Research And Application Of Multi-element Synergist On Intumescent Flame Retardant

In the past decades, environment-friendly flame retardants have developed rapidly.Among these flame retardants, intumescent flame retardants (IFR) are the most popular.However, most of IFR with a smaller molecules generally give rise to a high cost, highdosage and the IFR is easy to be damped and moved from inside to the surface of materials.Therefore, the novel cheaper IFR with high molecule, good flame retardant performanceand multi-function should be studied further.In this thesis, the novel phosphorus-nitrogen and phosphorus-silicon polymeric flameretardants were prepared using waste polyurethane, silicon tetrachloride, triphosphorusoxychloride and hydroxyethyl methacrylate as raw materials. The products werecharacterized by infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR),scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), differentialscanning calorimeter (DSC), differential thermal analytical balance (TG-DTA) and so on.The products were introduced to epoxy (EP) and polypropylene (PP). The flame retardancyand tension strength of materials were tested by limiting oxygen index (LOI) and tensiletesting. Specific research works are listed as follows:(1) Poly (hydroxyethylmethacrylate)(PHEMA) was obtained from solutionpolymerization by using hydroxyethyl methacrylate (HEMA) as monomers, benzoylperoxide (BPO) as initiator and1,4-dioxane as solvent. A novel phosphorus-andnitrogen-containing IFR PPM was prepared by modifying PHEMA with phosphorusoxychloride and MEL. PPM was applied into epoxy resins (EP) to analysis flame retardantproperties and mechanical properties. The optimum synthetic moore ratios for PPM are asfollows: n (P—Cl): n (MEL)=1:2. The LOI of EP/PPM (25%PPM) system is about27%,and the flame retardant grade can reach UL94V-1.(2) Two pre-polymerizable monomer (hydroxyethyl methacrylate acid trimethyl estergroup (MATSE) and hydroxyethyl methacrylate phosphate ester group (MADPE)) was gotby using hydroxyethyl methacrylate (HEMA) and methanol as raw materials to react withsilicon tetrachloride and phosphorus oxychloride respectively. Then copolymerizedMATSE and MADPE to obtain a new phosphorus-and silicon-containing flame retardantPMM. The optimum condition for the synthesis of PMM is: Using THF as solvent, themoore tatio between MATSE and MADPE is2to3. The concentration of monomer is30%.The reaction temperature is70℃，and the reaction time is11hours. Results show that: when15wt%of PMM and20wt%of APP were added in PP, the flammability can achievea UL94V0standard with a LOI of28.4%.(3) Flame retardant materials based on modified polyurethane (MPU) was prepared.Firstly, the phosphonic dichloride of polyurethane (PDP) was synthesized by using PU andphosphorus oxychloride (POCl3) as materials; Then, PDP was hydrolyzed and reacted withmelamine (MEL). Results show that the optimum reaction conditions are as follows: theconcentrations of PU and POCl3are about20g/L and400g/L respectively; the reactiontemperature is80℃and reaction time is13h. The content of phosphorus and nitrogen canreach3.1%and14.2%respectively. The LOI of MPU is about28%, and the flameretardant grade can reach UL94V-0.