disclosed is a method of coating a fibrous or filamentous organic polymeric substrate by forming a liquid which comprises an organic compound having a vapor pressure of less than about 400 mm at room temperature , applying the liquid to the substrate , evaporating any solvent which is present , and exposing the liquid to an ionized non - polymerizing inorganic gas . also disclosed is a coated substrate comprising a fibrous or filamentous substrate made of an organic polymeric material and a saturated aliphatic hydrocarbon coating on the substrate polymerized and chemically bonded to the polymeric material . a laminate is made by impregnating the treated substrate with an organic impregnating resin , heating the impregnated treated substrate to evaporate any solvent and to partially cure the organic impregnating resin , forming a prepreg , forming a stack of a plurality of prepregs , and heating the stack under pressure to fully cure the impregnating resin . copper can be placed at one or both ends of the stack prior to fully curing the impregnating resin in order to form a circuit board .