An Overview of Some Reactive Routes to Flame-Retardant Fibre-Forming Polymers: Polypropylene and Polyacrylonitrile

Abstract

The thermal degradation and flammability characteristics of some common fibre-forming polymers, such as polypropylene (PP) and polyacrylonitrile (PAN), are described in this review paper. The flame retardance of these polymers is principally affected by reactive routes that were primarily developed in our laboratories. The modifying groups that are incorporated into polymeric chains include phosphorus- or phosphorus/nitrogen-containing moieties in different chemical environments. The degradation characteristics and extent of flame retardance were mainly evaluated using routine thermal and calorimetric techniques. Elements of flame-retardant mechanisms occurring in the condensed and vapour phases were also identified. Furthermore, we also explored the effects of molecularly dispersed β-cyclodextrin, including its physical mixtures, on the thermal and combustion characteristics of PAN. Given that both types of polymers are often used in the form of fibres, and that the aspect ratio of fibrous materials is relatively high, even nominal enhancements in their fire retardance are highly welcomed. Hence, the preliminary results of our research on chemically modified PAN incorporating molecularly dispersed β-cyclodextrin are encouraging in terms of their enhanced fire retardance, and hence this field warrants further exploration.