Non-isocyanate polyurethanes (NIPU) from renewable resource have attracted much attention for significant benefit for sustainable development and green production. However, the low molar mass and poor mechanical properties of NIPU...
Establishment of both mechanically robust yet facile healable and recyclable epoxy resin systems are highly desirable and still present significant challenges. Herein, by fully utilizing epoxidized vegetable oils and dithiol...
Tailoring the performance of waterborne
polyurethanes through composition
control and structural optimization to meet the highly diversified
modern demands is still one of the primary challenges faced by the
polyurethane industry. Herein, various natural phenolic acids as neutralizers,
for the first time, were applied for the preparation of castor oil-based
cationic waterborne polyurethanes (CWPUs). The effects of these neutralizers
on the microstructure (phase separation and hydrogen bond) and performance
(mechanical properties, antibacterial activities, etc.) of the CWPUs
were systematically investigated and compared with those of other
commonly used neutralizers. The results indicate that apart from serving
as neutralizers, phenolic acids also acted as antiplasticizing agents
for the CWPU films by increasing the rigidity of the hard segment
and hydrogen bond number. Also, the hydrophobic, rigid, conjugated
structure of phenolic acids endowed the resulting CWPU films with
excellent water resistance and UV protection. The introduction of
phenolic acids also endowed the resulting polyurethane films with
good antibacterial performance against both Gram-positive and Gram-negative
bacteria. This study provides a novel and facile approach to tailor
the performance of environmentally friendly cationic waterborne polyurethanes
through natural phenolic acid neutralizers, along with eliminating
long-standing issues of WPUs, such as irritating odor and air pollution.
In this paper, two novel fully renewable internal emulsifiers have been successfully synthesized from epoxidized soybean oil and natural acids (adipic and pimelic acid) by a solvent-free and self-catalytic method. It is found that the emulsifiers show similar chemical structure and functions with typical petroleum based internal emulsifiers (dimethylol butanoic acid and dimethylol propionic acid), in which the hydroxyl groups act as a cross-linking and the carboxylic acid groups provide the ionic segment. These two novel internal emulsifiers were employed together with castor oil to prepare a series of high biocontent anionic waterborne polyurethane dispersions (PUDs). The unique structure of these two emulsifiers and their good compatibility with castor oil offer PUDs excellent storage stability. Additionally, the biocontent of the polyurethane are high up to 77.7%. Moreover, the adhesive properties of the biobased pressure sensitive adhesives (PSA) were comprehensively investigated by shear resistance, tack, and 180°peel strength test. The PSAs had a shear strength of 1.18 h to more than 100 h, a tack of 1.78−5.66 N, and a peel strength of 1.23−2.77 N/mm, all WPU PSA show good pressure sensitive adhesive properties, which would further expand the application of these novel vegetable oil-based waterborne PUDs.
Plant oils are becoming of high industrial importance due to the persisting challenges befalling with the utilization of fossil fuels. Thus, developing methodologies to produce multifunctional materials by taking advantage of the unique structure of plant oil is highly desired. In this study, castor oil served as a cross-linker and soft segments, by incorporating scalable rhodamine 6G derivatives, to systematically synthesize a series of smart polymers that possess self-toughening and multistimuli-responsive capabilities. The polyurethane elastomers showed 10 times and 60 times increases in tensile strength and toughness, respectively, in comparison with the unmodified polyurethane due to the existence of large amounts of hydrogen bonding, dynamic C−N spiro bonds, rigid benzene ring, and high cross-link densities. The novel polyurethane elastomers exhibited excellent reversible multichromic behaviors in response to light, pH, and mechanics. Notably, the resulting polyurethane elastomers exhibited ultrasensitive sustained photochromism with tunable white emission and rapid reversibility. This study provides a simple and effective strategy to utilize plant oil for multifunctional material preparation and paves the way to open access for application of plant oil-based products in a variety of industry applications, such as sensors, self-fitting tissue scaffolds, and switchable devices.
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