High density polyethylene barrier properties

Surface fluorination changes the polymer surface drastically, the most commercially significant use of polymer surface direct fluorination is the creation of barriers against hydrocarbon permeation. The effectiveness of such barriers is enormous, with reductions in permeation rates of two orders of magnitude. Applications that exploit the enhanced barrier properties of surface-fluorinated polymers include (1) Polymer containers, e.g., gas tanks in cars and trucks, which are produced mostly from high-density polyethylene, where surface fluorination is used to decrease the permeation of fuel to the atmosphere and perfume bottles. (2) Polymeric membranes, to improve selectivity commercial production of surface-fluorinated membranes has already started.13... 

The MDPE and HDPE resins were developed to address formulator s needs when an LDPE resin was not adequate on the basis of parameters such as weight loss, adsorption, or additional package rigidity is required. The MDPE resins provide intermediate properties between low- and high-density polyethylene, where more rigidity than LDPE and less rigidity than HDPE are required. The HDPE resins are of a natural milky color with much better barrier properties than LDPE and MDPE. 

Oriented LCP layers can be coextruded with other thermoplastics, such as polyethylene terephthalate, nylon, polycarbonate, and high-density polyethylene. The primary benefit of the LCP layer is to improve the barrier properties of the container. For example, using an LCP layer comprising 5% of the wall thickness of a container along with PET and tie layer in the other 95% will increase the oxygen barrier by more than 20 times compared with a pure PET... 

High density polyethylene film contains a nucleating agent. The film has a 15% improvement in the water vapor and oxygen barrier property. The nucleating agent is a zinc glycerolate. ... 

High density polyethylene (HDPE) has balanced mechanical properties with good chemical resistance. It has better barrier properties against gases and vapors. It is also harder and stiffen The structure of HDPE is described as semi-crystalline [31]. LDPE is soft and flexible [32,33]. High density polyethylene has been identified as a primary material for solid waste minimization and recycling in blow molding. 

Low haze is generally desirable from a packaging standpoint, because it permits a clear view of the contents. However, film strength is compromised when more transparent low density polyethylene resins are used in preference to high density polyethylene in addition, the barrier properties are inferior. A compromise must therefore be found between optical and mechanical properties. 

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