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 5 9 cm(-1), respectively, were identified for Delta upsilon = 2, 3, 4, a nd 5. The vinyl stretch progression, being much weaker, was identified through the Delta upsilon = 3 transition. Several bending progression s appeared belonging to the cis, trans, and vinyl isomers, two of whic h 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 hi gher quantum transition while the comparable decrease for the bending absorptions was a factor of 4. (C) 1996 John Wiley & Sons, Inc.