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New developments in melt rheology aid formulating rigid vinyl compounds with improved extrusion processing
Author(s) -
Shah Pravin L.
Publication year - 1996
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.10087
Subject(s) - extrusion , rheometer , rheology , materials science , degradation (telecommunications) , capillary action , composite material , viscosity , reactive extrusion , computer science , telecommunications
This paper describes a new approach to the rheological characterization of PVC compounds using a capillary rheometer. Since the control of the thermal degradation rate of rigid PVC is very critical in extrusion, a new quantitative method of measuring the true degradation rate of PVC is proposed for formulating rigid vinyl compounds. The usefulness of this new technique is demonstrated in formulating PVC compounds with the lowest rate of degradation measured on the Kayeness capillary rheometer. This study shows a very good correlation between the capillary rheometer data and the extrusion melt temperature, melt viscosity, and the rate of degradation of PVC. The ideal melt temperature for extrusion is determined from the rheology data of each PVC compound to attain the longest run time. The study also shows how to measure the true melt temperature in extrusion, an important variable, to control the rate of degradation in processing. The results of this study show how the new rheology technique can be used as a practical tool for product development, quality control of the PVC compounds, and the development of optimum extrusion parameters.