An alternative approach towards more sustainable chitosan films, through their manufacture by thermo-compression molding, was explore in this work. This strategy permitted the reduction of production times and avoided the use of organic solvents since biopolymer and acid were mixed in their solid form. Furthermore, the acid used as a crosslinker was citric acid, a natural policarboxylic acid, which promoted the reaction with chitosan, as shown by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). This crosslinking reaction led to the formation of homogeneous structures, as observed by scanning electron microscopy (SEM), indicating a good compatibility among all the components of the mixture and enhancing the mechanical properties of the resulting films. In particular, an increase of 80% for tensile strength and an increase of 3000% for elongation at break were observed for the crosslinked films. In addition to the homogeneous surface of citric acid-incorporated films, all the films showed hydrophobic character and the addition of citric acid led to a more amorphous structure. In sum, citric acid-incorporated chitosan films manufactured by compression molding were found to show potential for food and pharmaceutical applications.

在这项工作中，探索了通过热压成型制造壳聚糖薄膜的另一种方法，以实现更具可持续性的壳聚糖薄膜。由于生物聚合物和酸以固体形式混合，因此该策略可以缩短生产时间并避免使用有机溶剂。此外，如傅立叶变换红外（FTIR）光谱，差示扫描量热法（DSC）和动态力学分析（DMA）所示，用作交联剂的酸是柠檬酸，一种天然的多羧酸，它促进了与壳聚糖的反应。如通过扫描电子显微镜（SEM）观察到的，该交联反应导致形成均质结构，表明混合物的所有组分之间的良好相容性并增强了所得膜的机械性能。尤其是，对于交联膜，观察到拉伸强度增加了80％，断裂伸长率增加了3000％。除了掺有柠檬酸的薄膜的均质表面以外，所有薄膜均显示出疏水性，柠檬酸的添加导致了更无定形的结构。总而言之，发现通过压模法制造的掺入柠檬酸的壳聚糖膜显示出在食品和药物应用中的潜力。