Study On Toughening Modification & Pyrolysis Kinetics Of Melamine Resin

Melamine foam is a kind of high-performance green foam with Flame-retardant, acoustic noise, thermal insulation, heat stable, health non-toxic, easy post-processing performance.Widely used in architectural acoustics, automotive, industrial noise, industrial insulation, rail transportation, aerospace navigation, equipment installation and air conditioning systems, cleaning systems, etc.. But pure melamine resin was a thermosetting polymer, and it formed a cross-linking network structure in three dimensions, a rigidity triazine ring included in the network structure, thus resulted in that the melamine resin has a poor forming foam performance. Foam formed is hard and crisp with poor mechanical properties, low intensity, small deformation capacity, poor tensile and flex. Therefore, improvement of toughness and decreasement of brittleness were an important goal on developing new foaming melamine resin.The melamine resin which was respectively modified with PEG-200 and tri(2-hydroxyethyl)isocyanurate was studied in this paper. Dynamic viscosity of resin system is used as the evaluation index of modified resin. The orthogonal experiment and single factor experiment were used to investigate the polymerizing reaction conditions of modified resin (such as material ratio,reaction time,amount of modifier,solid content) on the polymerization reaction system; Structure and thermal stability of modified resin were characterized and identified using infrared spectroscopy, nuclear magnetic resonance carbon spectra, thermal gravimetric; Toughness was characterized through determining the tensile strength and fracture elongation of the modified resins, and the optimal reaction conditions of appropriate foaming modified resin are obtained; Finally, Through studying the pyrolysis kinetics of the modified resin, provide reference values for further understanding the heat resistance and application of the foaming melamine.The results indicate that the appropriate conditions of PEG modified resin were as follows, pH is 9.5, n(F)/n(M)=2.8, solid content is 75%, reaction time is 50min, the amount of PEG is 5%; the appropriate conditions of THEIC modified resin were as follows, pH is 9.5, n(F)/n(M)=2.8, solid content is 75%, reaction time is 90min, the amount of THEIC is 10%. PEG, THEIC were involved in the reaction system and successfully implanted melamine resin molecular chain, increased the distance between the triazine ring, the toughness of the modified resin was improved; though the fire-retardant property of the modified resin with modifier was reduced; When the amount of PEG is 5% and amount of THEIC is 10%, the related tensile strength and fracture elongation of the corresponding modified resins basically reach the requirements of foaming resin GFDA-7, and the appropriate conditions of appropriate foaming modified resin were further obtained. Kinetic equation of PEG modified resin is dα/dt=2.5368×1015 (1-α)[-1n(1-α)]-2 e-208.0769/RT.