Novel biodegradable composites based on treated lignocellulosic waste flour as filler. Part II. Development of biodegradable composites using treated and compatibilized waste flour

The usefulness of lignocellulosic waste flours, i.e., spruce, olive husk and paper flours as a source of filler for the preparation of cost-effective and biodegradable polymer matrix composites was studied. The biodegradable polyester Bionolle 3020 was used as matrix. Waste flour/matrix interfacial adhesion was promoted by means of flour surface treatment, acetylation and propionylation, and the addition of maleic anhydride-grafted Bionolle as compatibilizer. The compatibilizer was synthesized in an intensive mixer through a maleic anhydride grafting reaction in the presence of dicumyl peroxide as initiator. The produced composite materials were characterized by means of mechanical property measurements, scanning electron microscopy, water absorption and biodegradation studies. Compatibilizer addition resulted in materials with improved mechanical properties, while flour treatment with acetic and propionic anhydride significantly reduced material water uptake. In addition, waste flour incorporation into the polymeric matrix increased its biodegradation rate.