RAMAN SPECTROSCOPY AND CURE KINETICS STUDIES OF A DLS 772 AND 4 4’DDS EPOXY SYSTEM DURING THERMAL AND MICROWAVE CURING

Year 2019, Volume: 2 Issue: 1, 57 - 77, 30.06.2019

Babatunde Bolasodun Ademola Agbeleye Richard Day

Abstract

This
research was carried out in order to further understand the effects of
microwave heating on the functional groups and curing of epoxy systems. Raman
Spectroscopy was used to record the stokes and the antistokes spectra of
Diglydicydyl Ether of Bisphenol A (DGEBA) and 4,4’ Diphenyldiaminosulfone (DDS)
epoxy system at different temperatures during conventional and microwave cure,
and their molecular temperatures were calculated from the data obtained. The
temperatures showed that thermal heating does not excite the functional groups
of the epoxy resin and the hardener, as their molecular temperature was in the
same region as the cure temperature whereas Raman spectroscopy was unable to
produce any stokes or antistokes spectra during microwave curing of the epoxy
system. The cure kinetics of the DLS 772 / 4, 4’ DDS system was also studied by
using Differential Scanning Calorimetry (DSC) and a Microwave heated
calorimeter. The DSC results showed that microwave curing of the DGEBA / 4, 4’
DDS system began at a higher temperature than thermal curing. Higher rates of
reaction and activation energies were also observed in the microwave cured
samples. The temperature at which fractional conversion began increased with
increase in heating rate during microwave curing, but it was independent from
heating rate during conventional cure. The rates of reaction also increased
with an increase in heating rates for both thermal and microwave cure. These
results suggest that, compared to conventional heating, microwave heating is
more efficient curing technique which leads to more uniform cure and less
internal stresses within the material.

Keywords

Raman Spectroscopy, Epoxy, Microwave, Cure Kinetics

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