Interfacial and mechanical properties of environment-friendly "green" composites made from pineapple fibers and poly(hydroxybutyrate-co-valerate) resin

Physical and tensile properties of pineapple fibers were characterized. Tensile properties of pineapple fibers, like most natural fibers, showed a large variation. The average interfacial shear strength between the pineapple fiber and poly(hydroxybutyrate-co-valerate) (PHBV) was 8.23 MPa as measured by the microbond technique. Scanning electron microscopy (SEM) photomicrographs of the microbond specimens revealed an adhesive failure of the interface. Fully degradable and environment-friendly "green" composites were prepared by combining pineapple fibers and PHBV with 20 and 30% weight content of fibers placed in a 0 degrees/90 degrees/0 degrees fiber arrangement. Tensile and flexural properties of these "green" composites were compared with different types of wood specimens. Even though tensile and flexural strength and moduli of these "green" composites were lower than those of some wood specimens tested in grain direction, they were significantly higher than those of wood specimens tested in perpendicular to grain direction. Compared to PHBV virgin resin, both tensile and flexural strength and moduli of these "green" composites were significantly higher. SEM photomicrographs of the fracture surface of the "green" composites, in tensile mode, showed partial fiber pull-out indicating weak bonding between the fiber and the matrix. (C) 1999 Kluwer Academic Publishers.