Abstract This paper investigates evidence regarding the influence of a CaSt2 residual additive in the optical properties of a commercial polystyrene. This work proposes an in-line optical detector operating by illuminating the polymer with a red monochromatic light in order to evaluate its thermal behavior during a heat cycling. The detection system was bench validated by measuring the light absorption of aqueous solutions of organic acid dyes. The system showed great sensitivity in detecting the contamination’s effect on the polymer, as a great impact on the polymer’s behavior was observed due to the presence of the additive during different thermal cycles. The detector system showed that the salt’s presence elevates absorbance by five times when the temperature is higher than its fusion temperature. The in-line optical detector has proved to be suitable to quantify the presence of additives that affects the polymer’s optical properties. CaSt polystyrene inline line cycling dyes contaminations contamination s polymers cycles salts salt

Abstract The thermo-mechanical degradation of PET during extrusion was studied in the transient state. Active agents, water, causing hydrolysis by chain scission and pyromellitic dianhydride PMDA, causing chain extension, were added to the extrusion flow as pulses. They change the PET molecular weight, affecting its the melt flow elasticity, which was followed in-line by a rheo-optical detector set in an instrumented slit-die, measuring synchronously, pressure drop and flow birefringence ( Δ n 12). The effect of the extrusion shearing level, set by 90º kneading blocks with different lengths, was also quantified. The results, as of residence time distribution curves, show the degree of thermo-mechanical degradation as hydrolysis and chain extension for each pulse type and concentration. Thus, assuming collinearity and full birefringence orientation along the melt flow the first normal stress difference N 1 can be monitored in-line. thermomechanical thermo mechanical state agents water PMDA pulses weight elasticity inline line rheooptical rheo optical slitdie, slitdie slit die, die slit-die synchronously 12. 12 . 12) level º lengths quantified results curves concentration Thus inline. line.