Technical Paper Archive

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Event: 182nd Technical Meeting
Location: Cincinnati, OH
Date: October 09, 2012
Author: Roderic Quirk, Hongwei Ma, Shih-Fan Wang
Paper Number: 43

Price: $20.00

  • One of the most unique and important aspects of living alkyllithium- initiated anionic polymerization is the ability to prepare poly(1,3-dienes) and styrene-diene copolymers with high 1,4-microstructure in hydrocarbon solution. [1] These high 1,4-polydienes exhibit low glass transition temperatures and excellent elastomeric properties after crosslinking.[2,3] For example, butyllithium-initiated polymerization of 1,3-butadiene produces a polymer with 91% 1,4-microstructure (55% trans- and 35% cis-) and a glass transition temperature of -90 0C.[1] A important control variable for alkyllithium-initiated polymerization of 1,3-dienes is the ability to increase the amount of 1,2-enchainment by addition of increasing amounts Lewis bases, which systematically increases the glass transition temperature of the polymer.[4,5] Thus, polybutadiene with 9'1"% 1,2-microstructure can be prepared by effecting the polymerization in cyclopentane at 5 BC in the presence of 1 equivalent of 1,2-bispiperidinoethane relative to lithium,[6,'1"] bidentate bases have proven to be most effective for this purpose.[1] However, the practical extension of this procedure to higher temperature results in decreasing amounts of 1,2-microstructure.[8] For example, polybutadiene with only 31% 1,2-microstructure is formed with one equivalent of 1,2-bispiperidinoethane at T0 0C.['1"] Thus, there has been continuing interest in finding Lewis bases that would generate high 1,2- polydiene microstructures while exhibiting less temperature sensitivity with respect to 1,2-diene enchainment in alkyllithium-initiated polymerizations.

    Papers from 182nd Technical Meeting

    Items from 182nd Technical Meeting