Novel Applications of Viscoplastic Fluids: Creating New Products for the Pulp and Paper Sector

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This proposal investigates a novel platform technology, i.e. hydrodynamic focusing coupled with reactive multi-fluid layering, to 3D print hollow hydrogel tubes. This technology is similar to the production of a spider's silk and our goal is to create an eco-friendly alternative to PVC tubing for extracorporeal circuits. Our immediate scientific need is to increase the fracture energy of these tubes by about 5-fold and we propose to do so by reinforcement with micro- or nano-fibrillated cellulose, i.e. building blocks of wood fibres. Literature reviews indicate that the fracture toughness increases dramatically by small additions of these reinforcing materials. Critically, the question we address is understanding of the relationship between orientation distribution of the reinforcement fibre to the end-use mechanical properties.      Our approach will blend computation and experimentation. We will estimate the orientation distribution using a probability density function that obeys a steady-state Fokker-Planck relationship. This approach is based on moment tensors of the fibre orientation probability distribution function, and crucially rely on accurate closure approximations that will be calibrated through experiment using x-ray micro-computed tomography. Experimentally, we will develop an inlet manifold to control orientation-distribution of the reinforcing fibres in the hydrogel tubing and demonstrate this on our lab-scale device.      The impact of the work will be two-fold. Scientifically, gaining insight into the macroscale and microscale physics of a dispersed fibrous phase under different flow conditions are significant steps forward in the fields of fluid mechanics and process engineering. On the numerical front, high-fidelity simulations of the interactions of the fibres with each other and with the background flow, that occur at the scale of fibres, are still rare in the literature. On the engineering side, if this process is shown to be feasible, parallelization is immediately available for industrial production. This will allow manufacturing of filaments, tubes or films from wood fibre raw material for future production of high-performance bio-composites as well as for textile production. A five-year project is proposed to be conducted by one post-doctoral fellow, two PhD students and 5 undergraduate assistants in either Chemical or Mechanical Engineering.