Polyethylene foam

Various geometric coring patterns ki polyurethanes (171,175) and ki latex foam mbber (176) exert significant influences on thek compressive behavior. A good discussion of the effect of cell size and shape on the properties of flexible foams is contained ki References 60 and 156. The effect of open-ceU content is demonstrated ki polyethylene foam (173). 

The clean, durable, nondust-forrning character of polyethylene foam has led to its acceptance in packaging missile parts (230). Polyethylene foam sheet has also displaced polystyrene foam sheet for packaging glass bottles and containers because of its greater resUiency and tear resistance. 

Economics. Rigid foam systems are typically in the range of 32 kg/m (2 Ibs/fT) and, in 1992, had a foam price of about 3.63/kg ( 1.65 per lb) with hquid foam systems at about 2.75/kg. Unit prices for pour-ia-place polyurethane packaging systems fall between the competitive expandable polystyrene bead foam at 3.30/kg and low density polyethylene foams at 5.80/kg. 

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. 

The Hst price of 35 kg/m polyethylene foam boards is about 0.58/BE ( 6.90/kg) and that of cross-linked polyethylene foam is about 0.33 to 0.88/kg more expensive than uncross-linked polyethylene foam depending on the density and thickness of the foam. 

There has been interest, particularly in Japan, in the production of cross-linked low-density polyethylene foam. Some processes, such as the Furukawa process and the Hitachi process, use chemical cross-linking techniques whilst others, such as the Sekisui process, involve radiation cross-linking. 

Example 2.9 A solid polyethylene beam is 10 mm thick and IS mm wide. If it is to be replaced with a sandwich section with solid polyethylene in the two outer skins and polyethylene foam (density = 200 kg/m ) in the centre, calculate the dimensions of the sandwich beam if it is to have optimum stiffness at the same weight as the solid beam. If the foam material costs 20% more than the solid material, calculate the increase or decrease in cost of the sandwich beam. 

Difluorochloro-ethane (CH5CCIF2) An effective replacement for CFC-12 in rigid polyurethane, polystyrene, and polyethylene foam insulation applications. Uses include both residential and commercial construction and process piping. 

Swell Ratio Parameter for Prediction of Chemically Crosslinked Low Density Polyethylene Foam Expansion Characteristics... 

Polystyrene and polyurethane (thermoset) foams dominate the market, with PVC and polyethylene foams accounting for less than 1%. 

Table 4.4 Examples of some polyethylene foam properties...

Generally, the properties of polyethylene foams for sandwich technology are ... 

Cell Polyethylene Foam, University of Twente, Netherlands, 2000 (www.ub.utwente.nl/ webdocs/ct/1/tOOOOOlc.pdf). [Ph.D. Thesis]... 

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

Brookfield, Ct., 2002, Session IV, p. 103-12, 27cm, 012 POLYETHYLENE FOAM RESIN OUTLOOK Harden W... 

Brookfield, Ct., SPE, 2002, Paper 192, Session M38-Rotational Molding Materials, pp.5, CD-ROM, 012 INVESTIGATION OF THE PROCESSING CHARACTERISTICS AND MECHANICAL PROPERTIES OF METALLOCENE POLYETHYLENE FOAMS FOR ROTATIONAL MOULDING... 

EFFECT OF CELL SIZE ON THE PHYSICAL PROPERTIES OF CROSSLINKED CLOSED CELL POLYETHYLENE FOAMS PRODUCED BY A HIGH PRESSURE NITROGEN SOLUTION PROCESS... 

THE USE OF POLYFUNCTIONAL MONOMERS IN COMPRESSION-MOULDED LOW-DENSITY POLYETHYLENE FOAM FORMULATIONS... 

Journal of Cellular Plastics 37, No. 1, Jan. 2001,p.21-42 THERMAL CONDUCTIVITY OF A POLYETHYLENE FOAM BLOCK PRODUCED BY A COMPRESSION MOULDING PROCESS Martinez-Diez J A Rodriguez-Perez M A De Saja J A Arcos y Rabago L O Almanza O A... 

COMPRESSION MODULUS OF OPEN-CELLED POLYETHYLENE FOAM... 

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... 

A textured metallocene polyethylene foam sheet suitable for use in a floor covering is made using a highly coactivated azodicarbonamide package which blows the metallocene polyethylene effectively. The preferred coactivators are zinc oxide and urea. The textured surface of metallocene polyethylene foam is formed by a chemical embossing process which utilises a liquid triazole having an alkyl moiety as a foam-expansion inhibitor. The triazole is dissolved in a non-polar solvent to form the foam inhibitor. The preferred inhibitor is a hydrocarbon which may be halogenated. 

Advances in Polymer Technology 20, No.2, Summer 2001, p.108-15 ROTATIONAL MOULDING OF TWO-LAYERED POLYETHYLENE FOAMS... 

Houston, Tx., 27th Feb.-lst March 2000, p.449-56 THIN GAUGE POLYETHYLENE FOAM EXTRUSION Sreenath G K... 

POLYETHYLENE FOAM WASTE UTILISATION FOR LIGHTWEIGHT CONCRETE PRODUCTION... 

Orlando, El., 7th-11th May, 2000, paper 268 ROTATIONAL MOLDING OF POLYETHYLENE FOAM BY PELLETS... 

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