Abstract:

The presence of a large number of hydroxyl groups on the molecular backbone of starch endows the strong intermolecular hydrogen bonding interaction that limiting the free movement of the molecular chain，thus making it difficult for starch to achieve thermoplastic processing. That limits large⁃scale application of starch in plastic products. In this work， the esterification reaction of tert⁃butyl acetoacetate （t⁃BAA） with starch at different ratios was carried out in dimethyl sulfoxide （DMSO） solvent environment， so that the weak polar groups of acetoacetyl were introduced to modify the hydroxyl groups of starch to break the strong hydrogen bonds between starch molecules. And with the addition of modified montmorillonite （MMT）， the thermal stability of esterified starch was further promoted. The results indicated that the esterified starch with a degree of substitution of 0~1.57 was obtained， and the interlayer spacing of montmorillonite was successfully expanded from 1.53 nm to 2.02 nm， even showing a partial peeling state. Moreover， the thermoplastic processing was realized without adding plasticizer and its hydrophilicity was reduced， realizing the starch to achieve the thermoplastic processing without adding any other plasticizer， and then getting hydrophobic surface.

Key words: starch, montmorillonite, nanocomposite, thermoplastic processing, esterification reaction