Moisture-mediated self-healing kinetics and molecular dynamics in modified polyurethane urea polymers

Wittmer, Anastassija; Wellen, Renate Maria Ramos; Saalwächter, Kay; Koschek, Katharina

doi:10.1016/j.polymer.2018.07.059

Cited by 16 publications

(15 citation statements)

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“…The authors used the increase in the lower relaxation time T 2 and its exponent in the three components fitting as the main parameters to confirm the increased mobilization of chains with increased humidity and increased amount of UDETA. Matching the variation of a mobile fraction with observations from other optical techniques, they could define a threshold of at least 59% of mobile-like dynamics to achieve self-healing [45].…”

Section: Discovery and Characterization Of New Materialsmentioning

confidence: 99%

Time Domain NMR in Polymer Science: From the Laboratory to the Industry

2019

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Highly controlled polymers and nanostructures are increasingly translated from the lab to the industry. Together with the industrialization of complex systems from renewable sources, a paradigm change in the processing of plastics and rubbers is underway, requiring a new generation of analytical tools. Here, we present the recent developments in time domain NMR (TD-NMR), starting with an introduction of the methods. Several examples illustrate the new take on traditional issues like the measurement of crosslink density in vulcanized rubber or the monitoring of crystallization kinetics, as well as the unique information that can be extracted from multiphase, nanophase and composite materials. Generally, TD-NMR is capable of determining structural parameters that are in agreement with other techniques and with the final macroscopic properties of industrial interest, as well as reveal details on the local homogeneity that are difficult to obtain otherwise. Considering its moderate technical and space requirements of performing, TD-NMR is a good candidate for assisting product and process development in several applications throughout the rubber, plastics, composites and adhesives industry.

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Section: Discovery and Characterization Of New Materialsmentioning

confidence: 99%

Time Domain NMR in Polymer Science: From the Laboratory to the Industry

2019

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“…To our knowledge, this is the first report of moisture-healing property of NIPU-based coatings. Intrinsic moisture-healing properties of polyelectrolytes, , boronic-ester polymers, , and some polyurethane-polyureas , were only very recently reported. Moisture-healing property of these NIPU-based coatings was due to the presence of different polar groups, especially −OH groups in its structure.…”

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confidence: 99%

Biobased Nonisocyanate Polyurethanes as Recyclable and Intrinsic Self-Healing Coating with Triple Healing Sites

et al. 2021

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Polymer coatings having high amounts of renewable carbon and self-healing properties are highly sought after in a sustainability perspective. We report here the development of bio-/ CO 2 -derived nonisocyanate polyurethane (NIPU) coatings which are recyclable and healable via three different types of healing mechanisms. These NIPUs contain furan rings in their main chain which after cross-linking with bismaleimides form organogels having a thermo-reversible sol−gel transition and solvent-borne coatings with improved properties. Judicial selection of the bismaleimide cross-linker structure enabled us to produce recyclable and intrinsic healable coatings mediated by heat (thermo-healing), moisture (moisture-healing), and, more interestingly, dry conditions at room temperature (self-healing). The intrinsic moisture-healing property of NIPU-based coatings is unprecedented and is mainly due to the presence of hydroxyl functionalities in the NIPU structure. The uniqueness of these cross-linked biobased NIPU as recyclable coatings having triple healing sites present in their structure gives these materials potential for sustainable and functional applications.

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“…The experiments were conducted on a Bruker mq20 ND minispec following the previously published procedures. 29,79,80 Specifically, free induction decays were recorded as a function of acquisition time t acq directly after a single 901 pulse (FID) and after a mixed magic-sandwich echo (MSE). The latter refocuses the full signal over the significant instrumental dead time of about 15 ms and thus enables a reliable fit to the data (the total MSE echo delay amounts to 6 Â 15 ms = 90 ms).…”

Section: Methodsmentioning

confidence: 99%