Novel fabrication route for auxetic polyethylene. Part 1. Processing and microstructure

One method for producing synthetic auxetic materials is starting with polymer powders and using a combination of compaction, sintering, and extrusion. This article presents a novel variation on this route, omitting the extrusion stage and generating the required microstructure by compaction followed by multiple sintering. The effects of single, double, and quadruple sintering on compacted cylinders are examined in terms of a detailed microstructural examination, study of density and dimensional variations, and measurement of Poisson's ratio. The best results were obtained by compaction followed by double sintering, resulting in a strain dependent Poisson's ratio as low as v = -0.32. This new technique has great potential for increasing the range of geometries that can be fabricated and is very akin to ceramic sintering techniques. (c) 2005 Society of Plastics Engineers.