Macromolecular Intumescent Flame Retardants Research Articles

A macromolecular intumescent flame retardant with thermal cross-linking groups for poly(ethylene terephthalate) with enhanced fire safety

To improve the flame retardancy of poly(ethylene terephthalate) (PET) without loss of its mechanical properties, a macromolecular intumescent flame retardant (SPPO) with thermal-responsive groups was developed in an effective way. As 8 wt% of SPPO was melt-blended into PET, the prepared PET/SPPO composite achieved a V-0 rating during UL-94 tests without melt-dripping, and exhibited substantial reduction in the total heat release (THR), peak heat release rate (PHRR), total smoke production (TSP) and average carbon monoxide yield (av-COY) by 44.8 %, 39.0 %, 63.3 % and 45.8 %, respectively, in comparison with pure PET. The improved flame retardancy of this composite was considered to be ascribed to the formation of intumescent residues of SPPO. The generated physical barrier increased the melt viscosity by triggering the cross-linking reactions of the C≡N groups in SPPO, effectively inhibiting the melt-dripping of PET during burning. The tensile strength was also well-retained for PET composites when different contents of SPPO were added into PET, demonstrating the good compatibility between SPPO and PET matrix, which can meet the requirements of industrial application.

N‐alkoxyamine‐containing macromolecular intumescent flame‐retardant‐decorated ZrP nanosheet and their synergism in flame‐retarding polypropylene

High‐efficiency macromolecular intumescent flame retardant (MIFR) is urgently demanded but of great challenge. In this work, a novel N‐alkoxyamine‐containing MIFR‐decorated zirconium phosphate (ZrP) nanosheet (denoted as RQMIFR‐ZrP) was synthesized and combined with ammonium polyphosphate (APP) to endowed polypropylene (PP) with excellent flame retardancy. With the addition of 6.3 wt% RQMIFR‐ZrP and 18.7 wt% APP, PP classed a UL‐94 V‐0 rating with a high LOI value of 39.5%. Moreover, the peak heat release rate, the total heat release, the peak of CO production, and the peak of CO2 production of PP/RQMIFR‐ZrP/APP decreased by 94.0%, 83.2%, 91.3%, and 91.7%, respectively. It revealed that RQMIFR‐ZrP not only generated nitroxyl radicals (NO•) to suppress the chain degradation of PP but also promoted to form high‐quality intumescent char layers with the catalytic carbonization and layered barrier effect of ZrP nanosheet, which effectively prevented PP from burning. This work provides a new approach to preparing high‐performance flame‐retardant polymer.

Synthesis of a novel N‐alkoxyamine containing macromolecular intumescent flame retardant and its synergism in flame‐retarding polypropylene

AbstractEndowing intumescent flame retardant (IFR) with free‐radical quenching capability is a promising method to improve its efficiency. Herein, a novel N‐alkoxyamine containing macromolecular intumescent flame retardant (RQMIFR) was synthesized via nucleophilic substitution reaction and combined with ammonium polyphosphate (APP) to improve the thermostability and fire resistance of polypropylene (PP). The results showed that there was a good synergism between RQMIFR and APP, which effectively enhanced the thermostability and flame retardancy of PP. When the content of RQMIFR was 8.33 wt% and APP was 16.67 wt%, the limiting oxygen index of PP increased from 19.0% to 39.5% and achieved a UL‐94 V‐0 rating. Besides, the peak heat release rate, total heat release, carbon monoxide production, and carbon dioxide production were remarkably reduced. It was revealed that during combustion, RQMIFR generated nitroxyl free‐radicals and quenched the active free radicals produced by PP both in gas and condensed phase. Simultaneously, RQMIFR and APP worked synergistically to form a compact intumescent char layer through the esterification, cross‐linking, cyclization, and foaming reactions, thus effectively improved the thermostability and flame retardancy of PP.

Enhanced flame retardancy and mechanical properties of waterborne polyurethane based on the phosphorus and nitrogen containing polybutadiene acrylonitrile

AbstractTo further improve fire resistance of waterborne polyurethane, the macromolecular intumescent flame retardant (APBDH) was designed and prepared from 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), 4‐aminothiophenol, benzaldehyde, and hydroxyl‐terminated polybutadiene acrylonitrile (HTBN). Then, it was incorporated into waterborne polyurethane (WPU) to preparing flame retarded WPU (FR‐WPU). TGA results suggested that the incorporation of APBDH into WPU increased thermal stability of FR‐WPU. The fire resistance of FR‐WPU were investigated by limiting oxygen index (LOI) test, the vertical burning test (UL‐94), SEM‐EDS analysis, the Laser Raman test, and cone calorimeter test. An LOI value of 28.82% and a UL‐94 V‐0 rating can be achieved when the WPU sample conjugated with 7.5 wt% APBDH. It indicated that the fire resistance of FR‐WPU remarkably improved and displayed both gas and condensed phase mechanism. As the content of APBDH increased, the tensile strength and the elongation at break of FR‐WPU increased firstly and then decreased. The thermo‐mechanical behaviors indicated that the storage modulus increase at first and then descend with the addition of APBDH, while the Tgs firstly decreased and then increased. Additionally, the Tgh increased with the addition of APBDH.

Fire retardance and smoke suppression of polypropylene with a macromolecular intumescent flame retardant containing caged bicyclic phosphate and piperazine

ABSTRACTA macromolecular intumescent flame retardant (FR) named PPPAP was designed and synthesized with phosphorus chloride (the acid source), 2,6,7‐trioxa‐l‐phosphabicyclo[2.2.2]‐octane‐4‐methanol (the charring agent), and anhydrous piperazine (the blowing agent). Then, it was used to prepare an intumescent flame‐retardant polypropylene (FR‐PP). The thermal stability, flame retardancy, and fire performance of the FR‐PPs were investigated. The results show that the initial decomposition temperature and char residue at 700 °C of PPPAP were 260.8 °C and 31.8%, respectively. The limiting oxygen index (LOI) value of polypropylene (PP) was enhanced with increasing PPPAP content. With the addition of 40 wt % PPPAP, the LOI value of FR‐PP was 29%, and it passed the vertical burning UL‐94 V‐0 rating. The cone calorimetry results indicate that not only the peak heat‐release rate but also the total smoke production of PP significantly decreased to 65.7 and 79.5%, respectively, with the incorporation of only 20 wt % PPPAP. The FR mechanism suggested that PPPAP played a part in both the gas and condensed phases, and the formation of the intumescent char layer during combustion was the dominant FR mechanism. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47593.

Preparation of a Novel Intumescent Flame Retardant Based on Supramolecular Interactions and Its Application in Polyamide 11.

The flammability and melt dripping of the widely used bio-based polyamide 11 (PA 11) have attracted much attention in the last decade, and they are still a big challenge for the fire science society. In this work, a novel single macromolecular intumescent flame retardant (AM-APP) that contains an acid source and a gas source was prepared by supramolecular reactions between melamine and p-aminobenzene sulfonic acid, followed by an ionic exchange with ammonium polyphosphate. The chemical structure of AM-APP was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. AM-APP and TiO2 were then introduced into PA 11 by melt compounding to improve the fire resistance of the composite. The fire performance of PA 11 composites was evaluated by the limiting oxygen index (LOI), vertical burning (UL-94), and cone calorimetry tests. The results showed that the presence of 22% AM-APP and 3% TiO2 increased the LOI value from 22.2 to 29.2%, upgraded the UL-94 rating from no rating to V-0, completely eliminated melt dripping, and significantly decreased the peak heat release rate from 943.4 to 177.5 kW/m2. The thermal behaviors were investigated by thermogravimetric (TG) analysis and TG-FTIR. It is suggested that AM-APP produces an intumescent char structure and releases inert gases, whereas TiO2 may consolidate the char layers, leading to the improvement in the fire resistance of PA 11.

The fire performance of polylactic acid containing a novel intumescent flame retardant and intercalated layered double hydroxides

In this work, a novel single macromolecular intumescent flame retardant (DT-M) was prepared by self-assembly of diethylenetriamine penta-(methylenephosphonic) acid with melamine, and modified layered double hydroxides (LDH) were also prepared by intercalating phytic acid into LDHs. The chemical structures of DT-M and phytic acid intercalated LDHs (PA–LDH) were fully characterized by different analytical instruments, and then were introduced into PLA by melt compounding to prepare a flame retardant biodegradable PLA composite. The fire performance evaluation of PLA composites by limiting oxygen index (LOI), vertical burning (UL-94) and cone calorimeter tests indicated that the introduction of 14% DT-M and 1% PA–LDH increased the LOI value from 19.4 to 38.9%, upgraded the UL-94 rating from no rating to V-0, and decreased the peak heat release rate from 812 to 301 kW m−2. The analysis for decomposition products of PLA composite and the observation of morphology of the char suggested that DT-M and PA–LDH took effects in both condensed phase through promoting char formation and gas phase through releasing inert gases.

A THEIC-based polyphosphate melamine intumescent flame retardant and its flame retardancy properties for polylactide

A macromolecular intumescent flame retardant tris(2-hydroxyethyl) isocyanurate polyphosphate melamine (TPM) was synthesized, its structure was confirmed by Fourier transform infrared spectroscopy (FTIR), 1H and 31P nuclear magnetic resonances (NMR). The flame retardancy and combustion properties of PLA/TPM composites were evaluated by limiting oxygen index (LOI), UL-94, and cone calorimetry tests. It was found that PLA with 25wt% APP/TPM (0.5:1) acquired LOI 36.5% and achieved UL-94 V-0 rating with no melt dripping. Cone calorimetry tests showed that pHRR and THR of PLA/TPM composites were dramatically reduced compared with that of pure PLA, the HRR curve suggested that TPM could accelerate char forming process. TGA demonstrated that TPM effectively improved thermal stability of PLA. The possible thermal degradation mechanism, structure and morphology of char layer were studied by FTIR, XPS and SEM.

Flame retardancy and mechanical properties of a novel intumescent flame‐retardant unsaturated polyester

A novel macromolecular intumescent flame retardant (MIFR) was synthesized. Unsaturated polyester (UP) filled with MIFR as flame‐retardant additive was prepared. The effects of MIFR on properties such as tensile strength, impact strength, flame‐retardant behavior, thermal stability, and morphology of char were studied. Its flammability and burning behavior were characterized by UL 94 and limiting oxygen index. Twenty‐four percent of MIFR were doped into UP to get 30.5% of limiting oxygen index and UL 94 V‐0, whereas its tensile strength and the impact strength were decreased by only 7.2% and 7.0%, respectively. Activation energy for the decomposition of samples was obtained by using the Kissinger equation. The results for UP containing MIFR, compared with UP, show that the weight loss, thermal stability, and the decomposition activation energy decreased, and the char yield increased, showing that MIFR can catalyze decomposition and carbonization of UP to form an effective charring layer to protect the underlying substrate. J. VINYL ADDIT. TECHNOL., 22:350–355, 2016. © 2014 Society of Plastics Engineers

Thermal degradation and flame retardancy of rigid polyurethane foams containing a novel intumescent flame retardant

A novel cheap macromolecular intumescent flame retardants (MIFR) was synthesized, and its structure was a macromolecule containing phosphorus characterized by IR. Rigid polyurethane foam (PUF) filled with MIFR as fire retardant additive was prepared. The effects of MIFR on properties such as density, compressive strength, flame-retardant behavior, thermal stability, and morphology of char were studied. The compressive strength of the MIFR-filled PUF increased initially and then decreased with further increase of MIFR content while its density straightly increased. Its flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). Twenty five percent of MIFR was doped into PUF to get 24.5 of LOI and UL 94 V-0. Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for PUF containing MIFR, compared with PUF, the mass loss, thermal stability, and the decomposition activation energy decreased, the char yield increased, which shows that MIFR can catalyze decomposition and carbonization of PUF to form an effective charring layer to protect the underlying substrate.

Thermal Behavior of Epoxy Resins Containing Manganese Compounds

A novel cheap macromolecular intumescent flame retardants (Mn-MIFR), was synthesized. Epoxy resins (EP) were modified with Mn-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Mn contents of 4.0 % get a LOI of 26.5% and char yield of 18.2%. Dilatation, SDR and MSD of EP/Mn-MIFR decreased. The degradation behavior of the EP/Mn-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Mn and P at the residue were increased.

The Thermal Properties of Unsaturated Polyester Resin Treated with Intumescent Flame Retardants

A novel cheap macromolecular intumescent flame retardant (IFR), was synthesized. Unsaturated polyester resin (UPR) was modified with IFR to get the flame retardant UPR, whose flammability and burning behavior were characterized by limiting oxygen index (LOI). 22.7% of weight of IFR was doped into UPR to get 28.5 of LOI. The thermal properties of epoxy resins containing IFR were investigated with thermogravimetry (TG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for UPR containing IFR, compared with UPR, IFR decreased weight loss, thermal stability, increased the char yield, which shows that IFR can catalyze decomposition and carbonization of UPR.

The Thermal Properties of Rigid Polyurethane Foams Treated with Flame Retardant

A novel cheap macromolecular intumescent flame retardants (MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by IR. Rigid polyurethane foam (PUF) were modified with MIFR to get the flame retardant PUF, whose flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). 25% of weight of MIFR were doped into PUF to get 24.5 of LOI and UL 94 V-0. The thermal properties of epoxy resins containing MIFR were investigated with thermogravimetry (TG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for PUF containing MIFR, compared with PUF, MIFR decreased weight loss, thermal stability, increased the char yield. The activation energy for the decomposition of EP is 205 kJ/mol while it becomes 162 kJ/mol for PUF containing MIFR, decreased by 42 kJ/mol, which shows that IFR can catalyze decomposition and carbonization of PUF.

Thermal Degradation of Epoxy Resins Containing Aluminum Compounds

A novel cheap macromolecular intumescent flame retardants (Al-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-aluminum characterized by IR. Epoxy resins (EP) were modified with Al-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Al contents of 4.0 % get a LOI of 26.8% and char yield of 19.5%. Dilatation, SDR and MSD of EP/Al-MIFR decreased. The degradation behavior of the EP/Al-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Al and P at the residue were increased.

Thermal Degradation of Epoxy Resins Containing Copper Compounds

A novel cheap macromolecular intumescent flame retardants (Cu-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-copper characterized by IR. Epoxy resins (EP) were modified with Cu-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Cu contents of 3.0 % get a LOI of 27.0% and char yield of 19.4%. Dilatation, SDR and MSD of EP/Cu-MIFR decreased. The degradation behavior of the EP/Cu-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Cu and P at the residue were increased.

Epoxy Resins Treated with Magnesium-Containing Compounds in Material Engineering

A novel cheap macromolecular intumescent flame retardants (Mg-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus- magnesium characterized by IR. Epoxy resins (EP) were modified with Mg-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Mg contents of 4.0% get a LOI of 27.0% and char yield of 19.8%. Dilatation, SDR and MSD of EP/Mg-MIFR decreased. The degradation behavior of the EP/Mg-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Mg and P at the residue were increased.

Epoxy Resins Treated with Novel Silicon-Containing Flame Retardant

A novel cheap macromolecular intumescent flame retardants (Si-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-silicon characterized by IR. Epoxy resins (EP) were modified with Si-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Si contents of 3.0 % get a LOI of 27.5% and char yield of 23.8%. Dilatation, SDR and MSD of EP/Si-MIFR decreased. The degradation behavior of the EP/Si-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Si and P at the residue were increased.

Epoxy Resins Treated with Metal-Containing Flame Retardant

A novel cheap macromolecular intumescent flame retardants (Zn-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-silicon characterized by IR. Epoxy resins (EP) were modified with Zn-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Zn contents of 3.0 % get a LOI of 27.5% and char yield of 20.5%. Dilatation, SDR and MSD of EP/Zn-MIFR decreased. The degradation behavior of the EP/Zn-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Zn and P at the residue were increased.

A novel intumescent flame‐retardant epoxy resins system

AbstractPentaerythritol diphosphonate melamine–dicyandiamide–formaldehyde resin salt, a novel macromolecular intumescent flame retardants (IFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by IR, NMR and element analysis. The flame retardancy and thermal behavior of a new IFR system for epoxy resin were investigated by LOI, UL‐94 test, TG, and IR. Activation energy for the decomposition of samples was obtained using Kissinger equation. 25% of weight of IFR were doped into epoxy resin to get 27.5 of LOI and UL 94 V‐0. The TG curves and IR spectra show that IFR decreases the initial decomposition temperature and the maximum weight loss rate of epoxy resin, and enhances the thermal stability of epoxy resin at high temperatures and char yield. The activation energy for epoxy resin containing IFR was decreased by 44.8 kJ/mol, which shows that IFR can catalyze decomposition of epoxy resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Thermal degradation and flame retardancy of epoxy resins containing intumescent flame retardant

Abstract Pentaerythritol diphosphonate melamine-urea-formaldehyde resin salt, a novel cheap macromolecular intumescent flame retardants (IFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by IR. Epoxy resins (EP) were modified with IFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). 25 mass% of IFR were doped into EP to get 27.2 of LOI and UL 94 V-0. The thermal properties of epoxy resins containing IFR were investigated with thermogravimetry (TG) and differential thermogravimetry (DTG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for EP containing IFR, compared with EP, IFR decreased mass loss, thermal stability and R max, increased the char yield. The activation energy for the decomposition of EP is 230.4 kJ mol−1 while it becomes 193.8 kJ mol−1 for EP containing IFR, decreased by 36.6 ...