A new arithmetic for linear free radical copolymerization

As a consequence of their method of production, polymer chains are polydisperse in size, composition and sequence distribution. In this work we present a new method of uniquely identifying these “polymer isomers” termed “Digital Encoding of Polymeric Chains”. The method involves replacing distinguishable features of the chain such as monomer units, branches, etc. with a number. This unique sequence of numbers provides a digital code, which, depending on the base of the arithmetic used (binary, ternary) can be translated into a unique decimal equivalent number. We have applied this technique to the case of binary copolymerization in a CSTR at steady state and show how the sequence spectra of the chain populations are conveniently obtained. Furthermore, the technique shows that rich information about the copolymerization kinetics, reactivity ratios and termination mode can be obtained from analysis of the short chains of the distribution. The implications for this in parameter estimation and controlled polymerization are discussed in this paper.