Synthesis, characterization and seawater biodegradability of paramylon mix ester derivatives with different DS

A two-step synthesis method was established to prepare paramylon mix ester derivatives with low total DS by introducing long chain hexanoate into biodegradable polysaccharide esters with short chain acetate. The relationship between the chemical structure of paramylon mix esters and their thermal properties and seawater biodegradability was investigated. Among the possible hydroxyl groups of paramylon backbone, hydroxyl group on C6 position is prior to be substituted for both paramylon acetate (PaAc) and paramylon acetate hexanoate (PaAcHex). Prepared paramylon esters are amorphous and more thermal stable than neat paramylon. PaAcHex showed lower Tg and more flexibility when hexanoate were added more. The capability of biodegradability of mix esters with different collocations was also determined. Hexanoate with low DS provides paramylon esters with effective mechanical properties without losing the seawater biodegradability. These results of collocations of short and long ester chains were verified to be an effective thought to realize the coexistence of thermoformability, mechanical property and biodegradability.