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Centralized waste plastic recycling is economically challenging, yet distributed recycling and additive manufacturing (DRAM) offers a path that provides consumers with direct economic incentives to recycle. This study explores the technical pathways for DRAM of complex polymer composites using a case study of windshield wiper blades, which are a thermopolymer composite made up of a soft (flexible) and hard material. The distributed manufacturing methods ran from mechanical grinding to fused granular fabrication, heated syringe printing, 3-D printed molds coupled to injection molding and filament production in a recyclebot to fused filament fabrication. The particle size, angle of repose, thermal and rheological properties are characterized for the two sub-materials to define the conditions for the extrusion. A successful pathway was found and the mechanical properties of the resultant components were quantified.Finally, the means to convert scrap windshield wiper blades into useful, high-value, bespoke biomedical products of fingertip grips for hand prosthetic was demonstrated. This study showed that the DRAM model of materials recycling can be used to improve the variety of solutions for a circular economy.

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We report the first measurements of the effect of ammonia gas on the temperature dependence of the conductivity and thermoelectric power of polypyrrole films. Our data are for samples of very different conductivities, extending down to a temperature of 200 K for low‐conductivity polypyrrole gas sensors, and down to 4.2 K for more highly‐conducting PPy(PF6) samples. We demonstrate that (except for the most metallic case) our polypyrrole samples show greater sensitivity to ammonia as the temperature is lowered (i.e. the fractional reduction in conductivity is greater at lower temperatures). Remanent decreases in conductivity are present after the removal of ammonia for higher pressure exposures, and remanent increases in the metal‐like thermoelectric power for the PPy(PF6) for samples grown at higher temperatures. Our results indicate that the mechanism of this conductivity decrease in PPy(PF6) is that ammonia causes a reduction in the size of metallic regions as disordered barrier regions are thickened. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1331–1338, 2006

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