Technology was developed for impregnating polyamide fibres with phosphorus-and boron-containing compounds with fireproofing properties. The effect of the formula for the impregnating compositions on the physicomechanical properties and combustibility of the fibres was determined. The compositions increase adhesion of polyamide fibres to vulcanized chloroprene rubber.A great deal of attention has recently been focused on the problem of reducing the combustibility of chemical fibres widely used both in pure form and mixed with other polymers in sectors where fire safety is extremely important: auto interiors, aircraft, work clothes, heaters for industrial and domestic construction, rubber cord composites (conveyor belts, hoses).Chemical methods of fireproofing are among the most effective methods of reducing the combustibility of materials. They are varied and include use of a wide range of impregnation or coating compositions which have high resistance to fire and high temperatures.Polycaproamide fibres with a valuable set of properties are most widely used in manufacture of rubber cord composites. However, the high combustibility and inflammability significantly decrease the resistance of articles made from them to open flames.To eliminate this drawback, we developed new fireproofing compositions based on a phosphorus-and boroncontaining oligomer (PBO), triethanolamine (TEA), and carboxymethylcellulose (CMC). The impregnating compositions were 15-25% aqueous solutions of PBO neutralized with TEA.Polycaproamide fibres (420-tex 252KNTS twisted fibre) were impregnated for 15 min at room temperature. The treated fibres were dried to a constant weight and then thermostated for 30 min at 100°C.The dependence of the basic physicomechanical indexes of the fibres on the formulas of the impregnating compositions was investigated to determine the efficacy of the fireproofing compositions and the optimum processing conditions (Table 1).CMC in the amount of 0.1% of the mass of PBO, which reacted with the PBO, forming water-insoluble products, was added to the formula of the impregnating compositions to eliminate partial washing off of the fireproofing compounds when the modified fibres were exposed to water. The data in Table 2 indicate the change in some properties of polyamide fibres with a change in the concentration of PBO in the impregnating compositions containing CMC.The study of combustion of the impregnated fibres showed that after removal of the sources of open flames, they self-extinguished. Reducing the CMC content in the impregnating compositions increased the resistance of the treated fibres to open flames (Table 3).The results of the study suggest that after treatment of polyamide fibres with the impregnating compositions, the weight loss in thermooxidative degradation decreased significantly.The increase in the strength of the polyamide fibres is probably due to localization of microdefects on their surface during treatment with the impregnating compositions, since microdefects are the source of destruction of...
The strong interaction between rubber and filler leads to the formation of an interphase region at the boundary. Its properties differ from the properties of the remaining matrix, and it has a considerable influence on the properties of the elastomeric composite. The dependence of the volume fraction of interphase polymer layer φδ on the volume fraction of filler φf for particles of different shape and structure was calculated. The values of φδ for the individual particles and linear aggregates are higher than for aggregates of ellipsoidal structure. All dependences pass through a maximum at different φf: for individual particles and linear aggregates roughly at φf = 0.1, for aggregates of ellipsoidal structure at φf = 0.3. The results were compared with data on the adsorption of dibutyl phthalate by different grades of carbon black (CB) having an identical specific surface (N326, N330, N351, N358). The more CB aggregates accessible to elastomer molecules there are, the higher is φδ. Thus, CBs of chain structure have, at all φf, higher φδ values than CBs with aggregates of ellipsoidal structure. The obtained results open up the possibility of predicting the optimum content of ingredients in the elastomeric composites.
The paper presents findings of a study of physical-chemical properties of sunflower husk melanins, as well as their influence on the thermal oxidative aging resistance of elastomer compositions. It has been found that melanins reveal a high level of antioxidant activity and can be used as antiaging agents in elastomer compositions.
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