Professor B.A.Sc., M.A.Sc. (Toronto), Ph.D. (Cambridge), P.Eng., FCAE  

  3D Printing, Composite Science and Reinforced Polymers 3D Printing of reinforced thermoset and thermoplastic composite materials.  Structure/property relationships in 3D printed composites as well as conventionally processed composite materials; manufacture and properties of wood fiber reinforced thermoplastics and thermosets.  ENGINEERING DESIGN: Creative Product Design with an emphasis on novelty and materials selection and the resultant intellectual property issues. Optimizing the Performance of Natural Fibre Composites and Paper The properties of materials can not be directly controlled: we are only able to control the structure of a material. In order to obtain the desired properties, we must first understand the complex relationship between structure and properties. Our group studies this relationship in polymers, composites and paper with an emphasis on strength, stiffness and fracture resistance. Students interested in materials science are needed, and a typical project includes elements of both experimental and theoretical work. Here are some of the current projects we are working on. Wood and Bio Fibre Reinforced Thermoplastics: Over the past ten years, our group has shifted resources into the area of natural fibre reinforced polymers (NFRP). NFRP represents the fastest growing area of the plastics industry, because these products can provide excellent performance in an environmentally friendly way. Recycled polymers can be combined with waste wood or agricultural fibres to produce useful structural materials, however, it is difficult to match the outstanding properties of wood and synthetic fibre composites. We work on experiments and models that help us to optimize the NFRP structure, so that the maximum properties are obtained. Highlights of the past five years include the first published comprehensive mathematical models for predicting strength and modulus of short fibre NFRPs. Recently, we have also worked on new methods for imaging the internal structure of composites, and in particular, we are one of only two groups using x-ray microtomography to examine natural fibre reinforced thermoplastics. This technique produces a high resolution 3D map of the inside of the composite structure. A typical image is show at right. My group has also published a series of four papers, one book chapter and numerous conference presentations on the creation and dispersion of nanocellulosic fibres. Along with a new method of creating the fibres, we developed a successful technique for melt blending an aqueous slurry of nanocellulosic fibers with molten hydrophobic thermoplastics. Paper Science: In the past five years, we have examined the phenomenon of local roughening caused by rewetting in a printing process using optical profilometry. We have been able to determine the key aspects of paper structure that lead to resistance to rewetting. We have also confirmed, by tracking coloured microspheres before and after calendering, that the reduction in coating roughness during this process must be attributed entirely to thickness compression rather than lateral flow of the coating. We followed this up be designing a new microcompression tester, unique in the world, capable of measuring stress and strain during the compression of thin films at very high speeds. This work was funded by a consortium of paper companies and they will use the results to design new coatings that produce smoother paper. Work is ongoing in these areas, and applications from qualified and ambitious students and Post Doctoral Fellows are always welcome.