Polymerization of 1-hexene using α-diimine nickel catalysts: Stochastic simulation of branch distribution

This work presents a new stochastic model to simulate the chain-walking mechanism during the polymerization of 1-hexene with α-diimine nickel catalysts based on the kinetic mechanism and branching data provided in the literature. Poly(1-hexene)s produced present short-chain branches such as methyl and butyl as well as longer chain branches showing very good agreement with the experimental branching data available. The new stochastic model is capable to cope with regioselective insertions of α-olefins and typical occurrence of 1,ω enchainment leading to the formation of longer chain branches and allows the calculation of molar mass and branching distributions. Another important result is that model simulations were able to unveil deficiencies for the kinetic mechanism to accurately predict the branching distribution at low temperatures. It is also shown that model probabilities may be interpreted in kinetic terms and properly correlated to the reaction polymerization temperature.