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Non-rubber components are critical in the formation of the natural rubber (NR) vulcanization network, which leads to outstanding mechanical properties of NR. This study reports the effect of NR endogenous proteins (C-serum protein/lutoid protein [CSP/LP]) on the formation of vulcanization networks at the molecular level. Results indicate that CSP/LP has a positive effect on vulcanization. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses demonstrate that the decrease in vulcanization time of CSP/LP is ascribed to coordination interaction between Zn2+ and amide bond. The interaction increases the availability of ZnO in the matrix, thereby promoting the formation of the vulcanized network. CSP/LP also participates in the construction of the vulcanization network as a new crosslinking point, thus increasing crosslinking density and improving the mechanical properties of the NR. This study provides new research ideas for studying the relationship among component–structure–property of NR materials and developing high-strength and high-toughness elastomer materials.

Nonrubber components (NRCs) play an important role in the outstanding mechanical property of natural rubber (NR). The main inositol component of NRCs in natural rubber latex (NRL) is l-quebrachitol. In this study, the influence of l-quebrachitol on the properties of centrifuged natural rubber (CNR) was investigated. The NRL was centrifuged twice to remove most of the NRCs. After that, l-quebrachitol was added in the latex with per hundreds of rubber (phr) vary from 0% to 0.8%, and the vulcanized CNR were prepared. It is shown that the properties of vulcanized CNR were greatly changed, with T 90 reduced from 19 to 15 min, the tensile strength increased from 5 to 9 MPa, T g reduced by about 2°C, and the ability for strain-induced crystallization was enhanced. It was proved by FTIR results that l-quebrachitol was linked to the CNR crosslinking network with ester bond.

The molecular polarizability and dipole moments of the fragments of copolymer fluoroelastomers was evaluated by the quantum chemical method. It was shown that the polarity of fluororubbers is provided by the presence of vinylidene fluoride units. The dynamic mechanical analysis method was used to obtain the frequency and temperature dependencies of the storage modulus E′ and the mechanical loss tangent tan δ of fluororubbers and vulcanizates on their basis. The characteristic features of the influence of the rubbers composition and vulcanization on the mechanical and thermophysical characteristics of elastomers were established. The values of tensile strength and elongation at break were obtained for vulcanizates of the studied fluoroelastomers, as well as the Mooney viscosity and the compression set values. The crucial influence of the rubber polarity and the vulcanization network parameters on the specified parameters was identified. The swelling kinetics of rubbers and vulcanizates on their basis in 1,2-dichloroethane at 50°С was studied. The sorption limitation degree of the solvent at the appearance of the vulcanization network and its parameters were evaluated. It was found that with regard to the reduction in their equilibrium degree and swelling rate in dichloroethane, elastomers go in the following order: SKF-26 > Elaftor 3061R > Elaftor 7075 > Elaftor 1000R, symbatically to the decrease in their polarity. [ABSTRACT FROM AUTHOR]