Modification and characterization of starch nanoparticles

乳胶是聚合物颗粒在水中的分散体，在多种应用中都很有用，如油漆，它们在表面上形成保护涂层，或作为粘合剂确保构成纸和纸板的无纺布纤维的附着力，或作为地毯衬底，在那里它们为编织纤维提供强度和支撑。聚合物乳胶通常是由石油馏分油生产的。随着石油供应变得越来越稀缺和昂贵，该行业正在寻找更便宜、更环保的石油基乳胶替代品。Ecosphere®是Ecosynthetix从玉米或木薯淀粉原料中制备的碳水化合物为基础的乳胶。因此，Ecosphere®由可再生资源生产，并在水中形成稳定的交联淀粉颗粒乳液，这种乳液已经在造纸工业中得到了应用。本课题旨在通过化学修饰这些生物胶凝物，扩大对其的理解和应用范围，并表征这些修饰赋予纳米颗粒的性质。Ecosphere®纳米颗粒将通过疏水垂坠、带正电荷和负电荷的基团或其组合的共价附着以及线性聚合物的附着（接枝）来修饰。这些修饰的程度将被量化，它们对所获得的材料物理性质的影响将分别在分子和宏观水平上通过荧光和流变实验进行研究。他们的性能作为改进的生物橡胶粘合剂在纸张涂层应用将进行测试。此外，将通过监测其装载能力、靶向效力和对活细胞的毒性来探索使用改性Ecosphere®作为药物递送载体的可能性。总之，这组实验将提供对应用于Ecosphere®纳米颗粒的修饰所产生的结构-性能关系的全面理解。

Latexes are dispersions of polymer particles in water useful in multiple applications such as paints, where they coalesce to form a protective coating on surfaces, or as binders ensuring the adhesion of non-woven fibers constituting paper and paperboard, or as carpet backing, where they provide strength and support for the woven fibers. Polymers latexes are typically produced from petroleum distillates. As oil supplies become scarce and more expensive, the industry is looking for cheaper and greener alternatives to petroleum-based latexes. Ecosphere® is a carbohydrate-based latex prepared by Ecosynthetix from corn or tapioca starch feedstocks. Ecosphere® is thus produced from renewable resources and forms stable emulsions of crosslinked starch particles in water that have already found applications in the paper industry. This proposal aims to expand the understanding and the scope of application of these biolatexes by chemically modifying them, and characterizing the properties imparted the nanoparticles by these modifications. Ecosphere® nanoparticles will be modified by the covalent attachment of either hydrophobic pendants, positively and negatively charged groups, or a combination thereof, and through the attachment (grafting) of linear polymers. The extent of these modifications will be quantified and their influence on the physical properties of the materials obtained will be investigated at the molecular and macroscopic levels with fluorescence and rheology experiments, respectively. Their performance as improved biolatex binders in paper coating applications will be tested. Furthermore the possibility of using modified Ecosphere® as drug delivery vehicles will be explored by monitoring their loading capacity, targeting efficacy, and toxicity to living cells. Together, this set of experiments will provide a comprehensive understanding of the structure-property relationships resulting from the modifications applied to the Ecosphere® nanoparticles.