discussed for the PB homopolymer. The PB block of the star-shaped block copolymer turned out

to be composed, before hydrosilylation, of 75 mole % of 1,2-PB units. The 1H NMR spectrum of

the hydrosilylated (PB(Si(OEt)3)-b-PEO)3 three-arm star block copolymer revealed a strong

decrease in the intensity of the signal corresponding to the -CH=CH2 protons of the pendant

double bonds at 3 = 4.9 ppm. Furthermore, the fact that the signal corresponding to the

SiOCH2CH3 methyl protons at 3 = 1.2 ppm greatly increased in intensity indicated that the

reaction occurred with a high efficiency, and a conversion of 85 % of the 1,2-PB pendant double

bonds was calculated. The efficiency of the reaction was confirmed by FTIR spectroscopy as

shown in Figure 5-16, where the absorbance peaks at 3100 cm-l and 1640 cm-l strongly

decreased in intensity after hydrosilylation.


+ HSi(OCHyCH3)3


PtO[(CH,=CH(Me),Si],O
Toluene~ / 80C /24h


m,


Figure 5-14. Hydrosilylation of the pendant double bonds of the (PB-b-PEO)3 three-arm star
 block copolymers.