Bio-based photo-reversible self-healing polymer designed from lignin

Abstract

Through structure–activity relationship study and density functional theory, this research designs novel lignin-based photo-responsive crosslinkable polymer with engineerable self-healing properties by utilizing a green photo-polymerization method.

Linear Cyclobutane-Containing Polymer Synthesis via [2 + 2] Photopolymerization in an Unconfined Environment under Visible Light

“…An interesting feature of the [2 + 2] cycloaddition is its reversibility, and it was reported that the cyclobutane ring can undergo decyclization when irradiated with light of appropriate wavelengths. − We checked the possible decyclization of this polymer under irradiation with an UV light source (λ max = 275 nm), and a clear decrease in viscosity was observed after the system was irradiated for 24 h. The depolymerization of P1 can be further confirmed by overlaying GPC traces (Figure D). After 72 h of irradiation, the M n of P1 was found to be reduced from 140 to 10.6 kDa, suggesting a certain degree of degradation happened.…”

Eco-Friendly Photoreversible Adhesives Derived from Coumarin-Functionalized Epoxy Soybean Oil

“…The thermal stability of these three polymer networks was investigated with TGA, and thermograms are shown in Figure S6. Due to the structural similarity, all three polymers showed similar decomposition patterns with the thermal stability ( T 5% ) of 254, 287, and 321 °C, which shows the superior thermal stability of these crosslinked polymer networks compared to the previously reported bio-based polymer networks. , Figures S7–S9 show the DSC profiles of the polymer systems. As expected, the more flexible ESO-11-Coum showed lower glass-transition temperatures ( T g ) of 14 °C compared to the 24 and 45 °C of ESO-6-Coum and ESO-Coum, respectively.…”

“…It has the potential to increase the coating’s lifetime, which can help to reduce the energy consumption and environmental impact caused by standard coating repair techniques such as buffing and recoating. Previously, our group designed and synthesized stimulated healing polymer materials via various approaches. ,,− However, most of these systems were derived from petrochemical-based materials. We have designed and synthesized an eco-friendly, photoreversible system from commercially available, inexpensive, and renewable ESO in this study.…”

“…Moreover, it lowers the cost of producing polymer materials by utilizing low-cost light sources like laser and light-emitting diodes . Among the light-stimulated reactions, the reversible [2 + 2] cycloaddition reactions have attracted much attention as they do not require any initiators or catalysts and no byproducts are formed. − However, only a few compounds can undergo this type of reaction, including coumarin, cinnamic acid, and thymine . Coumarin is a plant-derived compound that undergoes dimerization in the presence of 365 nm light and from a cyclobutane ring, while irradiating with 254 nm of light cleaves the cyclobutane rings to reform the double bonds .…”

Organocatalytic [2 + 2] Photopolymerization under Visible Light: Accessing Sustainable Polymers from Cinnamic Acids

“…[15] Among various reactions of cinnamic acids, [2 + 2] photo-cycloaddition could be one of the most suitable reaction types to transform cinnamic acids into macromolecular materials (Figure 1). [16][17][18][19][20][21][22][23] However, due to the weak/no absorption of visible light and the low efficiency in inter-system crossing (ISC) to triplet states, the [2 + 2] photopolymerization of biscinnamate monomers did not proceed in solution. [24] Known examples were conducted in solid states under high-energy ultraviolet light irradiation, and polymer products were often found of low solubility and processibility (Figure 2a).…”