Polymer conformation and NMR chemical shifts, 8. Monomer‐ and stereo‐sequence dependences of ¹³C NMR spectrum of poly(methyl acrylate‐<i>co</i>‐styrene)

<jats:title>Abstract</jats:title><jats:p>The <jats:sup>13</jats:sup>C NMR spectra of poly(methyl acrylate‐<jats:italic>co</jats:italic>‐styrene) are interpreted by a theoretical procedure which consists of conformational analysis of the random copolymer chain and shielding calculation. The conformational probabilities of the diad sequences constituting poly(methyl acrylate‐<jats:italic>co</jats:italic>‐styrene) are calculated by a matrix method which is conducted by the statistical mechanics of polymer chains. All the elements of the matrices are determined by the force field method. As significant shielding factors for <jats:sup>13</jats:sup>C nuclei, paramagnetic, diamagnetic, and anisotropic terms are taken into account. The calculation is used to assign the observed split peaks for the carbonyl carbon and methoxyl carbon in the copolymer. A good agreement between calculation and observation of the peak splittings due to the distribution of the monomer sequence as well as that of the stereo sequence was obtained by considering the feasibility of rotational isomerization at the side chain ester group in two successive MA units.</jats:p>