Mastication of rubber. VI. Viscosity and molecular weight relationships for natural rubber after cold mastication

Values of limiting viscosity number, Huggins' interaction constant, k ′, osmotic molecular weight and Flory‐Huggins' constant, μ, of masticated and unmasticated rubber have been compared. A calibration of limiting viscosity against molecular weight has been obtained formasticated rubber, but one is not available for unmasticated rubber due to the occurrence of different extents of branching. A mechanism is advanced of rupture during mastication of molecules above a critical molecular weight.