Tailored PCL/Macaíba fiber to reach sustainable biocomposites

Abstract

Biocomposites processed with polycaprolactone (PCL) and macaíba fiber (MF) were melting extruded in this work with MF content ranging from 10% to 20%. MF was naturally added to PCL as also chemically treated with maleic anhydride (MA), sodium hydroxide (NaOH), and 3-Methacryloxypropyltrimethoxysilane (Silane). Afterwards biocomposite were thermally, spectroscopically, mechanically and morphologically characterized. From the gathered results, higher thermal stability was observed for biocomposites upon higher MF content, regarding the chemical treatment MA presented the best performance whereas NaOH the lowest, similar trend was also verified with mechanical behavior. From contact angle and water absorption results it was suggested macaíba oil exudation to the surface acts decreasing interaction with water and, therefore, increasing the contact angle, while the added MF provide more opened structure which favors the water entrance, whereas the time and polarity effects should be recognized, which eases H2O entrance from surface to biocomposites core and improve interactions between PCL matrix and MF, respectively being translated in higher compatible biocomposites. Summing up, biocomposites with 10% of natural or treated macaíba fiber presented the best synergism. MF addition to PCL provides a sustainable alternative to PCL biocomposites, besides supplying the literature with new information on applications of natural and chemically treated macaíba fibers.