Influence of the Microstructure of Vulcanized Polybutadiene Rubber on the Dielectric Properties

A. RODRÍGUEZ-GARRAZA; P. A. SORICHETTI; A. J. MARZOCCA; C. L. MATTEO; G. A. MONTI

POLYMER TESTING

ELSEVIER SCI LTD

Año: 2011 vol. 30 p. 657 - 662

0142-9418

Dielectric relaxation spectra in the frequency range from 10 Hz to 1 GHz were obtained at room temperature to study the influence of the network structure formed during vulcanization on the dielectric properties of polybutadiene rubber (BR).Two polybutadiene rubbers with different cis, trans and vinyl content in their molecular structure were used to prepare compounds with a cure system based on sulphur and TBBS (N-t-butyl-2-benzothiazole sulfenamide). Samples of each compound were vulcanized at 433 K for several times in order to obtain different crosslink densities. Structural changes in both compounds during vulcanization were measured by means of solid-state C-13 NMR spectroscopy. Dielectric permittivity was measured as function of the frequency and analyzed using the Havriliak-Negami model. The results show a clear dependence of the dielectric parameters on the crosslink density and 1,4-cis content.