Valorization of oat hull fiber from agri-food industrial waste as filler for poly(3-hydroxybutyrate- co -3-hydroxyhexanoate)

Oat hull fibers are an agri-food industrial waste used in this research as a filler for a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) matrix, to obtain a fully bio-based polymer-matrix composite material. The compounding process was carried out with a twin-screw extruder, avoiding chemical solvents and employing a technology commonly used by the industrial field. Silanization procedure was run to improve the affinity between the matrix and the filler. Compounds were structurally, microstructurally, mechanically and thermally characterized. Results denote that also at 8 v/v%, oat hull fibers work not only as inert filler, but also they have a slightly improving effect on mechanical properties of neat biopolymer, increasing of almost 12% the Young’s modulus, without a loss in tensile elongation at break. Therefore, this research study is a noteworthy approach which reduces the material costs and PHBH volumes, while valorizing waste biomasses.