End of Useful Life/recycling
Carbon-fiber-reinforced polymers (CFRPs) have a long service lifetime when protected from the sun. When it is time to decommission CFRPs, they cannot be melted down in air like many metals. When free of vinyl (PVC or polyvinyl chloride) and other halogenated polymers, CFRPs can be thermally decomposed via thermal depolymerization in an oxygen-free environment. This can be accomplished in a refinery in a one-step process. Capture and reuse of the carbon and monomers is then possible. CFRPs can also be milled or shredded at low temperature to reclaim the carbon fiber, however this process shortens the fibers dramatically. Just as with downcycled paper, the shortened fibers cause the recycled material to be weaker than the original material. There are still many industrial applications that do not need the strength of full-length carbon fiber reinforcement. For example, chopped reclaimed carbon fiber can be used in consumer electronics, such as laptops. It provides excellent reinforcement of the polymers used even if it lacks the strength-to-weight ratio of an aerospace component.
Despite its high initial strength-to-weight ratio, one structural limitation of CFRP is its lack of a fatigue endurance limit. As such, failure cannot be theoretically ruled out from a high enough number of stress cycles. By contrast, steel and certain other structural metals and alloys do have an estimable fatigue endurance limit. Because of the complex failure modes of such composites, the fatigue failure properties of CFRP are difficult to predict. As a result, when utilizing CFRP for critical cyclic-loading applications, engineers may need to employ considerable strength safety margins to provide suitable component reliability over a sufficiently long service life.
Read more about this topic: Carbon-fiber-reinforced Polymer
Famous quotes containing the words life and/or recycling:
“It is not enough that our life is an easy one. We must live on the stretch, retiring to our rest like soldiers on the eve of a battle, looking forward to the strenuous sortie of the morrow.”
—Henry David Thoreau (1817–1862)
“Both the Moral Majority, who are recycling medieval language to explain AIDS, and those ultra-leftists who attribute AIDS to some sort of conspiracy, have a clearly political analysis of the epidemic. But even if one attributes its cause to a microorganism rather than the wrath of God, or the workings of the CIA, it is clear that the way in which AIDS has been perceived, conceptualized, imagined, researched and financed makes this the most political of diseases.”
—Dennis Altman (b. 1943)