Desenvolvimento de compósitos de polipropileno (PP) com bagaço de malte e argila organofílica

Abstract

Brewery residue, named malt bagasse (BM), was incorporated into commercial polypropylene (PP) alongside with organophilic clay (AO). Different composites, determined according to mixture design established by MINITAB program, including grape seed oil and compatibilizer agent (high density polyethylene graphtized with maleic anhydride), were processed in a twin-screw extruder. After characterization of BM and processing of PP / BM / AO mixtures, specimens were obtained, and mechanical property of impact resistance and scanning electron microscopy were conducted. The experimental results allowed to conclude that: malt bagasse, like other lignocellulosic fillers (sugar cane straw and bagasse, coffee husk and others), exhibits a relevant hydrophilic character; use of BM, without any direct chemical treatments, did not allow that residue provided any reinforcing action; and an intermediate performance was only achieved when a reduced AO content was added. Scanning electron microscopy (SEM) proved a relevant lack of adhesion between BM filler and thermoplastic matrix. Positive points of the experimental investigation were: probable increase in the biodegradation of composites when BM is present; and, non-reinforcing filler character associated to the residue.