Kinetic aspects of the silver ion release from antimicrobial polyamide/silver nanocomposites
Kinetic aspects of the silver ion release from antimicrobial polyamide/silver nanocomposites
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DOI：
10.1007/s00339-008-4434-1
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发表时间：
2008-06-01
影响因子：
2.7
通讯作者：
Munstedt, H.
中科院分区：
文献类型：
--
作者：
Damm, C.;Munstedt, H.
在聚合物的熔融加工过程中，通过热还原醋酸银，在不同的聚酰胺中原位生长了球形银纳米颗粒。大多数颗粒的直径约为20 nm。不同的聚酰胺/银纳米复合材料的银离子释放的绝对量和动力学有很大的不同，尽管所有材料中的填料含量相同(1.5wt.%)，银粒子的形貌也没有太大差异。研究的一个结果是，长期银离子释放的绝对量随着用作基质材料的聚合物的最大吸水率而指数增加，因为银离子只在水存在的情况下由元素银粒子形成。此外，还发现银离子的长期释放量随着水在聚合物中扩散系数的增加而增加。聚合物的吸水性能也控制着银离子的释放动力学：对于被水增塑的强亲水性聚酰胺，如PA6或PA6.6，银离子的释放是零级过程。对于含较少亲水性聚酰胺的纳米复合材料，如脂环族聚酰胺或聚四氢呋喃修饰的P12(PA12-聚四氢呋喃)，银离子的释放是由扩散控制的。从银离子释放的效果来看，聚四氢呋喃修饰的PA6、PA6.6、PA12和PA12以及填充了1.5wt.%的银纳米粒子的脂环族聚酰胺对大肠杆菌具有抗菌活性。但是，只有以PA6、PA6.6和P12-聚四氢呋喃为基质的纳米复合材料才适合作为长期生物杀灭材料。
Spherical silver nanoparticles were grown in situ in different polyamides by a thermal reduction of silver acetate during melt processing of the polymers. Most of the particles have a diameter of about 20 nm. The absolute amount as well as the kinetics of the silver ion release from the various polyamide/silver nanocomposites differ strongly, although the filler content in all materials is the same (1.5 wt. %) and the morphologies of the silver particles are not very different. One result of the investigations was that the absolute amount of the long-term silver ion release increases exponentially with the maximum water absorption of the polymers used as matrix materials, because silver ions are formed from elemental silver particles in the presence of water, only. Moreover, it was also found that the long-term silver ion release increases with a growing diffusion coefficient of water in the polymer. The water absorption properties of the polymers govern the kinetics of the silver ion release, too: for strong hydrophilic polyamides like PA6 or PA6.6, which are plasticized by water, the silver ion release is a zero-order process. For nanocomposites with less hydrophilic polyamides like a cycloaliphatic polyamide or a P12 modified with polytetrahydrofurane (PA12-poly-THF), the silver ion release is governed by diffusion. As expected from the efficacy of the silver ion release, PA6, PA6.6, PA12 and PA12 modified with polytetrahydrofurane and a cycloaliphatic polyamide filled with 1.5 wt. % of silver nanoparticles are active against Escherichia coli. But, only nanocomposites with PA6, PA6.6 and P12-poly-THF as matrix materials are suitable as long-term biocidal materials.