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04/Aug/2017
Recycling of plastic waste - curse or a blessing?
In our fast-paced „throwaway society“
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31/May/2017
Plastics for E&E applications, “fuse box meets dryer” 2017 in Würzburg
As in previous years „Kunststoffzentrum (SKZ
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01/Aug/2016
pinfa's first workshop in China confirms interest in halogen free FRs
In June 2016, over 250 people from academia, indus
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02/Nov/2015
1st International Asia-Oceania Symposium on Fire Safety Materials Science and Engineering (AOFSM’1 2015)
The 1st International Asia-Oceania Symposium on Fi
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19/Oct/2015
European fire tests for cables in building and CE-marking
In 2008, in the context of the Construction Produc
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02/Sep/2015
Electrical fires and fire safety requirements for E&E equipment
In a U.S. statistical overview from NFPA[i] on ele
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Intumescent flame retardant systems

Mode of action: formation of a voluminous, insulating protective layer through carbonization and simultaneous foaming

Intumescent systems puff up to produce foams. They are used to protect combustible materials such as plastics or wood, and those like steel, which lose their strength when exposed to high temperatures, against the attack of heat and fire.

Basically, intumescent flame retardant systems consist of the following:
1. "Carbon" donors (e.g. polyalcohols such as starch, pentaerythritol)
2. Acid donors (e.g. ammonium polyphosphate)
3. Spumific compounds (e.g. melamine)


Process of intumescent mechanism


1. Softening of the binder/polymer (e.g. polypropylene)


2. Release of an inorganic acid (e.g. ammonium polyphosphate)


3. Carbonization (e.g. of polyalcohols)


4. Gas formation by the spumific compound (e.g. melamine)


5. Foaming of the mixture


6. Solidification through cross-linking reactions

The picture below shows how the foam looks in the end. This coating expanded from a 1 mm layer to a 100 mm foam.