Molecular mechanics investigation of some acrylic polymers using SPASIBA force field

• With SPASIBA force field, calculated wavenumbers of PMMA match experimental ones.
• The normal modes have been assigned using the potential energy distributions.
• The SPASIBA parameters were extended to other acrylic polymers.
• The transferability principle of Shimanouchi was validated using SPASIBA force field.

The First generation SPASIBA force field is used to study normal vibrational modes of PMMA, and then extended to other thermoplastic polymers, namely PMA, PMAA and PAA, in order to determine its parameters transferability. To this end, FTIR and FTR spectra of pure PMMA samples, prepared by the emulsion polymerization of MMA and initiated by sodium, are recorded in 400–3500 cm−1 and 200–3500 cm−1, respectively. A detailed vibrational analysis was performed on the obtained spectra and the observed frequencies are assigned to their respective vibrational modes, supported by potential energy distribution (PED) analysis. Our numerical results reveal an RMS value of 7.8 cm−1 corresponding to IR wavenumbers and 8.7 cm−1 relatively to Raman wavenumbers. Our vibrational calculations on PMA, PMAA and PAA polymers reveal that the parameters transferability criterion, established by Shimanouchi, is verified for the SPASIBA force field.