Mechanical property improvement and fire hazard reduction of ammonium polyphosphate microencapsulated in rigid polyurethane foam

Abstract

Ammonium polyphosphate (APP) is an effective phosphorus‐containing flame retardant. But APP also has excellent hygroscopic capacity and decreases the mechanical property of composite. The aim of the study was to microencapsulate APP with polymethyl methacrylate (PMMA) to prepare microencapsulated ammonium polyphosphate (PMAPP) in order to eliminate the harmful effects caused by the mechanical property of composite. The microcapsules are characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and hydroscopicity test and observed by scanning electron microscopy (SEM). Fire hazard of rigid polyurethane foam (RPUF) is evaluated using a cone calorimeter and limited oxygen index test. The mechanical property of RPUF is studied by compressive strength test. The results show that APP has been microencapsulated by PMMA successfully and the shell does not decrease the beneficial effect of APP on fire hazard of RPUF. Furthermore, the shell also reduces the damage of APP on the mechanical property of composite. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48307.

Effects of ammonium polyphosphate microencapsulated on flame retardant and mechanical properties of the rigid polyurethane foam

“…The SEM photograph of POAPP is shown in Figure 1. Compared with the surface morphology and shape of APP, [12] the POAPP is much large and irregular. Furthermore, many wrinkles appear on the surface.…”

“…Then POAPP begins to decompose, especially polyurea loses its weight before 400 C. [20] And polyphosphoric acid is generated from APP. [12] After that, the weight loss of POAPP from 400 C to the end is resulted from the volatilize and break down of polyphosphoric acid. The decomposition of polyurea happens before the main decomposition stage of APP, which has little effect on the formation of carbon residue layer.…”

“…Microencapsulation of APP is a currently effective method to compensate for the shortcoming. [9][10][11] Li et al [12] successfully prepared microcapsules with polymethyl methacrylate as the wall material and APP as the core material. The polymethyl methacrylate shell protected APP from water and increased the compatibility of APP and polymer.…”

Effects of hexaphenoxycyclotriphosphazene and glass fiber on flame‐retardant and mechanical properties of the rigid polyurethane foam

“…[ 1,2 ] However, the applications are limited because of the inventive and poor flame retardancy of the polyurethane foams. [ 3,4 ] So improving the flame‐retardant properties of RPUF has become significant and indispensable. [ 5 ]…”

One‐step fabrication of superhydrophobic sponge with magnetic controllable and flame‐retardancy for oil removing and collecting

“…Therefore, the exploration of novel superhydrophobic PU sponges which owns the flameretardancy is very attractive. In the past decades, various compounds, such as layered double hydroxide, [10] halloysite nanotubes, [21] hexagonal boron nitride, [22] expandable graphite, [23] ammonium polyphosphate, [24] zirconia and alumina powder, [25] ammonium polyphosphate @ layered double hydroxide, [26] and multiwalled carbon nanotubes, [27] had been employed to enhance the flame retardance of PU sponge. Among all of the flame-retardant fillers, clay is the most striking because of its low cost and some of its benefits to the properties and processing of the filled polymers.…”