DIFFERENT SPATIAL HETEROGENEITY OF NETWORKS PREPARED BY A 2-STAGE IRRADIATION OF NATURAL-RUBBER

Natural rubber networks were prepared by a two stage gamma-irradiation of rubber latex to yield materials of different spatial heterogeneity . The maximum overall dose is 250 kGy for each sample. Characterizatio n of network include swelling, ESR measurements using spin probe and m echanical measurements. The application of spin probe method enables t o estimate network morphology from the complex ESR spectra. The morpho logy of the network is determined by the dose and ratio of preirradiat ed and nonirradiated latex at the same overall dose. The potential eff ects of spatial heterogeneity on mechanical properties of rubber netwo rks are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.