Abstract: A polymer composition including a crosslinkable thermoplastic matrix, a crosslinking agent, a blowing agent, and at least one cell opener is provided. A method of producing an open cell polymer foam from the polymer composition is also provided. The method includes heating a foamable precursor under positive pressure to a temperature greater than a decomposition temperature of the crosslinking agent and below a decomposition temperature of the chemical blowing agent to produce a primary foam. Then, the method includes heating the primary foam to a temperature greater than the decomposition temperature of the chemical blowing agent and then allowing the primary foam to cool to a temperature below a softening temperature of the crosslinkable thermoplastic polymer to form the open cell polymer foam. The produced open cell polymer foam has an open cell content of at least 80% immediately following the step of allowing the primary foam to cool.