Silicon‐terminated telechelic oligomers by ADMET chemistry: Synthesis and copolymerization

Abstract

Methoxydimethylsilane and chlorodimethylsilane-terminated telechelic polyoctenomer oligomers (POCT) have been prepared by acyclic diene metathesis (ADMET) chemistry using Grubbs' ruthenium Ru(Cl2)(CHPh)(PCy3)2 [Ru] or Schrock's molybdenum Mo(CHCMe2Ph)(N2,6C6H3iPr2)(OCMe(CF3)2)2 [Mo] catalysts. These macromolecules have been characterized by FTIR, 1H-, 13C-, and 29Si-NMR spectroscopy. The molecular weight distributions of these polymers have been determined by GPC and vapor pressure osmometry (VPO). The number-average molecular weight (Mn) values of the telechelomers are dictated by the initial ratio of the monomer to the chain limiter. The termini of these oligomers (Mn = 2000) can undergo a condensation reaction with hydroxy-terminated poly(dimethylsiloxane) (PDMS) macromonomer (Mn = 3300) [HOSi(CH3)2O{Si(CH3)2O}x Si(CH3)3], producing an ABA-type block copolymer, as follows: (CH3)3SiO [Si(CH3)2O]x[CHCH(CH2)6]y[OSi(CH3)2]xOSi(CH3)3. The block copolymers were characterized by 1H- and 13C-NMR spectroscopy, VPO, and GPC, as well as elemental analysis, and were determined by VPO to have a Mn of 8600. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 849–856, 1999