松香改性纳米纤维素对Pickering乳液稳定机制及响应性调控研究

In view of the weakness of the stability and stimuli-responsiveness of Pickering emulsion prepared by nanocellulose (CNCs) and its derivatives as emulsifier, a new type of amphiphilic CNCs is designed to construct Pickering emulsion system with high stability and responsiveness under environmental change. In this project, rosin is used as raw material, primary, middle and tertiary amine are introduced into the ternary phenanthrene ring skeleton, and they are used in the hydrophobic modification of CNCs to regulate the amphiphilicity of CNCs and to give CNCs stimuli-responsiveness so that the rosin modified CNCs are obtained. The self-assembly and adsorption behavior of rosin modified CNCs at oil/water interface are induced and regulated by the strong hydrophobic interaction and stimuli-responsiveness of the rosin rigid skeleton, and the Pickering emulsion system with high stability and stimuli-responsiveness are constructed. The effect of rosin rigid structure on the self-assembly of rosin modified CNCs at the oil/water interface and the formation of a tight interface film are revealed. The stability mechanism and response regulation mechanism of Pickering emulsion system stabilized by rosin modified CNCs are clarified, and the stability model and stimulation response model are established. It provides a new theoretical basis for the design and preparation of functional Pickering emulsion system with high stability and stimulation response, and to provide a new idea for the high-value utilization of rosin in the emulsion filed.

针对目前以纳米纤维素（CNCs）及其衍生物为乳化剂制备的Pickering乳液稳定性和刺激响应性不能兼顾的不足，设计制备新型两亲CNCs并构建高稳定性且在环境变化下具有响应性的Pickering乳液体系。本项目以松香为原料，在氢化菲环骨架上引入伯、仲、叔胺等基团，并将其用于CNCs的疏水改性，调控CNCs的两亲性并赋予其刺激响应性，得到松香改性纳米纤维素；利用松香刚性骨架的强疏水作用和刺激响应性诱导并调控CNCs在油水界面的自组装和吸附行为，构建兼具高稳定性和刺激响应性的Pickering乳液体系。揭示松香刚性结构对诱导CNCs在油水界面自组装并形成紧密界面膜的影响规律，阐明松香改性纳米纤维素对Pickering乳液体系的稳定机制和响应性调控机制，建立其稳定模型和刺激响应模型，为功能性Pickering乳液体系的设计与制备提供新的理论依据，为松香在乳液领域的高值化利用提供新的研究思路。

松香是我国重要的特色林业资源，松香树脂酸及其衍生物具有与石油基芳香族和脂环族化学物相类似的刚性和疏水性，以其为原料通过化学修饰得到的系列衍生物在香精香料、医药及化工等领域得到了广泛应用。针对目前以纳米纤维素及其衍生物为乳化剂制备的Pickering乳液稳定性和刺激响应性不能兼顾的不足，设计制备了新型两亲纳米纤维素，并构建了具有高稳定性和响应性的Pickering乳液体系。.以松香为原料制备一种CO2/N2响应型松香活性中间体—马来海松酸缩水甘油酯3-二甲氨基丙胺酰亚胺（MPANGG），随着CO2/N2的交替通入可以在阳离子（MPANGGH+）和非离子（MPANGG）之间可逆转换。向MPANGG和MPANGGH+水溶液中分别加入纳米Al2O3，稳定Pickering乳液所需MPANGG或MPANGGH+的量都大大减少。机理分析表明带电纳米粒子分散在连续相中，利用纳米粒子之间的静电排斥力提高乳液的稳定性。.以脱氢枞醇和纳米纤维素为原料，在纳米纤维素结构中引入氢化菲环刚性结构，制备得到脱氢枞基缩水甘油醚改性纳米纤维素。由于纳米纤维素的亲水性较强，引入松香疏水刚性基团后，解决了纤维素亲水性的问题。结果表明，脱氢枞基缩水甘油醚改性纳米纤维素可以较好的吸附于Pickering乳液的油水界面，有效提升了Pickering乳液的稳定性能。.通过酰胺化和酯化等反应向纳米纤维素结构中引入松香刚性疏水骨架及刺激响应性基团，制备得到了CO2/N2响应型松香酰亚胺改性纳米纤维素。研究表明，松香酰亚胺改性纳米纤维素含量在0.01wt%时，即可获得高稳定性和刺激响应性的Pickering乳液。通过盐酸或氢氧化钠调节Pickering乳液中水相的酸碱性或在Pickering乳液中间隔通入CO2和N2气体，可实现Pickering乳液乳化/破乳状态之间的智能调控。.本项目利用松香刚性骨架的强疏水作用和引入的刺激响应性基团构建兼具高稳定性和刺激响应性的Pickering乳液体系，为功能性Pickering乳液体系的设计与制备提供新的理论依据，为松香在乳液领域的高值化利用提供新的研究思路。