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Handler:
An organization that prepares recyclable plastics by
sorting, densifying and/or storing the material until
a sufficient quantity is on hand. When the handler completes
processing, the material is not ready to be manufactured
into a new product, but it has been made more valuable.
(Waste Reduction Strategies for Rural Communities, prepared
by the MaCC Group, with support from Tennessee Valley
Authority, March 1994).
Hauler:
A company that transports post-consumer plastic and
other materials to a handler or other processor. (Stretch
Wrap Recycling: A How-To Guide, APC, 1994).
High Density
Polyethylene (HDPE):
HDPE refers to a plastic used to make bottles for milk,
juice, water and laundry products. Unpigmented HDPE
bottles are translucent and have good barrier properties
and stiffness. They are well suited to packaging products
with short shelf lives such as milk. Pigmented HDPE
bottles generally have better stress crack and chemical
resistance than bottles made with unpigmented HDPE.
These properties are needed for packaging such items
as household chemicals and detergents, which have a
longer shelf life. Injection-molded HDPE is resistant
to warpage and distortion. It is used for products such
as margarine tubs and yogurt containers. (Plastic Packaging
Opportunities and Challenges, APC, February 1992).
Hardness
Resistance of a (polymer) surface to deformation. The
different hardness measures applied for characterising
polymers are:
(a) Shore hardness (two scales, A for softer and D for
harder materials)
(b) Ball indentation hardness (also useable on profiled
surfaces because of bigger measuring device).
Heat deflection temperature
(HDT)
Heat deflection temperature (HDT) indicates how loaded
material deforms at higher temperatures. Test bars are
placed in a heating bath, resting horizontally on two
supports. A constant load is applied in the center of
the specimen and the bath temperature is raised at a
constant rate. The temperature of the bath at which
the flexural deflection of the loading point has reached
a predefined level is the heat deflection temperature
of the material.
Heterophasic copolymers
Heterophasic copolymers also contain ethylene (and possibly
higher a-olefins) as comonomer. The production is however
carried out in a two-stage process, resulting in a multiphase
structure with a homopolymer matrix and inclusions consisting
of amorphous EP-copolymer and crystalline PE. Variations
of molar mass and composition of the elastomeric phase
in relation to the matrix allow a wide variation of
properties (stiffness, toughness and transparency).
Heveaplus MG
Trade name for a natural rubber methyl methacrylate
graft copolymer, obtained by polymerisation of methyl
methacrylate in the presence of a natural rubber latex.
Typically contains 30-50% methyl methacrylate, which
confers increased modulus and the ability to stick two
unlike surfaces together.
High density polyethylene
(HDPE)
Coming from a low pressure process based on special
catalysts (Ti- or Cr-based), HDPE has a linear polymeric
chain, combined with a higher density and melting point.
To fit special applications, the molar mass distribution
can be adjusted in a wide range by means of catalysts
or polymerisation technology. New applications are opened
for HDPE as well as other low pressure PEs by applying
metallocene (single-site) catalysts, which allow the
production of very narrow molar mass distributions and
the better distribution of comonomers.
Homopolymers
Homopolymers (HOMO) consist only of one monomer units;
their properties can be regulated via molar mass distribution
and the degree of isotacticity (stereoregular structure).
Hydrocarbon
An organic compound that consists exclusively of the
elements carbon and hydrogen. Generally, the term hydrocarbon
is used for the chemicals that are derived from natural
gas, oil and coal.
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Plastic
Brief
