Role Evaluation of Active Groups in Lignin on UV-Shielding Performance

Abstract

The contribution of the active groups in lignin to ultraviolet (UV)-shielding performance still remains unclear. In this study, we employed 16 lignin model compounds and theoretical calculations to ascertain the contribution of different functional groups to UV-shielding performance. These results showed that the order of UV-shielding performance on functional groups wasMoreover, the synergism between the para-substituted electron-donating group −OH and the electron-withdrawing group allyl on the aromatic ring played a major role in UV-shielding performance of lignin models, whereas the additive effect of meta/ortho-substituted −OCH 3 played a secondary role. Furthermore, we found that the hydrophile− lipophile balance (HLB) value of lignin models also greatly affected the sunscreen protection factor (SPF) of lignin model-based sunscreens. A closer HLB value of lignin to 8.89 corresponded with a higher SPF of the lignin model-based sunscreen. The commercial photoprotective ingredient ethylhexyl methoxycinnamate (EHMC) and lignin models had a synergistic effect on UVshielding performance caused by the π−π stacking interaction between the parallel-displaced stacked aromatic rings of lignin models and EHMC. Additionally, the UV irradiation test showed that these sunscreens prepared using lignin models and EHMC exhibited good photostability.

Effect of Molecular Organization on the Properties of Fractionated Lignin-Based Thiol–Ene Thermoset Materials

“…Based on the distance within these repeating features, D 2 and D 3 can be attributed to T-shaped and sandwich π–π stacking (combined parallel displaced and cofacial parallel stacked) interactions between the abundant lignin aromatic rings. ,− This should however be considered a simplification due to the highly complex three-dimensional lignin network structures. These π–π stacking interactions between aromatic rings normally play an important role in the stability of the systems and their properties. ,, It is however not clear how these internal stacking interactions scale when being imbedded into a larger structural ordering. D II order 3 and D II order 4 ( D II order 3 or 4 = D 3 or 4 /2) were attributed to be the so-called second-order signal of D 3 and D 4 .…”

Artemisia sieversiana Ehrhart ex Willd. Essential Oil and Its Main Component, Chamazulene: Their Photoprotective Effect against UVB-Induced Cellular Damage and Potential as Novel Natural Sunscreen Additives

“…In the present time, chemical sunscreens, which are composed of synthetic small-molecule substances, account for 80% of commercial sunscreens . Due to their inadequate protection against UV, as well as their side effects on marine ecosystems and human health, there has been growing interest in developing natural substitutions to chemical sunscreens. , Botanical antioxidants can act as natural chemophotoprotectors with the potential to neutralize ROS production while also enhancing the endogenous antioxidant capacity of the skin .…”

Whiten Lignin-Based Sunscreen via Fractionation and Ultrasonic Cavitation

“…The aromatic rings and carbonyl groups are chromophoric structures, and hydroxyl and methoxy groups are auxochromes. 35 XPS characterization was thus employed to study the surface chromophore distribution of EHL before and after fractionation. As shown in Figure 3e Preparation and Characterization of EHL-Based Capsules.…”