Effect of unmodified rice straw on the properties of rice straw/polycaprolactone composites

The composite materials based on rice straw (RS) fiber and polycaprolactone (PCL) were prepared by a solution-casting method and characterized. The composites were prepared using different fiber loadings (1.0, 3.0, 5.0, and 7.0 wt%). The prepared composites (Cs) were characterized by using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electro-optical microscopy, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis, and mechanical properties were investigated. The XRD results showed that the intensity of the peaks decreased with the increase of RS content from 1.0 to 7.0 wt% in comparison with PCL peaks. SEM micrographs indicated poor adhesion between RS and PCL matrices, and FT-IR spectroscopy showed that, with the increase of loading percentages of RS, the intensity of the peaks is decreased from 1.0 to 7.0 wt%, and the interaction between RS and PCL was a physical interaction. Thermal stability was decreased with increasing the RS contents. Tensile measurement showed an increase in tensile modulus from 1.0 to 7.0 wt% loading of RS into the PCL, but a decrease in tensile strength and elongation at the break as the RS contents are increased, although there is a modest increase in tensile strength of the Cs material with 3.0 wt% loading of RS.