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Large amounts of post‐consumer carpet are discarded every year. Most of this waste is currently landfilled, while a small percentage is incinerated. The face carpet fibers, consisting primarily of nylon 6 and nylon 6,6, represent the majority component in the carpet waste. Recent financial incentives and environmental constraints have motivated the industrial sector to develop recycling strategies for these fibers. Depolymerization into their constituent monomers is the most complex recycling route, but at the same time it produces the most valuable product. A second alternative involves the use of solvents for the extraction of carpet fiber components in their polymeric form. Finally, a third recycling option yields thermoplastic mixtures by melt blending the carpet waste. The recent literature on the recycling of nylon from carpet waste is reviewed in this paper. The paper also includes a section focusing on the current state of carpet recycling at the Industrial level.

The transient normal force response in a concentrated suspension of spherical particles upon startup of shear, following a period of rest, was found to depend on the direction in which shear was restarted. When shear was restarted in the same direction, the normal force signal rapidly grew to its positive steady-state value. However, when shear was restarted in the opposite direction, the normal force signal was initially negative and decreased, within the response time of the instrument, to a negative minimum, from which it gradually increased, passing through zero, to its positive steady-state value. This is believed to be the first experimental confirmation of this phenomenon, which had been suggested by the numerical simulations of previous investigators.