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Dr Winnie Tang


Postdoctoral research fellow

Academic and research departments

Department of Chemistry.

My publications

Publications

We report prediction of selected physical properties (e.g. glass transition temperature, moduli and thermal
degradation temperature) using molecular dynamics simulations for a difunctional epoxy monomer
(the diglycidyl ether of bisphenol A) when cured with p-3,30
-dimethylcyclohexylamine to form a dielectric
polymer suitable for microelectronic applications. Plots of density versus temperature show decreases
in density within the same temperature range as experimental values for the thermal degradation and
other thermal events determined using e.g. dynamic mechanical thermal analysis. Empirical characterisation
data for a commercial example of the same polymer are presented to validate the network constructed.
Extremely close agreement with empirical data is obtained: the simulated value for the glass
transition temperature for the 60 C cured epoxy resin (simulated conversion a = 0.70; experimentally
determined a = 0.67 using Raman spectroscopy) is ca. 70?85 C, in line with the experimental temperature
range of 60?105 C (peak maximum 85 C). The simulation is also able to mimic the change in processing
temperature: the simulated value for the glass transition temperature for the 130 C cured epoxy
resin (simulated a = 0.81; experimentally determined a = 0.73 using Raman and a = 0.85 using DSC) is ca.
105?130 C, in line with the experimental temperature range of 110?155 C (peak maximum 128 C).
This offers the possibility of optimising the processing parameters in silico to achieve the best final properties,
reducing labour- and material-intensive empirical testing.