(46i) Simulation of Thermoset Polymerization

For decades the multi-billion dollar urethane industry has been founded on urethane formulations created primarily as an art by researchers with years of experience and laboratory trial and error. It is now possible to simulate the critical resin and foam forming processes, and to use that simulation to develop new formulations. The simulation has been used to estimate concentration, temperature, and density profiles.

The most recent advances have included the ability to simulate how changes in viscosity impact the mass transfer processes that limit cell growth (density) and slow down reactions as the gel hardens. These simulations are able to quantify underlying phenomena that till now were based primarily on speculation, such as: a) how some blowing agents are trapped in the resin because the resin cures before they can diffuse to the cell, b) the extent to which the pressure in foam cells decrease as temperature cools, c) the reasons why some foams shrink upon cooling, and d) the vapor pressure (and impact on emissions) of isocyanate monomers during the foaming process.

Simulation is now ready for use as a primary research and development tool for a) variations in foams to meet new criteria on density versus strength, b) adopting the use of new monomers, c) adopting the use of new catalysts, d) adopting the use of use blowing agents (or mixtures thereof), e) reducing emissions, and f) routine characterizing of monomer performance. This talk will summarize simulation capabilities and demonstrate the latest capabilities related to impact of viscosity on mass transfer processes.