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Abstract

This thesis describes studies of the action of a number of sulphur oxyacid salts as flame retardants for cellulose (cotton) and of the sulphur-bromine synergism observed when inorganic sulphates and related compounds are used in conjunction with an organic bromine compound, decabromobiphenyl oxide (DBBO).

In the Introduction, a general description is given of the phenomena of combustion, flame and fire with special reference to the processes involved in the burning of organic polymers and its inhibition. An account is given of the properties and of the importance as textile fibre of cotton, which was the form of cellulose used in the present investigation; and a review is included of previous work on the thermal decomposition and combustion of cellulose and of mechanisms involved in its flame retardance.

The Experimental section describes the techniques used to prepare the cotton samples and to determine their flammability by means of the limiting oxygen index method, A description is given too of the computer method used to fit polynomial functions to the observed data for cotton-additive systems and to plot these functions in the form of triangular diagrams. Measurements of flammability were complemented by studies of the thermo analytical behaviour of untreated cotton and of numerous treated cotton samples. In some cases, determinations were made of the amounts of carbon monoxide liberated during breakdown of the various cottons and of the elemental composition of solid residues remaining after various stages of decomposition.

In the Results section, the flammability measurements and thermoanalytical and microanalytical behaviour are recorded for all the cotton-sulphur oxyacid salt systems in the absence and presence of DBBO, It is shown that some of the systems used are very efficient flame retardants and attention has been concentrated mainly on the four best sulphur compounds in this respect, viz. aluminium sulphate, zinc sulphate, ammonium sulphamate and ammonium sulphate.

In the Discussion section, some mechanisms are first proposed to account for the flame-retardant effects of the various sulphur oxyacid salts in terms largely of their differing abilities to cause dehydration of the cellulose to form carbon. The order of flame-retardant effic-iency of the corresponding sulphur oxyacid salt-DBBO systems is somewhat different and explanations are advanced to account for the differences observed. It is clear that, with some of the system studied, bothcondensed-phase and gas-phase mechanisms may be involved.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > Q Science (General) Q Science > QD Chemistry
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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