Reactive processing of LLDPEs with peroxides in counter-rotating nonintermeshing twin-screw extruder. IV. Effects of molecular structure of LLDPEs

The effects of reactive extrusion with peroxide have been compared for two linear low-density polyethylenes (LLDPEs). Resin C is a butene copolymer, while Resin B is an octene-ethylene copolymer. Both have similar molecular weight distributions, but Resin B is significantly richer in terminal vinyl groups. Under the same reactive extrusion conditions, Resin B is much more reactive. Resin C is easier to process in this system, producing products clean of microgel. Concurrently, however, a given peroxide level produces less molecular weight enhancement and long-branch formation in Resin C. Reactive extrusion with peroxide is suitable to effect improvements in the processability of LLDPEs for film applications, provided that the choice of peroxide and the process details are tailored to the characteristics of the particular LLDPE.