Estimation of the Polyisoprene Macromolecular Structure by Multi-Detection Size Exclusion Chromatography

VEGA, J.R.; MINARI, R.J.; GUGLIOTTA, L.M.; MEIRA, G.R.

Río de Janeiro (Brasil)

Congreso; Macro 2006 - World Polymer Congress, 41 Simposio Internacional de Macromoléculas; 2006

Molecular weight and branching distributions of polyisoprene (PI) produced by emulsion polymerization were estimated by multi-detection size exclusion chromatography. Specific viscosity and concentration measurements together with the average degree of branching predicted by a global mathematical model were used to estimate the PI structure parameter. The linear PI intrinsic viscosity was predicted by the Mark-Houwink equation, with its slope ´a´ determined from linear anionic PI standards, and the constant ´K´ adjusted to adequately predict the behavior of linear radicalary PI. The molecular weight distribution becomes broader as the reaction proceeds. As expected, the estimated branching degree increases with the molecular weight and with the monomer conversion.