The influence of temperature of poly(vinyl chloride) melt
The final stage of PVC gelation during kneading until the moment of equilibrium state of the torque has been discussed. The processing of unplastified PVC compounds was carried out in the Brabender mixing chamber at chamber temperature (Tch) 150, 160, 170, 175, 180, 185 or 200° and at rotational speed of the blades: 5, 10, 20, 30 or 40min-1 (for the temperature 150° also rotational speed 50 or 60min-1 was used). The shear rate values from 2.18 to 26.04s-1 corresponded with the range of rotational speed mentioned above. The change of the real temperature of the compound during kneading (TE) and its effect on PVC gelation degree (G) were analyzed. A progress of gelation was studied using MFR measurements and SEM observations. It was found that TE value affects the degree of gelation at the last stage of kneading while the effect of residence time of the compound in the chamber (tE) appeared to be insignificant. Apart from the high gelation level, revealed by DSC and MFR results, the processing at high shear rate leads to significant inhomogenenity confirmed by SEM method.
The influence of temperature of poly(vinyl chloride) melt on the equilibrium state of gelation process (in English)