Fourier transform infrared and Raman spectral analysis of trans-1,4-polyisoprene

Polyisoprene is the most widely used polymer in industry and commerce. Four ier transform infrared (FTIR) and Raman spectra of trans-1,4-polyisoprene h ave been recorded in the range of 4000-400 and 4000-100 cm(-1), respectivel y. In the present investigation, detailed assignments of the observed funda mental bands of trans-1,4-polyisoprene has been analysed in terms of peak p ositions and relative intensities. With the hope of providing more and effe ctive information on the fundamental vibrations., a normal co-ordinate anal ysis has been performed on trans-1,4-polyisoprene, by assuming Cs symmetry. The simple general valance force field (SGVFF) method has been employed in normal co-ordinate analysis and to calculate the potential energy distribu tion (PED) for each fundamental vibration. The PED contribution correspondi ng to each of the observed frequencies shows the reliability and accuracy o f the spectral analysis. The validity of the SGVFF method as a practical to ol for complete analysis of vibrational spectra. even for a polymer of this complexity, is confirmed in the present work. (C) 2001 Elsevier Science B. V. All rights reserved.