Wool nonwovens as candidates for commodity auxetic materials. (18th December 2020)

• Record Type: Journal Article
• Authors: Verma, Prateek; Smith, Casey L; Griffin, Anselm C; Shofner, Meisha L
• Is Part Of: Engineering research express. Volume 2:Number 4(2020)
• Publication Date: 2020-12-18
• Subjects: wool -- nonwovens -- felts -- fiber networks -- micro-computed tomography -- auxetic -- negative Poisson's ratio; Engineering -- Periodicals; 620.005
• DOI: 10.1088/2631-8695/abd1c8
• Languages: English
• ISSNs: 2631-8695

Abstract

Abstract: Advances in the field of auxetics have realized fabricated auxetic materials such as foams, fabrics, and fibers as well as a better theoretical understanding of the auxetic response. Because of their unique properties and applications, commodity auxetic materials are particularly desirable. Needle-punched nonwovens, several kinds of paper, and many knitted and woven fabrics have the potential to be auxetic, either as-produced or through a processing or design solution. In this study, we examine the out-of-plane Poisson's ratio of as-produced and heat-compressed wool nonwovens. The wool nonwovens were found to be out-of-plane auxetic as-produced, and their auxetic character became more pronounced at higher treatment temperatures. Their behavior could be similar to that of paper, where straightening of a bent fiber was responsible for thickness increase. The prescribed processing conditions to enhance auxeticity could potentially be incorporated in their existing production, providing a pathway to generating commodity auxetics.