Comprehensive characterization of spathe fibres extracted from Cocos nucifera: physical, chemical, mechanical, thermal, and acoustic properties for insulation applications

In this study, a complete characterization of fibres extracted from the spathe of the Cocos nucifera plant and the properties of spathe fibres are compared with coir fibre extracted from the outer husk of coconut. Coconut spathe fibre is available as bio waste in bulk. The spathe fibres were carefully extracted, pre-treated with NaOH, and porous nonwoven fibre mat were prepared. The physical properties of spathe fibres were measured as per ASTM standards, and average length, diameter, and linear density were found to be 222 mm, 330 μm, and 58.85 tex, respectively. Chemical compositions, XRD analysis, single fibre tensile strength and elongation, morphological analysis by scanning electron microscopy (SEM), and thermal characterization by TGA were also carried out. Spathe fibres treated with NaOH resulted in a 5% reduction in crystallinity index and more surface unevenness and pits. Developing acoustic insulation fibre mat from spathe fibre is a first-of-its-kind study. The sound absorption coefficient of the spathe fibre mat obtained from the impedance tube tester brings out a maximum absorption coefficient of 0.950 at 3150 Hz. The results were compared with coir fibre extracted from the outer husk of coconut and concluded that coconut spathe fibre is a suitable alternative for synthetic and other natural fibres.