| Recently, traditional epoxy molding compounds are facing great challenges with the development of the electronics and composite materials, the conventional epoxy resins are unable to satisfy some applications, which require higher thermal resistant, better flame retardant and lower moisture absorption. Thus, it is necessary to design and develop high thermal resistant, good flame retardant and low moisture absorption epoxy resin systems for these applications.This paper introduces a kind of epoxy resin curing agent synthesis method and process from the molecular structure design. A novel phosphoric flame retardant epoxy resin curing agent for epoxy resins, was synthesized via condensation reaction of4-hydroxybenzaldehyde with C=C, followed by the addition of9,10-Dihydro-9-oxa-10-phosphaphen-anthrene10-oxide (DOPO) to the resulting linkage. Chemical structures of these materials were characterized with FTIR and1H-NMR spectra,. The thermal and flame retardant properties of the epoxy resins cured by various equivalent ratios phenol formaldehyde nolovc (PN) and P-OH were investigated by the nonisothermal differential scanning calorimetry (DSC), the thermogravimetric analysis (TGA), and limiting oxygen index (LOI) test. The obtained results showed that the cured epoxy resins possessed high char was maintained in P-OH/CNE systems than that in PN/CNE system and the results indicated their excellent flame retardancy.The curing kinetics of CNE in presence of P-Containing curing agent (P-OH) was explored by non-isothermal differential scanning calorimetry (DSC) technique. The basic cure process was determined through extrapolation. The Flynn-Wall-Ozawa isoconversional method and Kissinger method were used to evaluate the effective activation energy (Ea) was61.3kJmol-1and63kJmol-1, respectively. |
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