Abstract: The present invention is related to expandable vinyl aromatic polymers comprising comminuted coke, said comminuted coke having an average stack height (Lc) of carbon crystallites at least 4 nm, a volume median particle diameter (D50) comprised between 1 and less than 5 ?m and being characterized by a span (D90?D10)/D50 below 2.5 Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: The present invention is related to an expandable vinyl aromatic polymer composition comprising: from 0.5 to 15 parts by weight of dispersed athermanous particles selected from the group consisting of coke, carbon black, graphite and combinations of them, having a volume median particle diameter (D50) comprised between 0.5 and 35 ?m, as obtained from laser light scattering measurements according to ISO 13320 using MEK as solvent for vinyl aromatic polymers; from 2 to 10 parts by weight of blowing agent; from 0.2 to 5 parts by weight of halogenated flame retardant; and from 0.02 to 5 parts by weight of zinc-modified hydrotalcite; per 100 parts of vinyl aromatic polymer.

Abstract: The present invention is related to expandable vinyl aromatic polymers comprising comminuted coke, said comminuted coke having an average stack height (Lc) of carbon crystallites at least 4 nm, a volume median particle diameter (D50) comprised between 1 and less than 5 ?m and being characterized by a span (D90?D10)/D50 below 2.5 Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: The present invention is related to expandable vinyl aromatic polymers comprising comminuted coke, said comminuted coke having an average stack height (Lc) of carbon crystallites less than 4 nm, a volume median particle diameter (D50) comprised between 0.8 and 4 ?m and being characterized by a span (D90?D10)/D50 below 2.5. Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: The present invention is related to expandable vinyl aromatic polymers comprising from 1 to 10% by weight of homogeneously dispersed coke particles having a volume median particle diameter (D50) comprised between 0.5 and 8.5 ?m and from 0.1 to 5% by weight of a halogenated block copolymer. The invention further is related to a method for producing said expandable vinyl aromatic polymers and to the expanded foams.