Abstract : Using published specific heat data, the entropy, enthalpy, and Gibbs free energy of polybutene-1 (PB) were calculated over the temperature range 0 to 315K. The encraty, C sub p/T vs. T, calculated for PB exhibits a maximum at 60K and a small inflection at about 250K, which is associated with the glass transition. The difference, C sub p-C sub v, was calculated at 298.15K and found to be 0.047 cal/gm deg. The thermodynamic functions were also calculated for butene-1. At 265K the entropy of polymerization is 32.57 cal/mole deg, and the free energy of polymerization was found to be -12.1 kcal/mole. (Author)