的实验，以进一步表征复合材料并确定等效老化时间，该老化时间可提供16天后50％湿度样品的机械性能。吸水率和表观孔隙率随老化时间而逐渐增加，特别是对于横向层压板而言。这些特征损害了复合材料的弯曲性能。与经受三点弯曲的样品相比，经受四点弯曲的层压材料显示出增加的吸水水平和改善的挠曲性能。16天后，亚麻复合材料在50％湿度下的挠曲性能与将复合材料浸入水中少于一天的挠曲性能相当。