Influence of Water Amount and Immersion Time on the Sisal Fibers Hornification Process

ABSTRACT

Hornification is phenomenon that can be promoted by wetting and drying treatment, which modify the microstructure of the lignocellulosic fibers, by promoting the stiffening of the polymeric structure of the fibercells. This process increases fiber mechanical behaviour and reduces water absorption and dimensional variation. The objective of this research is to investigate the influence of several variables on hornification process such as wetting time, fiber/water ratio and the number of wetting and drying cycles on the treatment and its effect on fibers chemical and mechanical properties. Sisal fibers were used. A pre-treatment of 1 h in water (T = 80 °C) and drying at 40°C was applied. Treatments with 1 and 5 cycles of wet and drying were also studied. In both cases two wetting time was applied (1 h and 3 h at 22 °C) and two fiber/water ratio (1:10 and 1:40). The raw and treated fibers were evaluated by thermogravimetric analysis, infrared spectroscopy, wettability analysis, and tensile test. The results showed that lower fiber/water ratios provide better hornification in sisal fibers. Immersion times of 3 hours was efficient to improve tensile strength, increasing stiffness in all studied cases.

抽象

角化是一种润湿和干燥循环的处理方法，通过促进纤维细胞的聚合物结构硬化，从而改变木质纤维的微观结构，从而增强其尺寸稳定性. 本研究旨在研究几个变量对角化过程的影响，如润湿时间、纤维/水比、润湿和干燥周期数对处理及其对气管纤维化学和机械性能的影响. 使用了西沙纤维. 对这些纤维进行1小时在水中（T = 80°C）的预处理，在40°C干燥。还使用了1和5循环的湿和干燥角化. 在这两种情况下，都应用了两个润湿时间（22°C时为1小时和3小时）和两个纤维/水比（1：10和1：40）. 通过热重力分析、红外光谱学、润湿性分析和直接牵引测试对原始纤维和经过处理的纤维进行评估. 结果表明，较低的纤维/水比为西化纤维提供了更好的角化. 3小时的浸泡时间可以有效地促进拉伸强度的变化，在所有基于氢键能量增加的情况下，增加刚度.

KEYWORDS:

• Sisal fibers
• fiber treatments
• hydrophobic
• mechanical properties

关键词:

• 西化纤维
• 纤维处理
• 疏水性
• 机械性能

Acknowledgments

The authors thank Universidade Federal de Lavras (Brazil) for supporting the experimental work, especially laboratories PPGCTM (UFLA) and NUMATS (UFRJ). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq Project 433514/2018-3), and Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG Project APQ-01311-18).