Effect of Ethylene-Glycidyl Methacrylate Copolymer on the Barrier Properties of Montmorillonite K 10 in Low-Density Polyethylene

A potential route to reducing material complexity in flexible packaging is to improve the oxygen barrier of polyethylene (PE)-based films. This study investigated the influence of ethylene-glycidyl-methacrylate copolymer (EGMA) on the structure and properties of low-density PE (LDPE) composites containing montmorillonite (MMT). Eight formulations containing, 0, 3,5 or 7 wt.%, with or without 10 wt.% EGMA, were produced via melt compounding. Microstructural analysis, density, thermal behaviour, surface wettability, tensile properties and oxygen permeation were evaluated. EGMA reduced the volume fraction of large MMT agglomerates by approximately 52-73% though localised clay-rich regions persisted. Oxygen barrier performance varied in a non-monotonical fashion with respect to formulation. LDPE containing a 5 wt.% MMT loading without the inclusion of EGMA compatibiliser exhibited the lowest permeation value, displaying a 25.1% reduction compared to neat LDPE. Within the EGMA-containing formulations, the best barrier performance was shown for a 3 wt.% loading, noting a 12% reduction compared to neat LDPE. There was no substantial impact on the tensile strength of composite samples regardless of loading level though higher MMT loadings generally increased modulus while reducing elongation. All measured densities remained below 0.97 cm3 in line with RecyClass guidelines. These findings show that EGMA improves large-scale MMT dispersion but does not consistently enhance barrier performance with the uncompatibilised 5 wt.% MMT formulation showing the most favourable combination of oxygen barrier and retained tensile properties.