Abstract
The mastication of Styrene-Butadiene Rubber 1500 were carried out by an open mill under four conditions. Two of the four samples were treated for 10 and 30 minutes at 15°C, respectively, and the other two were treated for 17 and 35 minutes at 50°C respectively. These four samples and the unmasticated sample were fractionated by a factional precipitation method using benzene as solvent and methanol as precipitant.
The intrinsic viscosities and the osmotic pressures of unmasticated fractions were measured in toluene, and for the masticated fractions only the intrinsic viscosities were measured. The relationship between the number average molecular weight and the intrinsic viscosity was determined for the unmasticated sample of Styrene-Butadiene Rubber 1500, and the molecular weight of the masticated samples were calculated by this relationship.
It was found that the width of the molecular weight distribution curve decreased with increasing the treating time and with decreasing the temperature of mestication. This width was much more influence by the mastication temperature than by in terms of an treating time. The effect of mastication was discussed by the appropriate parameter which is related to the average width of the distribution curve. The relationship between the number of the fractions and the molecular wight distribution were discussed.
