Abstract The effect of blue crab chitosan acetylation degree (AD) on its rheological, thermal and film-forming properties was investigated. Determination of the dynamic viscoelastic properties (elastic modulus G’ and viscous modulus G”) of chitosan solutions revealed a typical Newtonian viscous-like behavior, with higher viscosity values at lower acetylation degrees. Moreover, the gelation temperature of blue crab chitosan was strongly dependent on its acetylation degree, with lower values at lower acetylation degrees. Regarding chitosan thermal stability, thermogravimetric profiles revealed greater thermal resistance for chitosans with lower acetylation degrees, showing significantly higher degradation temperature. Likewise, the values of glass transition temperature decreased with the increase of the acetylation degree. In another side, chitosan-based films, with lower acetylation degrees, are found to be more flexible, resistant and transparent. Therefore, blue crab chitosan acetylation degree modulated toughly its viscosity, elongation at break, tensile strength and thermal resistance. Further, chitosans with ADs less than 20% seemed to have potential industrial applications.

中文翻译：

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乙酰化度，一个调节壳聚糖流变、热和成膜性能的关键参数

摘要 研究了蓝蟹壳聚糖乙酰化度（AD）对其流变学、热学和成膜性能的影响。壳聚糖溶液的动态粘弹性特性（弹性模量 G' 和粘性模量 G”）的测定显示出典型的牛顿粘性样行为，在较低的乙酰化度下具有较高的粘度值。此外，蓝蟹壳聚糖的凝胶温度与其乙酰化程度密切相关，乙酰化程度越低值越低。关于壳聚糖的热稳定性，热重曲线显示乙酰化程度较低的壳聚糖具有更大的耐热性，显示出明显更高的降解温度。同样，玻璃化转变温度值随着乙酰化程度的增加而降低。在另一边，发现乙酰化程度较低的壳聚糖基薄膜更柔韧、更耐久且更透明。因此，蓝蟹壳聚糖乙酰化程度对其粘度、断裂伸长率、拉伸强度和耐热性有较强的调节作用。此外，ADs 低于 20% 的壳聚糖似乎具有潜在的工业应用。