Oxygen barrier property

Of the common commercial resias and films, PVDC has the best water-vapor and oxygen-barrier properties. High crystallinity confers resistance to the permeation of odors and flavors, as weU as to fat and oil. Because of its high chloride content, PVDC tends to corrode processing equipment, which increases manufacturing costs. Unlike other high oxygen-barrier materials, PVDC is almost insensitive to water and water vapor. 

The excellent chemical resistance and physical properties of PVA resins have resulted in broad industrial use. The polymer is an excellent adhesive and possesses solvent-, oil-, and grease-resistant properties matched by few other polymers. Poly(vinyl alcohol) films exhibit high tensile strength, abrasion resistance, and oxygen barrier properties which, under dry conditions, are superior to those of any other known polymer. The polymer s low surface tension provides for excellent emulsification and protective coUoid properties. 

Crystallization and Melting Point. The abihty of PVA to crystallize is the single most important physical property of PVA as it controls water solubiUty, water sensitivity, tensile strength, oxygen barrier properties, and thermoplastic properties. Thus, this feature has been and continues to be a focal point of academic and industrial research (9—50). The degree of crystallinity as measured by x-ray diffraction can be directly correlated to the density of the material or the swelling characteristic of the insoluble part (Fig. 2). 

Gas-Barrier Properties. The oxygen-barrier properties of PVA at low humidity ate the best of any synthetic resin. However, barrier performance deteriorates above 60% th (Fig. 9). No additives or chemical modifiers are known that can effectively reduce moisture sensitivity. The gas-barrier performance is affected by the degree of hydrolysis and rapidly diminishes as the hydrolysis is decreased below 98%. 

Due to these practical aims, membranes with low oxygen permeability have been developed. Some of them are PVA, PVA blends or their derivative membranes, due to the PVA excellent oxygen barrier properties [18],... 

The ability of PVA to crystallize is the single most important physical properly of PVA as it controls water solubility, wrier sensitivity, tensile strength, oxygen barrier properties, and thermoplastic properties. 

The oxygen-barrier properties of PVA at low humidity are the best of any synthetic resin. However, barrier performance deteriorates above 60% rh,... 

Nodax C4/C6 is said to be a natural fit for injection moulding and extrusion of sheet or film. The polymer has mechanical properties similar to a polyolefin and surface properties much like PET, including high receptivity to printing inks and dyes. Adhesion to LDPE and PP is good enough to avoid tie layers in multi-layer structures. Nodax s oxygen barrier property approaches that of EVOH. 

Collagen films formed by reticulations of amine and carboxyl groups gelatin-based films flexible, clear, widi good oxygen barrier properties, but poor moisture resistance classical formulations 20-30% gelatin, 10-30% plasticizer mid water. 

This specialist monomer (diacid) is used in various concentrations to increase the Tg of the polyester or to increase its oxygen barrier properties. The stiffness of the naphthalene (two benzene rings) reinforces the backbone of the polyester and inhibits bending at lower temperatures it also increases the pathway for oxygen molecules and hence provides an increased gas, parhcularly oxygen, barrier. A fairly new and naturally expensive monomer to manufacture, in the United States it is approved for use for some applications by 21 CFR 177.1637 and for others via the FDA premarket notification system and is... 

MAJOR. ADVANTAGES heat reflectivity, low emissivity, temperatme resistance, moisture and oxygen barrier properties, sealing properties, reinforcement... 

Nylons have relatively high melting points and can be steam autoclaved. Nylons can be injection moulded, blow moulded or made into sheet or film, and have a density range of 1.14—1.16. Multi-ply materials are employed for their oxygen barrier properties. 

Selar PA, poly(hexamethylene isophthalamide/terephthalamide) or 6-I/T (the diamine components are listed first, then the diacid components), is an amorphous polyamide which is marketed by Du Pont. As shown in Figure 1, it has unique properties for a barrier resin in that the oxygen barrier properties actually... 

PARA with semicrystalline PA improved oxygen barrier properties Dynamit Nobel, 1969... 

To improve the oxygen barrier properties of PA-6 (and PA-66), high T barrier type amorphous polyamides such as PA-6I/6T (Selar PA) have been blended [JCrizan et al., 1989 Blatz,... 

Poly(ethylene-CO-vinyl alcohol) is a thermoplastic used extensively in laminates for food containers due to its excellent film forming and oxygen barrier properties. Limited evidence for the disappearance of the polymer was provided [93]. Whether or not the copolymer is biodegradable is apparently related to the size and distribution of the ethylene blocks. 

Modest levels of IPA slow down crystallization and raise the oxygen-barrier properties. Higher levels of IPA break up crystallinity and lead to amorphous copolyesters with good barrier properties. On the other hand, these copolyesters, show poor impact and other mechanical properties. However, modest levels of CHDM slow down crystallization and decrease oxygen-barrier properties. 

A. Polyakova, D. M. Connor, D. M. Collard, D. A. Schiraldi, A. Hiltner, and E. Baer. Oxygen-barrier properties of polyethylene terephthalate modified with a small amount of aromatic comonomer. J. Polym. Sci., Part B Polym. Phys., 39(16) 1900-1910, August 2001. 

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