Benefits of Low Kenaf Loading in Biobased Composites of Poly(L-lactide) and Kenaf Fiber

Bast fibers from sterns of kenaf (Hibiscus cannabinus, L.), a warm-season tropical herbaceous annual plant, were dispersed into poly-L-lactide (PLLA) matrix by melt-mixing followed by compression molding. Low fiber fractions (1-5%) were investigated. The composites showed a slight lowering of thermal stability when evaluated by thermogravimentric analysis. X-ray diffraction and differential scanning calorimetry indicated an influence of kenaf on the crystallization of PLLA. The fiber dispersion in the polymer matrix was established by polarized optical microscopy. Scanning electron microscopy showed good fiber-matrix adhesion as revealed by the combination of dispersion, interaction, and crystallinity, which enabled an increase in the mechanical properties of the composite that scaled with concentration. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1294-1301, 2009