Azobis , telechelic

Amino-terminated telechelic polybutadiene was prepared by LiAlH4 reduction of amidino end-group in polybutadiene, which was polymerised by a water-soluble initiator, 2,2 -azobis(amidinopropane)dihydrochloride. The structure was analysed by 1H- and 13C-NMR, but functionality of 2.0 was obtained by a titration method [70]. Synthesis of co-epoxy-functionalised polyisoprene was carried out by the reaction of 2-bromoethyloxirane with living polymer that was initiated with sec-butyl lithium. The functionality of the resulting polyisoprene was 1.04 by 1H-NMR and 1.00 by thin layer chromatography detected with flame ionisation detection [71]. 

Kawabe et al. have made telechelic PS having carboxyl end groups using both succinic acid peroxide [225] and 4,4 -azobis(4-cyanovaleric acid) [226] as initiators. Other FR initiators utilized to make telechelic PS are shown below. 

Microwave irradiation Grafting onto method Various catalysts are used [4,4 -Azobis (4-cyanovaleric acid)] Telechelic polymers, polyethylene glycol, poly-dimethyl siloxane... 

Telechelics have also been synthesized from azo compounds similar to AIBN, but in which either the methyl (34) or the nitrile (35) group has been modified. Methyl-2,2-azobisisobutyrate (35 R = Me) (MAIB) has been used to initiate the polymerization of styrene to yield a,cu-bis(2-methoxycarbonyl-methylethyl)oligostyrene with a functionality of /=2. Using 3,3-azo-bis(3-cyanovaleric acid) (34 R = C02H) or 4,4-azobis(cyanopentanol) (34 R=CH20H) as initiator for styrene oligomerization respectively. - ... 

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