The evaluation of natural rubber processability

Natural rubber (NR) shows fluctuation of some properties that can cause undesirable changes in behaviour during its processing. In 1965, Standard Malaysian Rubber (SMR) specification was established to allow natural rubber classification into several quality groups according to impurities content and processing parameters. It determines limits for some analytical data – content of dirt, volatile matters, ash and nitrogen, and for physical quantities that were introduced to evaluate processing parameters – Wallace plasticity, Mooney viscosity and Plasticity retention index (PRI). But praxis shows, that the prediction of processing properties based on these parameters sometimes fails. New testing instruments offer to measure some rubber properties at wider range of deformation rates and/or at dynamic regime. The presented study map if extended testing possibilities can help technologists with above mentioned prediction of natural rubber behaviour.
Natural rubber (NR) shows fluctuation of some properties that can cause undesirable changes in behaviour during its processing. In 1965, Standard Malaysian Rubber (SMR) specification was established to allow natural rubber classification into several quality groups according to impurities content and processing parameters. It determines limits for some analytical data – content of dirt, volatile matters, ash and nitrogen, and for physical quantities that were introduced to evaluate processing parameters – Wallace plasticity, Mooney viscosity and Plasticity retention index (PRI). But praxis shows, that the prediction of processing properties based on these parameters sometimes fails. New testing instruments offer to measure some rubber properties at wider range of deformation rates and/or at dynamic regime. The presented study map if extended testing possibilities can help technologists with above mentioned prediction of natural rubber behaviour.