Improving the toughness and thermal properties of epoxy resin using for electronic packaging by interpenetrating polymer network

A series of Polydimethylsiloxane-Epoxy resin interpenetrating polymer networks (PDMS-ER IPNs) were synthesized with Hydroxyl-terminated Polydimethylsiloxane (PDMS), Diglycidyl ether of bisphenol A (Epoxy resin, ER), Toluenediisocyanate (TDI), 1,4- Butanediol and Dibutyltin dilaurate (DBTDL) as catalyst. The reaction completion was confirmed by the disappearance of the characteristic -NCO peak (at 2270 cm^-1) in the IR spectrum. Cured of PDMS-ER IPN and unmodified ER were investigated by measuring its tensile strength, break elongation, thermo-gravimetric curve, water absorption and the morphology of fractured surfaces. The results show that the PDMS-ER IPN with correct ratios has excellent mechanical properties with better break elongation, tensile strength, bending strength and flexural modulus than the unmodified ER. The toughening effect of the IPN was demonstrated by the SEM micrographs of the fractured surface of the samples. Water absorption tests and thermogravimetric analysis showed that the PDMS-ER IPN exhibited better water resistance and thermal stability than the unmodified ER. The PDMS-ER IPN with high toughness and thermal resistance is suitable for the use of electronic packaging.