Specific volume, compressibility, and volume thermal expansivity of rubber-sulphur compounds

The specific volume, compressibility, and volume thermal expansivity of rubber-sulphur specimens containing from 3 to 31 percent of sulphur have been determined at temperatures from 10 to 85 C for pressures up to 800 bars (790 atmospheres) . The specific volume was determined at atmospheric pressure by means of a pycnometer. The specific volumes at the other pressures were obtained from measurements of the lengths of rods of the materials as the pressures were applied. The comprcssibilities a nd volume thermal expansivities were computed from these results. The effect of pressure on the specific volume was found to be a function of the sulphur content and the temperature. The specific volume may be computed from the equation V = V a(l+ aP+ i3P2) , where Va is the specific volume at atmospheric pressure, P is the pressure, and a and 13 are coefficients. For temperatures between 10 a nd 85 C and for specimens containing up to X percent of sulphur where X is given by the equation X =( T+30 )/3.7 and Tis the temperature in degrees centigrade, Va, a and 13 have the following values: Va= 1.1015 +0.00073( T-25) -X[O.00932+0.000007( T-25) 1 a= -10-51 53.7 +0.258(T-25) -X[1.35-0.00217(T-25)ll i3=10-Q[12.0+0.083(T-25)-0.34 Xl For temperatures between 10 and 85 C and for specimens containing between X and 32 percent of sulphur where X is given by the equation X = (T+42)/3 .7, Va, a, and 13 have the following values: Va = 1.0450+0.00038( T-25) -X[O.00601 + 0.0000064 ( T -25) 1 a = -10-51 35.6+0.326(T-25) -X[O.352+0.00672(T-25)ll 13 = 10-g~9.1 +0.0683( T-25) -0.221 Xl