Jatobá wood flour: An alternative for the production of ecological and sustainable PCL biocomposites

The industrial residue of Jatobá wood flour (JWF) was reused during production of biocomposites based on polycaprolactone (PCL), 50% by weight of JWF was added to PCL matrix. Initially, maleic anhydride-grafted polycaprolactone compatibilizer (PCL-g-MA) was synthesized and characterized using X-ray diffraction (XRD), nuclear magnetic resonance (NMR) and degree of grafting. Afterwards, PCL/JWF and PCL/JWF/PCL-g-MA biocomposites were processed in an internal mixer and injection molded. From the gathered results, increase in torque and reduction in the melt flow index of PCL/JWF biocomposites were verified related to neat PCL. Upon addition of PCL-g-MA to PCL/JWF there was a lubricating effect with reduced torque and increased fluidity. PCL/JWF displayed increased elastic modulus, Shore D hardness, and heat deflection temperature (HDT) around 158.5%, 16% and 24.5%, respectively, related to PCL. Nevertheless, there was decline in tensile strength and impact strength, which were improved in PCL/JWF/PCL-g-MA, suggesting higher interaction among phases, providing greater stress transfer. An interesting finding was the nucleating effect of JWF in PCL matrix, as the increased degree of crystallinity and accelerated crystallization. Morphology of PCL/JWF evidenced several voids, but upon compatibilization with PCL-g-MA, the interfacial adhesion and wetness increased, improving the mechanical properties. JWF reusing presents great potential to produce sustainable biocomposites, reducing the final product costs.