Tfa. Haselwander et al., VINYLIC POLYMERIZATION OF NORBORNENE BY PD(II)-CATALYSIS IN THE PRESENCE OF ETHYLENE, Macromolecular rapid communications, 18(8), 1997, pp. 689-697
Pd(II) catalysts with nitrilo ligands and BF4- counter ions give the b
est results in vinylic polymerization of norbornene. Absolute molecula
r weight determination of polynorbornene (PN) by means of light scatte
ring and the three-dimensional shape of PN were also investigated. By
correlation of molecular weights (M) over bar(W) with intrinsic viscos
ity (Staudinger-index) [eta], yield a close to 0.5 exponent for the Ma
rk-Houwink equation with sol vents chlorobenzene and cyclohexane at 25
degrees C expected for polymer molecules with confined conformation.
The vinylic polymerization of norbornene with [(CH3CN)(4)Pd][BF4](2) (
I) in nitromethane in the presence of ethylene results in PN with narr
ow molecular weight distribution. No termination and transfer reaction
s were found, nor any incorporation of ethylene could be detected.