林木半纤维素的高效分离和转化既是生物质利用的重要组成部分，也是木质纤维高效利用面临的重要科学问题。本项目以不同生长阶段的四种桉树（巨尾桉，尾巨桉，巨桉，赤桉）为原材料，在阐明桉树木质素—碳水化合物复合体（LCC）的化学结构特征、变化规律和解离机制的基础上；研究不同生长阶段半纤维素组分的组成和溶出机制，构建半纤维素组分的清洁高效分离新技术，并通过结构和流变特性研究半纤维组分的化学结构特征和理化性质。再以分离半纤维素组分为原料，通过多种化学修饰构建半纤维素基膜材料、多孔材料和催化材料；揭示半纤维素理化性能与材料结构及性能关系；探讨半纤维素基功能材料在食品包装及催化反应等方面的应用，阐明材料结构与性能的调控途径。本项目研究成果将为桉树遗传育种及多级资源化高效利用、特别是桉树等林木半纤维素高效分离及其功能材料构建、应用提供相关的理论基础和技术支撑。

Effective isolation and conversion of woody hemicelluloses to high value-added products is one of the most important and challenging issues in biomass utilization. In this project, lignin-carbohydrates complexes (LCCs) from four kinds of Eucalyptus species (Eucalyptus grandis x E.urophylla, Eucalyptus urophylla x E.grandis, E.grandis, and Eucalyptus camaldulensis) at different stages will be isolated and their chemical structures will be fully elucidated. The isolated LCCs will be used as models to investigate the dissociation mechanisms of the LCCs during different pretreated conditions. Based on the interpreted information obtained from LCCs, more effective methods for isolating hemicelluloses will be established. After the fully understood the chemical composition, structural features, molecular properties, and rheological properties of the isolated hemicelluloses, films, porous and catalytic materials will be prepared from the hemicelluloses by various approaches, and the influencing mechanisms and their interactions of physical and chemical properties of the native hemicelluloses and the prepared functional materials will be thoroughly investigated. Furthermore, the utilizations of the films, porous materials and catalytic carriers in food packaging and catalytic reactions will be also studied by various chemical modifications and compounding methods, and the regulatory mechanism of structure and properties of these materials will be revealed and established. In short, this project will provide important theoretical basis for genetic breeding and multiple applications of Eucalyptus as well as technical support to prepare value-added products from the hemicelluloses.