Thermal Analyses of Loose Agave, Wheat Straw Fibers and Agave/Wheat Straw as New Hybrid Thermal Insulating Materials for Buildings

ABSTRACT

Agave (AF) and wheat straw (SF) fibers are good raw materials for thermal insulation. In this study, loose agave or wheat straw fibers and hybrid boards of agave/wheat straw with different compositions and densities are tested for their thermal insulation qualities. Three new novel hybrid specimens are considered. In all specimens, cornstarch (CS) was used as a binder for the fibers. Thermal conductivity coefficient is obtained for each specimen in the temperature range 10–60°C with the resulting average value in the range 0.04555–0.06835 W/m K. Without binding, loose fibers of agave and wheat straws have an average thermal conductivity of 0.043592 and 0.044678 W/m.K, respectively, at the same range of temperature. Micrographs of the wheat straw fibers (SF) are conducted using the scanning electron microscope (SEM) which showed an average outer diameter between 1.28 and 1.98 mm and an average diameter of the bound porous tubes (multicellular) within the straw in the range 34.5 to 75.6 μm. Fourier transformation infrared (FT-IR) analyses of the wheat straw fiber are carried out which indicated stretching wavenumbers which present different chemical functional groups. Thermogravimetric analysis of the wheat straw fiber (TGA and DTGA) showed that the straws lose less than 3% of its mass at temperatures as high as 184°. Finally, the differential scanning calorimetry (DSC) analysis test of the wheat straw fiber indicates that endothermic transition starts at 342°C with a peak value at 749°C. Three-point bending moment tests for bound specimens are made and show an increase in both flexural stress and flexural modulus of the hybrid specimens. Using these hybrid specimens, agro, renewable and environmentally friendly materials in buildings will share in energy saving when used as insulation materials for building walls.

摘要

玛瑙（AF）和麦秸（SF）纤维是良好的保温材料. 本研究以松玛瑙或麦秸纤维及不同组成及密度之玛瑙/麦秸杂化板为试材，探讨其保温品质. 考虑了三个新的杂交样品. 在所有标本中，玉米淀粉（CS）被用作纤维粘合剂. 在10-60^oC的温度范围内获得每个试样的导热系数，所得平均值在0.04555-0.06835W/m K范围内. 在相同温度范围内，玛瑙和麦秸松散纤维的平均导热系数分别为0.043592和0.044678w/m.K. 利用扫描电子显微镜（SEM）对麦秸纤维（SF）进行了显微观察，结果表明：麦秸纤维的平均外径在1.28～1.98mm之间，麦秸纤维内部结合多孔管（多细胞）的平均直径在34.5～75.6mm之间. 对麦秸纤维进行了傅立叶变换红外光谱分析，结果表明，麦秸纤维的拉伸波数呈现不同的化学官能团. 对麦秸纤维（TGA和DTGA）的热重分析表明，麦秸在184^oC高温下的失重率小于3%. 最后，对麦秸纤维进行了差示扫描量热（DSC）分析，发现麦秸纤维的吸热转变始于342^oC，峰值在749^oC. 对粘结试件进行了三点弯曲试验，结果表明，混杂试件的弯曲应力和弯曲模量均有所提高. 在建筑中使用这些混合的、农业的、可再生的和环境友好的材料作为建筑墙体的隔热材料将有助于节约能源.

KEYWORDS:

• Agave fibers
• wheat straw fibers
• thermal conductivity measurements
• hybrid agave/wheat straw fibers
• thermogravimetric analysis
• three-point bending moment tests

关键词:

• 玛瑙纤维
• 麦秸纤维
• 热导率测量
• 玛瑙/麦秸纤维杂交
• 热重分析
• 三点弯曲力矩试验

Acknowledgments

The authors extend their appreciation to the Deputyship for Research & Innovation, “Ministry of Education” in Saudi Arabia for funding this research work through the project number IFKSURG-080.

Conflict of Interest

The authors declare that there is no conflict of interest.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the The Deputyship for Research & Innovation, “Ministry of Education” in Saudi Arabia for funding this research work through the project number IFKSURG-080.