Granda Luis Angel, Oliver-Ortega Helena, Fabra Maria José, Tarrés Quim, Pèlach Maria Àngels, Lagarón José Maria, Méndez José Alberto
LEPAMAP Group, Department of Chemical Engineering, University of Girona, EPS, PI, Maria Aurèlia Capmany 61, 17003 Girona, Spain.
Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
Polymers (Basel). 2020 May 7;12(5):1071. doi: 10.3390/polym12051071.
Nowadays, the interest on nanofibrillated cellulose (CNF) has increased owing to its sustainability and its capacity to improve mechanical and barrier properties of polymeric films. Moreover, this filler shows some drawbacks related with its high capacity to form aggregates, hindering its dispersion in the matrix. In this work, an improved procedure to optimize the dispersability of CNF in a thermoplastic starch was put forward. On the one hand, CNF needs a hydrophilic dispersant to be included in the matrix, and on the other, starch needs a hydrophilic plasticizer to obtain a thermoformable material. Glycerol was used to fulfil both targets at once. CNF was predispersed in the plasticizer before nanofibrillation and later on was included into starch, obtaining thin films. The tensile strength of these CNF-starch composite films was 60% higher than the plain thermoplastic starch at a very low 0.36% / percentage of CNF. The films showed a noticeable correlation between water uptake, and temperature and humidity. Regarding permeability, a ca. 55% oxygen and water vapor permeability drop was found by nanofiller loading. The hydrolytic susceptibility of the composite was confirmed, being similar to that of the thermoplastic starch.
如今，由于其可持续性以及改善聚合物薄膜机械性能和阻隔性能的能力，纳米纤化纤维素（CNF）受到了更多关注。此外，这种填料存在一些缺点，因其具有很强的形成聚集体的能力，阻碍了其在基体中的分散。在这项工作中，提出了一种优化CNF在热塑性淀粉中分散性的改进方法。一方面，CNF需要一种亲水性分散剂才能被纳入基体，另一方面，淀粉需要一种亲水性增塑剂来获得可热成型的材料。甘油被用来同时实现这两个目标。在纳米纤维化之前，CNF先在增塑剂中预分散，随后被加入到淀粉中，从而得到薄膜。在CNF含量仅为非常低的0.36%时，这些CNF - 淀粉复合薄膜的拉伸强度比纯热塑性淀粉高出60%。这些薄膜在吸水率、温度和湿度之间呈现出明显的相关性。关于透气性，通过添加纳米填料发现氧气和水蒸气的渗透率下降了约55%。证实了复合材料的水解敏感性，与热塑性淀粉相似。
