Synthesis of low molecular weight polystyrene by anionic techniques and intrinsic viscosity–molecular weight relations over a broad range in molecular weight

Anionic polymerization techniques have been used to prepare low molecular weight (M ≤ 10,000) polystyrene of M̄w/M̄n ≤ 1.1. The preparation and characterization of polymers are described. Good agreement with results reported by others was obtained for the viscosity‐molecular weight relation in benzene at 25°C., viz. [η] = 1.0 × 10−3 M̄n0.5, for 500 < M̄n ≤ 10,000. For high molecular weight fractions (2.5 × 104 < M ≤ 1.5 × 106) of anionically prepared polystyrene, the expression, [η] benzene = 8.5 × 10−5M0.75, was found to be applicable and in agreement with relations given in the literature. Under theta conditions—cyclohexane as solvent at 34.5°C.—a single expression, [η] = 8.4 × 10−4M0.5, was found to apply over the entire molecular weight range, 500 < M ≤ 1.5 × 106.