| 摘要 |
PURPOSE:To obtain the titled polyisoprene which can give a coating having few pinholes, by solution-polymerizing isoprene in the presence of an organometallic compound, removing unreacted isoprene or/and isoamylene and cyclizing the polyisoprene. CONSTITUTION:A polyisoprene solution is obtained by polymerizing isoprene monomer in a solvent (e.g., benzene) to a conversion >=99% by using an organometallic compound of the formula RM (wherein R is alkyl, aryl or aralkyl and M is Li, Na, K or Ce) as an initiator for living polymerization and adding a short-stop to the reaction mixture. This solution, as such or after dilution with a solvent, is striped of the solvent at a pressure of 5-1,500Torr and a temperature of, preferably, 0-100 deg.C until the content of unreacted isoprene or/and isoamylene is decreased to 1pt.wt. or below per 100pts.wt. polyisoprene. After the polyisoprene concentration is adjusted to 1-20%, the solution is reacted with 1-15pts.wt. acid catalyst to obtain a cyclized polyisoprene solution.
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