THE FLAMMABILITY OF POLYACRYLONITRILE AND ITS COPOLYMERS .1. THE FLAMMABILITY ASSESSMENT USING PRESSED POWDERED POLYMER SAMPLES

This paper is the first in a series of four which investigates the bur ning behaviour and the influence of flame retardant species on the fla mmability of fibre-forming polymer and copolymers of acrylonitrile. A pressed powdered polymer sheet technique is described that enables a r ange of polymer compositions in the presence and absence of flame reta rdants to be assessed for limiting oxygen index, burning rate and char residue determinations. The method offers a rapid, reproducible and c onvenient means of screening possible flame retardant systems, and LOI values compare favourably with those of films and fabrics comprising the same polymeric type. Burning rates, however, are sensitive to chan ges in physical sample character such as form (film vs. powder sheet) and density. Thus the technique forms an excellent basis for the gener ation of burning data which will enable comprehensive studies of acryl ic polymer flammability and flame retardancy to be undertaken.