(57) Fire retardant and heat resistant yarns and fabrics include an inner core comprised of oxidized polyacrylonitrile encapsulated by an outer shell comprised of a liquid-resistant and strengthening polymer material. The liquid-resistant and strengthening polymer material includes one or more types of cured silicone polymer resin. A fluorchemical may be at least partially impregnated into the inner core prior to applying the liquid-resistant and strengthening polymer material in order to further enhance the liquid shedding properties of the yarns or fabric. Because the silicone polymer resin only encapsulates the yarn, but does not form a continuous coating over the whole fabric, the treated fabric is still able to breath through pores and spaces between individual yarn strands that make up the fabric. The liquid-resistant and strengthening polymer material increases the strength, abrasion resistance, durability and liquid and gel shedding capability of the fire retardant heat resistant yarn or fabric.