|
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
(a)Crystal morphology of a polymer film or part
(b)Phase morphology of heterophasic polymer systems
(blend, copolymer)
(c) Powder morphology of a polymer powder from the polymerisation
reactor.
|
Plastic
Brief
