| 摘要 |
PURPOSE:To obtain a polymer having a sharp MW distribution, by removing residual monomer and low-MW matter by decreasing the pressure in a polymerization vessel when the amount of residual monomer has a predetermined value in the bulk polymerization of a vinyl monomer. CONSTITUTION:The pressure in the whole polymerization apparatus is decreased, cocks 7 and 9 are shut. While the polymerization vessel 2 is being kept in the state of decreased pressure, it is fed with a vinyl monomer (e.g., methyl methacrylate), a polymerization initiator, a chain transfer agent, etc., from a feed inlet 1, the cock 6 is shut, and the bulk polymerization of the mixture is started by heating by a heating furnace 3. When the polymerization proceeds beyond a gelation point and a predetermined amount of residual monomer is reached, the cocks 7 and 9 are opened to distil off residual monomer and low- MW matter through a condensing tube 4 to a receiver 5 cooled by a cold trap 8.
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