A new natural rubber concept: Mastication with some practical examples
To effectively use natural rubber (NR) in the rubber industry, it is essential to reduce its viscosity (or molecular weight) through a process known as NR mastication or breakdown, in order to achieve suitable plasticity. During this process, natural rubber chains are broken by the application of shear forces. However, the resulting chain ends are highly reactive free radicals, which tend to recombine, causing the viscosity to increase again. To prevent this undesirable reaction, chemical peptizers have been used for many years. These substances release free radicals during NR breakdown and bond with the shortened NR chains, thereby deactivating them. As a result, the viscosity remains relatively stable over time.