Nguyen Tinh, Petersen Elijah J, Pellegrin Bastien, Gorham Justin M, Lam Thomas, Zhao Minhua, Sung Lipiin
National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899.
Carbon N Y. 2017 May;116:191-200. doi: 10.1016/j.carbon.2017.01.097. Epub 2017 Jan 31.
Multiwall carbon nanotubes (MWCNTs) are nanofillers used in consumer and structural polymeric products to enhance a variety of properties. Under weathering, the polymer matrix will degrade and the nanofillers may be released from the products potentially impacting ecological or human health. In this study, we investigated the degradation of a 0.72 % (by mass) MWCNT/amine-cured epoxy nanocomposite irradiated with high intensity ultraviolet (UV) light at various doses, the effects of UV exposure on the surface accumulation and potential release of MWCNTs, and possible mechanisms for the release resistance of the MWCNT surface layer formed on nanocomposites by UV irradiation. Irradiated samples were characterized for chemical degradation, mass loss, surface morphological changes, and MWCNT release using a variety of analytical techniques. Under 295 nm to 400 nm UV radiation up to a dose of 4865 MJ/m, the nanocomposite matrix underwent photodegradation, resulting in formation of a dense, entangled MWCNT network structure on the surface. However, no MWCNT release was detected, even at very high UV doses, suggesting that the MWCNT surface layer formed from UV irradiation of polymer nanocomposites resist release. Four possible release resistance mechanisms of the UV-induced MWCNT surface layer are presented and discussed.
多壁碳纳米管（MWCNTs）是用于消费和结构聚合物产品中的纳米填料，以增强多种性能。在风化作用下，聚合物基体将降解，纳米填料可能会从产品中释放出来，从而可能影响生态或人类健康。在本研究中，我们研究了0.72%（质量分数）的MWCNT/胺固化环氧纳米复合材料在不同剂量的高强度紫外（UV）光照射下的降解情况、UV照射对MWCNTs表面积累和潜在释放的影响，以及UV照射在纳米复合材料上形成的MWCNT表面层的抗释放可能机制。使用多种分析技术对辐照后的样品进行化学降解、质量损失、表面形态变化和MWCNT释放的表征。在295nm至400nm的UV辐射下剂量高达4865MJ/m时，纳米复合材料基体发生光降解，导致在表面形成致密、缠结的MWCNT网络结构。然而，即使在非常高的UV剂量下也未检测到MWCNT释放，这表明由聚合物纳米复合材料的UV辐照形成的MWCNT表面层具有抗释放性能。本文提出并讨论了UV诱导MWCNT表面层抗释放的四种可能机制。
