Influence Of Ammonium Polyphosphate Research Articles

Influence of Ammonium Polyphosphate on the Flame Retardancy and Mechanical Properties of Coconut Shell Powder-Reinforced PLA

Influence of Ammonium Polyphosphate on the Flame Retardancy and Mechanical Properties of Coconut Shell Powder-Reinforced PLA

The influence of ammonium polyphosphate on the smoke toxicity of wood materials

As one of the most widely used flame retardants, the influence of ammonium polyphosphate (APP) on the smoke toxicity of wood materials is still unclear. Three kinds of wood materials were prepared, including wood, plywood, and flame-retardant plywood (FR-plywood), and their smoke compositions were characterized by thermogravimetric-Fourier-transform infrared (TG-FTIR) spectrometry and a cone calorimeter coupled with solvent absorption (CONE-SA). The results showed that compared with plywood, the CO, HCN and nitrogen oxide (NOx) emissions of FR-plywood with APP increased by about 1.7 times, 6 times, and 1.1 times at a heat flux of 50 kW m−2, respectively. And fractional effective dose (FED) model was established. According to this model, the lethal concentration to produce death in 50% of test animals (LC50) of the FR-plywood was 3.3 times lower than that of plywood.

Influence of ammonium polyphosphate on flame-retardant behavior and smoke suppression property of EVA/magnesium hydroxide composites

ABSTRACTTo overcome the flammability and smoke generation of EVA, samples with different mass fraction of magnesium hydroxide (MH) and ammonium polyphosphate (APP), have been prepared by internal mixer and cured by compression molded. The fire characteristics including smoke and heat production of EVA composites were studied by cone calorimeter test (CCT), limiting oxygen index test, UL-94 test, scanning electron microscopy, and thermogravimetric (TG) analysis, respectively. For the sample EVA5 loading 10.0 mass% APP and 40.0 mass% MH, the LOI value can be increased to the value of 31.1 and reach V-0 level. The CCT test showed that APP and MH could significantly improve the fire safety of EVA. Remarkably, the peak of heat release rate, the peak of smoke production rate, and total smoke release for EVA5 were decreased by 75.4%, 88.1% and 70.8% compared with pure EVA, respectively. TG test showed that APP promoted the char formation in the degradation process of EVA; as a result, the residual carbon was increased. The results indicated that APP combined with MH could facilitate the formation of the rigid intumescent char and obviously enhance the flame retardancy, smoke suppression and thermal stability of the EVA matrix.

Influence of Ammonium Polyphosphate on Thermal Decomposition of Reconstituted Tobacco and CO Evolution

The thermal behaviors and burning characteristics of reconstituted tobacco (RT) are strongly related with evolved gaseous products. The effect of ammonium polyphosphate (APP) as an additive of RT on the pyrolysis behavior and CO evolution was studied, emphasizing the role of heating velocity in reducing CO delivery of the mainstream smoke by APP. Thermogravimetric analysis (TGA) was employed to investigate the influence of APP on RT thermal behavior. Slow and flash pyrolysis of RT were compared to discuss the role of heating rate in decreasing CO by APP. TGA results demonstrated that, in dependence on APP concentration, APP influenced exothermal amount and weight loss rate during RT thermal decomposition, promoted the formation of char and retarded the thermal decomposition of RT. In addition, APP had a considerable influence on the evolution of gaseous products during thermal decomposition of RT. Both CO delivery per cigarette and that per puff in the smoking process were significantly reduced in dependence on APP content in RT. Comparative analysis of CO evolution patterns in the flash and slow pyrolysis elucidated that heating rate played a key role in decreasing CO evolution by APP. The results suggest that APP is a potential burning additive for controlling CO delivery in mainstream smoke of RT.

Influence of ammonium polyphosphate-/poly(acrylic acid)-based layer by layer architectures on the char formation in cotton, polyester and their blends

Ammonium polyphosphate and poly(acrylic acid) have been chosen to build a complex, four-layered (or quadlayered) hybrid organic-inorganic architecture exploiting the Layer by Layer assembly, in order to promote the formation of an aromatic and stable carbonaceous structure (char), able to thermally protect cotton, polyester and their blends. To this aim, a different number of quadlayers (namely, 1, 5 and 10) consisting of poly(diallydimethylammonium chloride)/poly(acrylic acid)/poly(diallydimethylammonium chloride)/ammonium polyphosphate have been deposited on the chosen fabrics and investigated. Thermogravimetric analysis coupled to isothermal tests performed in a gravity convection oven at fixed temperatures has shown that the presence of such architectures is able to enhance the char formation in a remarkable way. Furthermore, infrared spectroscopy has pointed out the aromatic nature of the residues left by the treated fabrics upon heating at high temperatures, regardless of the quadlayer number and the fabric type.

Halogen‐free intumescent flame retardant acrylonitrile‐butadiene‐styrene/poly(ethylene terephthalate) blends

AbstractThe influence of ammonium polyphosphate (APP) with and without synergistic agents — aluminum hypophosphite (Al(H2PO2)3), epoxy resin (E‐44), and Zeolite 4A — in acrylonitrile‐butadiene‐styrene/poly(ethylene terephthalate) (ABS/PET) blends was investigated. The limiting oxygen index (LOI) and UL94 tests were used to investigate flame properties. The results showed that APP with and without synergistic agents all improved the flame retardancy of ABS/PET systems. The ABS/PET/APP + 2 wt % Al(H2PO2)3, ABS/PET/APP + 2 wt % E‐44, and ABS/PET/APP + 3 wt % Zeolite 4A systems achieved the best flame retardancy rating of V0 and LOI values were 32, 34, and 30.5, respectively. The thermal degradation behaviors analyzed by thermogravimetric analysis (TGA) indicated APP mainly accelerated the degradation of PET and led to the increase of charring residues. Al(H2PO2)3 and E‐44 resulted in synergistic effects on the charring process of ABS/PET/APP. SEM revealed that the intact, dense, and strong char layer formed on the surface of the ABS/PET/APP/ Al(H2PO2)3 (or E‐44) system, which was significantly different from the loose and porous char layer of ABS/PET and ABS/PET/APP systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Influence of ammonium polyphosphate on the flame retardancy and mechanical properties of ramie fiber‐reinforced poly(lactic acid) biocomposites

AbstractFully degradable natural fiber/degradable polymer composites have received much research attention and have various applications such as in automotive components. But flammability limits their application; it is important to improve the flame retardancy of fully degradable composites with environmentally friendly flame retardants. Flame‐retarded ramie fiber‐reinforced poly(lactic acid) (PLA) composites were prepared using three processes: (1) PLA was blended with ammonium polyphosphate (APP), and then the resulting flame‐retarded PLA was combined with ramie fibers; (2) ramie fibers underwent flame‐retardant treatment with APP, which were then compounded with PLA; and (3) PLA and ramie, both of which had been flame‐retarded using APP, were blended together. The APP in the composites is shown to be very effective in improving flame retardancy according UL94 test and limiting oxygen index measurements. Thermogravimetric analysis shows that the improved flame retardancy is due to increased char residue at high temperature. The loading of APP disturbs the compatibility between PLA and fibers, which can be directly observed using scanning electron microscopy. Furthermore it has an influence on the dynamic mechanical properties and mechanical properties according dynamic mechanical analysis and mechanical measurements. The results show that composites produced using the third process not only have the best flame retardancy but also comparatively better mechanical properties. Copyright © 2009 Society of Chemical Industry

Influence of ammonium polyphosphate on the mechanism of thermal degradation of an acrylic binder resin

AbstractThe thermal behavior of an acrylic binder resin used in back coatings for textile applications was studied. The influence of the crystalline form of the fire‐retardant additive on the thermal behavior was investigated. This resin formed a carbon char during its thermal degradation, so it may be assumed that it acts as a charring agent in intumescent systems with ammonium polyphosphate (APP) as the acid source. Thermogravimetric and spectroscopic analyses of acrylic binder resin/APP mixtures demonstrated the influence of the crystalline form of APP. The degradation mechanism of the binder resin could be described by ring closure and the formation of unsaturations. APP leads to the formation of a phosphocarbon structure that is thermally stable, whatever the crystalline form was of APP. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 717–729, 2004

Intumescent flame retardants for polymers. I. The poly(acrylonitrile)–ammonium polyphosphate–hexabromocyclododecane system

AbstractThe influence of ammonium polyphosphate (APP) and hexabromocyclododecane (HBCD) as flame retardant (FR) on poly(acrylonitrile) (PAN) has been examined. The APP–HBCD system behaves as an intumescent flame retardant (IFR) formulation, APP being the char‐forming agent and HBCD the blowing agent. A negligible gas‐phase mode of action was ascertained for HBCD with this substrate. A synergism between the two FR agents was observed, corresponding to about 50% increased efficacy with respect to the separate effects of the two components. Thermogravimetry (TG), oxygen index (OI), nitrous oxide index (NOI) experiments and phosphorous residue measurements were performed to substantiate the conclusion that a conclusion that a condensed phase mechanism of action accounts for all the facts observed.

Smoke suppression by ammonium polyphosphate in poly(acrylonitrile) combustion

AbstractThe influence of ammonium polyphosphate (APP) on the smoke emission of poly(acrylonitrile) (PAN) has been examined, and its mechanism of action as a smoke suppressant agent has been investigated. Smoke density and corresponding residual char data, as a function of temperature, were obtained in order to characterize the smoke propensity of PAN. The amount of generated smoke, both in smoldering and flaming conditions, was considerably lowered by the presence of APP, and higher char yields were obtained. Beside the smoke suppression, flame inhibition effect of APP on PAN was evidenced. Thermogravimetry (TG), oxygen index (OI), and nitrous oxide index (NOI) experiments were also performed. On the basis of our data, APP appears to act as a char‐forming agent in PAN combustion. Both smoke suppression and flame inhibition effects can be considered a consequence of this action.