Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA
Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA
Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA
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Results <strong>and</strong> Discussion 155<br />
3.7.2 FT-NIR Spectra<br />
The spectroscopic analysis has been extended also to near infrared region 22 for<br />
verifying the disappearance <strong>of</strong> the peak corresponding to primary amino group at<br />
about 4930 cm −1 .<br />
In Figure 3.43 the FT-NIR spectrum <strong>of</strong> the hardener agent K 21 is illustrated.<br />
Figure 3.43: K 21 FT-NIR spectrum between 4000 <strong>and</strong> 6000 cm −1 .<br />
Finally in Figure 3.44 a comparison <strong>of</strong> the FT-NIR spectra <strong>of</strong> the epoxy system<br />
microwave <strong>and</strong> conventionally cured is shown.<br />
The two FT-NIR signals are very similar, <strong>and</strong> no peaks are present in the region<br />
around 4930 cm −1 . Therefore it is not possible to relate the observed behaviour<br />
to differences in fractional conversion or reaction path possibly induced by the use<br />
<strong>of</strong> microwave radiations.<br />
No residual reagents, epoxies or amines, can be found in samples cured in both<br />
the way. Therefore a complete conversion has been reached, <strong>and</strong> the absence <strong>of</strong><br />
homopolymerization reactions has been also verified.<br />
22 Wavenumber between 4000 <strong>and</strong> 1000 cm −1 .<br />
155