This paper presents an approach to prepare polysiloxane-based conductive composites filled with low-cost silver coated copper (Ag-coated Cu) microscale flakes by using the hyperbranched poly(amine-ester) (HBP3-MA) as modifier which is obtained by the reaction between the hyperbranched poly(amine-ester) (HBP3-OH) with terminal hydroxyl and maleic anhydride.The structure of the HBP3-MA was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR).Curing condition of the compound system was studied by differential scanning calorimetry (DSC) since HBP3-MA was involved in the curing reaction of polysiloxane.The structural morphology (the size and dispersion) of in situ reduced AgNPs and the composite system was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).Also

conductivity mechanism of the composites reinforced by metal nanoparticles was discussed.At the curing temperature

silver acetate decomposed and silver nanoparticles (AgNPs) were in situ generated in the polymer matrix.The low temperature sintering of AgNPs anchored on the surface of Ag-coated Cu flakes enhanced the interfacial bond of Ag-coated Cu flakes and decreased the overall contact resistance.Last

the conductivity and shear strength of the composites were studied.When the content of silver acetate was 4.4 phr

the optimum volume resistivity and the shear strength were achieved

which were 3.610-3cm and 0.32 MPa

respectively.