The objective of this study was to produce and characterize gelatin foamed films using extrusion. Three “optimum” formulations containing tannic acid, nanoclays (Cloisite Na+), glycerol, water, and gelatin, as well as three “controls” without tannic acid and nanoclays were prepared by calendering. Furthermore, the three “optimum” formulations were produced by extrusion film blowing only, since no stable processing conditions could be obtained for the controls. A complete set of sample characterization was performed, including morphological, mechanical, physical, and thermal properties. The results showed that besides the processing method, the thickness was also controlled by the glycerol and water content, leading to density slightly above unity, with higher values for the optimum materials. The calendered films from the optimum formulations showed overall a higher number of cells and cell density than the controls. Higher elastic moduli and tensile strengths were obtained for the films from the optimum formulations made by either method because of the reinforcing effect of the tannic acid and nanoclays, but this led to lower strain at break. The thermal profiles were similar for all films, with higher stability for the optimum formulations. The results were also explained via chemical interactions between the components as observed by Fourier transform infrared spectroscopy. Overall, the optimum formulations not only produced better foamed films in terms of general properties but were much easier to process by both methods (calendering and blowing).

中文翻译：

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基于明胶的全生物基泡沫薄膜的制备和表征

本研究的目的是生产和表征使用挤出的明胶泡沫薄膜。通过压延制备了三种含有单宁酸、纳米粘土（Cloisite Na+）、甘油、水和明胶的“最佳”配方，以及不含单宁酸和纳米粘土的三种“对照”。此外，三种“最佳”配方仅通过挤出吹膜生产，因为无法获得稳定的加工条件作为对照。进行了一套完整的样品表征，包括形态、机械、物理和热性能。结果表明，除了加工方法外，厚度还受甘油和水含量的控制，导致密度略高于统一，最佳材料的值更高。与对照相比，来自最佳配方的压延薄膜总体上显示出更高的泡孔数量和泡孔密度。由于单宁酸和纳米粘土的增强作用，由任一方法制成的最佳配方的薄膜获得了更高的弹性模量和拉伸强度，但这导致断裂应变较低。所有薄膜的热分布相似，最佳配方具有更高的稳定性。还通过傅立叶变换红外光谱观察到的组分之间的化学相互作用来解释结果。总的来说，最佳配方不仅在一般性能方面产生了更好的泡沫薄膜，而且更容易通过两种方法（压延和吹塑）进行加工。由于单宁酸和纳米粘土的增强作用，由任一方法制成的最佳配方的薄膜获得了更高的弹性模量和拉伸强度，但这导致断裂应变较低。所有薄膜的热分布相似，最佳配方具有更高的稳定性。还通过傅立叶变换红外光谱观察到的组分之间的化学相互作用来解释结果。总的来说，最佳配方不仅在一般性能方面产生了更好的泡沫薄膜，而且更容易通过两种方法（压延和吹塑）进行加工。由于单宁酸和纳米粘土的增强作用，由任一方法制成的最佳配方的薄膜获得了更高的弹性模量和拉伸强度，但这导致断裂应变较低。所有薄膜的热分布相似，最佳配方具有更高的稳定性。还通过傅立叶变换红外光谱观察到的组分之间的化学相互作用来解释结果。总的来说，最佳配方不仅在一般性能方面产生了更好的泡沫薄膜，而且更容易通过两种方法（压延和吹塑）进行加工。但这导致断裂时的应变降低。所有薄膜的热分布相似，最佳配方具有更高的稳定性。还通过傅立叶变换红外光谱观察到的组分之间的化学相互作用来解释结果。总体而言，最佳配方不仅在一般性能方面产生了更好的泡沫薄膜，而且更容易通过两种方法（压延和吹塑）进行加工。但这导致断裂时的应变降低。所有薄膜的热分布相似，最佳配方具有更高的稳定性。还通过傅立叶变换红外光谱观察到的组分之间的化学相互作用来解释结果。总的来说，最佳配方不仅在一般性能方面产生了更好的泡沫薄膜，而且更容易通过两种方法（压延和吹塑）进行加工。