| Abstract: | Previous work on the emission of smoke and fumes from overheated aircraft interior materials has included simple monitoring of acids and alkalies by means of a glass electrode in a water-bubbler. In order to put these measurements on a quantitative basis and as part of an attempt to assess the significance of acidic or alkaline fumes in terms of irritant effects, a two-way pH-stat automatic titration apparatus is now used. A small sample of material is heated at a controlled rate to 500°C in a stream of flowing air. The effluent is bubbled through water and automatically titrated for acids or alkalies. The temperatures at which these emissions occur and their amounts can be measured. Good recoveries of acids, alkalies and of both evolved consecutively have been achieved. To assess the utility of the apparatus for actual materials, the acid evolved from various types of PVC was compared. The emissions from three different nylons and from a composite cable were also investigated. Reference materials with various known additives are now being examined by the method and comparisons with irritancy measurements are being made. Ion-chromatography will be used to study the individual acid evolved. |
