| 摘要 |
<p>A liquid polymn. reaction medium is prepd. by combining (a) a stereospecific Ziegler catalyst (e.g. VCl3 on an inert carrier, Pr3Al and TiCl4); (b) a liquid 2-4C olefin monomer (e.g. butadiene, isoprene) which is a non-solvent for the resulting cryst. homopolymer, and (d) a solid particulate nucleating agent which is insoluble in the polymerisation reaction medium; polymerising the monomer at a temp. below the cryst. m.p. of the homopolymer and below the decomposition temp. of the catalyst whilst subjecting the reaction mixt. to a gentle rotating motion at a rate sufficient to prevent agglomeration of the polymer particles being formed; and continuing polymn. long enough to convert the liquid reaction medium into a homopolymer comprising essentially dry particles; and finally separating same. Catalyst system can contain pptd. material acting as nucleating agent. When no catalyst ppte. is present, the inert carrier can function as nucleating agent. Butadiene, isoprene are suitable monomers.</p> |
