Synthesis And Properties Of Phosphorus-containing Epoxy Resin

Epoxy resin is a very important traditional material, and is widely used inadhesives, coatings and conmposites. But epoxy has a poor flame retardant,which limites its application, so it is very important to improve this property.As phosphorus-containing compounds produce few harmful gases, and theyare much effective, so organic phosphorus is paid more attention.In this paper, a novel phosphorus-containing epoxy resin is synthesized, whichcan be mixed with other epoxy resins as flame retardant. DMMP and EG werefirst used to synthesize intermediate, then ECH was employed as rawmaterials to synthesize phosphorus-containing epoxy resin. With differentmolar ratio of EG/DMMP, three kinds of products were obtained. Theirinfluences to epoxy resin were investigated.Intermediate with different molecular weight were synthesized throughtransesterification of DMMP and EG. Synthetic technology was determined:temprature at170-180, the amount of catalyst was1wt%of the total massof raw materials, and the reaction time was5h. Structures of the intermediatewere confirmed by hydroxyl value titration, FTIR and1H-NMR.Three intermediate obtained in the first step were reacted with ECH to synthesize phosphorus-containing epoxy resin. Synthetic technology wasdetermined: the amount of catalyst was0.6ml, mass fraction of NaOH was40%, and temprature of ring-close reaction was30. Structures of productswere confirmed by epoxy value titration, FTIR and1H-NMR.The synthesized phosphorus-containing epoxy resin was mixed withepoxy resin E-51, LOI, tensile strength and elongation of cured products weretested. When phosphorus content was3%, LOI of32.0could be reached,while tensile strength reduced slightly, but elongation increased.