Abstract Bacterial cellulose is a biopolymer that is gaining attention due to its 3D structure, higher purity, porosity and surface area. However, this material can interact with water molecules from the surrounding environment, resulting in alterations of its properties. Hence, the purpose of this study was to analyze the modifications on the mechanical, water vapor permeability and optical properties of bacterial cellulose films as a function of the water activity. Results indicated that water acted as a plasticizer, mainly affecting mechanical and water vapor permeability properties. The moisture adsorption isotherms allowed predicting the moisture content of the bacterial cellulose films at several relative humidity conditions. Values for tensile strength and burst strength ranged from 15.50 to 22.28 MPa and from 145.03–338.10 g, respectively. The elongation and the distance to burst ranged from 1.36 to 3.71 % and from 0.39 to 1.86 mm, respectively. These values increased due to the plasticizing effect of the water molecules. Water vapor permeability values ranged from 1.35·10−12 to 3.13·10-11 g/ m s Pa, showing a significant increase up to 0.48 of water activity. Bacterial cellulose films showed excellent UV-barrier properties in the different water activities evaluated.

中文翻译：

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细菌纤维素薄膜：水相互作用的评价

摘要 细菌纤维素是一种生物聚合物，因其具有 3D 结构、较高的纯度、孔隙率和表面积而备受关注。然而，这种材料可以与周围环境中的水分子相互作用，导致其特性发生改变。因此，本研究的目的是分析细菌纤维素膜的机械、水蒸气渗透性和光学特性随水活性的变化。结果表明，水作为增塑剂，主要影响机械和水蒸气渗透性能。水分吸附等温线允许预测细菌纤维素膜在几种相对湿度条件下的水分含量。拉伸强度和爆破强度值的范围分别为 15.50 至 22.28 MPa 和 145.03-338.10 克。伸长率和爆裂距离分别为 1.36 至 3.71 % 和 0.39 至 1.86 毫米。由于水分子的增塑作用，这些值增加。水蒸气渗透率值范围为 1.35·10-12 至 3.13·10-11 g/ms Pa，表明水分活度显着增加至 0.48。细菌纤维素薄膜在评估的不同水活性中表现出优异的紫外线阻隔性能。