Abstract:
The thesis reports studies of cure kinetics and the glass transition
temperature advancements of three commercial epoxy resin systems: MY 750
/ HY 5922 (Vantico), MTM 44 -1 (ACG) and 8552 (Hexcel Composites). This
investigation was conducted with the utilisation of Differential Scanning
Calorimetry (DSC) and Temperature Modulated DSC (TMDSC). Appropriate
phenomenological cure kinetics models were built to predict the degree of
cure as a function of temperature/time profile. The validity of superposition of
dynamic and isothermal experimental data was established. Rheological
measurements were performed in order to determine the gelation region
under given cure conditions. The cure modelling methodology was validated
against an international Round-Robin exercise led by the University of British
Columbia (Canada).
The effects of carbon nanoparticle incorporation on the cure kinetics and
the glass transition temperature advancement of two of the epoxy systems
were also studied. Cure kinetics models were developed for the
nanocomposites containing commercial multiwalled carbon nanotubes and a
direct comparison was made with the models of the neat resin systems. The
glass transition temperature advancement is shown to be affected in the early
stages of the cure.
The state of the dispersion of the nanoparticles was studied in order to
correlate it with the observed effects upon the cure and on the morphology of
the cured samples. The presence of carbon nanotube clusters is shown to
have an influence on the phase separation in the MTM 44-1 resin system.
As a potential industrial application of this study, optical fibre
refractometers were utilised as an on-line cure monitoring technique. A good
correlation was established between the measured refractive index changes
during the cure and the degree of cure predicted by the above mentioned
models, for the neat resin systems and their nanocomposites.
