The possibility of modifying viscose fibre with hybrid systems containing flame retardants was demonstrated. The effect of the flame retardants on the physicomechanical properties of the fibres was determined. Bath compositions and modification parameters that ensure the sorption-diffusion reaction of the flame retardant and fibre and production of material with a high oxygen index (greater than 70%) were developed.A great deal of work has been done to create fibres with reduced combustibility. Different flame retardants (FR) are used to give fibres fireproof properties. Multicomponent systems that simultaneously contain several kinds of flame retardants (FR) have recently been used. These so-called hybrid compositions have a synergistic effect due to the combustion inhibitors they contain -phosphorus and nitrogen.We previously selected the FR and determined the temperature and duration of modification of viscose fibres [1] with hybrid systems. The FR Pyrofax (PF), diamidomethylphosphate (T-2), and methazine (MTZ) were incorporated in the hybrid systems and the following sequence of manufacturing operations was established; impregnation, heat treatment, washing, drying. We investigated the effect of the composition of the modifying systems on the properties of the viscose fibres.The viscose fibres were modified from water baths containing 20 and 30 wt. % mixtures of FR consisting of T-2, PF, MTZ, and phosphoric acid (PA). In addition, all components of the modifying bath containing phosphorus and nitrogen affected thermooxidative degradation and combustion of the fibre; methazine held the FR in the fibre, and PA played the role of a catalyst that accelerates the reaction of the reactive groups in FR and the fibre. Based on previous studies on sorption of FR, the duration of impregnation with a solution of FR of 20% concentration was 60 sec, and it was 30 sec for the 30% concentration.The amount of sorbed flame retardants increased both with an increase in their content in the bath from 20 to 30 wt. % and with a change in the ratio of methazine and phosphoric acid in it (Fig. 1). The weight losses in heat treatment and washing were lower in the fibres modified in a bath with a high content of MTZ and PA.The efficiency of the reaction (E r , %) of FR with viscose fibre [2] was determined with the equationwhere ω la , ω im are the amount of FR retained by the fibre after laundering and impregnation, respectively.Simultaneously increasing the content of both MTZ and PA in the modifying bath increased the effectiveness of the reaction and the content of FR in the fibre (Table 1). Simultaneously increasing the content of both MTZ and PA in the bath gave the fibre higher resistance to wet treatments and increased E r by 6-16%.Since the fibres were modified from water baths and viscose fibre is hydrophilic, the effect of the modification conditions on the deformation-strength properties of the fibre is natural.The studies established a correlation between the ratio of the components in the bath and the properties of the ...
