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| Glossary |
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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
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End Product:
A fabricated value-added item that does not include Bales, flake or pellets. (1995 post-consumer plastic Plastics Recycling/Recovery Rate Survey, Glossary of Terms, R.W. Beck & Associates).
Endocrine:
For more information on the theory of endocrine disruption go to the Canadian Chemical Producers Association, the Chemical Manufacturers Association, the Chlorine Chemistry Council or the Bisphenol-A Web Site sponsored by the Global Bisphenol-A Industry Group of The Society of the Plastics Industry, Inc. and the European Chemical Industry Council (CEFIC).
Energy Recovery:
The process of recovering the thermal energy produced when fuels are converted to gases and residues through the combustion process. The thermal energy generally is recovered through the use of heat exchangers that extract the energy from the hot combustion gases. Heat exchangers can be air to air units similar to those used in residential or commercial hot air heating systems or air to water/steam units (boilers) that can be designed to generate either hot water or steam, similar to residential and commercial hot water and steam generation heating systems. Large electric power production facilities, including modern waste-to-energy plants, that supply needed power to our homes, hospitals and factories, maximize thermal energy recovery efficiency through the utilization of high temperature, high pressure steam generating boilers that recover both the radiant energy from the combustion process inside the furnace as well as the energy in the hot combustion gases. The high heating value of plastics makes them a valuable source of energy that can be readily recovered in modern waste-to-energy plants. (Tchobanoglous, George, Hilary Theisen and Rolf Eliassen, "Solid Wastes, Engineering Principles and Management Issues," McGraw-Hill, Inc., New York, 1977; Gershman, Brickner & Bratton, Inc., "Small-Scale Municipal Solid Waste Energy Recovery Systems," Van Nostrand Reinhold Company, New York, 1986).
Environmental Marketing Guidelines:
U.S. Federal Trade Commission (FTC) Guides for the Use of Environmental Marketing Claims, issued in July, 1992, are voluntary guidelines for product manufacturers using environmental advertising and marketing. They are intended to help prevent misleading environmental marketing claims. (Environmental Packaging; U.S. Guide to Green Labeling, Packaging and Recycling. Thompson Publishing Group, October 1995).
Extrusion:
One of the most common plastics processing techniques covering a vast range of applications in which resins are melted, heated and pumped for processing. Extrusion machines accomplish these tasks by means of one or more internal screws. In extrusion, the material to be processed is sheared between the root of the screw and the wall of the barrel that surround it. This process produces frictional energy that heats and melts the substance as it is conveyed down the barrel. Melted extrudate from the machine is further processed after the extrusion phase, which typically produces pellets, sheet, cast film, blown film, fibers, coatings, pipes, profiles or molded parts. (Modern Plastics Encyclopedia 1995)
Elastomer
A polymer with the properties of rubber. Polymers that can be formulated as elastomers are polyurethane, butyl rubber, silicones and specially treated ethylene-propylene copolymers.
End-group
A constitutional unit with only one attachment to a chain
Environmental stress cracking
Under certain conditions of stress and environment like oils, detergents or soaps, ethylene plastics may fail mechanically by cracking. This phenomenon is called environmental stress cracking resistance (ESCR). ESCR properties can be tested in accelerated tests by presence of starter notches, surface active agent, elevated temperature and mechanical loading. Test result is the time when 50 % of the samples have failed.
Expanded polymer
Alternative name for cellular polymer, but the term is often restricted to those cases where the material has been produced by allowing a gas to expand within a polymer melt and then cololing the melt, thus trapping the gas bubbles in the now solid polymer. The gas is produced either by the injection under pressure or by the chemical decomposition, usually induced by the high temperatures of melt processing of a blowing agent.
Extruder
Equipment for melting, pressurising and homogenising plastics by means of a rotating screw. Different configurations are possible; the most simple one being a single screw extruder mainly used for conversion processes like cast film extrusion, fibre spinning, film blowing or pipe and profile extrusion. For more demanding applications like compounding of polymer powder before pelletization or the mixing of polymers, twin screw extruders are used where the two normally intermeshing screws can be moved in a corotating (same direction) or counterrotating (opposite direction) fashion. These machines normally contain different mixing elements, most important being kneading blocks for the local creation of extensional flow. |
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