Assignment of the Carbon-Hydrogen Stretching and Bending Vibrations of Poly(Methyl Methacrylate) by Selective Deuteration

The C—H stretching and C—H bending vibrations of the methylene, α-methyl, and ester methyl groups of poly(methyl methacrylate) are discussed and assigned on the basis of the infrared spectra of its three deuterated derivatives: PMMA—CD3—OCD3, PMMA—CD2—OCD3, and PMMA—CD2—CD3. The digital analog of PMMA is obtained by coaddition of the Fourier transform infrared spectra of the deuterated PMMA derivatives. The experimental and digital PMMA spectra are compared in the regions of the C—H stretching and C—H bending vibrations: the agreement in frequency is excellent and the relative intensities are practically the same in the C—H stretching vibrations region. However, their relative intensities strongly differ in the C—H bending region.