Solid State 13C NMR Analysis of Vulcanized Rubbers XVI. The Competitive Vulcanization of Natural Rubber and Polybutadiene Blends

Abstract Solid state 13C NMR was used to study the competitive vulcanization of blends of natural rubber and high cis polybutadiene. A NMR sampling technique utilizing the stacked homopolymers was developed that helps to determine the spectral differences occurring due to competitively vulcanizing an elastomer blend. The small amount of interfacial crosslinking was expected to be undetectable but has been tentatively observed. Concentration of crosslinks at the interface may occur from limited solubility of curative species in both rubbers. The NMR spectra also showed inhibition of cis-trans isomerization in natural rubber with addition of polybutadiene.