Inelastic neutron scattering from isotactic polypropylene

We used inelastic neutron scattering to probe the low-energy excitations in semicrystalline isotactic polypropylenes with different degrees of crystal linity. The contributions from the amorphous and crystalline regions to the total scattering intensity were extracted under the assumption of a weight ed linear contribution of the two regions in a simplified two-phase system. The resulting intensity from the amorphous region showed a peak at 1.2 meV that was in good agreement with the previously determined boson peak chara cteristic of atactic polypropylene. The possibility of a contribution to th e boson peak region by longitudinal acoustic mode modes that are characteri stic of semicrystalline polymers and appear in the same low-frequency regio n is discussed. (C) 2001 John Wiley & Sons, Inc.