Double modified amino phenolic resin particles: A novel modifier to thermally stable, mechanically-strong and tough epoxy

Abstract

We proposed a method to prepare double modified amino phenolic resin (D-APS) particles, which includes a hydrothermal synthesis and subsequent two-step modification. The prepared D-APS particle has a uniform spherical morphology. There were abundant and evenly dispersed amino hydrogen and phosphaphenanthrene groups on its surface. The formed D-APS/epoxy composite possesses improved mechanical properties at room and cryogenic temperature. At room temperature, the tensile strength of epoxy composite firstly increased and then decreased with the increase of D-APS loading. A maximum tensile strength of 98.4 MPa was obtained when the D-APS loading was 3.0 wt%. The fracture toughness of D-APS/epoxy composite containing 3 wt% D-APS particle was 1.68 MPa m1/2. At 90 K, a maximum tensile strength of 208.4 MPa was obtained when the D-APS loading was 3.0 wt%. The corresponding KIC is 3.23 MPa m1/2. A 49 °C increase in 50 wt% mass loss temperature for epoxy composite containing 3 wt% D-APS particle is observed. DMA tests show that D-APS was also helpful to increase the glass transition temperature of epoxy composites. Possible modification mechanism of D-APS/epoxy composites was also discussed.