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Polyurethane foams debuted over 60 years ago. At the present time these types
of foams make up the largest segment in the thermosetting foam industry.
This book describes polyurethane (PUR) and urethane linkage-modified
polyisocyanurate (PIR) foams. A characteristic of these foams lies in the
versatility of their physical properties, such as flexibility, viscoelasticity, semi-
flexibility, rigidness, and heat and flame-resistance at a wide variety of foam
densities. This versatility is derived from molecular design by the choice of
raw materials and foaming reactions.
For example, polyurethane foams are prepared by the reaction of polyols
with polyisocyanates in the presence of blowing agents. The molecular
weight and the functionality of polyols affect the resulting foam properties.
Polyisocyanates act as the jointing agent of polyols. Therefore, urethane and
related foams are recognized as building block polymers.
Blowing agents are the key materials for polyisocyanate-based foams.
Due to the ozone depletion problems in the stratosphere, physical blowing
agents have gone through a revolutionary change. ChJorofluorocarbons,
(CFCs), and hydrochlorofluorocarbons (HCFCs) have been phased out.
The next generation of blowing agents includes hydrofluorocarbons (HFC),
Cg-hydrocarbons, water, and liquid carbon dioxide. This book highlights this
next generation of blowing agents.
This book is intended to be informative to people in research and
development, production, processing, testing, marketing, sales, and foam
applicators, as well as professors, students, and others. |
