Styrene‐Assisted Maleic Anhydride Grafting of Linear Low‐Density Polyethylene for Ethylene‐Vinyl Alcohol Blend Compatibilization

ABSTRACT Weak interfacial adhesion limits ethylene‐vinyl alcohol (EVOH)/polyethylene blend performance. Styrene‐assisted melt grafting was used to prepare maleic‐anhydride‐functionalized linear low‐density polyethylene (LLDPE) for compatibilization. Purification comparisons, independent‐batch controls, spectroscopy, and gel measurements supported functionalization with limited insoluble residue. The purified products had titrimetric MAH‐equivalent acid contents of 1.340 ± 0.041 wt% after batch mixing and 1.069 ± 0.053 wt% across five twin‐screw runs; these values are operational grafting indices, not structure‐specific graft contents. In 1:1 EVOH/LLDPE films, carbonyl and hydroxyl‐band changes were consistent with polar interactions but did not establish interfacial ester formation. Tensile testing used four specimens per direction from one preparation batch per formulation. Within these batches, the highest mean machine‐direction strength occurred at 2 phr and the highest transverse‐direction strength and toughness at 6 phr. These observations identify candidates for further screening, not a validated optimum. Single‐measurement rheology, including two commercial compatibilizers, provided descriptive melt‐response comparisons without establishing reproducibility or a performance ranking.