Characterization of Acacia caesia Bark Fibers (ACBFs)

ABSTRACT

The stem bark of Acacia caesia, or Senegalia caesia, richly available in the Western Ghats of Tamilnadu and Kerala, India, does potentially offer a ligno-cellulosic fiber, which was characterized in this work, studying its chemical composition, morphology, and thermal degradation. The as-received fibers, which were extracted as technical fibers with diameters ranging between 100 and 150 µm, had a density of 1200 kg/m³. Their composition included 37% cellulose, 20% hemicellulose and 18% lignin, not very dissimilar, among other fibers, from alfa esparto and particularly coir. Their thermal degradation onset was at 308°C, which suggested a potential in composite application with traditional oil-based matrices and possibly also in the long run on bio-based ones. However, their high roughness and easy splitting of the fibers suggested that possible use as the filler for composites would require fiber treatment, namely, to remove undesired loose parts, hence regularizing their geometry. This would also serve to reduce the likeliness of longitudinal splitting, which is a widely recognized occurrence during stripping of bark fibers.

摘要

印度泰米尔纳德邦和喀拉拉邦西部高止山脉丰富的印度相思树 (Senegalia caesia) 的茎皮确实可能提供一种木质纤维素纤维, 本研究对其进行了表征, 研究了其化学成分, 形态和热降解. 从直径在100至150微米之间的技术纤维中提取的接收纤维密度为1200kg/m3. 它们的成分包括37%的纤维素, 20%的半纤维素和18%的木质素, 与阿尔法埃斯帕托 (alfa esparto) 和椰子 (尤其是椰子) 的其他纤维没有太大区别. 其热降解起始温度为308°C, 这表明其在与传统油基基质的复合应用中具有潜力, 并且从长远来看, 也可能在生物基基质上具有潜力. 然而, 其高粗糙度和容易分裂的纤维表明, 可能用作复合材料的填料需要进行纤维处理, 即去除不需要的松散部件, 从而调整其几何形状. 这也将有助于减少纵向分裂的可能性, 这是剥皮纤维过程中广泛认可的现象.

KEYWORDS:

• Acacia caesia
• bark
• thermal characterization
• morphology
• chemical characterization
• crystallinity

关键词:

• 印度相思
• 树皮
• 热特性
• 形态学
• 化学表征
• 结晶度

Highlights

• New agrowaste ACBFs have been proposed, extracted to a diameter of 100-150 µm and characterized

• The degradation temperature of ACBFs is compatible with use with polymer composites

• Microscopical studies of surface morphology clarified the possible use of ACBFs as short fibers for the presence of kinks and twists and layering with softer binding material

• The crystallinity index of ACBFs cellulose has been elucidated

• Surface roughness appears still too high to proceed for use in composites without chemical treatment

Acknowledgements

The KSU authors are grateful to the Deanship of Scientific Research, King Saud University for funding through Vice Deanship of Scientific Research Chairs.

Disclosure statement

No potential conflict of interest was reported by the author(s).