Synthesis of fluorine contained hyperbranched polysiloxane and their effect on the thermal conductivity of epoxy resins

Abstract To improve the thermostability properties of epoxy (EP) resin, two kinds of novel hyperbranched polysiloxanes containing fluorine were prepared via the sol–gel process and the convenient transesterification process, respectively (F‐HBPSi‐1 and F‐HBPSi‐2). These two prepared F‐HBPSi were then used as modifier phased to blend with EP to obtain two new series polymer alloys F‐HBPSi‐1/EP and F‐HBPSi‐2/EP. The dielectric properties and thermal conductivities of the cured F‐HBPSi/EP resins were measured, while their thermal properties were also investigated by thermogravimetry (TG). The results showed that both the thermal conductivities and the thermostability properties of these two F‐HBPSi/EP were increased effectively, without further damaging their dielectric properties. Meanwhile, the F‐HBPSi‐2/EP exhibits better thermal conductivities and thermostability properties than that of F‐HBPSi‐1/EP. The improved overall performance of F‐HBPSi‐2/EP can be attributed to the low viscosity and excellent compatibility of F‐HBPSi‐2, as well as the good synergism between fluorine and silicon.