Lignin is a natural anti-UV biopolymer, and the use of lignin as a sunscreen additive is an attractive strategy for lignin valorization. However, its dark color and the variation in anti-UV performance seriously hinder its application as a commercial sunscreen ingredient. In this study, modification of a commercial alkali lignin (AL) is undertaken to significantly improve its anti-UV performance and color. Two small molecule UV absorbers, dihydroxybenzopheone (UV0) and methylenebis-benzotriazolyl tetramethylbutylphenol (MBBT) were grafted onto the AL via atom transfer radical polymerization reaction, leading to a terpolymer, AL-g-UV0/MBBT (AUM). Subsequently, submicron spheres of AUM were assembled by the solvent shifting method. The physio-chemical properties of AUM and its submicron spheres were characterized. The results showed that the color difference value (ΔE) of AUM submicron spheres was significantly reduced to 16.73 from 72.21 with AL. Moreover, with the application of AUM spheres in sunscreen, the sun protection factor (SPF) was significantly improved to 46.2 at 10 % loading compared to 4.2 with AL at the same loading, and the ΔE was reduced to 45.59 compared to 65.86 with AL. This study provides useful information and insights into design and development of lignin-containing sunscreens.

中文翻译：

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用于防晒应用的木质素三元共聚物亚微米球的合成


木质素是一种天然的抗紫外线生物聚合物，使用木质素作为防晒添加剂是木质素增值的一种有吸引力的策略。然而，它的深色和抗紫外线性能的变化严重阻碍了它作为商业防晒成分的应用。在本研究中，对商业碱性木质素 （AL） 进行了改性，以显着改善其抗紫外线性能和颜色。两种小分子紫外线吸收剂二羟基苯并苯二酮 （UV0） 和亚甲基双苯并三唑基四甲基丁基苯酚 （MBBT） 通过原子转移自由基聚合反应接枝到 AL 上，得到三元共聚物 AL-g-UV0/MBBT （AUM）。随后，通过溶剂转移法组装 AUM 的亚微米球。表征了 AUM 及其亚微米球体的物理化学性质。结果表明，AL 组 AUM 亚微米球体的色差值 （ΔE） 从 72.21 显著降低至 16.73。此外，随着 AUM 球体在防晒霜中的应用，防晒系数 （SPF） 在 10% 负载下显著提高至 46.2，而在相同负载下使用 AL 时为 4.2，ΔE 降低至 45.59，而使用 AL 时为 65.86。本研究为含木质素的防晒霜的设计和开发提供了有用的信息和见解。