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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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Methanolysis:
An advanced recycling process where methanol is introduced to PET or other polyester-based material in a chemical processing plant. The polyester is broken down into its basic molecules, including dimethyl terephthalate and ethylene glycol. These precursors are then re-polymerized into purified raw resin. (Modern Plastics Encyclopedia 1995).
Materials Recovery Facility (MRF):
A facility that receives materials in a form unacceptable by the marketplace. The MRF separates, removes contamination, sorts, densifies, and stores recyclable material types. Each material is prepared to meet the requirements of a specific market. MRFs are generally considered handlers. (Waste Reduction Strategies for Rural Communities, prepared by the MaCC Group, with support from Tennessee Valley Authority, March 1994).
Monomer:
A relatively simple compound that can react to form a polymer (i.e., polymerize). (Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., edited by Michael L. Berins).
Municipal Solid Waste (MSW):
A phrase for garbage generated from residential, commercial, institutional and industrial sources that falls into six basic categories-durable goods, non-durable goods, containers and packaging, food wastes, yard trimmings and miscellaneous organic and inorganic wastes. Wastes from these categories include appliances, newspapers, clothing, food scraps, boxes, disposable tableware, office and classroom paper, wood pallets and cafeteria wastes. (Characterization of Municipal Solid Waste in the United States: 1994 Update, prepared for U.S. EPA Municipal and Industrial Solid Waste Division Office of Solid Waste, November 1994).
Macromolecule
A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of a number of constitutional units
Macromonomer
A monomer which is a polymer of an oligomer
Melt flow rate (MFR)
Melt mass flow rate or melt flow rate (MFR) gives an indication of melt processing properties of a polymer. Shear rate range is, however, narrow and much lower than in the most of processing applications. It gives thus very limited information about melt flow behaviour. The method is a kind of capillary measurement.
The equipment consists of a barrel, a piston with a place for loading masses and a die. The sample is charged into the barrel and heated up to a specified temperature. After that the piston is loaded extruding the polymer through the die.
Melt flow rate (MFR) is defined as a mass flown through the die in 10 min. The weights mostly used with polyolefins are 2.16 kg, 5 kg, 10 kg and 21.6 kg. In addition to the evaluation of flow properties MFR serves as a rough estimation of molecular weight.
Usually also Flow Rate Ratio (FRR) is determined. This ia defined as a ratio of two MFR values obtained with two different weights. FRR can be used as a rough estimation of molecular weight distribution.
Metallocene
A catalyst which contains a metallocene compound of a transition metal. Often used as a synonym for single site.
Molecular Weight Distribution
The relation between the number of molecules in a polymer and their individual chain length. It is often also called molar mass distribution (MMD). Technical polymers are always polydisperse as a result of the nature of the catalyst and the polymerisation conditions. The MWD is often characterised by size exclusion chromatography (SEC), but it can also be calculated approximately from rheological data for purely linear polymers.
Morphology
Morphology is the internal or external structure of a solid substance. Important sub-definitions include
- Crystal morphology of a polymer film or part
- Phase morphology of heterophasic polymer systems (blend, copolymer)
- Powder morphology of a polymer powder from the polymerisation reactor.
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