Study Of Flame-Retardant And Impact Toughening Modification For Poly (2, 6-Dimethyl-1, 4-Phenylene Oxide) Based On Synegstic Effects Of Phosphate And Polysiloxane

In odrder to develop a demestic product of polyphenylene oxide (PPO), promote its competitiveness, and broaden its application areas, we performed a study on flame retardant and impact toughening modification for poly(2,6-dimethyl-1,4-phenylene oxide) based on synegstic effects of phosphate and polysiloxane. The mechanical properties and thermal stability of PPO mamufactured by Blue-star and Asahi were compared in this paper. Flame-retarded PPO was prepared by addition of phosphorus and polysiloxane flame retardants, and the flame retardancy, mechanical properties, and flame retardant were studied. The synergistic pattern and content of the flame retardants were determined by the experiments.In this work, the mechanical properties of the domestic and imported PPO were measured, and its structures were analyzed by TGA, DSC, FTIR and H1 NMR. There is hardly difference in the mechanical properties of domestic and imported POM, but the toughness of Asahi PPO slightly exceeds Bleu-star PPO. Besides, The DSC and TGA study indicate that the thermal stability of blue star PPO is worse than the imported POM. The ratio of the hydrogen study by H1 NMR illustrate that the molecular weight of Asahi PPO beyond the Bleu-star PPO, and the molecular weight distribution of Bleu-star PPO is wider than Asahi PPO.A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)/polystyrene/maleated poly(styrene-ethylene-butylene-styrene) compounds containing resorcinol bis(diphenyl phosphate) (RDP) and poly(dimethyl-diphenyl siloxane) (PDMDPS) were prepared through melt extrusion, and their flammability characteristics and mechanical properties were evaluated. As was expected, the incorporation of RDP enhanced the flame retardancy of PPO compounds, but hardly made the 1.6mm samples obtain the UL 94 V-O rating. The compounds could achieve the V-0 rating only by combination of RDP with PDMDPS. Fourier transform infrared spectroscopic and morphological studies on the residual chars after vertical burning test suggested that the excellent flame retardancy of this compounding system be correlated with the retention from the synergistic effect of silica and phosphate in the char, whose cross-linked silica enhanced the formation of a compact char to retard combustion, and thus improved the flame-retardant efficiency.Thermogravimetric analysis indicated that the presence of PDMDPS improved the char yielding as well as the decomposition temperature of PPO compounds. The addition of RDP into PPO compounds resulted in a reduction of impact resistance. However, the Izod impact strength could be improved in the presence of RDP and PDMDPS. The morphological study on impact fracture surfaces indicated that the toughening effect of PDMDPS on the PPO compounds was attributed to the deformation and multiple cracks induced by PDMDPS, and consequently enhances the impact energy absorption of the matrix. This work provides a very effective flame retarding formulation for PPO compounds with improved impact toughness.