In the context of replacing polyurethane foam in DH pre-insulated pipes due to the toxicity of the diisocyanates, and facilitating recycling by eliminating the need to separate material layers of the sandwich structure, the foaming of PB-1 with CO2 is being studied. The assessment of the plasticization effect induced by CO2 in the polymer melt and determination of the melting point depression is required for the establishment and optimization of the foaming processing window. In this paper, a method for the determination of the melting point through image analysis is presented, validated and used for the study of PB-1 – CO2 solutions. The obtained results through image analysis agree with those obtained with differential scanning calorimetry, validating the method. The CO2 - induced melting point depression of PB-1 was determined as ΔT = 140C.