Abstract
Polymer melts are compressible liquids of bulk modulus ⋃109Nm−2. Most polymer melt processes operate at pressures of 106 to 107 Nm−2 (10 to 100atm) with a bulk compression of less than 1%. However, in some— notably injection moulding—pressures of the order of 108 N m −2 (1000 atm) may be employed. Bulk compression then is becoming appreciable and the consequent reduction in free volume reduces the mobility of the molecules. This manifests itself as a viscosity increase. Large mouldings may require very high pressures indeed. In such cases allowance should be made for the reduced melt fluidity in the processing specifications.
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© 1978 Applied Science Publishers Ltd
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Lenk, R.S. (1978). The Influence of Pressure on the Viscosity of Polymer Melts. Viscosity and Molecular Weight. In: Polymer Rheology. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-9666-9_4
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DOI: https://doi.org/10.1007/978-94-010-9666-9_4
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-9668-3
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