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Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA

Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA

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Experimental 85<br />

same reason a wood 22 table <strong>of</strong> the same logger size has been put on it.<br />

For improving the reliability <strong>of</strong> temperature measurement the tip <strong>of</strong> the stem<br />

has been spread with thermoconductive oil. The tip has been placed under the<br />

bottom <strong>of</strong> the vessel for avoiding mechanical <strong>and</strong> electrical interferences with the<br />

epoxy mixture. The sample has been positioned on a disc <strong>of</strong> teflon at about 2 cm<br />

<strong>of</strong> height.<br />

The aluminum box has been hermetically closed for preventing the damage <strong>of</strong><br />

the electronic circuits.<br />

The datalogger has been used only during the experiments performed in static<br />

operative conditions, because with movable tray two unwanted phenomena occur:<br />

1. Mechanical vibrations impeding an accurate temperature measurement;<br />

2. Onset <strong>of</strong> parasitic electric currents along the stem generating remarkable<br />

temperature overshoots.<br />

2.6 Optimization <strong>of</strong> the Process Conditions<br />

For exploiting the full potentiality <strong>of</strong> the microwave oven 23 for the polymerization<br />

<strong>of</strong> the epoxy system it is necessary to place the sample in the centre <strong>of</strong> the<br />

applicator cavity at 2 cm <strong>of</strong> height, when the plant operates with moving tray, or<br />

in the position <strong>of</strong> coordinates (0,-5,2) [cm], when the it works as a static cavity.<br />

In dynamic operative conditions the tray velocity <strong>of</strong> 224 cm/min has been also<br />

selected for safety reason.<br />

A preliminary qualitative optimization <strong>of</strong> the operative conditions has been<br />

carried out for the best performance <strong>of</strong> the microwave curing processes.<br />

22 Material microwave sensitive.<br />

23 As verified through its characterization.<br />

85

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