Flammability limiting oxygen index

Polysulfones are transparent (though often slightly yellow), have low flammability (limiting oxygen index typically 38), and bum with little smoke production. Typical properties of some of the commercial polysulfones are shown in Table 4.31. 

Flammability, limiting oxygen index Fractional free volume Hardness Rockwell Durometer 23 C 150 C 220 C... 

Li etal. (2000a, 2001b) smdied the flammability of wood modified with acetic or propionic anhydrides, finding that this parameter, as determined by limiting oxygen index (LOI), was the same as that found for unmodified wood. Samples were also prepared which were impregnated with sodium silicate prior to anhydride modification. The latter treatment resulted in a decrease in flammability, as shown by an increase in the LOI of the wood. 

The polymer limiting oxygen index (LOI) value is 26,5 which corresponds to that of the isosorbide polyurethanes. It is again higher than that of conventional MDI polyurethanes with similar structure based on 1,4-cyclohexanedimethanol (LOI = 20) and indicates lower flammability of cellobiose polymers,... 

Kuila et al. [106] studied the flammability of EVA-LDH nanocomposites with different LDH loading. The results shown in Fig. 59 represent the findings on the limiting oxygen index (LOI) of neat EVA and its nanocomposites. 

Relative to carbon/carbon composites, the hybrid composites have a reduced thermal stability in air due to the resin content of the matrix. The flammabilities of the hybrid composites, as measured by the limiting oxygen index (LOI) test (63) are given in Figure 36. Pure carbon/carbon composites are not inflammable in... 

Figure 36. Limiting oxygen index (LOI) of flammability resistance for carbon/carbon composites and related hybrid composites with epoxy resin impregnant, as functions of bulk density and resin content (64).

The degree of flammability of a polymeric material may be predicted from its chemical structure. One of the most valuable criteria in fire research, the so-called limiting oxygen index (LOI) may be estimated either from the specific heat of combustion or from the amount of char residue on pyrolysis. Since both quantities can be determined if the chemical structure is known, also the LOI can be estimated. An approximate assessment of the LOI value direct from the elementary composition of the polymer is also possible. 

T o demonstrate more clearly the effect of structural factors on polymer flammability, we considered the relationship between the limiting oxygen index and the specific... 

The limiting oxygen index (LOI) measures the minimum oxygen content that is required to sustain a flame [10]. The specimen in this test is in a vertical orientation, but it is the top of the specimen that is ignited. Because the specimen burns in a candle-like fashion, LOI may not be representative of fire situations. However, LOI does give quantitative information and may be useful for ranking the relative flammability of samples. 

Flame retardance is another important property and is defined by different test methods. Some of the small-scale methods include horizontal flame spread (FMVSS 302, ASTM D-1692) vertical flammability (ASTM D-3014, so-called Butler Chimney Test), limiting oxygen index (ASTM D-2863), and smoke density (ASTM D-2840). 

Limiting oxygen index values (LOI) of a number of plastics are shown in Table IV. The LOI is the concentration of oxygen required to maintain burning. Polyphenylene sulfide has a value of 44, and falls among the least flammable types of plastics. 

Of the several test methods for evaluating the burning behavior of different polymers, the limiting oxygen index (LOI) will be used here to illustrate the relative flammability of materials. This test measures the minimum concentration of oxygen in an oxygen-nitrogen atmosphere that is necessary to initiate and support a flame. 

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