Near-IR spectrum of polybutadiene

The vibrational overtone spectrum of polybutadiene was recorded up to 14,000 cm(-1) and interpreted in the local mode model. The methylenic and olefinic CH stretch progressions, with anharmonicities of 66 and 59 cm(-1), respectively, were identified for Delta upsilon = 2, 3, 4, and 5. The vinyl stretch progression, being much weaker, was identified through the Delta upsilon = 3 transition. Several bending progressions appeared belonging to the cis, trans, and vinyl isomers, two of which belong specifically to the vinyl bending motion. The anharmonicities for these bends vary from 11 to 15 cm(-1). The relative intensity of stretching features decreased on average by a factor of 8 with each higher quantum transition while the comparable decrease for the bending absorptions was a factor of 4. (C) 1996 John Wiley & Sons, Inc.