Evaluation of Particles Released from Single-wall Carbon Nanotube/Polymer Composites with or Without Thermal Aging by an Accelerated Abrasion Test

Abstract

To provide data required for assessing the environmental health and safety risks of nanocomposites, abrasion-induced particle release from single-wall carbon nanotube (SWCNT)/polymer composites with or without thermal aging were evaluated by a shot blast system. First, overall composite weight loss (i.e., overall particle release) as a result of shot blasting was measured. Incorporating 5 wt% SWCNTs in polystyrene (PS) matrix was observed to reduce overall particle release by approximately 30% compared with pure PS. Heat treatment of the 5 wt% SWCNT/PS composites at 100°C for 10 days induced very slight change in overall particle release due to shot blasting. However, heat treatment at 350°C for 1 hr greatly deteriorated the abrasion resistance of the composites, enhancing overall particle release. Second, to verify the existence and form of SWCNTs released from the composites, released particles were observed by electron microscopy. Micron-sized particles with protruding SWCNTs and submicron-sized SWCNT clusters were observed in the particles released from the composites. Heat treatment of the composites at 350°C for 1 hr enhanced SWCNT release, which mainly formed clusters or rope-like bundles.

Keywords:

• CNT
• exposure
• release
• abrasion
• nanocomposite
• safety

ACKNOWLEDGMENT

The authors would like to thank the New Energy and Industrial Technology Development Organization of Japan (NEDO) for funding the study under a grant for “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society” (No. P10024).