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. Ten sile properties of pineapple fibers, like most natural fibers, showed a lar ge 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) photomicrog raphs of the microbond specimens revealed an adhesive failure of the interf ace. Fully degradable and environment-friendly "green" composites were prep ared 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. Ten sile and flexural properties of these "green" composites were compared with different types of wood specimens. Even though tensile and flexural streng th and moduli of these "green" composites were lower than those of some woo d specimens tested in grain direction, they were significantly higher than those of wood specimens tested in perpendicular to grain direction. Compare d to PHBV virgin resin, both tensile and flexural strength and moduli of th ese "green" composites were significantly higher. SEM photomicrographs of t he fracture surface of the "green" composites, in tensile mode, showed part ial fiber pull-out indicating weak bonding between the fiber and the matrix . (C) 1999 Kluwer Academic Publishers.