by Janice Hamilton

One would think that scientists already know all there is to know about polyethylene. After all, it has been around since the late 1930s and is used to make the ubiquitous plastic shopping bag, as well as toys and common packaging products.

However, some of polyethylene’s physical and chemical properties remain unknown, and Assistant Professor Paula Wood-Adams is investigating them.

“I am interested in plastics and how they behave when you melt them and shape them into objects,” she explained.

When Wood-Adams joined the Department of Mechanical and Industrial Engineering in May, she brought both an expertise in plastics and a background in chemical engineering to Concordia’s interdisciplinary materials science group.

She studied at the University of Alberta and worked as a research engineer for Dow Chemical in Edmonton for three years before coming to Montreal in 1993 to take graduate studies in chemical engineering at McGill University, under polymer expert John Dealy.

She has had a temporary position at McGill since 1998, teaching and carrying out industry-sponsored research. Then came the offer of a permanent position at Concordia.

Wood-Adams’ arrival has boosted the number of women in the department to two out of 25. She admits mechanical engineering is a field that still has a “masculine image,” and is pleased that a third woman will join the faculty in January.

Research support

Wood-Adams has a five-year NSERC University Faculty Award, an award designed to increase the representation of women and aboriginal people in the sciences and engineering. “It will pay part of my salary and allow me to reduce my teaching load and focus on research,” she said.
She said she was offered a research position with Dow in Texas, but turned it down, not only because Texas did not appeal. She prefers a university environment, where she has more freedom to go off on tangents and control the pace of her work. “I also like the contact with the students.”

Her research falls into an area known as rheology, the science of the deformation of materials. It looks at the properties of fluid and semi-solid materials such as clays, concrete, oils, inks and polymers.

Wood-Adams explained that polyethylene is sold to a processor as pellets. These pellets have to be melted, pumped and stretched into the desired form, so the material’s flow properties are important.

Recently, manufacturers started to use a new type of catalyst to make polyethylene. This catalyst improves flexibility of the polymerization process, but in order to use that flexibility, engineers have to understand how the structure of the polymer molecules affects the properties of the material. She has been investigating those properties.

Wood-Adams adds that polyethylene is a good learning tool because “what you learn from one polymer can apply to another, and polyethylene is easy to work with experimentally.”

Her other major research interest is theoretical. “There are different techniques to characterize the structure of polymer molecules: what they look like, their shape, how big they are. My interest is in how these techniques work from a theoretical point of view.” She is collaborating with the polymer group at Waterloo University.

Wood-Adams is continuing to supervise some students at McGill and to use experimental facilities there. She says Concordia has given her “a little bit of space” to set up a lab here, and she has applied for money to buy some instruments. She expects to have more space when the new engineering building is complete. Meanwhile, she will find her niche in the materials science group.