Effect of macromolecular structure modification of kapok fibers by silane treatment on mechanical properties of their reinforced composites

Abstract The present study investigates the usability of lignocellulosic kapok fibers as a reinforcement for lightweight composites. Kapok fibers are modified by dewaxing followed by a silane coupling agent at different concentrations. The crystallographic structure and the alignment of silane linkage polymer chains on fiber structure are examined using X‐ray Diffraction (XRD). The linkage of chemical bonds (SiOC And SiOSi) between the polymer structure of the fiber and silane coupling agent is confirmed from FTIR spectroscopy. Additionally, the small angle X‐ray scattering (SAXS) study is done considering kapok fiber as a nonideal two‐phase system and the study investigates the modification occurring within the macromolecular structure of the kapok fiber. Following the grafting of silanes onto the fiber, silane‐modified kapok fiber‐reinforced epoxy composites are fabricated using the hand lay‐up technique. The chemical treatments on the fiber, enhanced flexural, tensile and impact strength of the composites by 132%, 102%, and 146% respectively.