Influence of Halobutyl Caouthoucs and Sevilen on the Properties of Rubber Based of Butadiene Nitrile Caoutchouc

The influence of halobutyl rubbers BBK-232, HBK-139, and the polyethylene–vinyl acetate copolymer 11808-340 (Sevilen) on the rheometric, physicomechanical, and dynamic properties of rubber based on butadiene–nitrile rubber SKN-4045 intended for products resistant to seawater was analyzed. The rubber compound included butadiene–nitrile rubber SKN-4045, bromobutyl rubber BBK-232, chlorobutyl rubber HBK-139; sulfur as the curing agent; guanidine F and Altax as vulcanization accelerators; zinc oxide and stearic acid as activators; Naftam-2 as the antidegradant; rosin, petroleum bitumen, and factice as softeners; trans-polynorbornene and carbon blacks P 514 and P 803 as fillers. The compound was prepared on LB 320 160/160 laboratory rolls. Its vulcanization characteristics were measured using an MDR 3000 Basic rheometer. The compound was then vulcanized in a P-V-100-3RT-2-PCD press. Physicomechanical properties of the resulting vulcanizates and their changes, as well as the degree of swelling after exposure to seawater, were determined. Dynamic parameters (loss tangent and elastic modulus) of the vulcanizates were measured using a Metravib VHF 104 dynamic mechanical analyzer at 1000 Hz and 30°C. The results show that adding a defined amount of Sevilen 11808-340 to the compound improves its rheometric properties (longer scorch time and optimum vulcanization time, lower maximum and minimum torque) and increases the tensile strength and elongation at break. Rubber based on SKN-4045 and HBK-139 containing 5.0 phr of Sevilen exhibits enhanced strength. After one-day and one-week exposure to seawater, the physicomechanical properties, hardness, and swelling degree of the vulcanizates remain within acceptable limits. Rubber based on SKN-4045, HBK-139, and Sevilen at a weight ratio of 75 : 25 : 5 is characterized by improved performance and dynamic properties.