| 摘要 |
<p>A continuous process for the grafting of ethylenically unsaturated monomers onto homopolymers of ethylene and copolymers of ethylene and C4 - C10 higher alpha-olefins is disclosed. The process involves feeding to an extruder an admixture comprising (i) a major portion of the above polymer of ethylene, (ii) the monomer, (iii) 25-500 ppm of an organic peroxide and (iv) a minor portion of a normally solid thermoplastic polymer having a melting point of less than 185.degree.C and a shear viscosity at 200.degree.C and a shear rate o 400 sec-1 that is not more than 50% of that of the polymer of ethylene. The organic peroxide is in the form of a composition with the thermoplastic polymer. The admixture is mixed in a first zone at a temperature above the melting point of the polymers for at least ten seconds but for less than 25% decomposition of the peroxide and then in a second zone for a period that is at least four times the half-life of the peroxide. A grafted polymer having a melt index that is 20-100% of that of the polymer prior to grafting is obtained. The grafted polymer may be used in a variety of end-uses, for example, the manufacture of film, moulding of articles, extrusion coating of metals and coextrusion processes.</p> |
