木质素乙醇溶液法分级及其防晒性能研究

Study on Ethanol Fractionation of Lignin and Its Sunscreen Performance

中文关键词:  木质素  乙醇分级  结构表征  防晒霜  紫外吸收

Key Words:lignin  ethanol fractionation  structural characterization  sunscreen  ultraviolet absorption

中文摘要:

      木质素作为自然界含量仅次于纤维素的生物质资源，其聚芳香结构具有紫外吸收特性，研究价值较高。但工业木质素因来源和提取工艺不同，相对分子质量和结构不均匀，产品性能各异。本研究采用乙醇溶液法分级纯化玉米芯工业木质素（EL 0），得到EL 100、EL 70和ELR 3种级分，再将各木质素级分分别掺入商用婴儿面霜中制备木质素基防晒霜，并评估其防晒性能。对制备所得木质素基防晒霜进行防晒性能测试可得，分级前后木质素样品的紫外吸收能力由强到弱依次为ELR > EL 70 > EL 0 > EL 100；当木质素基防晒霜中木质素质量分数为10%时，EL 0防晒霜的防晒系数（SPF）值仅为12.55；ELR防晒霜的SPF值达51.79，防晒性能增强，但产品颜色较深；EL 70防晒霜的SPF值为48.88，同时颜色相对较浅，应用领域更加广泛。研究结果表明，乙醇溶液法分级处理可有效降低木质素结构的非均质性，优化木质素在防晒产品中的作用效果。

Abstract:

      Lignin， as a biomass resource second only to cellulose in nature， is of high research value because of its polyaromatic structure with ultraviolet absorption properties. However， industrial lignin has uneven molecular mass and structure due to different sources and extraction processes， and the product properties vary. In this study， the ethanol solution method was used to grade purified corn kernel industrial lignin （EL 0） to obtain three lignin grades： EL 100， EL 70， and ELR. Then the graded lignin was blended into commercial baby creams to prepare lignin-based sunscreens， respectively， and to evaluate their sun protection properties. The sunscreen properties of prepared lignin-based sunscreens were tested， the results showed that UV absorption capacity of lignin samples before and after fractionation was ELR > EL 70 > EL 0 > EL 100 in descending order. When the mass fraction of lignin of lignin-based sunscreens was 10%， the sun protection factor （SPF） value of EL 0 sunscreen was only 12.55； the SPF value of ELR sunscreen reached 51.79， which enhanced the sunscreen performance while made the product darker in color. With an SPF value of 48.88， the EL 70 had a relatively lighter color for a wider range of applications. The results indicated that the graded treatment by ethanol solution method can effectively reduce the inhomogeneity of lignin structure and optimize the effect of lignin in sunscreen products.