A computer program for the visualization of stereoregular polymers

Abstract

AbstractThis paper describes a computer program that is useful in the elucidation and visualization of particular stereoregular polymer chains. The input is the fractions of isotactic, syndiotactic, and heterotactic triplets in a real polymer as determined by some technique such as NMR. The program calculates a matrix of conditional transition probabilities from these fractions. This matrix in conjunction with a random‐number generator is used with Monte Carlo techniques to calculate a specific sequence of 0's and 1's. The sequence contains 101 elements. This is the generated polymer chain. The number of various kinds of doublet, triplet, etc., is then counted for this particular generated chain, and compared with that calculated from the matrix for the chain of infinite length. Comparisons among these sets of figures show that the generated polymer chains are usually quite typical of the infinite chain.The application of NMR techniques to the determination of the relative numbers of isotactic, heterotactic, and syndiotactic triplets in synthetic polymers was pioneered by Bovey (1) several years ago. The data thus obtained can be used in a straightforward manner to calculate various average properties of the polymer chain. Although these average properties may be used to describe the polymer, frequently it is difficult to visualize exactly what a typical polymer chain might look like from a stereoregularity point of view. This paper describes a computer program that calculates various sequence averages for an infinite polymer chain and that generates by Monte Carlo techniques a polymer chain typical of the NMR data. In addition the program, by calculating various sequence averages for the generated polymer chain, permits evaluation of just how representative the generated polymer is.