Effects of Chemical Treatment, Hybridization, and Hybrid Fiber Stacking Sequence and Orientation on Tensile and Impact Strength of Continuous Sisal Fiber Reinforced Polyester Composites

ABSTRACT

This paper has presented the enhancement of tensile and impact strength of continuously aligned sisal fiber reinforced polyester composites through chemical treatment and hybridization. Sodium hydroxide (NaOH) and baking soda (NaHCO₃) were used for sisal fiber treatment. Comparisons on the effect of sodium hydroxide and baking soda treatments on tensile and impact strength of the composites were performed. Unidirectional glass and carbon fibers were selected as hybrid fibers. Nineteen laminates were prepared as per the standards. The laminates were made of pure sisal fiber and hybridized with glass or carbon fibers at different stacking sequence, orientation, and volume fraction. The effects of glass and carbon fibers hybridization on tensile and impact strength of the composites were studied and compared. Further enhancements on the tensile and impact strength of the composites were investigated through alterations on the stacking sequence, orientation, and volume fraction of the hybrid fibers. Symmetric hybrid composites which avoided sisal/sisal plies interface have shown more than 95% and 130% rise in their tensile strength by adding about 8% volume of glass and carbon fibers respectively. Moreover, with only about 8% carbon fiber inclusion in the laminates, almost 60% improvements in the impact strength were discovered.

摘要

通过化学处理和杂化处理, 提高了连续取向剑麻纤维增强聚酯复合材料的拉伸和冲击强度. 采用氢氧化钠 (NaOH) 和小苏打 (NaHCO3) 处理剑麻纤维. 比较了氢氧化钠和小苏打处理对复合材料拉伸和冲击强度的影响. 选择单向玻璃纤维和碳纤维作为混杂纤维. 按标准制备了19块层合板. 以纯剑麻纤维为原料, 与玻璃纤维或碳纤维以不同的堆积顺序, 取向和体积分数进行混杂. 研究并比较了玻璃纤维和碳纤维混杂对复合材料拉伸和冲击强度的影响. 通过改变混杂纤维的堆积顺序, 取向和体积分数, 进一步提高复合材料的拉伸和冲击强度. 对称混杂复合材料避免了剑麻/剑麻层间的界面, 分别加入8%体积的玻璃纤维和碳纤维, 其拉伸强度提高了95%和130%. 此外, 当层合板中只有约8%的碳纤维夹杂时, 冲击强度几乎提高了60%.

KEYWORDS:

• Sisal fiber
• alkali treatment
• hybridization
• stacking sequence
• fiber orientation
• continuous alignment

关键词:

• 剑麻纤维
• 碱处理
• 杂交
• 堆垛顺序
• 纤维取向
• 连续对准

Acknowledgments

The authors are grateful to School of Mechanical and Industrial Engineering and School of Civil Engineering at Ethiopian Institute of Technology Mekelle (EIT-M), Mekele University for their support in materials, laboratory service, and research funding. We would like to thank Ashenafi Gebrelibanos for his support during the preparation of the composite laminates.