Characterization of Control and Chemically Modified Kenaf Fiber

ABSTRACT

Natural fibers are very flexible materials; their properties vary with physical structure and chemical composition. Chemical treatment of fiber can chemically modify, clean the fiber surface, increase the surface roughness and stop the moisture absorption process. In the present study, kenaf bast fibers were treated with sodium hydroxide (NaOH), sodium carbonate (Na₂CO₃), ortho phosphoric acid (H₃PO₄), acetic acid (CH₃COOH) and zinc chloride (ZnCl₂) each with different concentrations. The morphological properties were investigated using scanning electron microscopy (SEM) which shows many impurities on untreated kenaf fiber surface. NaOH and ZnCl₂ treated kenaf fiber surface is more rough than other chemical treatments. X-ray diffraction (XRD) was carried out to evaluate crystallinity index. NaOH treated kenaf fiber shows highest crystallinity index of 76.87%. Fourier transform infrared (FTIR) spectroscopy was performed to characterize chemical functional groups. In untreated kenaf fiber broad band at 3469 cm⁻¹ confirms the presence of OH group. After chemical treatments this band disappears which confirms the removal of the OH groups. Thermo gravimetric analysis (TGA) carried out shows low fixed carbon content (64%) and maximum ash content (22%) for NaOH treated kenaf fiber.

摘要

天然纤维是非常柔软的材料 ; 它们的性质随物理结构和化学成分的不同而不同. 纤维的化学处理可以化学改性, 清洁纤维表面, 增加表面粗糙度并停止吸湿过程. 在本研究中, 红麻韧皮纤维分别用不同浓度的氢氧化钠 (NaOH), 碳酸钠 (Na2CO3), 邻磷酸 (H3PO4), 乙酸 (CH3COOH) 和氯化锌 (ZnCl2) 处理. 利用扫描电子显微镜 (SEM) 研究了红麻纤维的形态特征, 发现未经处理的红麻纤维表面存在许多杂质. NaOH和ZnCl2处理的红麻纤维表面比其他化学处理更粗糙。采用X射线衍射 (XRD) 对结晶度指标进行了评价. NaOH处理的红麻纤维结晶指数最高, 为76.87%. 傅立叶变换红外光谱 (FTIR) 用于表征化学官能团。在未经处理的红麻纤维中, 宽带为3469厘米−1确认OH组的存在。经过化学处理后, 该条带消失, 这证实了OH基团的去除. 热重分析 (TGA) 表明, NaOH处理的红麻纤维的固定碳含量较低 (64%), 灰分含量最高 (22%)

KEYWORDS:

• Kenaf fiber
• chemical treatment
• scanning electron microscopy
• thermo gravimetric analysis
• Fourier transform infrared spectroscopy
• X-ray diffraction

关键词:

• 红麻纤维
• 化学处理
• 扫描电子显微镜
• 热重分析
• 傅里叶变换红外光谱
• X射线衍射

Highlights

• Studied the effect of different chemical agents such as aodium hydroxide (NaOH), sodium carbonate (Na₂CO₃), ortho phosphoric acid (H₃PO₄), acetic acid (CH₃COOH) and Zinc chloride (ZnCl₂) on kenaf bast fibres properties.

• XRD analysis carried out showed fibers treated with NaOH and ZnCl₂ has high degree of crystallinity.

• In TGA analysis strong alkali NaOH shows much effect on moisture, ash and fixed carbon content.

• In morphological analysis weak alkali shows pore formation and strong alkali shows rougher surface compared to untreated fiber.

Unique of study

• Natural fibres are best substitute for synthetic reinforcement like glass and carbon fibre. To improve the compatibility of natural fibre, it should be modified in its structure hydrophilic nature into partial hydrophobic nature for better compatibility with hydrophobic resins.

• There are some of the studies which reported surface modification of kenaf bast fibre, but these all are based on sodium hydroxide. This study mainly focuses on effect of the different chemical treatments on kenaf bast fiber properties.

Acknowledgments

The authors wish to thank Institute of Chemical Technology (ICT Mumbai) for providing facility in fiber characterization.

Disclosure statement

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