Characterization and comparative evaluation of thermal, structural, chemical, mechanical and morphological properties of six pineapple leaf fiber varieties for use in composites

Natural fibers are candidates to replace conventional mechanical reinforcements in composites. Six cultivars of fibers of different pineapples varieties were characterized by tensile tests, thermogravimetry, X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The elastic modulus and tensile strength values were in the range of 15–53 GPa and from 210 to 695 MPa, respectively. The final volatile loss temperatures for the six varieties were in the range between 175 and 195 °C and the onset temperatures in the range of 240–260 °C. The high degree of cellulose crystallinity index influenced the mechanical properties, hence suitable for composite reinforcement. This study aims to add information value to the literature regarding pineapple leaf fibers and its characteristics for technical and engineering applications. It was demonstrated that within the pineapple family, there are intrinsic variabilities for natural materials, indicating different potential uses for each variety.

► The six pineapple leaf fiber varieties meet the requirements to be used as fibrous reinforcement in composites. ► Young's modulus ranged from 15 to 53 GPa and tensile strength between 210 and 695 MPa. ► The mechanical properties had a direct relationship with cellulose crystallinity index. ► There is a inverse relationship between the area and the cellulose crystallinity index. ► The six pineapple leaf fiber varieties have satisfactory values of degradation temperature for use as reinforcement in some polymer matrices.