Abstract: Prepare a polymeric nanofoam using a continuous extrusion process by providing a polymer melt of a polymer composition in an extruder, introducing carbon dioxide to a concentration above the solubility in the polymer melt, cooling the polymer melt without increasing the pressure to achieve conditions where all of the carbon dioxide is soluble in the polymer composition and then extruding the polymer composition and carbon dioxide mixture through an extrusion die so as to experience a pressure drop of at least five MegaPascals at a rate of at least ten MegaPascals per second and allowing the polymer composition to expand into a polymeric nanofoam.

Abstract: Prepare a polymeric nanofoam using a continuous extrusion process by providing a polymer melt of a polymer composition in an extruder, introducing carbon dioxide to a concentration above the solubility in the polymer melt, cooling the polymer melt without increasing the pressure to achieve conditions where all of the carbon dioxide is soluble in the polymer composition and then extruding the polymer composition and carbon dioxide mixture through an extrusion die so as to experience a pressure drop of at least five MegaPascals at a rate of at least ten MegaPascals per second and allowing the polymer composition to expand into a polymeric nanofoam.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material: b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel: c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die: and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.