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The effect of molecular weight blending on PVC melt rheology
Author(s) -
Park I. K.,
Riley D. W.
Publication year - 1980
Publication title -
journal of vinyl technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 0193-7197
DOI - 10.1002/vnl.730020306
Subject(s) - materials science , crystallinity , rheology , melt flow index , shear rate , composite material , suspension (topology) , activation energy , shear flow , shear (geology) , atomic packing factor , newtonian fluid , flow (mathematics) , thermodynamics , polymer , chemistry , crystallography , mechanics , copolymer , organic chemistry , physics , mathematics , homotopy , pure mathematics
The effect of molecular weight blending on melt flow characteristics has been studied with a 50/50 mixture of suspension PVC resins with the respective M w of 56,300 and 123,000. The dynamic shear measurements were made with the Rheometrics Visco‐Elastic Tester at angular frequencies of 0.1 to 40 radians/s. In the temperature range of 160 to 215° C, all samples showed three distinct flow regions marked by three different values of the activation energy. The high molecular weight fraction introduced a relatively strong influence on the melt flow characteristics of the blend due to the effect of its relatively high crystalline content. These samples also failed to show a Newtonian flow behavior at 190°C at an extremely low shear rate corresponding to 10 −4 radians/s., possibly reflecting the effect of the remnant crystallinity of the material.