W. Fortuniak et al., Controlled synthesis of siloxane polymers and siloxane-siloxane block copolymers with 3-chloropropyl groups pendant to the siloxane chain, MACRO CH P, 202(11), 2001, pp. 2306-2313
Linear polysiloxanes bearing 3-chloropropyl groups pendant to the polymer c
hain and containing a vinyl functional group at one chain end were synthesi
zed by anionic ring polymerizations of 2,4,6-tri(3-chloropropyl)-2,4,6-trim
ethylcyclotrisiloxane, 1, and 2-(3-chloropropyl)-2,4,4,6,6-pentamethylcyclo
trisiloxane, 2, initiated with butyl lithium silanolate in tetrahydrofuran.
The polymerizations led to high yields of polymers with narrow molecular w
eight distributions. The precise functionalizations of the polymers were pe
rformed by a termination method quenching the polymerization by dimethyl-vi
nylchlorosilane. Diblock copolymers AB of narrow molecular weight distribut
ionand a high topological purity were obtained by the sequential anionic co
polymerization of hexamethylcyclotrisiloxane D-3,with monomers 1 and 2.