Influence of the Type of Polymer Base on the Kinetics of Water Swelling of Vulcanizates

Abstract

The water absorption capacity of rubbers based on various types of rubbers was studied: butadiene-nitrile grade BNKS-28AMN, a mixture of isoprene SKI-3 and butadiene SKD in a ratio of 70:30 wt.h., ethylene-propylene diene grades SKEPT-40 and Vistalon 8800 (ExxonMobil Chemical, USA) with the addition of an increased amount of water-swelling additives (100 by weight of the superabsorbent «Aquasin» and 70,0 by weight of sodium-carboxymethylcellose per 100,0 by weight of rubber) when exposed to distilled water, 3 and 10 % aqueous solutions of NaCl for 20 days, the resistance of rubbers to thermal aging was studied. It was found that the VNR based on the rubbers SKEPT-40 and Vistalon 8800 exceeds the VNR on butadiene-nitrile rubber and general purpose rubbers both in terms of the degree of swelling in water and salt solutions, and in terms of resistance to thermal aging. Prolonged swelling is accompanied by an increase in the size of rubber images without visible leaching of additives from the thickness of the samples. The results obtained can be used in the development of sealing elements of water- and oil-swelling packers.