Chemistry

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This is the collection for the University of Waterloo's Department of Chemistry.

Research outputs are organized by type (eg. Master Thesis, Article, Conference Paper).

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Browsing Chemistry by Subject "3D printing"

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    3D printing of soft hydrogels incorporating functional nanomaterials
    (University of Waterloo, 2017-01-10) Wu, Yun
    Tissue engineering (TE) scaffolds are required to closely mimic the human body environment to enable the study of cell behavior in vitro and allow the fabrication of artificial tissue constructs. The scaffolds should possess controlled structural and mechanical properties, such as stiffness and porosity. In addition, its physical and chemical properties, such as electrical conductivity, should be able to promote cell differentiation and growth. In the search of developing an ideal scaffold, hydrogels that incorporate functional nanomaterials scaffolds are being explored. This study, as a fulfillment for a master’s degree, investigates the ability of cells to survive in a three-dimensional (3D) printed soft hydrogels incorporated with functional materials. In this work, alginate, a natural polymer, was used as the main hydrogel material. It can physically crosslink by adding CaCl2 or chemically crosslink after methacrylation, by introducing carbon-carbon double bonds. However, pure alginate hydrogel is mechanically and rheologically weak. Previous mechanical tests indicated that cellulose nanocrystals (CNC)-incorporated alginate-based hydrogels increased the mechanical strength of the scaffolds, which can contribute to the interactions between CNC and polymeric networks. Rheological tests showed that the incorporation of cellulose nanocrystals into the alginate matrix introduced strong shear thinning behavior and improved shear modulus. The enhancement of rheological properties improved the printability and fidelity of the hybrid pre-gel solution. Finally, cell viability was explored by suspending 3T3 fibroblasts in the bioink. It was shown that the hybrid bioink was nontoxic and the cell viability remained high over a 7-days period. This master’s thesis demonstrates the feasibility of 3D printing of soft hydrogels for the fabrication of 3D scaffolds that mimic real tissues. It is anticipated that a broad array of ink compositions with suitable viscosity can be printed and multiple cell lines can grow in the same scaffold. This research provides a platform for the fabrication of biocompatible polymers and stretchable biosensors within an engineered scaffold.
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    Development of Advanced Polymer-Soil Composites as High-Performance Construction Materials
    (University of Waterloo, 2023-01-23) Nazareth, Boris Peter
    Construction using earth materials is an old building practice that can be traced back to approximately 10,000 BC. Costs for this type of construction are low because local materials are utilized, and structures are built with the simplistic technology available. More developed countries have moved on from earth materials to those such as concrete due to the better mechanical properties that they possess. However, the production of concrete has a detrimental impact on the environment as its production requires large amounts of energy, raw materials, and releases significant amounts of carbon dioxide. Polymer materials have been identified as useful soil-stabilizing additives because of their ability to fill voids between sand particles. Although polymers have been studied for their use in soil stabilization, they have not been explored as a potential substitute for concrete in construction. This research aimed to produce a composite building material with compressive strength values on par with that of concrete. In Chapter 2, the attempted functionalization of polymers was described to highlight methods capable of modifying polymers (plastics) for use. However, these experiments were paused to investigate the effectiveness of the highlighted functional group. A polymer solution was synthesized to exploit a covalent bond that forms between the polymer and the solid components of soil/sand. The production and compressive strengths of the formed polymer composites were outlined in Chapter 3. The results revealed the effectiveness of increasing amounts of the polymer solution. Variables that influenced the curing rate of the polymer composites were also investigated. This proof of concept study showed that polymer composites can be made to possess high compressive strength values.