Polyurethane is a common polymeric coating, providing abrasion resistance, chemical durability, and flexibility to surfaces in the biomedical, marine, and food processing industries with great promise for future materials due to its tunable chemistry. There exists a large body of research focused on modifying polyurethane with additional functionalities, such as antimicrobial, non-fouling, anticorrosive action, or high heat resistance. However, there remains a need for the characterization and surface analysis of fluoro-modified polyurethanes synthesized with commercially available fluorinated polyol. In this work, we have synthesized traditional solvent-borne polyurethane, conventionally found in food processing facilities, boat hulls, and floor coatings, with polyurethane containing 1%, 2%, and 3% perfluoropolyether (PFPE). Polyurethane formation was confirmed by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, with the urethane band forming at 1730 cm−1 and the absence of free isocyanate stretching from 2275–2250 cm−1. X-ray photoelectron spectroscopy (XPS) was used to confirm perfluoropolyether polymerization with an increase in the atomic percentage of fluorine. Wettability and hydrophobicity were determined using a dynamic water contact angle with significant differences in advancing the water contact angle with the inclusion of perfluoropolyether blocks (PU–co–1PFPE 131.5° ± 8.0, PU–co–2PFPE 130.9° ± 5.8, and PU–co–3PFPE 128.8° ± 5.2) compared to the control polyurethane (93.6° ± 3.6). The surface orientation of fluorine supported the reduced critical surface tensions of polyurethane modified with PFPE (12.54 mN m−1 for PU–co–3PFPE compared to 17.19 mN m−1 for unmodified polyurethane). This work has demonstrated the tunable chemical qualities of polyurethane by presenting its ability to incorporate fluoropolymer surface characteristics, including low critical surface tension and high hydrophobicity.
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Synthesis and properties of linseed oil-based waterborne non-isocyanate polyurethane coating
Significant strides in the development of non-isocyanate polyurethane (NIPU) have been made in the coatings industry. Aligned with green chemistry principles, this study explores the use of bio-based, low volatile organic compounds and fast-curing waterborne NIPU for coating applications. The linseed oilbased cyclic carbonate was synthesized via a thiol–ene click reaction and was followed by an esterification reaction directly from linseed oil. In this structure, the cyclic carbonates are introduced as pendant functional groups to accelerate the curing. Next, a series of linseed oil-based waterborne NIPUs were synthesized and developed from the linseed oil-based cyclic carbonate, a bio-based fatty acid diamine, and an internal dispersion agent. Different formulations of the linseed oil-based NIPU coatings were designed by varying the internal dispersion agent content and urethane content, and a solvent-borne NIPU was included in the study for comparison purposes. The NIPU coatings with different formulations achieved a broad range of thermal stabilities, viscoelastic properties, and mechanical properties. The general coating properties—including hardness, solvent resistance, impact resistance, and adhesion—were evaluated to demonstrate the practical application of the waterborne NIPU in coatings. The linseed oil-based waterborne NIPU coatings exhibited performance comparable to both a solvent-borne NIPU coating and a commercial waterborne isocyanate-based polyurethane coating.
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- Award ID(s):
- 1943860
- PAR ID:
- 10514153
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Green Chemistry
- Volume:
- 25
- Issue:
- 23
- ISSN:
- 1463-9262
- Page Range / eLocation ID:
- 10082 to 10090
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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