modacrylic fiber

mod′a•cryl′ic fi′ber

(ˈmɒd əˈkrɪl ɪk, ˌmɒd-)

n. any of various synthetic copolymer textile fibers, as Dynel, containing less than 85 percent but more than 35 percent of acrylonitrile. [1955–60; mod(ified) acrylic]