Anionic polymerization of secondary aminostyrene and characterization of the polymer

✍ Scribed by Kazunori Se; Shinichi Kudoh

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 173 KB
• Volume: 71
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990321)71:12<2039::aid-app14>3.0.co;2-9

✦ Synopsis

Preparation by anionic living technique and characterization of poly-(secondary aminostyrene) having narrow molecular weight distribution were investigated. N-isopropyl-N-trimethylsilyl-4-vinylbenzylamine (SBA) was purified by use of sec-butylmagnesium bromide as a purging reagent under high vacuum. SBA was anionically polymerized with n-butyllithium or cumylpotassium in tetrahydrofuran at Ϫ78°C under high vacuum to yield the corresponding polymer (PSBA) in 100% yield. Subsequent deprotection of the trimethylsilyl group from PSBA produced poly(N-isopropyl-4-vinylbenzylamine) (PBA) of the desired molecular weights (M n : 1.3 ϫ 10 4 -17 ϫ 10 4 , determined by membrane osmometry) with narrow molecular weight distribution (M w /M n : 1.07-1.03, determined by gel permeation chromatography). The living lithium carbanion of PSBA can initiate styrene (St) to yield PSBA-b-PSt block copolymer (M n ϭ 4.0 ϫ 10 4 , M w /M n ϭ 1.05), and the polystyryllithium can initiate SBA to yield PSt-b-PSBA (M n ϭ 3.7 ϫ 10 4 , M w /M n ϭ 1.25). The deprotection of the trimethylsilyl group from the two block copolymers produced new block copolymers containing poly(secondary aminostyrene) block. Anionic reactivity of SBA and basic properties of PSBA are discussed in terms of the 13 C chemical shift of ␤-carbon in the vinyl group of SBA and steric effect.