Polyethylene film properties

Poly(ethylene-co-propylene), 24 703 Polyethylene fabrics, flashspun high density, 17 466 Polyethylene fibers, 26 761 high performance, 13 382 Polyethylene film, properties of,... 

Examples of polyethylene film properties Property guide for thermoset plastics Elastomer names... 

The film tube is collapsed within a V-shaped frame of rollers and is nipped at the end of the frame to trap the air within the bubble. The nip roUs also draw the film away from the die. The draw rate is controlled to balance the physical properties with the transverse properties achieved by the blow draw ratio. The tube may be wound as such or may be sHt and wound as a single-film layer onto one or more roUs. The tube may also be direcdy processed into bags. The blown film method is used principally to produce polyethylene film. It has occasionally been used for polypropylene, poly(ethylene terephthalate), vinyls, nylon, and other polymers. 

Linear Low Density Polyethylene. Films from linear low density polyethylene (LLDPE) resias have 75% higher tensile strength, 50% higher elongation-to-break strength, and a slightly higher but broader heat-seal initiation temperature than do films from LDPE. Impact and puncture resistance are also improved over LDPE. Water-vapor and gas-permeation properties are similar to those of LDPE films. 

Table 17. Physical Properties of a Multilayer Barrier Film and a Polyethylene Film ...

Considerable amounts of polyethylene film are produced using coaxial extrusion processes in which two or more melt streams are combined in the die to produce extruded film of two or more layers of plastics materials. Layers in such a composite may be included, for example, to improve barrier properties, to enhance sealability or even simply to act as an adhesive between dissimilar layers. 

Andrew Peacock is a Development Associate with Tredegar Film Products, Richmond, Virginia. Previously he worked as a Senior Research Chemist with Exxon Chemical Company, Baytown, Texas. Publications include the Handbook of Polyethylene - Structures, Properties and Applications , nine patents in the field of polymer science, and numerous journal articles. Dr. Peacock received a B. Sc. in Chemistry from the University of London, England, an M. Sc. in Polymer Science and Technology from Lancaster University, England and a Ph. D. in Chemistry from the University of Southampton, England. 

Cellular Polymers 111. Conference proceedings. Coventry, 27th-28th April 1995, paper 14. 6124 INFLUENCE OF LOW MOLECULAR ADDITIVES ON GAS TRANSPORT PROPERTIES IN POLYETHYLENE FILMS AND FOAMS... 

Some of the commonly used techniques for measuring contact angle [215, 216, 217] are the sessile drop method, captive bubble method and Wilhelmy plate method. These techniques have been extensively used and well documented for characterisation of modified PE surfaces [218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230] for various applications. Whitesides et al. [231 ] studied the wetting of flame-treated polyethylene film having ionisable organic acids and bases at the polymer-water interface. The effect of the size of substituted alkyl groups in amide and ester moieties on the surface hydrophilicity was also studied [232]. The biocompatibility of the polyethylene film surface modified with various water-soluble polymers was evaluated using the same technique [233]. The surface properties of hy-perbranched polymers have been very recently reported [234]. 

Table 2.18 also demonstrates that permeability properties are dependent on the degree of crystallinity. Figure 2.62 presents the permeability of polyethylene films of different densities as a function of temperature. Again, the Arrhenius relation becomes evident. 

Probably the most widely reported information concerning petrolatum s effect on damaged skin was a 1992 article by Ghadially and coworkers.71 Newspapers across the United States reported the results of this study, which showed that, when applied to skin that had been damaged by acetone, petrolatum accelerated the recovery of the skin s normal barrier properties. It was noted that this is in contrast to materials that are highly impermeable to water vapor (such as polyethylene films) which hinder barrier repair. However, another publication has indicated that the repair of the permeability barrier in human skin is not delayed by occlusion.72... 

Cotton has mechanical properties superior to paper and has been used in a similar way by Lebl.P Polystyrene-grafted polyethylene film has also been used by researchers from Rockefeller University.P l Researchers from Pfizer used material prepared from resin sandwiched in between two sheets of polypropylene mesh.P The sandwich was fused together with a polymer with a low melting point. 

Stratum Corneum Structure. Reviewers agree that for most compounds the rate-limiting barrier properties of skin are located within the SC (2, 10, 12, 15, 16, 21), The texture and cohesiveness of this tissue are familiar to anyone who has ever peeled bits of it from sunburned skin large sheets of SC can be separated from skin (2). Such sheets look like used polyethylene film, and their resistance to water diffusion approximates that of Mylar film of similar thickness (16). However, each sheet is a mosaic made of individual cells (2). 

See also Kuijk et al [46], who showed that the stress at the freeze line is the key morphological parameter in determining the mechanical properties of blown polyethylene films. 

Antimicrobial Edible films were prepared from natural fiber of pectin and other food hydrocolloids for food packaging or wrapping by extrusion followed by compression or blown film method. Microscopic analysis revealed a well mixed integrated structure of extruded pellets and an even distribution of the synthetic hydrocolloid in the biopolymers. The resultant composite films possess the mechanical properties that are comparable to films cast from most natural hydrocolloids that consumed as foods or components in processed foods. The inclusion of polyethylene oxide) alters the textures of the resultant composite films and therefore, demonstrating a new technique for the modification of film properties. The composite films were produced in mild processing conditions, thus, the films are able to protect the bioactivity of the incorporated nisin, as shown by the inhibition of Listeria monocytogenes bacterial growth by a liquid incubation method. 

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