Ordered formations of flexible chain polymers

The Influence of the Structural Organisation of Nitrile Butadiene Rubbers on their Vulcanisation

“…The dissimilar nature of change in the dynamic viscosity of NBR and SKDL rubbers when stearic acid is introduced at 130°C, discovered for the first time, is due to the presence in the former of nanoformations formed by sections of alternating units, which are stronger than the nanoformations of microblocks of trans-1,4-butadiene units [5][6][7]12]. The difference in the behaviour of the dynamic viscosity of NBR copolymers themselves is a possible indication of the dissimilar size of these formations in them.…”

“…According to data of NMR spectroscopy [19], macromolecules of this rubber consist of microblocks of cis-1,4-and trans-1,4-butadiene units separated by isolated 1,2-units. According to data of IR spectroscopy [7] and the diffusion method [20], microblocks of units of the same type selectively aggregate, forming in SKDL two types of nanoformation. Here, the nanoformations of trans-1,4-butadiene units are stronger and break down entirely in the region of 120°C [20].…”

“…The size of the nanoformations of alternating units inevitably influences features of the crosslinking of NBR macromolecules, because the degree of looseness of the packing of chain fragments in their disordered part should differ in this case. According to data of the diffusion method, it is the disordered part of the chain fragments that determines the actual concentration of vulcanising system ingredients present [6][7][8].…”

“…The dependence of the duration of the induction period (a) and the increase in torque (b) on the content of cis-1,4-butadiene units for rubber mixes based on initial rubbers(1)(2)(3)(4)(5) and also on rubbers containing 1 part stearic acid(6)(7)(8)(9)(10). Rubbers: 1, 6 -AMN; 2, 7 -SKN-18S; 3, 8 -SNT-K; 4, 9 -SKN-1865; 5, 10 -SNT-V…”