Caracterização dos materiais lignocelulósicos da castanha do Brasil (Bertholletia excelsa), preparação e caracterização de seus compósitos com polipropileno
Resumen
This research aimed to characterize the lignocellulosic materials of the
Brazil nut (Bertholletia excelsa) extraction process and to develop biocomposites
incorporating these materials with homopolymer and copolymer polypropylene
matrices. The study and characterization of lignocellulosic materials involved the
research of the socioeconomic context and the morphological, physical,
chemical, thermal and mechanical behavior characteristics. The development
and characterization of biocomposites involves the beneficiation and
compatibilization of the lignocellulosic fillers with polypropylene-graft-maleic
anhydride, the extrusion of the biocomposites in different formulations, the
injection molding of test specimens and the characterization of the resulting
biocomposites in relation to general physical properties, moisture absorption,
thermal behavior, mechanical behavior under tensile and flexural stress, and
impact resistance behavior. The results showed that the lignocellulosic materials
are composed of the pericarp of the fruit and of the seed shells, respectively with
three and five distinct layers, each one with its characteristics. The biocomposites
presented higher hardness, higher elastic modulus, higher tensile and flexural
strength, higher moisture absorption, lower impact strength and lower rupture
elongation when compared to the pure polypropylenes of the matrices. The
utilization of the polypropylene copolymer matrix provided better performance in
relation to the impact absorption behavior. The performance of the filler from
mesocarp of the pericarp biocomposities was superior to those filled with seed
shells. Compared to other biocomposites, common woods and plastics, in
general, the developed biocomposites showed good performance.