Influence of the reaction chemistry on the polymerization of polyurethanes

Student thesis: Master's Thesis

Abstract

Polyurethanes are widely used in industrial applications because of their versatility. They can be made into elastomers, thermoplastics and thermosets by selecting the right raw materials from which polyurethane is synthesised. Controlling the manufacturing of polyurethanes, generally reaction injection molding, is often by simulation of this process. These simulations need a well-developed model describing the kinetics during the cure. In this work it is the goal to develop such a model.
Starting from a model linear polyurethane system consisting of methylene diphenyl diisocyanate and dipropylene glycol, which was extended with diethylene glycol monomethyl ether and cyclohexanol, the fast polyurethane reaction was studied. Different calorimetric techniques such as differential
scanning calorimetry and microcalorimetry were used. A multitude of temperature programs and procedures were applied over a wide temperature range to ensure relevant data for the model. Furthermore the ratio of monomers was varied over a range relevant for possible industrial applications.
This allows for a thorough study of the reaction mechanism and better predictions from the model. For the development of the model, the kinetics were evaluated in several steps, from a model-free kinetics approach to a mechanistic model that covers the complexity of the reaction mechanism.
Finally off-stoichiometric systems were included in the model to successfully predict the cure kinetics over a wide range of compositions and temperatures.
Date of Award2 Feb 2017
Original languageEnglish
SupervisorGuy Van Assche (Promotor), Luk Van Lokeren (Advisor) & Robrecht René Verhelle (Advisor)

Keywords

  • polymerization
  • reaction kinetics
  • polyurethane
  • thermal analysis
  • calorimetry
  • modelling

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