in one aspect , the invention is directed to a biocidal composition , comprising a mixture of a substantially oxidation - resistant thermoplastic polymer having a melting point of about 60 ° c . to about 100 ° c . ; and a composition for releasing chlorine dioxide gas upon exposure to moisture . in another aspect , the invention provides a polymeric matrix comprising the biocidal composition and having a moisture vapor transmission capability of about 100 to about 1000 grams per 24 hours per square meter per mil of thickness . the invention further provides a manufactured article comprising the biocidal composition , for example manufactured by extrusion , injection molding or blow molding .