The Phase State of Calcium Stearate in Bnks Butadiene–Acrylonitrile Rubbers

The Effect of a Surfactant on the Structure of Vulcanisates of Butadiene–Acrylonitrile Rubbers

“…In the work, use was made of butadiene-acrylonitrile rubbers with different contents of acrylonitrile units: SKN-18, SKN-26, and SKN-40. The structural characteristics of the SKN rubbers are given in another paper by the present authors [7]. These rubbers did not contain an emulsifier in sufficient quantity for it to appear on XDA diffraction patterns [6].…”

“…An emulsifier (surfactant)sodium alkylsulphonate (C 15 ) -was introduced into the rubbers in a quantity of 2 parts. Vulcanisates both with and without surfactant were obtained at 170°C using a sulphur-sulphenamide vulcanising system and had an identical degree of crosslinking, the same as earlier [7].…”

“…Small-and large-angle diffraction patterns, as previously [7], were recorded in a "transmission" regime on a DRON-3M instrument (CuK a radiation, Ni filter). The accuracy of determination of the angular position of reflexes 2q was ±0.01°.…”

The Effect of An Anionic Emulsifier on the Ozone Resistance of Vulcanisates of Butadiene–Acrylonitrile Rubbers

“…According to data of NMR spectroscopy [1], macromolecules of butadiene-acrylonitrile rubbers comprise microblocks of trans-1,4-butadiene units and sequences of alternating trans-1,4-butadiene units and acrylonitrile units. Macromolecular fragments of the same type, by virtue of the differences in their geometric and chemical structure, are selectively segregated, forming ordered formations of two types, respectively, according to data of X-ray diffraction analysis (XDA) [2,3] and the diffusion method [4,5]. The introduction of anionic surfactant causes changes in the ordered structure of the butadiene-acrylonitrile copolymer (SKN), which depend on their comonomer composition and the prehistory of specimens, according to XDA data.…”

“…However, the content of these units in SKN-18 is higher than their content in SKN-26, like the total content of butadiene units ( Table 1). The increased activity of the double bonds of vulcanisates of SKN-26 is due, it seems, to the fact that their disordered part is looser [2,3]. This facilitates the occurrence of the reaction of double bonds with ozone of greater molar volume.…”