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Synthesis and Investigation of Properties of Biocompatible Polyurethane Acrylate Based Nanocomposites/Cellulose Nanocrystals

Beik Mohammadi, Mahbubeh | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55262 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shojaei, Akbar; Salkhi, Samaneh
  7. Abstract:
  8. Bio-based shape memory polymers with fast-response have high potential for use in medical applications. In this study, biocompatible and biodegradable nanocomposites based on shape memory polyurethane acrylates (SMPUA)/cellulose nanocrystals (CNC), were synthesized by in-situ polymerization. CNC is a natural and renewable nanoparticle that has been considered for medical applications due to its excellent mechanical and biological properties and surface chemistry. At the first phase of this study, in order to synthesize UV-curable shape memory polyurethane acrylate, polycaprolactone diol (PCL-Diol), hexamethylene diisocyanate (HDI) and hydroxyethyl methacrylate (HEMA) were used as an reactive diluent during two-step melt polymerization. In the next step, cellulose nanocrystals were prepared by acid hydrolysis by sulfuric acid from cotton linter and nanoparticles were surface functionalized with 3-methacryloxypropyltrimethoxysilane (MPS) to enhance its compatibility with organic media matrix and the participation of nanoparticles in crosslinking. The resulting cellulose nanocrystals have a needle shape and the results show that surface modification of nanoparticles reduces the crystallinity and leads to changes in the morphology of nanoparticles. In the final step, the UV-curable PUA/CNC and S-CNC nanocomposite with low nanoparticle content (0.25%, 0.5%, 1% and 2%) were synthesized through in-situ polymerization. The morphology, thermal and mechanical properties, shape memory properties, biodegradability and biocompatibility of PUA and PUA/CNC and S-CNC nanocomposite were investigated. Homogeneous distribution of nanoparticles in the polymer matrix, improvement of mechanical (Increase in modulus and tensile strength, in terms of MPa, from 33.2 to 53.3 and from 18.9 to 23.9 in the presence of 2% of CNC and increase to 49.1 and 23.2 in the presence of 0.5% of S-CNC.) and shape memory properties (Increase the percentage of shape fixity from 95.3 to 98.8 in the presence of 2% of CNC) as well as changes in water absorption and biodegradability according to the type and content of nanoparticles were observed. Further, the MTT assay has suggested the biocompatibility of base polymer and nanocomposites
  9. Keywords:
  10. Cellulose Nanocrystal ; Surface Modification ; Surface Functionality ; Acrylated Polyurethane ; Shape Memory Alloy ; Biocompatible Polymer ; Biodegradable Nanocomposites ; Polycaprolactone Composite ; Hydroxyethyl Methacrylat

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