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06/Aug/2018
Fraunhofer LBFs and PINFAs research activities on the recycling of plastics containing halogen free flame retardants
Recycling is an important issue with regard to the
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01/Sep/2017
New pinfa video: How effective are flame retardants for fire safety?
A new video from PINFA, the Phosphorus, Inorganic
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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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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.