Improved Process to Make Tubular Ethylene Based Polymers with High Melt Strength

摘要

A process to form an ethylene-based polymer comprises polymerizing a reaction mixture comprising ethylene, at least one monomeric chain transfer agent, and at least one chain transfer agent system comprising at least one chain transfer agent (CTA) in the presence of at least one free-radical initiator and in a reactor configuration comprising at least two reaction zones, reaction zone 1 and reaction zone i (i≥2), wherein the reaction zone i is downstream from reaction zone 1. The ratio of “the activity of the CTA system of the feed to the first reaction zone” to the “activity of the CTA system of the cumulative feed to the reaction zone i,” (Z₁/Z_i), is less than or equal to (0.8−0.2*log(Cs)), wherein Cs is from 0.0001 to 10.