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

✍ Scribed by Endo, Kiyoshi; Takakura, Yutaka; Otsu, Takayuki

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 238 KB
• Volume: 45
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199804)45:4<414::aid-pi968>3.0.co;2-c

✦ Synopsis

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 where 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 e †ects 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 favoured production of the polymer consisting of pre-

) 2 dominantly 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 conÐrmed to be produced with sec-BuLi in the presence of N,N,N@,N@-tetramethylethylenediamine (TMEDA) depending on the TMEDA/sec-BuLi mole ratios.

1998 SCI.