PROTON AND CARBON NMR-SPECTRA OF ALTERNATING AND STATISTICAL STYRENE METHYL-METHACRYLATE COPOLYMERS REVISITED

The alpha-methyl proton NMR resonances of the three different configurational methyl methacrylate centered triad sequences of alternating styrene-methyl methacrylate (SMMA) copolymers have been reassigned. Literature assignments are inconsistent with data and each other. Selective decoupling experiments were carried out in the present study to assign the carbon NMR resonances of the alpha-methyl groups of alternating styrene-methyl methacrylate copolymers. Subsequently, the carbon resonances of the aromatic Cl and alpha-methyl literature assignments of the statistical SMMA copolymers have been reconsidered and reassigned in terms of configurational triad sequences.