Phosphorus Flame Retardants for Polymeric Materials from Gallic Acid and Other Naturally Occurring Multihydroxybenzoic Acids

Table 7

Thermal degradation characteristics for blends of phosphorus esters of methyl 3,5-dihydroxybenzoate in DGEBA epoxy resin.

Additive	Additive level (wt%)	Phosphorus level (wt%)	(°C)^a	(°C)^b	Char^c (wt%)
None	0	0	390	423	10
35DHB-DEP	7.1	1	345	373	23
35DHB-DEP	14.2	2	329	355	26
35DHB-DPP	10.2	1	349	375	24
35DHB-DPP	20.4	2	328	356	27
35DHB-DOPO	9.6	1	369	394	15
35DHB-DOPO	19.2	2	354	379	18

^aExtrapolated onset temperature from the derivative plot of mass loss versus temperature. ^bPercentage of the initial sample mass. ^cNitrogen atmosphere.