Improved Fire- and Smoke-Resistant Materials for Commercial Aircraft Interiors A Proceedings (1995) / Chapter Skim
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Chapter 8. Fire Properties of Future Material Candidates
Chapter 8. Fire Properties of Future Material Candidates
Pages 115-128
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From page 115... ...
The additive route means that something is added to the polymer, either in a physical or a chemical fashion, to make that material more resistant to burning. The commonly useful additives include alumina trihydrate and magnesium hydroxide, halogens, phosphorus, antimony, and synergistic combinations of these, sometimes including nitrogen or other elements.
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From page 116... ...
Char formation offers the opportunity of portability from one polymer to another, and this offers great possibilities for the design of new flame retardants. ~ believe that we must begin to design flame retardants to perform a specific task upon interaction with the polymer and that a systematic investigation of reactions between polymers and additives will enable this design.
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From page 117... ...
Our goal should be to develop somewhat complete mechanistic information about the course of the chemical reactions that ensue between the polymer and the additive; only in this way can one learn if a particular additive will be useful with another polymer. Temperature Requirements For any flame-retardant reaction that one may consider, it is important to allow no reaction under normal conditions of temperature.
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From page 118... ...
The choice of oxidizing agents is not an easy one, especially considering the severe temperature requirements. A strong oxidizing agent will likely effect reaction at lower temperatures so the probable initial choice is a somewhat weak agent whose strength may increase with temperature.
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From page 119... ...
It is also important to perform cone calorimetry to determine the rate of heat release and associated information. If oxidation is useful for polymers in which the average oxidation state is fairly low, then reduction may be most useful for those polymers in which the oxidation state is fairly high, such as functionalized polymers, especially those that contain carbonyls.
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From page 120... ...
The cost of this rhodium compound is such that it could never be used as a flame retardant, but it is important to examine the potential of such reactions and to use them to identify other materials that may be useful. Since this rhodium compound functions as a hydrogenation catalyst, other hydrogenation catalysts should be investigated, not only with PMMA but also with other polymers, to determine the breadth of this reaction (ColIman, 19681.
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From page 121... ...
In the majority of polymers, double bonds are absent, so addition reactions may prove useful only in limited cases. These limit cases include polybuladiene, copolymers containing butadiene, and related materials.
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From page 122... ...
This type of chemistry appears to offer a real advantage for polymers that contain aromatic rings, such as polystyrene and copolymers containing styrene. The problems then that are presented in making Friedel-Crafts chemistry a viable means for cross-linkina of benzene rings in stvrenic and related polymers are two: catalyst and _ _ ~ ~ ~ of ..
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From page 123... ...
Polymers ~ think that it is important that one think not only about materials that may be used as flame retardants but also broadly consider venous classes of compounds and reaction types. If we can learn how a particular class of reagents interacts with a variety of polymers, we can then use this information to begin to design an additive (or reactive)
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From page 124... ...
or some other good char former to a polymeric substrate, either by physical or chemical means, and if this degrades to char before or at the same time as the substrate degrades, one has an effective flame-retardant system. Further developments in this area require the identification of suitable char farmers whose degradation temperatures are known, along with suitable methods to apply this to the appropriate substrate.
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1989c. Parameters affecting fire retardant effectiveness in intumescent systems.
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19SSa. Study of the mechanism of intumescence in fire retardant polymers: Part V-Mechanism of formation of gaseous products in the thermal degradation of ammonium polyphosphate.
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From page 127... ...
1994. The effect of some transition metal chlorides on the thermal degradation of poly(methyl methacrylate)
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From page 128... ...
and red phosphorus: An investigation with cross polarization, magic angle NMR spectroscopy. Journal of Polymer Science: Polymer Letters 19:409-414.
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