Analysis of the Stress Birefringence Induced by Extensional Flow on Polystyrene Samples

FRANCISCO F. ROSS; MARCELO DANIEL FAILLA; LIDIA MARÍA QUINZANI

Río de Janeiro, Brasil (16 al 21 de julio de 2006)

Congreso; World Polymer Congress, MACRO 2006 - 41th. International Symposium on Macromolecules; 2006

International Union of Pure and Applied Chemistry (IUPAC), Associação Brasileira de Polímeros

Planar flow was applied to molten polystyrene under different temperature and pressure conditions and the generated molecular orientation was conserved in the solid material by rapid cooling. The planar flow was generated using a specially designed deformation geometry which consists of two parallel rectangular plates, one fixed and another that moves squeezing out longitudinally the molten polymer. Cold water flowing in channels inside the plates is used to rapidly cool down the polymer samples. The final state of birefringence remaining in the solid  deformed samples was determined using a conventional optical system. The combination of flow and cooling generates a complex state of stresses whose intensities increase as the processing pressure increases and initial temperature decreases.