Why cotton kills

For a technical explanation of why cotton can kill you if you get wet while wearing it, why polyester, wool, and nylon are good things to wear if you may get wet or sweaty, and why rayon, viscose, tencel, lyocell, bamboo, and silk are almost as bad as cotton, see http://indefinitelywild.gizmodo.com/why-cotton-kills-a-technical-explanation-1688286083 .

Although that article doesn't mention acrylic fabrics, they also absorb very little water and dry quickly.  See, for example, http://www.teonline.com/knowledge-centre/acrylic-fibers.html .