Kombaya-Touckia-Linin Erland-Modeste, Gaucel Sébastien, Sougrati Moulay T, Stievano Lorenzo, Gontard Nathalie, Guillard Valérie
UMR, Ingénierie des Agropolymères et Technologies Emergentes, INRA, Univ. Montpellier, Montpellier SupAgro, CIRAD, 34060 Montpellier, France.
Institut Charles Gerhardt Montpellier, Univ. Montpellier, CNRS, 34090 Montpellier, France.
Nanomaterials (Basel). 2019 Aug 23;9(9):1193. doi: 10.3390/nano9091193.
Iron particles of sizes between 6 and 20 nm forming aggregates of 57 ± 17 nm were synthesized by chemical reduction of iron precursors on the surface of montmorillonite (MMT). This active MMT-Fe powder was then uniformly distributed in a linear low-density polyethylene (LLDPE) matrix by extrusion at atmospheric conditions, as confirmed by wide-angle X-ray scattering (WAXS), which also detected a partial exfoliation of the nanoclays. Thermogravimetric analysis (TGA) did not detect any significant modification of the degradation temperature between nanocomposites and active nanocomposites. Fe Mössbauer spectroscopy evidenced the formation of a majority of iron boride in MMT-Fe as well as in the active film containing it. The LLDPE.Fu15.MMT-Fe3.75 and LLDPE.Fu15.MMT-Fe6.25 films had oxygen-scavenging capacities of 0.031 ± 0.002 and 0.055 ± 0.009 g(O)/g(Fe), respectively, while the neat powder had an adsorption capacity of 0.122 g(O)/g(Fe). This result confirms that the fresh film samples were partially oxidized shortly after thermomechanical processing (60% of oxidized species according to Mössbauer spectroscopy). No significant difference in oxygen permeability was observed when MMT-Fe was added. This was related to the relatively small film surface used for measuring the permeability. The reaction-diffusion model proposed here was able to reproduce the observed data of O adsorption in an active nanocomposite, which validated the O adsorption model previously developed for dried MMT-Fe powder.
通过在蒙脱石（MMT）表面对铁前驱体进行化学还原，合成了尺寸在6至20纳米之间、形成57±17纳米聚集体的铁颗粒。然后，通过常压下的挤出将这种活性MMT-Fe粉末均匀分布在线性低密度聚乙烯（LLDPE）基体中，广角X射线散射（WAXS）证实了这一点，WAXS还检测到了纳米粘土的部分剥离。热重分析（TGA）未检测到纳米复合材料和活性纳米复合材料之间的降解温度有任何显著变化。Fe穆斯堡尔光谱证明在MMT-Fe以及含有它的活性薄膜中形成了大部分硼化铁。LLDPE.Fu15.MMT-Fe3.75和LLDPE.Fu15.MMT-Fe6.25薄膜的吸氧能力分别为0.031±0.002和0.055±0.009 g(O)/g(Fe)，而纯粉末的吸附能力为0.122 g(O)/g(Fe)。这一结果证实了新鲜薄膜样品在热机械加工后不久就被部分氧化（根据穆斯堡尔光谱，60%的氧化物种）。添加MMT-Fe时，未观察到氧气透过率有显著差异。这与用于测量透过率的薄膜表面积相对较小有关。这里提出的反应扩散模型能够重现活性纳米复合材料中O吸附的观测数据，这验证了先前为干燥的MMT-Fe粉末开发的O吸附模型。
