Adeboye, SAmuel Adepitan and Covenant University, Theses (2024) SYNTHESIS, MODIFICATION, AND CHARACTERISATION OF FUNCTIONAL POLYURETHANE COATING SYSTEMS FROM CASTOR OIL. Masters thesis, Covenant University.
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Abstract
Environmental challenges have driven production science towards using biodegradable and sustainable feedstocks for product development. Developing sustainable and high-performance coating materials to address the environmental concerns and technical demands of modern industries has become so critical that plant seed oils are considered viable renewable feedstocks capable of substituting petrochemical-based materials in polymeric material preparation. This study reports the synthesis and characterisation of functional organic polyurethane coatings from castor bean seed oil (CSO) (Ricinus communis seed oil). Graphene nanoparticles were modified into graphene oxide and incorporated within the polyurethane polymer matrix in a one-pot synthesis. Also, aminopropyltrimethoxysilane (APTMS) was used to alter silica nanoparticles and was incorporated into the polyurethane system. Bisphenol A and trimethylolpropane (TMP) were used as extenders, and their influences on the coating properties were also examined in the urethane systems. Physicochemical analysis of the feedstock and prepared coating formulations was conducted. Structural evaluation of synthesised materials was performed using proton nuclear magnetic resonance (1H NMR) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Synthesised urethane coatings were cured on silicon resin mould and mild steel. Thermal stability and crystallinity of pristine and composite films were studied using thermogravimetric analysis (TGA) and X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to analyse surface morphology. Water contact angle analysis revealed the hydrophobicity of the synthesised urethane films. Solubility, anticorrosive, and antimicrobial properties of prepared materials were evaluated. Spectroscopic analysis confirmed the structure of modified nanomaterials, pristine, and composite films. Surface morphology and photographic images showed successful incorporation of nanomaterials (graphene oxide and hybrid APTMSmodified silica) within the polymer matrix. Thermal stability, anti-corrosive, and antimicrobial properties of the coating films were enhanced with increasing percentages of nanomaterials in the polyurethane systems. Coating films exhibited improved hydrophobicity with rising percentages of modified nanoparticles. Film photographic retention tests showed no particle agglomeration and high transparency at 0.5% graphene oxide composition (0.5% PU-GO). It also shows that the polymer with 0.5% PU-GO is the most thermally stable. Similarly, composite films of modified silica in CSO showed enhanced thermal stability, hydrophobicity, antimicrobial activity, and corrosion resistance. The polymer with 5% PU-SNP was the most thermally stable at high temperatures. It also has the highest water contact angle and lowest corrosion rate, hence the most hydrophobic and corrosion resistant. In conclusion, the 0.5% loading of modified graphene oxide (0.5% PU-GO) nanoparticles is the optimum loading in applications requiring low and high temperatures. At the same time, 5% loading is the optimum loading of APTMS-modified silica (5% PU-SNP) in applications that require high temperature. These results present a viable, sustainable alternative for various industrial applications.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | renewable polymers, castor oil, polyurethane, nanomaterial, coatings. |
| Subjects: | Q Science > QD Chemistry |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Chemistry |
| Depositing User: | Patricia Nwokealisi |
| Date Deposited: | 15 Oct 2024 16:06 |
| Last Modified: | 15 Oct 2024 16:06 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/18505 |
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