A series of back-coated cotton fabrics comprising varying molar ratios of chlorine, bromine and antimony has been studied using a simulated match ignition test, LOI and thermal analysis (TGA and DTA). Results show that the presence of chlorine alone and in combination with bro mine increases LOI and carbonaceous char values at optimum halogen :anti mony molar ratios of 2.5-3.6:1 and bromine:chlorine molar ratios within the range 0.31-0.42. Only back-coated samples containing bromine pass the simu lated match test although at Br:Sb molar ratios above 4:1, LOI and char residual values decrease. It is evident that condensed and vapour phase flame retardant mechanisms are operating with efficiencies determined by halogen : Sb and Br/Cl molar ratios. Partial and whole replacement of halogen and antimony by phosphorus-containing and other flame retardants in the back-coating formulation that do not function in the vapour phase may be used to pass the simulated match test.

We have successfully synthesized and characterized new water‐soluble precursors of polyimides based on dianhydrides with diaminobenzene sodium sulfonate (DABSS) and diaminostilbene disodium sulfonate (DASBDSS). The precursors are soluble in water and methanol as well as in several aprotic solvents. The optimum inherent viscosities of the poly(amic acids), obtained by varying reaction temperatures, were measured using a conventional Ubbelohde viscometer. The average molar mass of the polymers expressed as the “poly(ethylene oxide)‐PEO/poly(ethylene glycol)‐PEG equivalent” molecular masses obtained by gel permeation chromatography (GPC) showed significant broad molecular mass distributions with their polydispersities ranging from 2.9 to 4.6. FT‐IR spectra revealed complete imidization of the polyimides. Their thermal properties were studied by techniques such as differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Polyimides derived from the dianhydrides and DASBDSS showed better thermal stability up to 40°C in nitrogen than in oxygen atmosphere. However, polyimides based on the dianhydrides and DABSS were slightly more stable in oxygen than in nitrogen atmosphere. In oxygen, all the synthesized polyimides exhibited weight losses of about 50% in the range of 450–510°C. The overall weight losses of these polyimides under nitrogen were less than 50% at 700°C. New network polymellitimides based on mellitic trianhydride (MTA) and DABSS, and co‐polymellitimides based on MTA, DABSS, and ODA (oxydianiline) were also synthesized and characterized successfully. Their thermal stabilities were compared with the linear polyimides using TGA and DSC.