Kinetics and Thermodynamic Studies of Polyurethane Formation based on Ximenia americana L (Wild Olive) Seed Oil Monoglyceride and Different Diisocyanate

Abstract

The renaissance of interest for renewable raw materials to replace petro-derived polyester or polyether-polyols used with diisocyanates in step-growth polymerization reactions for polyurethane production continues to dominate new frontiers. Accordingly, the objective of this paper was to prepare Ximenia americana seed oil monoglyceride, characterized the alcoholysis product for glycerides content, hydroxyl number and evaluate the kinetics and thermodynamics parameters for its copolymerization reactions with different diisocyanates in N, N’-dimethylformamide at varied isocyanate indices and temperatures using standard appropriate methods. The Results showed second-order rate constant (k), for the copolymerization reactions, with order TDI>HDI>MDI for diisocyanate reactivity with X. americana monoglyceride giving values up to 5.28×10-3 Lmol-1min-1 for the TDI-based reaction at 1.50 isocyanate index and a corresponding average degree of polymerization ( ) of 28.49 at 80oC. The activation energy (Ea), activation enthalpy (∆Ha) and entropy (∆S*), for copolymerization reaction are consistent with the order of reactivity of the diisocyanates, lowest values of Ea and ∆Ha with a corresponding highest values of ∆S* for TDI-based copolymerization reaction at 1.02 and 1.50 isocyanate indices. The study has provided informative data on kinetic and thermodynamics parameters useful for the synthesis of polyurethane materials from X. americana seed oil-derived monoester and petro-based diisocyanates.

Keywords

• Copolymerization; Diisocyanate; Kinetic; Isocyanate index; Monoglyceride ester