Influencing Behavior Study of Natural Almond Shell Filler on the Tensile, Thermal, and Free Vibrational Properties of Flax Fiber Intertwined Vinyl Ester Composites

ABSTRACT

The structural porosity weakness of a natural flax fiber-layered polymer laminate was reduced by the spatial rearrangement of natural almond shell filler occupying preferentially porous sites between the stacking layers, improving the properties of the polymer laminate. The present work investigates the mechanical, thermal, and free vibrational behavior of composites, including surface modification and the effect of almond shell filler loading in the flax fiber intertwined composites. Alkaline treatment of natural flax fiber and almond shell filler effectively reduced the hydrophilic contents of hemicellulose, lignin, and wax without altering the cellulose nature, as confirmed by FTIR analysis. Tensile strength was 35% higher for the alkaline-treated 10% almond shell-filled composite than the untreated filler composite. However, the tensile strength decreased beyond 10% of filler loading because of the poor dispersion of fillers in the matrix. As evident in the 10% filled almond shell composite, due to stronger interaction, polymer-mixed almond fillers act as a thermal insulating layer between the flax stacks, increasing thermal stability. Alkali treatment with an almond shell of 10 wt% filled flax fiber composite exhibited a higher natural frequency (185 Hz) and damping value (0.042) due to total internal dissipation of dynamic forces.

摘要

天然亚麻纤维层状聚合物层压板的结构孔隙率弱点通过天然杏仁壳填料在堆叠层之间优先占据多孔位置的空间重排而减少, 从而改善聚合物层压板的性能. 本文研究了亚麻纤维缠绕复合材料的力学、热学和自由振动行为, 包括表面改性和杏仁壳填料对亚麻纤维缠绕复合材料的影响. FTIR分析证实, 对天然亚麻纤维和杏仁壳填料进行碱处理可有效降低半纤维素、木质素和蜡的亲水性含量, 而不会改变纤维素的性质. 碱处理的10%杏仁壳填充复合材料的拉伸强度比未处理的填充复合材料高35%. 然而, 由于填料在基体中分散性差, 拉伸强度下降超过填料负载量的10%. 正如填充量为10%的杏仁壳复合材料所示, 由于相互作用更强, 聚合物混合杏仁填料在亚麻垛之间起到隔热层的作用, 提高了热稳定性. 由于动力的总内部耗散, 用10 wt%填充亚麻纤维

KEYWORDS:

• Natural almond shell
• flax bast fiber
• chemical treatments
• vinyl ester composites
• thermal degradation
• damped frequency

关键词:

• 天然杏仁壳
• 亚麻韧皮纤维
• 化学处理
• 乙烯基酯复合材料
• 热降解
• 阻尼频率

Highlights

• NaOH surface treatment increased natural fiber-filler and matrix adhesion.

• Almond shell increased the tensile strength of the flax polymer composite.

• Thermal stability was improved with the addition of almond shell filler.

• Stiffness combined with treatment and almond shell raised the natural frequency.

• Internal porous almond shell increased the damping of the flax polymer composite.

Acknowledgments

Dr. K. Ramraji would like to thank the management of Sri Sivasubramaniya Nadar College of Engineering for providing the Post-Doctoral Fellowship (PDF), and the authors gratefully acknowledge SSN research centre, Kalavakkam for conducting FTIR analysis.

Disclosure statement

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