Study of the Properties of Seawater-Resistant Rubber

Abstract The article investigates the effect of new styrene-butadiene caoutchoucs DSSK-615V, DSSK-621V, and DSSK-628V, as well as bromobutyl caoutchouc BBK-232, on the rheometric, physical-mechanical, and dynamic properties of rubber used to manufacture products resistant to seawater. The rubber mixture included butadiene-methylstyrene SKMS-30ARK and chlorobutyl KhBK-139 caoutchoucs, vulcanizing agent sulfur, vulcanization accelerators 2,2′-dibenzthiazole disulfide and guanide F, vulcanization activators zinc white and stearic acid, antioxidant naphtham-2, softeners rosin, SMPlast resin, petroleum bitumen, factis, and industrial oil I-12A, fillers technical carbons P 514 and P 803, natural chalk, and trans-polynorbornene. The rubber mixture was prepared on laboratory rolls LB 320 160/160. The vulcanization characteristics of the resulting rubber mixture were studied using an MDR 3000 Basic rheometer. Subsequently, the rubber mixture was vulcanized in a P-V-100-3RT-2-PCD press. The physical and mechanical properties of the resulting vulcanizates and their changes after soaking in seawater were determined. The dynamic parameters (mechanical loss tangent and modulus of elasticity) of the vulcanizates were studied using a Metravib VHF 104 dynamic mechanical analyzer at a frequency of 1000 Hz and temperatures of 30, 10, and 4°C. The research found that replacing SKMS-30ARK caoutchouc with styrene-butadiene caoutchoucs DSSK-615V, DSSK-621V, and DSSK-628V and KhBK-19 caoutchouc with BBK-232 bromobutyl caoutchouc leads to an increase in the minimum and maximum torques and a decrease in the times of the beginning and optimum vulcanization of the rubber mixture. Vulcanizates with new styrene-butadiene caoutchoucs have greater strength properties and lower relative elongation compared to vulcanizates based on bromobutyl caoutchouc BBK-232. After a daily exposure to seawater, the physical and mechanical properties and hardness, as well as the mass of vulcanizates after a week’s exposure to seawater, changed within acceptable limits. It was established that replacing SKMS-30ARK caoutchouc with DSSK-621V and DSSK-628V caoutchoucs leads to an increase in the tangent of the mechanical loss angle and a decrease in the elasticity modulus of vulcanizates. Lowering the temperature promotes an increase in the dynamic properties of vulcanizates. The rubber compound based on a combination of caoutchoucs DSSK-628V and KhBK-139 (BBK-232) at a mass ratio of 75 : 25 is characterized by improved dynamic properties.