Polyurethane (PUR) Foams
10/20/2008
“One of the most desirable
attributes of polyurethanes is their ability to be turned into foam. Blowing
agents such as water, certain halocarbons such as HFC-245fa
(1,1,1,3,3-pentafluoropropane) and HFC-134a (1,1,1,2-tetrafluoroethane), and
hydrocarbons such as n-pentane, can be incorporated into the poly side or added
as an auxiliary stream. Water reacts with the isocyanate to create carbon
dioxide gas, which fills and expands cells created during the mixing process.
The reaction is a three step process. A water molecule reacts with an isocyanate
group to form a carbamic acid. Carbamic acids are unstable, and decompose
forming carbon dioxide and an amine. The amine reacts with more isocyanate to
give a substituted urea. Water has a very low molecular weight, so even though
the weight percent of water may be small, the molar proportion of water may be
high and considerable amounts of urea produced. The urea is not very soluble in
the reaction mixture and tends to form separate "hard segment" phases consisting
mostly of polyurea. The concentration and organization of these polyurea phases
can have a significant impact on the properties of the polyurethane foam.
Halocarbons and hydrocarbons are chosen such that they have boiling
points at or near room temperature. Since the polymerization reaction is
exothermic, these blowing agents volatilize into a gas during the reaction
process. They fill and expand the cellular polymer matrix, creating a foam. It
is important to know that the blowing gas does not create the cells of a foam.
Rather, foam cells are a result of blowing gas diffusing into bubbles that are
nucleated or stirred into the system at the time of mixing. In fact, high
density microcellular foams can be formed without the addition of blowing agents
by mechanically frothing or nucleating the polyol component prior to use.”
Wikipedia:
http://en.wikipedia.org/wiki/Polyurethane (11/18/2008)
Warning: Sometimes the older links no longer work. Go to the US Patent number search page, copy the Patent number into the search box and search. For the articles, use your browser to go the Journal site.
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Notes
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Review Articles
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US Patents
12/2/2008
7,459,488
Composition and process for recovery of spilled hydrocarbons from aqueous
environments
7,459,107
Two-pack urethane foam composition, and two-pack urethane foam composition
injecting apparatus and method
11/25/2008
7,456,229
Process for the production of rigid and semi-rigid foams with low amounts of
diisocyanate using polymer polyols characterized by high solids and a high
hydroxyl number and the resultant foams
7,455,799
Method of producing polishing pad-use polyurethane foam and polyurethane foam
7,455,446
Co-injection mixing method and apparatus
10/7/2008
7,432,312
Polyurethane foam having deodorization property or antibacterial effect
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Journal Articles
2/13/209
Selective elimination of lead(II) ions by alginate/polyurethane composite
foams
(423-429)
Journal of Hazardous Materials 162 #1 (2009)
11/21/2008
Thermal and mechanical behavior of flexible
polyurethane-molded plastic films and water-blown foams with epoxidized soybean
oil
(p 1311-1317)
Journal of Applied Polymer Science 111 #3 (2009)
Abstract
Evaluation of flexible postconsumed polyurethane
foams modified by polystyrene grafting as sorbent material for oil spills
(p 1842-1849)
Journal of Applied Polymer Science 111 #4 (2009)
Abstract
11/7/2008
Polyurethane scaffold formation via a combination
of salt leaching and thermally induced phase separation
(p 921-932)
Journal of Biomedical Materials Research 87A #4 (2008)
Abstract
Flexible Polyurethane Foam with the Flame-retardant
Melamine
(469-480)
Journal of Cellular Plastics 44 #6 (2008)
[Abstract]
A Simple Transient Method for Measurement of Thermal
Conductivity of Rigid Polyurethane Foams
(481-491)
Journal of Cellular Plastics 44 #6 (2008)
[Abstract]
Preparation, characterization and applications of novel iminodiacetic
polyurethane foam (IDA-PUF) for determination and removal of some alkali metal
ions from water
(629-633)
Journal of Hazardous Materials 160 #2-3 (2008)
10/31/1008
Ignition, combustion, toxicity, and fire
retardancy of polyurethane foams: A comprehensive review
(p 1115-1143)
Journal of Applied Polymer Science 111 #2 (2009)
Abstract
Employment of polyurethane foam for the adsorption of Methylene Blue in
aqueous medium
(580-586)
Journal of Hazardous Materials 159 #2-3(2008)
10/24/2008
Liquefaction of wheat straw and preparation of
rigid polyurethane foam from the liquefaction products
(p 508-516)
Journal of Applied Polymer Science 111 #1 (2009)
Abstract
10/3/2008
Flame retardancy of whisker silicon oxide/rigid polyurethane
foam composites with expandable graphite
(p 3871-3879)
Journal of Applied Polymer Science 110 #6 (2008)
Abstract
9/26/2008
Microwave-assisted
Polyurethane Bond Cleavage via Hydroglycolysis Process at Atmospheric Pressure
(367-380)
Journal of Cellular Plastics 44 #5 (2008)
[Abstract]
A SUMMARY OF WORK CARRIED
OUT BY EUROPUR INTO EXTRACTABLE MATERIALS FROM FLEXIBLE POLYURETHANE FOAM
(p.235-249)
Cellular Polymers 27 #4 (2008)
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Roger D. Corneliussen
Editor
Telephone: 610 883 0055
rcorneliussen@4spe.org
www.maropolymeronline.com
Copyright 2008 by Roger D. Corneliussen