Effects of amines on the polymerization of isoprene withsec-butyllithium catalyst

Autor: Yutaka Takakura, Kiyoshi Endo, Takayuki Otsu
Rok vydání: 1998
Předmět:
Zdroj: Polymer International. 45:414-418
ISSN: 1097-0126
0959-8103
DOI: 10.1002/(sici)1097-0126(199804)45:4<414::aid-pi968>3.0.co;2-c
Popis: Polymerization of isoprene (IP) with alkyllithium (RLi) catalysts in the presence of amines such as triethylamine (TEA), 1,2-dipiperidinoethane (DPPE) and N,N,N',N'-tetramethyldiaminoalkanes [(CH 3 ) 2 N(CH 2 ) n N(CH 3 ) 2 where n=1, 2, 3, 4 and 6 (TMDAA)] has been studied. By adding the amines, the polymerization rate of IP was accelerated, and the contents of 3,4- and 1,2-units in the resulting polymers increased. The effects of methylene chain length of the TMDAA on the polymerization were examined. It was found that both the polymerization rates and the microstructure of the polymers depend on the methylene length of the TMDAA. The amines having 2 and 3 methylenes in (CH 3 ) 2 N(CH 2 ) n N(CH 3 ) 2 favoured production of the polymer consisting of predominantly 1,2- and 3,4-units. It was proposed that two types of active sites for the polymerization of IP were produced depending on the number n of the TMDAA. Two types of active species were confirmed to be produced with sec-BuLi in the presence of N,N,N',N'-tetramethylethylenediamine (TMEDA) depending on the TMEDA/sec-BuLi mole ratios.
Databáze: OpenAIRE
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