APPLICATION OF NUMERICAL-METHODS FOR THE CALCULATION OF SIZE DISTRIBUTION-FUNCTIONS OF POLYMERS PRODUCED BY IONIC POLYMERIZATIONS

The application of numerical methods for the calculation of the molecu lar weight distribution of living ionic polymerization, carried out in the presence of monofunctional and polyfunctional transfer agents, is described. The methods used include the numerical solution of a syste m of differential equations by the Runge-Kutta-Merson procedure and th e statistical Monte-Carlo approach. When a monofunctional transfer age nt is used, the Runge-Kutta-Merson procedure is quite useful for the c alculation of the molecular weight distribution for various polymeriza tion systems. When a polymerization is carried out in the presence of a polyfunctional transfer agent, the mechanism includes the coupling o f polymer chains. Due to the complexity of the system, the Runge-Kutta -Merson procedure is hardly applicable and problems of this type shoul d be solved by a Monte Carlo simulation procedure. Once a computer pro gram has been written, both methods allow the chemist to calculate the molecular weight distribution of a polymer as a function of the diffe rent kinetic parameters of the polymerization.