Oat hull fibers bleached by reactive extrusion with alkaline hydrogen peroxide in thermoplastic starch/poly(butylene adipate‐co‐terephthalate) composites

Abstract

The bleaching of fibers using alkaline hydrogen peroxide (AHP) can be used to promote modifications aimed at enhancing their interactions with polymers in composites. Reactive extrusion with AHP (7 and 20 wt%, hulls basis), pH 11.5, was used to modify oat hull fibers. The fibers were further compounded with a thermoplastic starch/poly(butylene adipate‐co‐terephthalate) blend to form sheets. The bleaching influenced the color of the fibers and subsequently the color of the composites. The rougher surfaces observed in the treated fibers improved their interfacial adhesion with the polymeric matrix. The treated fibers decreased the tensile strength, but the fibers treated with the higher concentration of H2O2 increased the elongation. The AHP‐treated fibers did not improve the overall thermal stability of the composites, and these fibers showed higher compatibility with the starch‐rich phase. Reactive extrusion showed to be an alternative method for modifying fibers for applications in composites. POLYM. COMPOS., 39:1950–1958, 2018. © 2016 Society of Plastics Engineers