Flame Retardant Finishing

You begin with the basics of burning characteristics of different fabrics such as cotton, wool and polyester via short video clips showing the burning behaviour of these fabrics, when burnt from the bottom level and from the top. Is it possible to change the basic characteristics of fabrics and make them fire or flame resistant? Which chemicals can behave as effective fire retardants for fabrics and how? This course will answer these questions by explaining the process of burning and comparing the enthalpy of combustion to give you an idea of how burning is exothermic in nature. A chemical is a flame retardant if, when added to materials during their manufacturing process, it reduces the likelihood of the finished product catching fire, slows down combustion and raises the ignition point of the fabric. This course explains the mechanism of flame retardancy and describes the concepts of the ‘sphere of influence’ and ‘fire triangle’. It discusses the importance of carbon monoxide evolution and char formation, which is an effective method of increasing the fire resistance of materials. You will understand how phosphorous compounds reduce flammability of a polymer by enhancing char formation.

Next, you will be introduced to inherently flame-resistant fibres like aramid and polyphenylene sulphide. These fibres do not break into combustible molecular fragments. For other fibres, we need chemical treatments to make them resistant to fire. Flame retardant or fire-retardant chemicals are usually added to or applied to furnishings such as foam, upholstery, curtains, fabric blinds, mattresses and carpets. In general, flame retardants are classified on the basis of whether they contain bromine, chlorine, phosphorus, nitrogen, metals or boron. Different fabrics react differently to these chemicals, hence specific flame retardants are used for a fabric type. For example, bromine compounds are effective for polyester, nylon and other synthetics. You will acquire knowledge of flame retardants and also learn how a flame-retardant finish is applied on the fabrics. You will be able to answer whether flame retardancy is a surface or bulk finish in a textile. Different application processes, such as the pad-dry-cure, spray-dry-cure and coat-dry-cure methods, are described in an easy-to-understand language and style. Lastly, you will gain an understanding of the standard tests, such as cone calorimeter, limiting oxygen index and vertical flame, for evaluation of flame retardancy.

Forest, industrial and city fires have been known to cause considerable damage to life and ecosystems. Flame-retardant textiles are not only used in protective clothing for fire fighters but also have varied use in areas where fire protection is essential, such as public transport or in other public places. Thus, the science of flame retardancy has been a critical field of study, aiming for continuous improvement and contribution since the 18th century. The first patent with flame retardant use was filed in 1735 by Obadiah Wyld and, in 1820, Joseph Louis Gay-Lussac suggested a solution to increase the fire retardancy of textiles used in the theatres in France. In this course, you will gain practical understanding of this aspect of textile finishing, making you more confident in your personal or professional areas of expertise such as the textile industry, fashion designing or pursuit of research in pure sciences.