A pilot interlaboratory comparison of protocols that simulate aging of nanocomposites and detect released fragments

作者：Wohlleben Wendel^*; Vilar Gemma; Fernandez Rosas Elisabet; Gonzalez Galvez David; Gabriel Claus; Hirth Sabine; Frechen Thomas; Stanley Deborah; Gorham Justin; Sung Li Piin; Hsueh Hsiang Chun; Chuang Yu Fan; Tinh Nguyen; Vazquez Campos Socorro

来源：Environmental Chemistry, 2014, 11(4): 402-418.

DOI：10.1071/EN14072

• dry aging
• lifecycle
• nanosilica
• polyamide
• release
• wet aging

The safe use of nanoparticles as fillers in nanocomposite materials depends, in part, on a good understanding of what is released from aging nanocomposites, and at which rate. Here we investigated the critical parameters of the nanoparticle release phenomenon by a pilot inter-laboratory study of a polyamide containing 4 mass % of silica nanoparticles (nanosilica). The main focus is on the validity range of the aging and release protocols. Both induced release by mechanical shear after dry weathering at different UV intensities and spontaneous release during wet weathering were investigated. We propose a combined protocol based on the finding that the characteristics of released fragments - which are the essential input for fate, transport and (eco-)toxicological testing - were reproducible between laboratories and between different aging, sampling and analysis protocols: the released fragments were a polydisperse mixture of predominantly composite fragments from the nanometre up to several micrometre diameter, and of clustered or individual nanosilica unbound to polymer. The unbound fraction was microscopically observed but could not be quantified. We found that aging conditions are very critical for the release rates, not for release characteristics. The sampling protocol tolerates some differences. Simplified aging + immersion protocols can at least partially replace, complement and extend dedicated weathering apparatus with run-off collection.

• 出版日期2014