Preparation and characterization of surface‐modified ammonium polyphosphate and its effect on the flame retardancy of rigid polyurethane foam

Chen, Yajun; Li, Linshan; Wang, Wei; Qian, Lijun

doi:10.1002/app.45369

Cited by 45 publications

(38 citation statements)

References 42 publications

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“…The additive type also have many advantages such as easy processing and having a good FR performance. Ammonium polyphosphate, triphenyl phosphate (TPhP), and expandable graphite are often used as intumescent in RPUFs due to their low toxicity, with halogen‐free contents and high effectiveness. Aluminum trihydrate (ATH), zinc borate (ZnB), and clays are also frequently used as additive‐type FRs in RPUF systems due to their good flame protection, low cost, and smoke suppressant properties.…”

Section: Indtroductionmentioning

confidence: 99%

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Akdoğan

Erdem

Üreyen

et al. 2019

J of Applied Polymer Sci

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Rigid polyurethane foam (RPUF) composites with triphenyl phosphate (TPhP), aluminum trihydrate (ATH), and zinc borate (ZnB) alone, as well as their binary blends, were prepared via a one-shot process. The amount of flame retardant (FR) or FR blend was varied from 10 to 50% by polyol weight percentage, and the weight fraction of the blends was also fixed at 40%. The effects of additives on thermal insulation, mechanical, and flame retardancy properties of the composites were investigated. Thermal conductivity of the neat foam (RPUF) decreased from 22.53 to 21.04-21.58 mW m −1 K −1 . The compressive strength of foams displayed an increase with increasing the amount of TPhP, ATH, and ZnB till 40% by weight. The limited oxygen index values of all foams increased and the flame spread rates of all foams significantly decreased. It was also observed that the flame was self-extinguished in some cases. The cone calorimeter test results indicated that the FR additives improved the flame retardancy of the RPUF. INDTRODUCTIONRigid polyurethane foams (RPUFs) are one of the most consumed polymeric materials to a great extent. They have wide range applications in insulation, transportation, building construction, domestic appliance, automobile industry, and many others because of their high closed-cell content, low thermal conductivity, high strength with low weight, good shock absorption, and so on. 1-3 Nowadays, humanity is under threat because of limited energy resources in the world. In that case, RPUFs possessing low thermal conductivity values come into prominence because RPUFs are one of the unique materials for thermal insulation. RPUFs predominantly contain closed-cell structures, and in the closed-cell structures of foams, a blowing agent constituting the gas is trapped during production. The thermal conductivity of an RPUF is strongly affected by this blowing agent. The lower thermal conductivity of the blowing agent causes the lower thermal conductivity of RPUF. 4,5 When RPUFs compare with the conventional thermal insulating materials such as brick, concrete, wood, glass fiber, and so on, the conventional materials need to be used at much higher thickness in an attempt to match the insulation performance of 50 mm RPUF, for instance, ranging from 1720 mm for brick, 200 mm for wood, and 80 mm for polystyrene. The excellent thermal insulation property of RPUFs is not the only parameter making RPUFs one of the most used engineering materials but also their high mechanical strength with low weight and their easy processability make it as an interesting material. 6,7 For example, RPUF is one of the most important structural element of the refrigerators' skeleton besides providing high insulation for home refrigerators.However, as in the case of a majority of polymeric materials, RPUF is also easily combustible. As a matter of fact that, it is more combustible than other materials because of its rigid cellular and organic structure, additionally, it contains flammable, explosive gases in its closed cells. During the burnin...

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Section: Indtroductionmentioning

confidence: 99%

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Akdoğan

Erdem

Üreyen

et al. 2019

J of Applied Polymer Sci

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“…Three effects have been quantitatively analyzed, the corresponding calculation formulas are shown in Equations 1-3 and the results are listed in Table 5. [44,45] Flame inhibition effect = 1 − EHC FR =EHC pure ð1Þ…”

Section: The Cone Calorimeter Testmentioning

confidence: 99%

Flame‐retardant behavior and protective layer effect of phosphazene‐triazine bi‐group flame retardant on polycarbonate

Chen

Qian

2020

J of Applied Polymer Sci

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A series of flame‐retardant polycarbonate (PC) composites with different ratios of phosphazene‐triazine bi‐group flame retardant (A3) were prepared. The flame retardant performance and thermal stability of PC/A3 composites were characterized by LOI, UL 94 vertical burning test, cone calorimetry test and TG. Results show that when the addition of A3 is 13.5%, the PC/A3 composite can pass UL94 V‐0 level with a LOI value of 29.3% and reduce the peak heat release rate by 47.5% during the combustion. TG results show that adding 5% A3 can increase the initial decomposition temperature of the PC by 7°C in nitrogen and 9°C in air. Investigation of the morphology and chemical structure of char residue demonstrates that A3 promotes the formation of more complete and compact char residue which acts as physical barriers to inhibit the transfer of heat and oxygen, resulting the good flame retardant properties. The analysis of gaseous pyrolysis product reveals that A3 also exerts a flame‐retardant effect in gas phase by releasing PO· free radicals.

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“…Chen et al have prepared two kinds of phosphorus‐containing organosilicon compounds with different polyether segments (PCOC‐OH and PCOC‐NH), which were used to modify APP. Chen et al have modified APP with the agent synthesized by hexachlorocyclotriphosphazene and γ‐aminopropyl triethoxysilane. Yan et al have obtained surface‐modified APP microencapsulated by melamine formaldehyde resin.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular self‐assembly modification of ammonium polyphosphate and its flame retardant application in polypropylene

Yuan

Dong

et al. 2020

Polymers for Advanced Techs

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In order to improve its water resistance and compatibility with polymer matrix, ammonium polyphosphate (APP) is modified with melamine-trimesic acid (MEL-TA) aggregates by supramolecular self-assembly technology. Chemical structure and morphology of APP@MEL-TA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. Intumescent flame retardant system of APP@MEL-TA and charring-foaming agent is introduced into polypropylene (PP) matrix. The flammability and combustion behavior of PP composites are investigated by limiting oxygen index (LOI), UL-94 vertical burning, and cone calorimetry tests. In terms of LOI values and cone combustion results, APP@MEL-TA performs better than pristine APP. Char residue of PP composites is investigated by SEM and Raman spectra. Flame retardant mechanisms are proposed based on thermal decomposition, combustion results, and analysis on char residue. K E Y W O R D S ammonium polyphosphate, flame retardant, polypropylene, supramolecular self-assembly, thermal stability 1 | INTRODUCTION Polypropylene (PP) is widely applied in a variety of applications, such as transportation, cables, housing, and electric industry. However, PP burns very rapidly with the release of a great deal of heat, which limits its applications in many fields. Thus, the improvement in flame retardant properties of PP has become an important research. Zhang et al 1 reviewed the research progress of halogen-containing flame-retarded PP. The obvious disadvantages of traditional halogen-based flame retardants are high fire toxicity and releasing of smoke during the combustion. 2 In addition, environment amity is the theme of whole society, and some halogen-containing flame retardants are undoubtedly damaging the environment. 3-6 Recently, halogen-containing flame retardants have been replaced by halogen-free counterparts, 7-9 which are characterized by their low fire toxicity. Intumescent flame retardants (IFRs) are the most popular halogen-free retardants because of their advantages of low smoke and toxicity during combustion. 10,11 Wang et al 12 prepared a novel IFR by the reaction of melamine (MEL) with methyl hydrogen siloxane, and this flame retardant system can effectively improve flame retardancy of PP.Acid catalyst, blowing source, and charring agent are three main ingredients for IFR system. 13,14 According to its elemental composition, ammonium polyphosphate (APP) acts as acid catalyst and blowing source because of its high phosphorus and nitrogen contents, both of which are primary flame retardant elements. 15,16 However, as an important component of IFR, APP has obvious disadvantages of weak water resistance and poor compatibility with polymer matrix. 3,17,18 Hence, it is of great significance to modify the surface of APP and improve flame retardant properties of resulting composites. In view of these deficiencies, many researches on surface modification of APP have been carried out. The surface characteristics of APP are modified by other flame retard...

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Preparation and characterization of surface‐modified ammonium polyphosphate and its effect on the flame retardancy of rigid polyurethane foam

Cited by 45 publications

References 42 publications

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Flame‐retardant behavior and protective layer effect of phosphazene‐triazine bi‐group flame retardant on polycarbonate

Supramolecular self‐assembly modification of ammonium polyphosphate and its flame retardant application in polypropylene

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