Abstract: Expandable vinyl aromatic polymers may contain comminuted needle petroleum coke with a polymodal particle size distribution. Foams obtained from such expandable vinyl aromatic polymers have a reduced thermal conductivity at a reduced foam density.

Abstract: The present invention discloses an expandable vinyl aromatic polymer comprising: a) a matrix of a vinyl aromatic polymer, b) 1-10% by weight, calculated with respect to the polymer (a), of a blowing agent embedded in the polymeric matrix, c) 0.1 to 5% by weight, calculated with respect to the polymer (a), of talcum having a D50 particle size, measured by sedigraph (ISO 13317-3), of between 2.3 and 5 ?m and a BET specific surface area, measured according to DIN 66131/2, of between 4.2 and 9.5 m2/g, d) 0.1 to 6% by weight, calculated with respect to the polymer of carbon black with a BET specific surface area, measured according to ASTM D-6556, of between 9 and 65 m2/g, e) 0.1 to 1% by weight, calculated with respect to the polymer (a), of polyethylene wax homogeneously distributed in the polymeric matrix.

Abstract: An expandable vinyl aromatic polymer may include a matrix of a vinyl aromatic polymer, 1-10% of an expanding agent, 0.1 to 5% talc, carbon black, and 0 to 20% fillers. The expanding agent may be englobed in the matrix. The talc may have a mean diameter above about 8 ?m as measured by Laser Mastersizer according to standard ISO 13320-1. The BET of the talc may be in the range 0.5-25 m2/g. The carbon black may be present in a proportion sufficient for a foamed material obtained from the expandable vinyl aromatic polymer to have a thermal conductivity ? of about 34 mW/m° K or lower. The fillers may be homogeneously distributed in the matrix.

Abstract: The present invention is an expandable vinyl aromatic polymer which comprises: a) a matrix of a vinyl aromatic polymer, b) 1-10% by weight calculated with respect to the polymer (a), of an expanding agent englobed in the polymeric matrix, c) 0.1 to 5% by weight calculated with respect to the polymer (a), of talc having a mean diameter above about 8 ?m, said mean diameter being measured by Laser Mastersizer according to standard ISO 13320-1, the BET of the talc being is in the range 0.5-25 m2/g, d) carbon black in a proportion sufficient for the foamed material obtained from the expandable vinyl aromatic polymer to have a thermal conductivity ? of about 34 mW/m° K or lower, e) 0-20% by weight, calculated with respect to the polymer (a), of one or more fillers, other than talc and carbon black, homogeneously distributed in the polymeric matrix. The expandable vinyl aromatic polymer of the invention is produced in the form of beads or granules.

Abstract: The present invention is an expandable vinyl aromatic polymer which comprises: a) a matrix of a vinyl aromatic polymer, b) 1-10% by weight calculated with respect to the polymer (a), of an expanding agent englobed in the polymeric matrix, c) 0.1 to 5% by weight calculated with respect to the polymer (a), of PiB (polyisobutene), homogeneously distributed in the polymeric matrix, d) 0-20% by weight, calculated with respect to the polymer (a), of one or more fillers, other than PiB, homogeneously distributed in the polymeric matrix, Wherein the proportion of PiB is adjusted to increase the Melt Flow Index (MFI) from an initial index to a final index such as the 10% compression strength of the foam made with said expandable vinyl aromatic polymer of the final index is essentially the same or higher than the foam made with said expandable vinyl aromatic polymer of the initial index. The expandable vinyl aromatic polymer of the invention is produced in the form of beads or granules.

Abstract: The present invention is an expandable vinyl aromatic polymer which comprises: a) a matrix of a branched aromatic ionomer, b) 1-10% by weight calculated with respect to the polymer (a), of an expanding agent englobed in the polymeric matrix, c) 0-20% by weight, calculated with respect to the polymer (a), of a filler homogeneously distributed in the polymeric matrix, in which, the branched aromatic ionomer comprises the product of co-polymerizing a first monomer comprising an aromatic moiety and an unsaturated alkyl moiety and a second monomer comprising an ionic moiety and at least two unsaturated moieties, wherein the ionic moiety has at least two ionizable groups, a cationic group that ionizes to form cations and an anionic group that ionizes to form anions, and wherein the cationic group is polyvalent and one capable of forming bridges to other molecules. The present invention also relates to the use of the expandable vinyl aromatic polymer to make expanded articles, in particular insulation boards.