Chemical cellulose-based fibers of decreased flammability

Natalia Korovnikova,Oleksandr Dubyna,Yana Svishchova,Volodymyr Oliinik

doi:10.15587/1729-4061.2020.214507

Abstract

The studies reported here have made it possible to determine the optimal ways of fire protection, in which the samples of modified complexite have reduced flammability. The sample with the ions of molybdenum (VI), treated with phosphoric acid, had the highest magnitude of oxygen index among five modified samples of the fiber. This is the most fire-protected sample, which contains three types of flame retardants: nitrogen (amidoxime groups of complexite, phosphorus (treatment with phosphoric acid) and molybdenum (VI). The obtained data indicate the chemical interaction of flame retardant with complexite.The morphology of fibers and the process of their destruction are influenced by the introduction of flame retardants. Scanning electronic microphotographs show the existence of a morphological change of the surface at modification of the complexite samples with flame retardant. The introduction of flame retardant into complexite affects the process of thermal destruction of the samples in the air and argon media. At the same time, the introduction of molybdenum (VI) significantly reduces the thermal stability of fibers. It is likely that processes of thermal destruction can be catalyzed by metals both in the air medium and in the argon medium. The magnitudes of order of reaction of thermal decomposition at the transition from a fiber sample treated only with acids to the samples of complexite containing molybdenum (VI) decreases up to 0.38. At the same time, the values of activation energies E, kcal/mol, and the enthalpy of the process of thermal destruction of complexite DH, kcal/mole also decrease. The mechanical properties of fibers at the introduction of flame retardants into the fiber composition change insignificantly. Depending on the composition of flame retardants, rupture load decreases by 6–11 %, lengthening of the samples decreases by 6–16 %.Thus, there are some grounds to suggest that it is possible to create fibrous materials based on cellulose with predetermined properties of reduced flammability.

Highlights

Cellulose-based fibers are the most important materials in the textile industry
The given curves of thermal destruction of modified CG complexite samples in the argon medium and in the air medium indicate a different nature of the curves of the weight loss of fiber samples at different temperature intervals
The sample of modified CG complexite with molybdenum (VI) ions, treated with phosphoric acid is the most fire protected with the magnitude of oxygen index of 29 vol %

Summary

Introduction

Like other types of fibers, cellulose fibers are ignited, have a high rate of combustion, and their flame spreads rapidly. In this case, toxic gases and smoke are released [1]. Flame retardants, which modify cellulose fibers, can suppress or delay ignition, the appearance of flames, and delay or reduce the rate of their combustion [2]. The use of such low-flammability textiles excludes the possibility of ignition of materials from low-calorie ignition sources. The ability flame propagation around the surface, the smoke-forming ability, and toxicity of decomposition products decrease as well [3, 4]

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Results

Conclusion