Properties of blends containing poly(α-olefin-co-maleic anhydride). I. Evidence for cocrystallization in blends of eicosane and poly-(1 -octadecene-co-maleic anhydride)

Blends of poly(1-octadecene-co-maleic anhydride) and eicosane prepared from solution and the melt have been studied by differential scanning calorimetry, dynamic mechanical analysis and wide-angle x-ray scattering. The melting point and heat of fusion associated with the side chains of the copolymer increased with increasing eicosane content for blends prepared from the melt. It is hypothesized that this behavior results from the cocrystallization of eicosane with the paraffin-like side chains of the copolymer. The Tg of the copolymer was decreased by the addition of eicosane, and the Tm of eicosane was observed to decrease at high concentrations of the copolymer for blends prepared by both mechanisms. The possible contribution of both crystal morphology and thermodynamics to this melting point depression is discussed.