ANALYSIS OF RHEOTENS OPERATIONAL VARIABLES TO ESTIMATE THE PROCESS ELONGATIONAL VISCOSITY OF POLYMER MELTS

M.L. OTTONE, M.B. PEIROTTI, AND J.A. DEIBER

Los Cocos

Simposio; V Simposio Chileno-Argentino de Polímeros; 2009

The relation between the rheometric isothermal elongational flow and other simple flow kinematics, is of interest in modern rheometry, because experimental data of the steady elongational viscosity of viscoelastic melts are difficult to obtain. In this sense, a technique used at present, is the isothermal melt spinning process in its well-known version designated Rheotens. This apparatus presents a challenging problem, which consists in translating measurements of the melt spinning kinematics and filament forces into those variables pertaining to pure elongation flow within the rheometric framework. According to what has been reported in the literature, different research groups have studied this difficult problem and proposed approximate solutions for this purpose. In the present work we use a computational model of the isothermal melt spinning process (Ottone et al., 2006) to simulate the experimental operation of the Rheotens for a polyethylene therephtalate (PET) sample, and then to extract the relevant information required for a quantitative comparison between melt spinning and rheometric elongational viscosities.