John M. Dealy

John M. Dealy

McGill University

March 23, 1937 – January 15, 2024

Chemical Engineer
Awarded Bingham Medal 1998
Fellow, Elected 2015

John M. Dealy was born in Waterloo, Iowa on March 23, 1937. He obtained his B.S. in Chemical Engineering from the University of Kansas in 1958. He continued studying Chemical Engineering at the University of Michigan for his M.Sc. and Ph.D., graduating in 1959 and 1963 respectively. He began teaching at McGill University in 1964, working his way up from Assistant Professor to Professor. During his time at McGill, he also served as Chair of the Department of Chemical Engineering (1993-1994) and Dean of the Faculty of Engineering (1994 to 1999). Dealy became Professor Emeritus in 2004.

Dealy made numerous outstanding contributions to the science of rheology and was a leader among rheologists serving the industrial community. His excellent knowledge and understanding of both rheology and polymer processing operations rank him amongst the most influential rheologists working in the processing of polymer melts. His development of a robust shear stress transducer and its successful incorporation into a sliding plate rheometer is one of the most significant contributions to experimental melt rheology. It solved many problems previously encountered in conventional sliding plate rheometers and marked the advent of measurements of non-linear viscoelasticity in concentrated polymer solutions and melts. As an example, Dealy popularized the use of Large Amplitude Oscillatory Shear (LAOS) in such systems and was the first to recognize and use exponential shear flow as a strong transient flow and compare it with extensional flows and unsteady shear flows. He also pioneered the development of correlations between rheological measurements and processability and the ways rheology can be used to understand polymer processing performance. His careful and innovative work on measuring die swell of molten polymers flowing through diverging and converging annular dies remains the definitive work on the subject. His work on the wall slip and melt fracture of molten polyethylenes and elastomers is another outstanding contribution. Dealy also developed the pressurized sliding plate rheometer, one of the few rheometer designs that can measure clearly the effects of pressure on the rheological properties and slip velocity of molten polymers and elastomers.

Dealy is a member of the Canadian Society of Chemical Engineering, the Society of Plastics Engineers, the Canadian Society of Rheology, and the Canadian Academy of Engineering. He is a Fellow of The Society of Rheology and served as President from 1987 to 1989, is a fellow of the Polymer Processing Society, and was awarded the 1997 S. G. Mason Award from the Canadian Rheology Group. He is known for teaching rheology in an understandable and logical way, as demonstrated in many of his manuscripts and both his books. His last book with Kurt Wissbrun, Melt Rheology and its Role in Plastics Processing, is a model of clarity, and his tutorial expository lectures in scientific meetings are well-remembered. Dealy’s invention of new experimental techniques and equipment for polymer melt rheology, clear writing, and instructive lectures have contributed greatly to the science of rheology and to the rheological community.

Sources

Dealy, John Michael. American Men and Women of Science, 29th ed.; Gale: Farmington Hills, MI, 2011; Vol. 2.

John M. Dealy. Chemical Engineering, McGill University (accessed Aug 21, 2019).

Note: This biography is an adaptation of the following article previously published by The Society of Rheology.

Savvas G. Hatzikiriakos and Jeffrey A. Giacomin. 1998 Bingham Medal Goes to John Dealy. Rheology Bulletin 1998, 67(2), 2.