Thermal Insulators and Methods Thereof

A method of making a thermal insulator comprising:

• mixing oxidized polyacrylonitrile fibers having crimped configurations with reinforcing fibers having outer surfaces comprised of a polymer with a melting temperature between 100° C. and 300° C.;
• heating the fiber mixture to a temperature sufficient to melt the outer surfaces of the reinforcing fibers to provide a non-woven fibrous web;
• and
• entangling the oxidized polyacrylonitrile fibers and reinforcing fibers with each other along a direction perpendicular to the non-woven fibrous web to provide an average bulk density of from 10 kg/m3 to 35 kg/m3 in the non-woven fibrous web.

A method of making a thermal insulator comprising:

• mixing oxidized polyacrylonitrile fibers with reinforcing fibers having outer surfaces comprised of a polymer with a melting temperature between 100° C. and 300° C. to obtain a non-woven fibrous web, wherein the oxidized polyacrylonitrile fibers represent over 85% by volume of fibers present that are not reinforcing fibers;
• heating the fiber mixture to a temperature sufficient to melt the outer surfaces of the reinforcing fibers to provide a non-woven fibrous web;
• and
• entangling the oxidized polyacrylonitrile fibers and reinforcing fibers with each other along a direction perpendicular to the non-woven fibrous web to provide an average bulk density of from 10 kg/m3 to 50 kg/m3 in the non-woven fibrous web.