壳聚糖大分子链的形态调控及其在微悬浮聚合中的分散稳定作用

发布时间：2018-06-08 21:24

本文选题：壳聚糖 + 微悬浮聚合　；参考：《高分子学报》2017年05期

【摘要】：以易去除可回用的壳聚糖(CS)为分散剂,通过微悬浮聚合制备微米级的软硬质聚合物胶粒.考察不同酸碱度下水相介质中CS大分子链的质子化程度、亲疏水性和形态结构,及其对油水界面处CS存在形态的影响,进而评估其对剪切均质化所制单体液滴的分散稳定作用.发现通过调节体系pH值可较容易地控制CS大分子链的质子化程度、亲疏水性以及在单体液滴表面的吸附效率和铺展程度,进而可在弱酸性环境下调控微悬浮聚合体系中CS的分散能力和稳定效果.特别是当pH值在6.0左右时,CS大分子链质子化程度和亲疏水性适中,链内易形成具有一定内聚密度的高分子链收缩构象、链间易形成由多根CS链缠结而成的疏松聚集状态.在此状态下的CS链对苯丙单体液滴具有较强的分散能力和稳定作用,因而通过微悬浮聚合可制得形态结构规整、分散状态良好的聚合物粒子.进一步与微悬浮聚合常用的无机粉末类和高分子类分散剂进行应用效果比较,发现CS具有形态调控性好、分散稳定效率高、易去除能回用、特别适合制备软质微米胶粒等优点,是一种有别于无机粉末类和高分子类分散剂的新型微悬浮聚合分散剂.
[Abstract]:Soft and hard polymer particles of micron size were prepared by microsuspension polymerization with easily removable chitosan (CS) as dispersant. The degree of protonation, hydrophobicity and morphological structure of CS macromolecular chain in aqueous medium with different pH and alkalinity, and its influence on the existence of CS at the oil-water interface were investigated, and the dispersion and stability of CS macromolecular chain on the monomer droplets produced by shearing homogenization were evaluated. It is found that the degree of protonation, hydrophobicity, adsorption efficiency and spreading degree of CS macromolecular chain can be easily controlled by adjusting the pH value of the system. Furthermore, the dispersion and stability of CS in microsuspension polymerization system can be regulated in weak acidic environment. Especially, when pH value is about 6.0, the degree of protonation and hydrophobicity of CS macromolecular chain is moderate, the conformation of polymer chain with certain cohesion density is easily formed in the chain, and the loose aggregation state formed by multiple CS chains entanglement between chains is easy to be formed. The CS chain in this state has strong dispersing ability and stabilizing effect on the droplets of styrene and propyl monomer, so the polymer particles with good morphology and good dispersion can be prepared by microsuspension polymerization. Compared with inorganic powder and polymer dispersant, it was found that CS has the advantages of good morphology regulation, high dispersion and stability efficiency, easy removal and reuse, especially suitable for preparing soft micron colloidal particles. It is a new kind of microsuspension polymerization dispersant, which is different from inorganic powder and polymer dispersant.
【作者单位】：浙江理工大学材料与纺织学院先进纺织材料与制备技术教育部重点实验室;
【基金】：国家自然科学基金(基金号51273182,51573168) 浙江理工大学521人才工程项目(项目号2015P03)资助
【分类号】：O636.1

【相似文献】