Alginates with excellent film‐forming ability have a promising potential as a safe and biodegradable food packaging material, but as a hydrophilic biopolymer, its general weakness against water has limited its applications. To surpass this weakness, in this study, coating of calcium alginate films with linseed or sunflower oils in micrometric (about 4.55 μm) and submicrometric (about 0.45 μm) thickness was performed, and the characteristics of the films were evaluated. All of the films were homogeneous, transparent and almost colourless. Micro‐coated films presented improved ultraviolet absorbing spectra. The scanning electron microscopy (SEM) images proved the formation of homogeneous and continuous submicron‐coated oil layers for both types of the oils, while some inhomogeneity and defects were observed in the micro‐coated films. Oxidative polymerization of linseed oil was confirmed by Fourier transform infrared (FTIR) spectral analyses. The mechanical strength of the films micro‐coated with linseed oil increased. Submicron coating improved water vapour barrier properties (from 2.20 to 2.92 g/mm/m²/day/kPa) as well as water vapour absorption of the alginate film compared to other films. This result was confirmed by thermogravimetric analyses. The increase in surface hydrophobicity of the films by coating resulted in a significant increase in contact angle (from 46.3° to 89.9° in maximum) and reduction of wettability. The film submicron coated with linseed oil showed the best performance with the least water vapour permeability, water vapour absorption and wettability.

中文翻译：

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通过干燥亚麻籽油的亚微米涂层改善藻酸盐包装膜的阻水性能

具有优异成膜能力的藻酸盐作为一种安全且可生物降解的食品包装材料具有广阔的发展潜力，但作为亲水性生物聚合物，其对水的一般弱点限制了其应用。为了克服这一弱点，在这项研究中，用亚麻籽油或葵花籽油以微米级（约4.55μm）和亚微米级（约0.45μm）的厚度涂覆海藻酸钙薄膜，并评估了薄膜的特性。所有的膜都是均匀的，透明的并且几乎是无色的。微涂膜呈现出改善的紫外线吸收光谱。扫描电子显微镜（SEM）图像证明了两种类型油的均质和连续亚微米涂层油层的形成，而在微涂层膜中观察到一些不均匀性和缺陷。亚麻籽油的氧化聚合反应通过傅里叶变换红外光谱（FTIR）光谱分析得到证实。微涂了亚麻籽油的薄膜的机械强度有所提高。亚微米涂层改善了水蒸气阻隔性能（从2.20至2.92 g / mm / m² / day / kPa）以及与其他薄膜相比的藻酸盐薄膜的水蒸气吸收率。通过热重分析证实了该结果。通过涂布膜的表面疏水性的增加导致接触角显着增加（最大从46.3°至89.9°）并降低了润湿性。涂有亚麻籽油的亚微米薄膜表现出最佳性能，而水蒸气渗透率，水蒸气吸收率和润湿性最低。