Thermodeformation properties of dynamically volcanized thermoplastic elastomers based on random polypropylene and nitrile butadiene rubber

The paper presents the results of a study of the thermodefomational characteristics of dynamically vulcanized thermoplastic elastomers based on random polypropylene and nitrile butadiene rubber (SKN). In order to improve the compatibility of polymer mixtures, Exxelor PO1200, a grafted copolymer of polypropylene with maleic anhydride, was used as a compatibilizer. The concentration of maleic anhydride in the composition of the grafted copolymer was 3.0 wt. %. It was shown that as a result of the loading of the compatibilizer, it seemed possible to improve the compatibility of bipolar mixtures, in which there was no separation between the components of the mixture. It was found that with the load of 30 wt. % SKN-18, as well as 40 wt. % SKN-26 or SKN-40 into the composition of random polypropylene, the polymer composition exhibits the properties of thermoplastic elastomers, as a result of which plastic deformation is replaced by a highly elastic characteristic for rubbers. The temperature regions of the solid, highly elastic, and viscous flowing states are determined. In order to give polymer blends greater elasticity, they were vulcanized using crosslinking agents such as dicumyl peroxide and sulfur. It is shown how, in the process of increasing the concentration of dicumyl peroxide from 0.25 to 1.0 wt. %, the thermomechanical properties of dynamically vulcanized thermoplastic elastomers significantly change. It was found that with the introduction of dicumyl peroxide in an amount equal to 1.0 wt. %, the melt flowability of vulcanized materials almost completely lose their ability to flow, and pass from a highly elastic state to a glassy one. With the load of sulfur in an amount of 1.0 to 10 wt. %, the melt flowability of the vulcanized thermoplastic elastomers is preserved.