Effect Of Water Resistance On Intumescent Flame Retardant To Polypropylene

In order to improve the water resistance of intumescent fire retardants,two methods were raised in this paper.At first, a new type of macromolecular charring agent, PAP, was used in this paper to replace the traditional water-soluble dipentaerythritol. APP/MMT was used as acid source to manufacture the fire retarded PP samples. A series of tests were carried out on the sample before and after the water immersion test, such as vertical combustion test, limiting oxygen index test, cone calorimeter test and tension test. The results show that, PAP, as a carbon source, has good flame retardancy and it can also improve the water resistance. Parts of the samples(2# and 3#) can still pass the UL-94 V-0 rating after the water immersion test. The use of PAP can decrease the loss of tensile strength after the water immersion test, and also can inhibit the increase of the elongation at break.At the same time, in order to study each component’s effect on water resistance specifically, we made a series of samples containing only one component. Though long-time immersion test, we test the weight loss rate at regular intervals, and draw weight loss rate time curve to provide support for basic research of the water resistance of flame retardant polypropylene system. The results showed that the leaching amount of APP/MMT,Ⅱ-APP and DPER is higher than other components in the immersion test. Three kinds of APP/MMT nanocompounds with different particle sizes were added to PP, and the one with the smallest particle size was found to dissolve out the minimum substance.On the basis of the above research, the full scale nanocomposites were introduced into the research. We studied the effect of polymer/clay/IFR on water resistance and flame retardant property. o-LDH-MMT and o-MMT were added to PP and PPg by melt blending method and we got the polymer / clay nanocomposites. APP/MMT IFR and APP IFR were added to the above PLS and two kinds of flame retardant system, PP/o-LDH-MMT/ IFR and PPg/o-MMT/ IFR, were prepared. Through the comparison of water resistance and flame resistance of different formulas, we studied on the different effect of clay existing in polymer phase and flame retardant agent phase. The results showed that the addition of o-LDH-MMT and o-MMT to polypropylene can significantly reduce the heat release rate,increase the amount of residual carbon and increase the mechanical strength and the insulation strength of residual carbon, which can greatly improve the properties of carbonlayer, and maintain a high level in the UL-94 test. In the water immersion test, the addition of o-LDH-MMT increased the rate of weight loss, but due to the use of PAP, the weight loss remained a lower value, and the samples could still maintain a high flame-retardant level after the immersion test.