| With the fast developed industry of polymer materials, retardant and relative study, production and application have leaped forward. Organosilicon flame retardant, which may be the most promising alternative instead of traditional retardants that would finally be eliminated as a result of the increasing pro-environment requirements and other material properties, exhibited a series of excellent properties and environment friendly properties that make them accord the tendency, so organosilicon will have great potential in retardants'exploration and application. For example, Organosilicon flame retardant have high when applied into PC, PC/ABS alloys, but when blends with polyolefin, they can rarely reach the degree of UL 94V-0. So our mainly work is employing other retardant elements on the basis of previously relative work, to creat synergistic effect between them, which will finally improve the organosilicon flame retardation and their range of application.Our work mainly contains:1. Synthezis silicon resin with varied content of phenyl with phenyl silane and amidosilane as starting materials under water reaction medium. Discuss the effect of strating materials ratios, reaction time, and reaction temperature and catalyst dosage on the products. The result indicates that the yield would be the highest (91.0%) with 90% phenyl silane and 10% amidosilane reacted for 4 hours at 50 oC.2. Use organic silicon resin with different content of phenyl to react with the intermediate spiro chloride phosphate to get the retardants with Si, P, N elements, then take characterization of organic silicon resin and organosoilicon retardants through FT-IR and 1H-NMR.3. Blend the organic silicon resin and organosilicon retardants synthesized above with PP and test their flame retardant properties and mechanism properties. With the increased amount of organic silicon resin and organosilicon, their Limited Oxgen Index (LOI) enhanced, which would be similar to phenyl as variation. For instance, when blended with 20 percent organic silicon resin and organosilicon retardants at a ratio 9:1, the LOI of PP increases from 17.8% to 25.5% compared to another sample with same dosage at the ratio 7:3; Moreover, P-groups contained organosilicon retardants, which have better properties, when blended with PP with the dosage of 20 percent at a ratio 9:1, will improve the LOI from 17.8% to 26.7%. For the mechanism properties, with the enhanced flame retardant properties, the tensile strength, flexible strength and impact strength declined a little while elongation at break decline a lot. Moreover, the introduction of P- group into the retardants had improved their mechanism properties.4. Analysis the thermal stability of the organic silicon resin and organosilicon retardants at N2 atmosphere through TG measurement, the samples show a big weight loss at 400oC and high amount of char residue at 900oC. For example, the organic silicon resin at ratio 8:2 would make the system weight lose 9.85% from 350oC to 500oC and 15.93% from 500oC to 900oC and the residue amount at 66.47% at 900 oC. The introduction of P-contained groups could reduce the retardants'thermal stability and the residue amount at 900oC.5. We employ TG-FTIR and the residue's FTIR methods to analysis the organic silicon resin and organosilicon retardants, the blends volatile matter and residue, to get a full understand of the whole thermal degradation process. The degradation contains two steps: the first step is the degradation of hydroxyl group and other small molecule in the base-structure; at the second step, the polymers are cracked into CO2, CO, NO2 and the other gas at the temperature of 500oC-900oC. The degradation temperature of PP/organosilicon retardants blends mainly located at 300oC, which was caused by the breakdown of the PP main chain. Moreover, we also observed effect from the polarizing microscope that the char layers increased with compact structure with the increament of organosilicon.
|
PDF Full Text Request