NMR Characterization of Copolymers That Exhibit Nonsymmetric Compositional Heterogeneity

The perturbed first-order Markovian model has been developed for copolymers that exhibit nonsymmetric chemical compositional distribution. An exponentially modified Gaussian function is first used to approximate the distribution. The theoretical probability expressions for the comonomer diads, triads, and tetrads are derived. Using these expressions, one can analyze the observed NMR data and fit them to the perturbed Markovian model. The formalism given herein is next extended to the general case of an arbitrary chemical composition distribution. Computer programs have been written to facilitate the analyses, and examples are given to illustrate the use of these computer-assisted approaches.