Light-scattering measurements on polyisoprene solutions. II. Rubber from fresh natural latex



The value of w for a sample of natural rubber from fresh latex of one clonal type is ∼2 × 106. As the latex ages, w diminishes and the gel content increases. Solutions of samples which have been masticated in oxygen contain very small particles of rubber, the existence of which is demonstrated by both light-scattering and electron-microscope measurements. The particles are heterodisperse and have a mean diameter of about 1000 A. As a result of their small size they are swollen very little in good solvents. They originate from the gel phase and either they are a product of mastication or, more probably, they are latex particles which have survived mastication.