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 kapokfibers as a reinforcement for lightweight composites. Kapok fibers aremodified by dewaxing followed by a silane coupling agent at differentconcentrations. The crystallographic structure and the alignment ofsilane linkage polymer chains on fiber structure are examined usingX-ray Diffraction (XRD). The linkage of chemical bonds (Si-O-C AndSi-O-Si) between the polymer structure of the fiber and silane couplingagent is confirmed from FTIR spectroscopy. Additionally, the small angleX-ray scattering (SAXS) study is done considering kapok fiber as anonideal two-phase system and the study investigates the modificationoccurring within the macromolecular structure of the kapok fiber.Following the grafting of silanes onto the fiber, silane-modified kapokfiber-reinforced epoxy composites are fabricated using the hand lay-uptechnique. The chemical treatments on the fiber, enhanced flexural,tensile and impact strength of the composites by 132\%, 102\%, and 146\%respectively.