Wenji Victor Chang
Associate Professor
Specific Research Interests
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Nonlinear Dynamic Properties of Elastomer Springs and Seals
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Biomechanical Properties of Cornea and Skin
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Asphalt Modification with Recycled Polymers
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Mold Flow Simulation of Short Fiber Filled Plastics
- Flammability and Long-Term Aging of Polymer Composites
Research Interest
Polymers-Composites-Adhesion-Mechanics
The central theme of my research is to develop a methodology for rational design of polymer-based products. Polymer or polymer composite product development is intrinsically a complex problem involving many paths and solutions. The material properties, especially the failure properties, are very sensitive to variation in processing conditions and fluctuation in raw material composition. To address this issue requires an interdisciplinary approach employing polymer chemistry, polymer physics, processing science and solid mechanics.
From Wettability to Adhesive Strength
The performance of composites is often limited by the properties and strength at the binder-fiber (or filler) interface. Because of its fundamental and practical importance, it is of great interest to relate the adhesive strength to the constitutive properties of the component phases. A phenomenological model has been developed to characterize solid surfaces, based on which material constants are determined. The model allows us to estimate the thermodynamic surface energy of solids and the interfacial energies between a solid and a solvent or between a pair of solids. A statistical thermodynamic model was developed (with Professor Shing) to quantify the interfacial structure of polymers adsorbed to a solid substrate. The practical adhesive strength depends also on the viscoelastic properties of the component phases, the effect of which is evaluated using nonlinear finite element analysis.
Cavitation in Polymer Thin Films
If macromolecules diffuse or flow in a porous medium, because their effective hydrodynamic radius is comparable with the size of the pores, their transport is hindered or restricted. This hindrance also affects their reaction and adsorption properties. We have developed a model that can take into account the effect of pore structure and flow and diffusion fields. Our study includes a new class of catalytic materials, namely pillared clays, which have attracted wide attention because of their flexible structure.
