Assessing life cycle environmental implications of polymer nanocomposites

Abstract

Research into the holistic evaluation of emerging nanotechnologies using systems analysis is pivotal for guiding their safe and sustainable development. This work presents the first energetic life cycle assessment of polymer nanocomposites (PNCs) that evaluates both thermoplastic and thermoset resins. Both simple carbon nanofiber (CNF) and carbon nanofiber-glass fiber (CNF-GF) hybrid nanocomposites are evaluated and compared with steel. The issue of life cycle inventory is tackled based on published literature and best available engineering information. A cradle-to-gate comparison reveals that CNF reinforced PNCs are 1.3-10 times more energy intensive than steel and thus the product use phase is likely to govern whether any net savings in life cycle energy consumption can be realized for PNC based products. A case study involving the use of CNF and CNF-GF reinforced PNCs in the body panels of automobiles is further presented and highlights that the use of PNCs with lower CNF loading ratios may result in net life cycle fossil energy savings relative to steel. Other factors such as cost, toxicity impact of CNF, and end-of-life issues specific to CNFs need to be considered to evaluate the final economic and environmental performance of CNF reinforced PNC materials. The results of this study can easily be used for evaluating other CNF based PNC applications.