Study On The Synthesis And The Flame Retardancy Of Two Triazine Compounds

Polyamide6(PA6) maintains a significant position of the five common engineering plastics, due to its perfect comprehensive properties. With the widespread use and increasing consumption, its poor heat resistance and low LOI are facing a more rigrous working environment, which restrict the application in electronic and electrical, transportation and some other fields.Polypropylene (PP) is a kind of general-purpose plastic, with good chemical stability, density of small and inexpensive process, which is taking a more important role. But its potential safety hazard comes along with its low melting point and low LOI.Triazine-based flame retardant is used in PA6as a replacement of halogenated flame retardants. The performance degradation occurred with the massive addition. A common flame retardant for PP consists of melamine(Mel), ammonium polyphosphate,(APP) and pentaerythritol(PER) which could impact the flame retardancy results from its low molecular weight. To settle the problems above, a novel melamine sulfamic acid salt and a tria(?)ne charring agent are synthesized by triazine as substrate, which are designed to apply in flame retardant of PA6and PP respectively.Melamine sulfamic acid salt containing nitrogen and sulfur is synthesized. The molecular structure of the product is characterized by IR,’H-NMR and elemental analysis, and the thermal property is investigated by TG. The results show that the target product is obtained, and the temperature above318℃at5%weight loss in TGA, showing the feasibility in flame-retardant PA6.The applications of the flame retardant combined with PER, and its individual utility are investigated in PA6resin. The flame retardancy, mechanical property and thermal stability of the flame retarded PA6are investigated by Vertical combustion analyzer, limit oxygen index instrument, tensile machine and TGA.When the dosage of MSAS is10wt%, the vertical burning test reaches UL94V-0(3.2mm), with the LOI at33.7%; meanwhile, the conservation rate of tensile strength is89.55%. It is obvious that the initial decompositon temperature reduces and the residual mass improved as the flame retardant systems processed into PA6. The flame retardant mechanisms of the flame retardant PA6are learnt via DSC, pyrolysis gas chromatography/mass spectrometry analysis, IR and elemental analysis. The depressed melting point results in dripping when burning which takes away the heat, contributing to flame retardant. The appearance of sulfur in both vapor phase and condensed phase indicates the sulfur in MSAS/PER works in vapor phase and condensed phase flame retardant; while sulfur in MSAS-flame-retardant PA6detected only in condensed phase shows the condensed phase mechanism of flame retardant.A triazine based charring agent N,N-(2,4-diamino-1,3,5-triazinyl) ethanediamine is prepared. By the means of the changes in pH value during the reaction, IR and elemental analysis, they show the expected product is obtained, however, the impurity accompanied. The process is determined through four conditions:the order of addition of reactants, synthesis temperature, ratio of acetone and water in solvent and different solvents. The molecular structure of the products are characterized by IR. The reaction is too complicated since the appearance of water in the medium for us to reach our goal, nevertheless, a better process is determined to the pilot scale experiment. TGA shows the temperature at5%weight loss is about244℃, indicates the availability to PP.The triazine-based charring agent is compounded with Mel and APP. The flame retardancy and thermal property of the flame retarded PP by the system are investigated via Vertical combustion analyzer and TGA. The results demonstate that PP could reach UL94V-0(3.2mm) loaded with5.1wt%charring agent,2.8wt%Mel and20.1wt%APP. TG and SEM manifest char layer formed on the surface of PP to protect the material.