Fabrication of epoxy-montmorillonite hybrid composites used for printed circuit boards via in-situ polymerization

Abstract

Montmorillonite (MMT)-filled brominated epoxy hybrid composites used for printed circuit boards (PCBs) are successfully prepared by in-situ polymerization by a careful choice of fabrication process. The characteristics of the composite are assessed by Inductance Capacitance Resistance meter (LCR), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Thermal Mechanical Analysis (TMA) and a universal tester. The dielectric study reveals that the incorporation of MMT filler into epoxy significantly reduces (i.e. by up to 36%) the dissipation factor, with a marginal reduction in the dielectric constant. The hybrid composites also exhibit better thermo-mechanical properties. With regard to thermal stability, the introduction of a small amount of MMT leads to an improvement in the glass transition temperature (T _g), a marked decrease in the coefficient of thermal expansion (CTE) at different temperature ranges, particularly above T _g, and a slight improvement in the mechanical properties such as Young's modulus and tensile strength. We observe a negligible trend but good resistance for moisture absorption compared with unmodified epoxy resin systems.

Keywords:

• MONTMORILLONITE
• EPOXY
• HYBRID COMPOSITE
• PCB