Influence of Alkali Treatment on Microstructure Transformation and Mechanical Properties of Palm-Fiber Cell Wall

ABSTRACT

Utilizing agricultural waste and natural fibers minimizes environmental impact and can improve the acoustic and thermal conditions of buildings. Natural fibers can be an alternative to non-biodegradable synthetic sound-absorbing materials. This study aimed to investigate the acoustic and thermal properties of insulating materials made from wool and sugarcane bagasse. Thermal conductivity, thermal resistance, acoustic and moisture absorption, and fire properties of five insulating materials made from sheep wool, goat fiber, camel wool as well as pith and fiber bundles of sugarcane bagasse were determined. The measurement of the sound absorption coefficient was performed in an impedance tube. The thermal resistance and thermal conductivity coefficient were measured according to the ASTM D5334–08 Standard. The findings show that camel wool has the highest sound-absorbing performance, thermal insulation, and fire-resistant properties. The lowest value of the noise reduction coefficient (NRC) was 0.52 for goat fiber, and the highest was 0.74 for camel wool. The maximum sound absorption coefficient of camel wool was 0.95 at a frequency above 1000 Hz. Thermal conductivity varies between 0.038 and 0.046W/(M.K). Hence, all materials tested can be considered thermally insulating. The results showed insulating materials made from wool, especially camel wool, had better performance than fiber and pith of sugarcane bagasse.

摘要

利用农业废弃物和天然纤维可以最大限度地减少对环境的影响，并可以改善建筑物的声学和热条件. 天然纤维可以替代不可生物降解的合成吸声材料. 本研究旨在研究由羊毛和甘蔗渣制成的隔热材料的声学和热性能. 测定了由羊毛、山羊纤维、驼毛以及甘蔗渣髓和纤维束制成的五种隔热材料的导热性、耐热性、吸音性和吸湿性以及防火性能. 吸声系数的测量是在阻抗管中进行的. 根据ASTM D5334-08标准测量热阻和导热系数. 研究结果表明，驼毛具有最高的吸声性能、隔热性能和耐火性能. 山羊纤维的降噪系数（NRC）最低为0.52，驼毛的降噪系数最高为0.74. 在1000 Hz以上的频率下，驼毛的最大吸声系数为0.95. 导热系数在0.038-0.046W/（M.K）之间变化. 因此，所有测试材料都可以被视为隔热材料. 结果表明，以羊毛，尤其是驼毛为原料的绝缘材料，其性能优于甘蔗渣的纤维和髓.

KEYWORDS:

• Sound absorption
• thermal insulation
• wool
• fiber
• Pith
• bagasse
• sugarcane

关键词:

• 吸音
• 隔热
• 羊毛
• 纤维
• 髓
• 蔗渣
• 甘蔗

Disclosure statement

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

Highlights

• Imaging technologies reveal fiber’s structure characteristics at the cellular level.

• Tensile properties of palm fiber are improved significantly during alkali treatment.

• The alkali treatment lead to the microstructure transformation of fiber’s cell wall.

• The removal of hemicellulose and lignin contributes to the improved crystallinity.