M. Avella et al., STEAM-EXPLODED WHEAT-STRAW FIBERS AS REINFORCING MATERIAL FOR POLYPROPYLENE-BASED COMPOSITES - CHARACTERIZATION AND PROPERTIES, Die Angewandte makromolekulare Chemie, 233, 1995, pp. 149-166
Composites of wheat straw fibers with polypropylene (iPP) and maleic a
nhydride modified polypropylene (iPPMA) were prepared. Before being mi
xed with polypropylene matrices, the wheat straw fibers were subjected
to a steam explosion process that induces morphological and structura
l changes in lignocellulosic materials. Such changes are able to enhan
ce the interactions with the thermoplastic matrix. Compared with iPP,
the modified matrix (iPPMA) has shown higher mechanical performances (
tensile and impact behavior) and a remarkable decrease of water absorp
tion, that is one of the main drawbacks of natural fiber composites. F
inally, the presence of covalent bonds between maleic anhydride and st
eam-exploded (STEX) fibers, by means of an esterification reaction, pr
oduced during the melt-mixing process, can explain the resulting good
interfacial adhesion found in iPPMA-based composites.