Structural Interaction And Gas Barrier Properties Of Ethylene-Vinyl Alcohol/Tin Phosphate Glass Composites

The strength of interaction between tin phosphate glass (PGlass) filler droplets and an ethylene-vinyl alcohol (EVOH) matrix were investigated by image, thermal, and rheological analysis. 10% PGlass droplets in EVOH were smaller than those previously observed in maleated polypropylene. Analysis using the Fox equation showed that EVOH/97 degrees C T-g PGlass composites are not miscible systems. Dynamic shear and extensional rheology data of those composites exhibited a weak physical network, with relaxation times longer than that of pure EVOH at all strain rates. The tensile properties of the EVOH/10 vol% PGlass composite showed it to be more ductile and flexible than a typical polymer/inorganic filler system, supporting interaction between PGlass and EVOH sufficient to interrupt polymer-polymer hydrogen bonding. While undrawn EVOH/PGlass composite films showed increased oxygen gas permeability when compared to undrawn neat EVOH film, the drawn composite films exhibited oxygen permeability 6-7 times lower than that of neat EVOH, attributed to the presence of high aspect ratio PGlass particles after orientation. The concept of hydrogen bonding between polymer and PGlass can likely be applied to other polymers such as polyamides which possess numerous hydrogen bonding sites. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 989-998