Phosphazenes -triphosphonitrile chloride and polyphosphonitrile chloride -are effective asphalt modifiers that expand the temperature range of its elastic-plastic state. The modulus of elasticity of asphalts modified with them allow recommending them for obtaining high-quality incombustible coatings.One of the basic methods of altering the physicomechanical properties of asphalts is to incorporate additives of different natures, including polymeric and oligomeric compounds. The interest in this problem has not abated since the 1940s [1, 2].We used triphosphonitrile chloride (TPNC) and polyphosphonitrile chloride (PPNC) as asphalt modifiers.These phosphazenes give different materials fire resistance: textiles, paper, leather [3,4]. Their availability and low cost are responsible for their wide use to a great degree. They are obtained in ammonolysis of phosphorus pentachloride with ammonium chloride. The phosphazenes were added to BN-11 asphalt (17.2% asphaltene content, 82.7% maltene content) heated to 125°C by portions while stirring vigorously for 1.5 h. When aluminum chloride was also added to the asphalt, a vacuum was created to eliminate hydrogen chloride 0.5 h before stirring ended. The physicomechanical properties of the composites obtained are reported in Table 1 and their rheological characteristics, determined on a Hoeppler viscometer at 30°C, are shown in Fig. 1 and Table 2.As Table 1 shows, when TPNC (a low-molecular-weight compound) was added, the range of the elasticplastic state of the asphalt changed by 18° due to a decrease in the brittleness temperature. On addition of 0.5 to 10 wt. % PPNC with a mol. wt. of 10,000, the softening point of the composite increased, attaining the maximum at a 10% concentration of this compound. The significant difference in the properties of the composite with 25% PPNC is due to the poor compatibility of the components at this concentration of PPNC.When the concentration of PPNC was increased to 10%, needle penetration and ductility at 25°C decreased, which indicates an increase in the mechanical strength of the composites. Although the region of the elastic-plastic state was 55° for the initial asphalt, it increased to 115 and 155° for composites with 5 and 10% PPNC. No such change was observed in the properties of the asphalt when other polar and nonpolar polymers were added. At a concentration of 10 wt. % polyethylene with mol. wt. of 19,000 and 70,000, this region increased (as a function of the brand and nature of the asphalt) on average to 87 and 115°, to 93° for polyvinyl chloride with mol. wt. of 50,000, and to 73° for polyvinyl acetate with mol. wt. of 59,000.
