Interfacial interaction, morphology, and tensile properties of a composite of highly crystalline cellulose and maleated polypropylene

Abstract

AbstractA composite of highly crystalline cellulose was synthesized via a melt‐mixing method with maleic anhydride (MA)‐grafted polypropylene (PP), MAPP, which was prepared by melt‐mixing PP with 0.25–8.0 phr (part of reagent per hundred parts of PP) of MA, and the morphology and tensile properties were examined with respect to the interfacial interactions of MAPP and cellulose. The graft degree (Gd) of MAPP increases with an increase in the initial MA amount up to 2.5 phr, beyond which it decreases because of the remaining of more free MA monomers and/or the formation of more oligomers remaining in the matrix. The morphology and tensile properties of the composite are affected strongly by Gd as well as the presence of the free MA in the matrix. For the MAPP without any free MA, even the Gd value as small as 0.25–0.5 wt % yields a maximal tensile strength. The existence of free MA monomers in the MAPP decreases the tensile strength, probably because of interrupting the interactions of the grafted MA groups with the OH groups of cellulose. The tensile properties of the composite correlate with the interfacial adhesion as well as the dispersion of cellulose microfibers in the matrix, both of which are determined by the interactions of the OH groups on cellulose with the grafted MA groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3830–3841, 2006