| 摘要 |
<p>Graft copolymers with low molecular weight side chains are prepared by (1) irradiating a propylene polymer material in the absence of oxygen, (2) adding a controlled amount of oxygen to the irradiated polymer material so that the polymer is exposed to an amount of oxygen greater than 0.004 % but less than 15 % by volume at a temperature of 40 °C to 140 °C, to produce an oxidized propylene polymer material containing greater than 1 mmol total peroxide per kilogram of propylene polymer material, (3) optionally, heating the oxidized propylene polymer material in a non-oxidizing atmosphere to a temperature of at least 80 °C but below the softening point of the polymer, and (4) treating the oxidized propylene polymer material in a non-oxidizing atmosphere with at least one grafting monomer that is capable of being polymerized by free radicals, in the presence of at least one additive to control the molecular weight of the side chains of the polymerized grafting monomer selected from (a) at least one hydroxylamine derivative polymerization inhibitor, and (b) at least one thio-, nitro-, or halogen-substituted aliphatic or aromatic compound, or an aliphatic or aromatic phosphine derivative, and (5) deactivating the residual free radicals in the resulting grafted propylene polymer material and removing any unreacted vinyl monomer from the material.</p> |
