Effect of layered aluminosilicates on the barrier properties of butyl rubber
Polimery 2012, No 7-8, 551
The effect of the type and amount of layered nanofillers (modified bentonites Nanofil 15 as well as new domestic products Nanobent ZR1 and Nanobent ZR2; Table 1.) on the permeation of polar butyl acetate and non-polar cyclohexane through composites of cross-linked butyl rubber (IIR), non-polar special elastomer, was studied. The barrier properties were assessed on the basis of breakthrough time (tp) of the liquid through the cured elastomer sample. Every filler used considerably increased the tensile strength (TSb) of cured IIR (Tables 2, 3.). However, no effect of nanofiller was found on the increase in relatively short breakthrough time (tp = 18 — 22 min) of cyclohexane — a solvent with similar polarity and high thermodynamic affinity to the rubber (Fig. 1) — through IIR vulcanizates, even when the amount of Nanobent ZR1 was increased to 10 wt. % (Fig. 3). The breakthrough time of cross-linked IIR containing 5 phr (weight parts per 100 parts of IIR) Nanobent ZR1, Nanofil 15, or HAF carbon black against polar butyl acetate was in the range of tp = 139—152 min and was statistically the same as the breakthrough time for non-filled vulcanizate (tp = 140 min). The addition of 5 phr nanofiller Nanobent ZR2 to IIR rubber gave an increase of about 15 % in the breakthrough time for this liquid (Fig. 2). A favourable effect of the nanofiller Nanobent ZR1 on the increase in breakthrough time for polar butyl acetate was observed only at 7.5 or 10 phr filler content (Fig. 3).