Class transition temperatures from molecular dynamics simulations

The glass transition temperature (T-g) of an amorphous polymer is probably its most important material property descriptor. It defines the domain of use. Low values are associated with elastomers, high values with structural plastics, and intermediate values with adhesives and non-woven fabrics. It would be a considerable convenience if T-g values could be predicted from only a knowledge of the polymer chemical structure. Recently, molecular dynamics simulations (MD) of bulk polymers have become a reality. As part of this development it has become possible to compute the equation-of-state behavior of a number of polymers. By extending the MD-generated volume-temperature curves to low temperature, breaks indicative of T-g may be located. Although the number of cases explored so far is small, the range of T-g values represented is wide. The simulation values for T-g are in encouragingly good agreement with experiment.