CHARACTERIZATION AND GEL POINT OF RANDOMLY LINKED HIGH CIS POLYBUTADIENE NETWORKS

Cis-Polybutadiene networks (98 % cis), crosslinked in the bulk state b y gamma irradiation were characterized ill terms of their mechanical p roperties. Data from stress-strain analyses, swelling degrees, stress relaxation and random-linking theory are in accordance and the estimat ed gel points practically coincide. Trapped entanglements contributed up to 30% to the network modulus, from which also the plateau modulus was determined. The tensile data were obtained from Mooney-Rivlin repr esentations. It was concluded that the assumption of additive contribu tions from chemical and entanglement crosslink densities in the Langle y theory works well in the range of doses investigated here. A compari son with a tube-like approach of these networks is made.