Synthesis And Applications Of Hyoerbranched Polyphosphate Ester

As a kind of hyperbranched polymers, hyperbranched polyphosphate ester not only has the over-all properties of hyperbranched polymers, such as generally lower intrinsic viscosity in comparison with those of liner polymers of similar structures, very good reaction activities, better compatibility with base polymers and large number of end groups, offering the possibility for further modification, but also with phosphate flame retardant excellent flame-retarding characteristics etc, is expected to widely used in aerospace, electronics, information, energy, transportation and military high-tech fields.A novel hyperbranched polyphosphate ester (HPPE) was synthesized via the polycond-ensation of bisphenol-A(BPA) as an A2monomer and trimethylolpropane (TMP) as a B3monomer, The influences of reaction conditions such as the amount of the catalyst, the molar ratio of A? to B3and the reaction time were studied. And the chemical structure of HPPE was characterized by FT-IR and1H-NMR to confirm its end groups. The best reaction conditions is:A2:B3molar ratio is1:1, the catalyst amount is1%of the amount of TMP, the reaction starting temperature is70℃, gradually warming up to110℃, under the nitrogen atmosphere, reaction time is4Hours.Curing kinetics of epoxy resin(EP)/DDM/HPPE (hyperbranched polyphospate ester) system was studied by employing differential scanning calorimetry (DSC) of DDM as curing agent and HPPE as toughening agent. SEM was eapplied to study the toughness and strength improvement mechanism of epoxy resin. The thermal property of the cured resin with HPPE was also studied by employing dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA). And the effect of HPPE content on the mechanical performance of the epoxy resin was investigated. The results indicated that both the tensile strength and the impact strength were enhanced to11.26%and306%respectively, with HPPE loadings of15%, and the LOI value increased from22to33and this proofed a good toughness, strength properties and flame retardant obtained.Oligomeric resorcinol bis(diphenyl phosphate)(RDP) and oligomeric bisphenol A bis(diphenyl phosphate)(BDP) were synthesized which were two kinds of phosphate flame retardants and the chemical structures were characterized by FT-IR. RDP BDP were used for the modification of epoxy resin, using dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA) to character the thermal properties of curing epoxy resin The effects of the amount of RDP or DBP on the mechanical properties and flame retardant of curing epoxy resin were also studied.The results of hyperbranched polyphosphate ester modified epoxy resin were compared with results of low molecular weight polyphosphate modified epoxy resin. It was found that witn the same amount, the toughness, strength properties and flame retardant of the former are better.