Kinetic analysis of urethane formation between castor oil-based ester polyol and 4,4’-diphenyl methane diisocyanate

ABSTRACT Kinetics of urethane formation between castor oil-based ester polyol (COEP) and 4,4′diphenyl methane diisocyanate (MDI) was evaluated using Differential Scanning Calorimeter (DSC) technique. The autocatalytic effect of urethane groups during polyurethane formation was confirmed through this study. DSC runs were made under dynamic heating schedule at various heating rates, viz.: 5, 10, 15 and 20 K/min. Single Heating rates like Chatterjee–Conrad and multiple heating rate method like Ozawa models were used to evaluate the kinetic parameter. Isocyanate index (Eq. of NCO/Eq. of OH) of 1 was used for the reaction between COEP and MDI. DSC thermograms exhibit two isotherms at 70°C and 120°C. Kinetic parameters adopting different models, in terms of activation energy, suggest that the urethane formation occurs grossly in two stages: the first step being standard uncatalysed urethane reaction and the following second step presumably autocatalysed urethane formation. The two exotherms were resolved into two portions. Kinetic analysis was undertaken for the unresolved DSC as well as the resolved ones, treating the resolved thermograms as the outcome of two independent competing reactions. GRAPHICAL ABSTRACT

[1]  G. Cabrera-Barjas,et al.  Development of eco-friendly polyurethane foams based on Lesquerella fendleri (A. Grey) oil-based polyol , 2020 .

[2]  A. Juhász,et al.  Uncatalyzed urethane forming reaction of 1,3-xylylene diisocyanate with aliphatic alcohols of varying chain lengths and polyols , 2020, Express Polymer Letters.

[3]  Ł. Piszczyk,et al.  Kinetics of cross-linking processes of fast-curing polyurethane system , 2020 .

[4]  S. Baeck,et al.  Polymerization Kinetics and Physical Properties of Polyurethanes Synthesized by Bio-Based Monomers , 2019, Macromolecular Research.

[5]  Qin Ning,et al.  Kinetic studies on the cure reaction of hydroxyl-terminated polybutadiene based polyurethane with variable catalysts by differential scanning calorimetry , 2016 .

[6]  Hong Juan Wang,et al.  Biodegradable foam plastics based on castor oil. , 2008, Biomacromolecules.

[7]  J. Martín.  Kinetic analysis of two DSC peaks in the curing of an unsaturated polyester resin catalyzed with methylethylketone peroxide and cobalt octoate , 2007 .

[8]  Yi Zhang,et al.  Thermal degradation kinetics of rigid polyurethane foams blown with water , 2006 .

[9]  K. Ninan,et al.  Rheo‐kinetic evaluation on the formation of urethane networks based on hydroxyl‐terminated polybutadiene , 2001 .

[10]  M. Nguyen,et al.  The Alcoholysis Reaction of Isocyanates Giving Urethanes: Evidence for a Multimolecular Mechanism. , 1998, The Journal of organic chemistry.

[11]  V. N. Krishnamurthy,et al.  Kinetics of copolyurethane network formation , 1997 .