High-Density Polyethylene Foams

EFFECT OF MOLECULAR WEIGHT ON MECHANICAL AND MORPHOLOGICAL PROPERTIES OF HIGH DENSITY POLYETHYLENE FOAMS... 

The thermal conductivity of a section of a commercially produced high density polyethylene foam channel was measured. The walls consisted of a 6.4 mm foam core with a skin of 1.6 mm thickness on either side. Sqnares were machined from the outer surface of the channel, so that heat flow throngh the entire thickness the core pins one skin layer and the complete section conld be... 

MULTIPLE-IMPACT PERFORMANCE OF HIGH-DENSITY POLYETHYLENE FOAM... 

High-Density Polyethylene Foams These foams are defined by the specific gravity (ca. 0.96 g/cc) and melt index of the basic resin. They have been used extensively in the U.S. and Europe, particularly for materials-handling applications, such as boxes, crates, and pallets because, imtil recently, they were much cheaper than polypropylene (13). 

Cell Flake, Pigment flakes, Eckart America LP Cellu-Cushion, High-density polyethylene foam. Sealed Air Corp. 

Lee JWS, Park CB. Use of nitrogen as a blowing agent for the production of fine-celled high-density polyethylene foams. Macromol Mater Eng 2006 291 1233-44. 

Zhang Y., Rodrigue D., Ait-Kadi A., High Density Polyethylene Foams. IV. Flexural and Tensile Moduli of Structural Foams, Journal of Applied Polymer Science, 90 (8) 2139-2149 (2003). 

Structural Components. In most appHcations stmctural foam parts are used as direct replacements for wood, metals, or soHd plastics and find wide acceptance in appHances, automobUes, furniture, materials-handling equipment, and in constmction. Use in the huil ding and constmction industry account for more than one-half of the total volume of stmctural foam appHcations. High impact polystyrene is the most widely used stmctural foam, foUowed by polypropylene, high density polyethylene, and poly(vinyl chloride). The constmction industry offers the greatest growth potential for ceUular plastics. 

There are three basic types of polyethylene foams of importance (/) extmded foams from low density polyethylene (LPDE) (2) foam products from high density polyethylene (HDPE) and (J) cross-linked polyethylene foams. Other polyolefin foams have an insignificant volume as compared to polyethylene foams and most of their uses are as resia extenders. 

Patent Number US 5916926 A 19990629 FOAMED HIGH DENSITY POLYETHYLENE... 

Crosslinked low-density polyethylene foams with a closedcell structure were investigated using differential scanning calorimetry, scanning electron microscopy, density, and thermal expansion measurements. At room temperature, the coefficient of thermal expansion decreased as the density increased. This was attributed to the influence of gas expansion within the cells. At a given material density, the expansion increased as the cell size became smaller. At higher temperatures, the relationship between thermal expansion and density was more complex, due to physical transitions in the matrix polymer. Materials with high density and thick cell walls were concluded to be the best for low expansion applications. 16 refs. 

Focusing collectors are usually cast acrylic Fresnel lenses, or mirrors of aluminized polyester film in frames of aluminum. These reflectors are either enclosed in a bubble of poly(vinyl fluoride) film, or under polycarbonate glazing, which may be covered with a fluorocarbon film to reduce the reflectivity. The absorbers for active systems are copper or aluminum since the temperatures are too high (325—370°C) for plastics. The frames, however, can be molded ABS, high density polyethylene or polyurethane, either solid or structural foam. Polybutylene or chlorinated PVC can be used for piping hot water, and tanks can be made of either reinforced polyester or blow- or rotational-molded, high density polyethylene (12—15). 

Doroudiani S, Park CB, Kortschot MT (1998) Processing and characterization of micro-cellular foamed high-density polyethylene/isotactic polypropylene blends. Polym Eng Sci 38 1205-1215... 

Thermoformed high density polyethylene (PE) and low density PE foams that can be molded into a variety of complex shapes are being increasingly used in supporting devices in the treatment of orthopaedic and disabling conditions. Some examples are wheelchair seats, spinal jackets, medical shoe inserts, and splint supports. 

The relationship between chemical structures and their physical performance is one of the central topics of polymer physics. lUPAC has recommended a whole set of names to describe the detailed chemical structures of polymer chains and their derivatives. However, in our daily communication, people prefer to use the popular names of polymers reflecting their characteristic physical performances, such as high-density polyethylene (HOPE), foamed polystyrene, thermoplastic elastomers, liquid crystal polymers, conductive polymers, and polyelectrolyte. Such terminology allows us to comprehend quickly the basic characteristics of chemical structures responsible for their specific physical properties. 

High-density polyethylene is currently used in netting applications for tree protection and oyster farming also HDPE, PP, and polystyrene (PS) foams are used in making packaging crates for vegetable/ffuit transportation. 

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