木质素具有优异的紫外线吸收性能，可以对全波段紫外线起到防护作用。作为一种来源丰富、天然、可再生的广谱紫外线防护剂，木质素的抗紫外辐射功能具有重要的开发利用价值。由于木质素结构复杂，其抗紫外辐射能力的构效关系与作用机制研究尚属空白。本研究提出采用具有代表性的木质素模型物，进行抗紫外辐射能力构效关系及作用机制研究。研究中将兼顾工业木质素结构特征，进行模型物设计、合成及结构鉴定。采用结构明确的木质素模型物，分别添加至纯护肤霜或者市售SPF15防晒霜中，进行抗紫外辐射性能评价，揭示木质素模型物结构和抗紫外辐射能力之间的关系。进而选取适当的模型物，研究其在不同UV波段抗紫外辐射性能和结构变化机制。最后，结合特定结构木质素抗紫外辐射性能评价，阐明木质素抗紫外辐射作用机制。该项目的成功实施，可以明确木质素在防晒应用中的有效结构，为木质素基防晒霜的开发利用提供理论依据。

As a highly abundant natural and renewable aromatic polymers, lignin has been proven to be a good UV-absorber and a nature broad-spectrum sun blocker. Using lignin as sunscreen additives can greatly promote the high-end applications of industrial lignins. However, the mechanism and structure-activity relationship of lignin under UV radiation remains unclear due to lignins’ complexity and heterogeneity. In this proposal, a series of model compounds representing structures both in industrial lignins and natural lignins will be designed and synthesized, and structure-activity relationship of lignin for anti-UV radiation and its mechanism will be conducted by using such compounds. In this study, each of these model compounds will be added into pure creams or SPF 15 commercial sunscreens as sun-screening agent, and its following UV absorbance will be evaluated by different methods. Subsequently, mechanism study of model compounds, together with the UV absorbance of certain industrial lignin preparations, for anti-UV radiation under UV radiation will be elucidated. This study will provide a theoretical basis for optimizing lignins as sun-screening agent in lignin-based sunscreens, which could be beneficial for utilization of lignocellulosic biomass.