Effect of Postcure on Properties of Molding Compounds
Tutor / director / evaluatorJansen, Kaspar
Document typeMaster thesis (pre-Bologna period)
Rights accessRestricted access - confidentiality agreement
Thermosetting polymers are widely used in electronic industries as encapsulates of electronic devices. It is well known that polymers and polymer-based composites show strong temperature and time dependent behavior. The aim of this study is to investigate the effect of postcure and thermal aging on the properties of molding compound. Knowledge of the effect of thermal aging is important for manufacturers since electronic devices are often exposed to high temperatures for long time periods. For instance if a product is placed close to the engine of a car, the effect of thermal aging has to be taken into account to predict accurately stresses and strains. Thermal aging results in a tremendous change of properties which might lead to failure of electronic components. The present work investigates the change of mechanical properties of molding compound after different thermal treatments. The main study is focused on the change of the glass transition temperature and the viscoelastic modulus, obtained through Dynamic Mechanical Analyzer. Afterwards, compiling all the obtained data, models have been found to describe the glass transition temperature, the rubbery modulus and the storage modulus as a function of thermal aging time. It is observed that thermal aging leads to an additional increase of cure shrinkage. This cure shrinkage is experimentally determined and modeled. The chemical composition of molding compound changes due to a chemical reaction at high temperatures (T>175ºC). The change in chemical composition could be determined by using InfraRed Spectroscopy.
|Effect of Postc ... ompound_Albert SANCHEZ.pdf||Report||1.412Mb||Restricted access|
|LITERATURE REVI ... N ON MOLDING COMPOUNDS.pdf||Annex||129.4Kb||Restricted access|