Lightweight lignocellulosic fibrous materials (LLFMs) offer a sustainable and biodegradable alternative in many applications. Enthusiastic interest in these materials has recently grown together with the newly risen interest in foam forming. Foam bubbles restrain fiber flocculation, and foam formed structures have high uniformity. Moreover, the bubbles support the fibrous structure during manufacturing enabling the formation of highly porous structures. Mechanical pressure cannot be applied in the manufacture of LLFMs as the materials would lose their porous structure. Water is therefore typically removed by a combination of drainage and thermal drying. Thermal drying of porous materials has been studied intensively. However, there are only a few studies on the drainage of fiber-laden foams. Thus, in this work, we conducted a systematic analysis of this topic. Our findings show that after drainage a stationary vertical moisture profile similar to that of pure foams is developed. Raising the initial fiber consistency was found to increase the final fiber consistency of the foam until the drainage ceased. Increasing mold height was found to increase the final consistency considerably. Without vacuum and heating, the shrinkage of samples during drainage was only slightly higher than the volume of the drained water. Drainage rate and final consistency increased clearly with increasing vacuum, but simultaneously sample shrinkage increased considerably. The best compromise was obtained with a vacuum of 0.5 kPa, which increased the final consistency by 60% without extra shrinkage. Using warm foam and heating the foam during drainage increased the final consistency considerably, but this also led to significant shrinkage of the sample.

轻质木质纤维素纤维材料（LLFM）在许多应用中提供了一种可持续且可生物降解的替代品。最近，对这些材料的热情与对泡沫成形的新兴趣一起增长。泡沫气泡抑制纤维絮凝，并且泡沫形成的结构具有高均匀性。此外，气泡在制造期间支撑纤维结构，从而能够形成高度多孔的结构。机械压力不能应用于LLFM的制造中，因为这些材料会失去其多孔结构。因此，通常通过排水和热干燥的结合来去除水。已经对多孔材料的热干燥进行了深入研究。然而，关于载有纤维的泡沫的排水的研究很少。因此，在这项工作中 我们对此主题进行了系统的分析。我们的发现表明，排水后，固定的垂直湿度曲线类似于纯泡沫。发现提高初始纤维稠度会增加泡沫的最终纤维稠度，直到排水停止。发现增加模具高度可以显着增加最终的一致性。没有真空和加热，排水过程中样品的收缩率仅略高于排水量。随着真空度的增加，排水速率和最终稠度明显增加，但同时样品的收缩率也大大增加。在0.5 kPa的真空度下可获得最佳折衷，这可以使最终浓度增加60％，而不会产生额外的收缩。