Free-standing and flexible biocomposite films formed by a polyaleuritate matrix and nanocellulose fillers (i.e., cellulose nanofibrils) have been fabricated by a sustainable process. For this, 9,10,16-trihydroxyhexadecanoic (aleuritic) acid from shellac and nanocellulose were blended at different ratios in water through a sonication process. Polymerization of the polyhydroxylated fatty acid into polyaleuritate was induced by a solvent-free, melting polycondensation reaction in the oven. These biocomposites were characterized to evaluate their chemical (by ATR-FTIR spectroscopy) and physical (e.g., density, thermal stability, rigidity, gas permeability, surface energy, etc.) properties. The compatibility between the polyester matrix and the polysaccharide fillers was excellent due to the interaction by H bonds of the polar groups of both components. The addition of nanocellulose increased all determined mechanical parameters as well as the wettability and the barrier properties, while the thermal stability and the water uptake were determined by the polyaleuritate matrix. The physical properties of these biocomposites were compared to those of petroleum-based plastics and bio-based polymers, indicating that the developed materials can represent a sustainable alternative for different applications such as packaging.

中文翻译：

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可持续，高阻隔的多醛酸酯/纳米纤维素生物复合材料

由多醛酸酯基质和纳米纤维素填料（即，纤维素纳米原纤维）已经通过可持续的方法制造。为此，通过超声处理将来自虫胶和纳米纤维素的9,10,16-三羟基十六烷酸（无醛）酸以不同比例混合在水中。通过在烘箱中进行无溶剂的熔融缩聚反应，可将多羟基化脂肪酸聚合成多醛酸酯。这些生物复合材料的特征在于评估其化学性质（通过ATR-FTIR光谱法）和物理性质（例如密度，热稳定性，刚度，透气性，表面能等）。聚酯基质和多糖填充剂之间的相容性极佳，这是由于两种组分的极性基团通过H键的相互作用。纳米纤维素的添加提高了所有确定的机械参数以及润湿性和阻隔性能，而热稳定性和吸水率则由多铝酸盐基质确定。将这些生物复合材料的物理性能与石油基塑料和生物基聚合物的物理性能进行了比较，表明开发的材料可以代表包装等不同应用的可持续替代品。