Emission of volatile organic compounds during processing and use of organoclay-based nanocomposites

Polymer based nanocomposites are a new broad class of materials widely used in a large range of applications as they generally exhibit improved properties compared with the neat polymer. These materials have been known for a few decades and they have been widely studied in academia and industries, regarding their preparation and properties characterization. More recently, environmental, health and public concerns related to air quality have imposed severe worldwide rules regarding the emissions of Volatile Organic Compounds (VOCs), odours and nanoparticles from such materials. Indeed some studies have shown that they may exhibit some risks to human health. In this study, measurements of VOCs, odours and nanoparticles emissions have been carried out on polyether-block-amide copolymer (PEBA) clay nanocomposites. Both the processing and the storage stages have been investigated. These measurements revealed that nanocomposites based on Cloisite™ 30B exhibit stronger odour than sodium montmorillonite (MMT) and that this may constitute a significant drawback for industrial applications despite their outstanding properties. This behaviour has been explained considering the nature of the emitted VOCs (Volatile Organic Compounds). Particularly it has been highlighted that potentially unhealthy compounds can be emitted during the storage of the material. Moreover, another processing route has been tested as an alternative to the use of organo-modified clays. This consists in injecting water during extrusion, with the aim of dispersing untreated MMT in order to get an exfoliated morphology. Measurements have revealed that in addition to substantial savings that can be achieved using this method, it also reduces emissions both during processing and further use, as compared with conventional processes.