Effects on the interfacial and mechanical properties of reed leaf fibers reinforced agar composites induced by hot water, Na2CO3 solution and ultrasound treatment

ABSTRACT

To investigate the feasibility of preparing biodegradable composites as food packing materials from reed leaf fibers to substitute disposable plastic, the fibers were treated by hot water (HWT), Na₂CO₃ solution (NCT) and ultrasound (UST), respectively and then combined with agar to prepare biodegradable composites through compression molding technique. The effects on the morphology, thermal properties of reed leaf fibers and the tensile cross-section morphology, the mechanical properties, the thermal conductivity and the moisture absorption profiles of the composites were studied. The amorphous components such as lignin and hemicellulose in reed leaf fibers were removed after HWT, NCT and UST. The fibers had a rough surface after hot water treatment which can lead to a better combination with agar induce an obvious improvement on the mechanical properties of the composites. The tensile strength, flexural strength and the impact strength of the HWT composite were 3.37 MPa, 19.7 MPa and 14.01 MPa, higher than that of the untreated (UT) composite and 22.99%, 16.36% and 69%, respectively. The HWT composite had a better hydrophobicity which equilibrium moisture absorption rate was 32.12%. The thermal conductivity of all the composites were less than 0.23 W·m⁻¹·k⁻¹, which were thermal insulating.

为了研究用芦苇叶纤维代替一次性塑料制备生物降解复合材料作为食品包装材料的可行性, 采用热水(HWT) [、Na2CO3溶液(NCT) 和超声波(UST) 对芦苇叶纤维进行处理, 然后分别与琼脂结合, 通过模压成型技术研究了芦苇叶纤维的微观形貌和热性能以及复合材料的拉伸断面形貌、力学性能、导热性能和吸湿性能、导热性能和吸湿性能. 经过HWT、NCT和UST处理后, 芦苇叶纤维中的木质素和半纤维素等非晶态成分被去除. 热水处理后纤维表面粗糙, 与琼脂结合良好, 复合材料的力学性能得到明显改善. HWT复合材料的拉伸强度、弯曲强度和冲击强度分别为3.37MPa、19.7MPa和14.01MPa, 高于未处理(UT) 复合材料的22.99%、16.36%和69%. HWT复合材料具有较好的疏水性, 其平衡吸湿率为32.12%. 所有复合材料的导热系数均小于0.23w·m^-1·k^-1, 为隔热材料.

KEYWORDS:

• Reed leaf fiber
• agar
• composites
• compression molding technology
• mechanical properties
• morphology

Keywords:

• 关键词
• 芦苇叶纤维
• 琼脂
• 复合材料
• 压缩成型技术
• 力学性能
• 微观形貌

Acknowledgments

This work was financially supported by the Regional Cooperative Innovation in Autonomous Region (2019E0241).

Additional information

Funding

The Regional Cooperative Innovation in Autonomous Region (2019E0241).