Study On Polypropylene Synergistically Flame Retarded By Aluminum Hypophosphite

In this thesis, I prepared aluminum hypophosphite(AHP) from sodium hypophosphite and aluminum sulfate via microemulsion, I regulated temperature and concentration of reagents to miniaturize the particle size of AHP, compared to commercial AHP synthetic AHP has smaller particle size and narrower particle size distribution, then apply synthetic AHP for the flameretardant modification of PP, when the addition is 30%wt, the LOI of PP specimen is 28.2%, while specimen with the same addition of commercial AHP’s LOI is only 27.1%, this proved that flame retardant with smaller particle size will be helpful to increase flame-resistant effect. The cone calorimetric outcome of PP specimens reflected that the PHRR and other parameters of PP with synthetic AHP is superior to PP with commercial AHP.In this thesis I studied how flame-retardant and synergistic effect system of synthetic AHP and melamine cyanurate(MCA) affect the flame-resistant property of polypropylene, then found that when the addition of flame retardant is 30%wt, the ratio of MCA/AHP is 7:3, this synergistic effect system come to a best ratio, the LOI of this PP specimen is 28%, and it meet UL94V-0 level test, however, the specimen with 30%wt pure MCA can only meet UL94V-2 level test, and its LOI is only 24%. The thermogravimetric analysis show that the residue of best-ratio specimen is 8.73%, while specimen with pure MCA is 0%. The cone calorimetric outcome reflected that the PHRR of best-ratio specimen is 389.8 kw/m2, however, PHRR of specimen with pure MCA is 475.9 kw/m2, what’s more, the TTI of specimen with AHP is 8 seconds later than specimen without AHP.In this thesis I studied how flame-retardant and synergistic effect system of synthetic AHP and modified APP(DAPP) affect the flame-resistant property of polypropylene, then found that when the addition of flame retardant is 30%wt, the ratio of DAPP/AHP is 9:1, this synergistic effect system come to a best ratio, the LOI of this PP specimen reach to 38.6%, a little AHP can lead to best synergistic effect. The thermogravimetric analysis show that the residue of bestratio specimen is 22.06%, while specimen with pure DAPP is 17.95%. The cone calorimetric outcome reflected that the PHRR and THR of best-ratio specimen are 254.4kw/m2 and 139.9MJ/m2 respectively, which is 11.3% and 19.6% lower than specimen with pure DAPP respectively, what’s more, the TTI of specimen with AHP is 4 seconds later than specimen without AHP. After I studied these two flame-retardant and synergistic effect systems I can draw a conclusion that synergistic effect system of AHP and DAPP has better synergistic effect.