Bd. Park et Jj. Balatinecz, MECHANICAL-PROPERTIES OF WOOD-FIBER TOUGHENED ISOTACTIC POLYPROPYLENECOMPOSITES/, Polymer composites, 18(1), 1997, pp. 79-89
This study investigates the mechanical properties of wood-fiber/toughe
ned PP composite modified by physical blending with an EPDM rubber to
improve impact toughness. Wood-fiber thermoplastic composites were pre
pared with a modified PP matrix resin, employing high shear thermokine
tic compounding aided with maleated PP for the fiber dispersion. The a
ddition of EPDM improved the impact toughness, while it reduced stiffn
ess and strength properties. To compensate the non-plane strain fractu
re toughness, the specimen strength ratio (R(sb)) was adopted as a com
parative measure of fracture toughness. The strength ratio increased w
ith the addition of EPDM, while it decreased with increasing wood-fibe
r concentration. The work of fracture increased with EPDM level except
at large wood-fiber concentration. The effectiveness of the impact mo
dification was assessed with the balance between tensile modulus and u
nnotched impact energy as a function of wood-fiber concentration. EPDM
rubber modification was moderately effective for wood-fiber PP compos
ites. The examination of fracture surfaces showed twisted fibers, fibe
r breakage, and fiber pull-out from the matrix resin.