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

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.