Laminar morphology development using hybrid EVOH-nylon blends

Abstract

Properties of blends having two types of hybrid dispersed phases as laminar morphology were investigated. The hybrid dispersed phases were prepared by preblending nylon and ethylene-vinyl alcohol (EVOH) in solid state (E / N) and in melt state (E/N). Oxygen and toluene barrier properties through the hybrid-dispersed phases in low-density polyethylene (LDPE) matrix were analyzed considering the morphological changes (number and size of layers). Oxygen barrier properties of the blends of LDPE-E / N hybrid dispersed phase having separate domains of nylon and EVOH were found to be linearly dependent on EVOH composition in the blend, but toluene barrier properties of the blends exhibited negative deviation. The other hybrid dispersed phase (E/N) in LDPE matrix, having comingled dispersed phase of nylon and EVOH, exhibited positive deviations in both oxygen and toluene barrier properties. Tensile properties also showed positive deviation. Basic studies on the melt blend (E/N) of EVOH and nylon 6 showed some miscibility, which was revealed from melting point depression, and positive deviation in complex viscosity and tensile properties of the blend.

Effect of the partially hydrolyzed EVA‐h content on the morphology, rheology, and mechanical properties of PA12/EVA blends

“…However, to obtain smaller sizes of dispersed phase, a compatibilizing agent must be used in PA12/EVA blends despite the low difference in solubility parameter of the blend [17,18]. An alternative is the use of hydrolyzed ethylene vinyl acetate copolymer (EVA-h), since it is expected that this material may specifically interact with polyamide by hydrogen bonding [19][20][21]. Moreover, the hydrolysis reaction of EVA by dielectric heating causes little reduction in molecular weight [22], thus reducing phase segregation between EVA and EVA-h.…”

Durability of nanosized oxygen-barrier coatings on polymers

“…Liquid-crystalline polymers also offer very low oxygen permeabilities, but suffer from their high price [37]. Multilayer films based on linear low-density polyethylene grafted maleic anhydride (LLDPE-gMA), coextruded with polyamide (PA) [38], and tailored blends, such as reactive blends of ternary blends composed of poly (vinyl-alcohol)/polyamide 6/poly(ethylene-co-ethyl acrylate) (PVOH/PA6/PEEA) [39], or blends possessing a process-induced laminar morphology [40,41] are devel- a Depends on crystallinity, orientation, and water vapor in case of polyamides [307]. b Depends on ethylene content.…”

Effect of phase morphology and interfacial strength on barrier properties of high density polyethylene/polyamide 6 membranes

“…However, the disadvantages of the method for improving barrier properties only by increasing pathway of small molecules passing through material are obvious. First, the formation of stable two‐dimensional sheets as dispersed phase in polymer blends closely relates to several basic parameters including composition, viscosity ratio, interfacial tension, and processing conditions and is hard to be controlled in practical processing [9–12]. Second, both barrier and resistance properties to polar and nonpolar molecules cannot be simultaneously improved.…”