Preparation And Characteristic Of The Poly(Vinyl Alcohol-co-ethylene)/Montmorillonite-phosphoryla Ted Soybean Protein Isolate Barriefrlm

Poly (vinyl alcohol-co-ethylene) (EVOH) is one of the highly impermeable polymers to oxygen. It has been commercially used in various multilayered packaging films as an oxygen barrier. However, in the presence of moisture, the interactions among H2O molecules and -OH groups of EVOH may result in a plasticization of the chains of EVOH, which will lead to an increase in the permeability of oxygen. The present work developed a novel poly (vinyl alcohol-co-ethylene)/montmorillonite-phosphorylated soybean isolate protein (EVOH/MMT-PSPI) nanocomposite barrier film via two-step mixing process and solution casting, and estimated its properties towards food packaging.PSPI was first used as an intercalating agent to achieve the highly intercalated MMT-PSPI nanocomposites. Then MMT-PSPI was combined with EVOH to get the EVOH/MMT-PSPI barrier film. The structure of barrier film the was proposed and confirmed. The structure of MMT-PSPI was associated the level of MMT loadings. An appropriate incorporation of MMT-PSPI resulted in a remarkable enhancement in mechanical (tensile strength/Young’s modulus) and barrier properties of the EVOH/MMT-PSPI films. In comparison with neat EVOH film, an incorporation of MMT-PSPI at 3 wt% could improve the oxygen and water vapor barrier properties of the nanocomposite films by 73.5 ± 3.1% and 61.3 ± 4.1%, respectively, meanwhile, tensile strength and Young’s modulus reached 48.2±2.4 MPa and 192.4±4.2 MPa, elongation at break still kept high at 225± 9.25% and the light transmittance of the films changed unobvious. However, excess MMT-PSPI loadings gave rise to a reduction in those packing properties due to the aggregation of MMT. Additionally, the intercalated MMT nanoplatelets from MMT-PSPI in the EVOH matrix could significantly suppress the moisture-derived deterioration in the oxygen barrier property.