Effect of an anionic emulsifier on the structure of butadiene-nitrile elastomers

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

“…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. Here, the surfactant in the rubbers forms a lamellar mesomorphic structure with a layer periodicity of 26 Å [6]. The revealed changes in the structural organisation of the rubbers in the presence of surfactant should have a considerable effect on the progress of the chemical reactions in the condensed state.…”

The Ozone Resistance of Vulcanisates Based on Skn Butadiene–Acrylonitrile Rubber in the Stress State

“…Thus, according to rheometric data, in the case of CBS there is an induction period of vulcanisation lasting 22, 10, and 8 min during the vulcanisation of SKN-18, SKN-26, and SKN-40 respectively. During the induction period preceding the formation of a chemical crosslink network there is an increase in the volume fraction of ordered formations of sequences of alternating units that do not break down during vulcanisation, especially in SKN-40 [3,4]. This in turn leads to an uneven distribution of chemical crosslinks in the volume of the elastomers, the more so the greater the volume content of such formations.…”

The Structure of Acrylonitrile-Butadiene Rubbers: Paramagnetic-Probe Study

“…Nitrile-butadiene rubbers (NBRs) are the products of high-temperature (303-323 K) or low-temperature (278 K) emulsion copolymerization of butadiene with acrylonitrile (AN) in the presence of emulsifiers (Necal emulsifiers for SKN rubber and ecologically friendly paraffinates for BNKS rubber) and have different chain microstructures and types of supramolecular organization [1][2][3].…”

“…WAXS and SAXS studies [1,2] revealed that statistical-average intermolecular distances L nonlinearly increase with the content of AN units in NBR. In this case, the value of L for BNKS is higher than that for SKN on condition that the content of AN units is the same ( Table 1).…”

“…The sequences of alternating trans-1,4-butadiene and AN units and microblocks of trans-1,4-butadiene units selectively segregate and form ordered structures of two types [1,2]. BNKS macromolecules contain longer sequences of alternating trans-1,4-butadiene and AN units than SKN macromolecules, in which the content of individual AN units is increased.…”