The statistical analysis of polymer fractionation data. Part II

The analysis of successive polymer fractionation data by conventional and statistical methods is discussed. The data from fractionations of polystyrene and styrene‐butadiene rubber are analyzed by the several methods and the molecular weight distributions so obtained are compared with the molecular weight distributions calculated from a knowledge of the kinetics of the polymerization systems. The direct statistical methods are shown to be superior to the alternative procedures. Such methods approximate the individual fraction distributions by simple statistical distributions (binomial or generalized exponential), the parameters of which are calculated directly from a knowledge of two average molecular weights (M̄n and M̄w).