Synthesis And Study Of Cyclotriphosphazene Derivatives Containing Oxygen Group And Their Flame-retard Ant For Epoxy Resin

Polyphosphazene are polymers having chemical structures containing alternating basedphosphorus and nitrogen atoms forming a ring structure and linear compounds havingchain-like backbones of phosphorus and nitrogen atoms with alternating double and singlebonds. As a new materials, phosphazenes have a wide range of research and application in allsocial sectors, especially in flame retardant material area. With the demand the fire-retardantmaterials is toward to halogen-free, low posin, low smoke, durable, low cost as well asenvironment friendship, as intumescent flame retardant phosphazene compounds attractedworld wide attention because of excellent flame retardancy. As one of three general purposethermosetting resins, Epoxy resin polyer with good properties have a wide application inmany fields, but its flammability has caused large hazard for human life and safety. So thispaper is to study the epoxy resin retardant with phosphazenes.First, hexachlorocyclotriphosphazene（HCCP） was prepared by the reaction of ammoniumchloride with phosphorus pentachloride. The optimal reaction conditions and larger factorseffecting reaction were obtained by orthogonal design, and the synthetic mechanism wasdiscussed preliminarily.Hexakis（4-aldehydephenoxy）-cyclotriphosphazene（PN-p-CHO）, hexakis （2-aldehyde-phenoxy）-cyclotriphosphazene（PN-o-CHO） and hexakis（4-nitrophenoxy）-cyclotriphospha-zene（PN-NO₂） were synthesized with HCCP as a raw material. Hexakis（4-h-ydroxypheno-xy）-cyclotriphosphazene（PN-p-OH）, hexakis（2-hydroxyphenoxy）-cyclotriphosphazene（PN-o-OH）, hexakis（4-aminophenoxy）-cyclotriphosphazene （PN-NH₂）, hexakis （4-carboxyl-phenoxy）cyclotriphosphazene （PN-p-COOH） were obtained respectively after reduction andoxidation reactions. Their structures and properties were characterized by elemental analysis,melting point, FTIR,1H NMR and31P NMR.As two monomer, dimethyl3,3’-（2-hydroxyethylazanediyl）dipropanoate （M₁） and methyl3-（bis（2-hydroxyethyl）amino）propanoate （M₂） were synthesized via Michael additionreaction of ethanolamine and diethanolamine with methyl acrylate respectively.The hyperbranched poly（amine-ester） with ester terminal groups and hydroxyl groups weresynthesized via reaction of two monomers with HCCP and PN-o-OH respectively. Thehyperbranched polytetrahydrofuran glycidyl ether was synthesized based on the reaction ofPN-p-OH with THF and epichlorohydrin using boron trifluoride etherate as catalyst. The molecular composition of the hyperbranched polymer were characterized by FTIR, NMR andGPC. The hydroxyl value of the hydroxyl end groups of hyperbranched poly（amine-ester）and epoxy value of the hyperbranched polytetrahydrofuran glycidyl ether were determined.The commercial epoxy resin Diglycidyl ether of bisphenol-A （DGEBA） was cured with4,4’-diaminodiphenylsulfone（DDS），4,4’-diaminodiphenylmethane （DDM），PN-p-NH₂andtheir mixture respectively; The epoxy resin prepolymers were obtained in turn after thereaction of DGEBA with PN-p-OH and PN-o-OH, and then cured with DDS, DDM and PArespectively; the hydroxyl end groups and ester end groups of hyperbranchedpoly（amine-ester） and hyperbranched polytetrahydrofuran glycidyl ether were added toDGEBA respectively, after reaction the products were cured with DDM. In this way, Thecured different flame retardant epoxy resins with the cyclotriphosphazene were obtained.Their thermodynamic stability and flame-retardant properties were evaluated by usingthermogravimetric analysis （TGA）.