STUDIES ON THE INFLUENCE OF FLAME RETARDANTS AND TEMPERATURE ON CELLULOSE PYROLYSIS IN AIR (PYROLYSIS).

摘要

Available from UMI in association with The British Library. Requires signed TDF.; A pyrolysis system and compatible analytical procedures were developed for the investigation of volatile products evolved during oxidative pyrolysis of cotton fabrics treated with various flame retardants. The flame retardants, studied at commercial levels of application, were condensed phase active ammonium polyphosphate (Amgard TR), a phosphonium salt--urea--polycondensate (Proban CC) and a phosphonopropionamide (Pyrovatex CP); and two vapour phase active treatments ammonium polyphosphate--ammonium bromide (Amgard CD) and an antimony (111) oxide--aliphatic bromide (Flacavon H14/587) formulation.; Preliminary experiments to identify the volatile products of interest were carried out using the departmental GC-MS. In all, over 40 compounds were identified. These qualitative analyses indicate that oxidative pyrolysis of some flame retarded fabrics produced more volatile species than did the untreated fabric. It was found that untreated cotton fabric gave no char with furan yields very much greater than those for the flame retardant treated fabrics. The two vapour phase active flame retardant treatments, Amgard CD and Flacavon (Sb/Br), resulted in low char yields coupled, as was to be expected, with the highest yields of volatiles and CO. The condensed phase retardants, Proban CC, Pyrovatex CP and Amgard TR, produced large amounts of char with Proban CC giving the most.; A model for the oxidative pyrolysis of cellulose is proposed on the basis of the detailed information obtained concerning the temperature dependence of the char and volatile products evolved when various flame retarded fabrics were pyrolysed.; Relative thermal stabilities of the fabric samples were also investigated via thermogravimetric (TG) analysis. It was found that fabrics treated with the condensed phase flame retardants i.e Amgard TR, E = 196.77 kJmol{dollar}sp{lcub}-1{rcub}{dollar}, Pyrovatex CP, E = 185.34 kJmol{dollar}sp{lcub}-1{rcub}{dollar}; and Proban CC, E = 217.36 kJmol{dollar}sp{lcub}-1{rcub}{dollar} raise the activation energy compared to that of untreated cotton, E = 157.71 kJmol{dollar}sp{lcub}-1{rcub}{dollar}. Volatile evolution probably occurs via 3-dimensional diffusion. The vapour phase retardant treated fabrics (Amgard CD and Flacavon (Sb/Br)) yielded TG curves which were too complex for simple interpretation. (Abstract shortened by UMI.)