In currently used shear rheometers, shear stress is inferred from a measurement of either total force or total torque. These methods are subject to experimental errors due to uncontrolled flow at the sample boundaries. Such errors can be avoided by measuring the shear stress locally, in the region of controllable flow, using a shear stress transducer. A new sliding plate rheometer for molten plastics has been developed to incorporate a recently developed shear stress transducer. The rheometer operates at temperatures up to 250$ sp circ$C. Static and dynamic calibrations showed that the shear stress transducer sensitivity is stable and that its frequency response is suitable for the study of molten plastics. This rheometer was equipped with a computer controlled servohydraulic linear actuator, which provided wide flexibility in shear history selection. Digital data acquisition and signal processing enabled the use of the discrete Fourier transform for nonlinear viscoelastic property determination. Important differences were observed between the locally measured shear stress and values inferred from total force in both large amplitude oscillatory shear and in reciprocating exponential shear tests. For these property measurements, free boundary errors can dominate the dynamics of total force measurements.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.76525 |
| Date | January 1987 |
| Creators | Giacomin, A. Jeffrey |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000550424, proquestno: AAINL44471, Theses scanned by UMI/ProQuest. |
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