Grupo de Materiales Compuestos Termoplásticos (CoMP), Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), Facultad de Ingeniería, Universidad Nacional de Mar del Plata (UNMdP) y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Colón 10850, B7608FLC, Mar del Plata, Argentina.
Department of Chemical and Food Engineering, Federal University of Santa Catarina, Florianópolis, SC 88040-900, Brazil.
Int J Biol Macromol. 2021 Mar 1;172:439-451. doi: 10.1016/j.ijbiomac.2021.01.048. Epub 2021 Jan 13.
The aim of this research work was to investigate novel tools given by nanotechnology and green chemistry for improving the disadvantages typically associated to the starch-based films: water susceptibility and brittle mechanical behavior. With this in mind, four food packaging film systems were developed from corn starch or corn starch nanocrystals (SNCs), and modified by phosphating under reactive extrusion (REx) conditions using sodium tripolyphosphate (NaPO - TPP) as a crosslinker. The structural, physicochemical, thermal, rheological and mechanical properties, as well as studies associated with the management of carbohydrate polymer-based plastic wastes (biodegradability and compostability) were carried out in this study. The hierarchical structure and the modification of the starch were dependent on the amylose content and degree of substitution (DS), which in turn depended on the hydrogen (H)-bonding interactions. In both cases, a higher molecular ordering of the starch chains in parallel was decisive to obtain the self-assembled thermoplastic starches. Beyond the valuable results obtained and scientifically analyzed, unfortunately none of the manufactured materials achieved to improve their performance compared to the control film (thermoplastic starch - TPS). It was even thought that the phosphated starch-based films could fertilize lettuce (Lactuca sativa) seedlings during their biodegradation, and this was not achieved either. This possibly due to the low content of phosphorus or its poor bioavailability.
本研究工作的目的是探索纳米技术和绿色化学提供的新工具，以改善与淀粉基薄膜相关的缺点：对水的敏感性和脆性机械性能。考虑到这一点，从玉米淀粉或玉米淀粉纳米晶（SNC）出发，开发了四种食品包装薄膜系统，并在反应挤出（REx）条件下用三聚磷酸钠（NaPO-TPP）作为交联剂进行磷酸化改性。在这项研究中，对结构、物理化学、热、流变和机械性能以及与碳水化合物聚合物基塑料废物管理相关的研究（生物降解性和可堆肥性）进行了研究。淀粉的分层结构和改性取决于直链淀粉含量和取代度（DS），而取代度又取决于氢键相互作用。在这两种情况下，获得自组装热塑性淀粉的关键是淀粉链的更高分子有序性。除了获得和科学分析的有价值的结果外，不幸的是，与对照薄膜（热塑性淀粉-TPS）相比，制造的材料都没有改善其性能。甚至有人认为，在可生物降解过程中，基于磷酸化淀粉的薄膜可以为生菜（Lactuca sativa）幼苗施肥，但这也没有实现。这可能是由于磷含量低或生物利用度差。
