Abstract: The invention relates to flameproof expandable polymerizates, wherein a flame retardant system consisting of a combination of at least one phosphorus compound as a flame retardant and at least one sulfur compound as an additional flame retardant or synergist is contained. According to the invention, it is contemplated that the phosphorus compound is elemental phosphorus and/or at least one inorganic phosphorus compound and/or at least one organic phosphorus compound of the following general formula (I) or (II): wherein the residues R1, R2, and R3 each independently represent organic or inorganic residues, and that said sulfur compound is elemental sulfur and/or at least one inorganic or organic sulfur compound and/or sulfur-containing compound.

Abstract: The invention relates to flameproof expandable polymers containing at least one blowing agent, wherein at least one phosphorus compound is contained as a flame retardant.

Abstract: A method for producing expandable polystyrene (EPS) or extruded polystyrene foams (XPS), starting from polystyrene already present in the polymerized state or polystyrene melts, the same containing at least one expanding agent and/or at least one flame or fire retardant and/or at least one radical former as a flame retarding synergist, either from the start and/or being added during the production process. To reduce the extent to which the molecular weight is decreased as a result of the chain decomposition occurring during the heating as part of the production process, at least one stable free radical from the group of organic nitroxyl radicals of the general formula (1) is added to the polystyrene and/or the melt thereof.