Flame Retardancy and Mechanical Properties of Chitosan and DOPO with Different Mass Ratios in Epoxy Resin

Abstract This work focused on the effects of chitosan (CS) and 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOPO) on the flammable propertied of epoxy resin matrix. The EP composites were fabricated by direct mixing method through a general curing method. The influence of CS, DOPO and CS / DOPO on the resin was investigated through cone calorimetry tests (CC), UL-94 vertical burning, limiting oxygen index (LOI), thermal gravimetric analyzer (TGA), differential scanning calorimeter (DSC) and thermogravimetric analyzer-Fourier infrared combined system (TG-FTIR). The char residues of modified EPs after CC tests were investigated by FTIR, EDX and XPS. Under the 10% addition of CS / DOPO in EP, with the mass ratio of CS and DOPO of 1 : 1, 1 : 2, 1 : 3, 2 : 1 and 3 : 1, the flame retardancy properties of EPs all increased, but only if EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 achieved a V-0 rating and their values of LOI were 33.7% and 32.5%, respectively. Compared with EP, the peak heat release rate, peak smoke produce rate and total heat release of EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 decreased, especially, total smoke release decreased by 61.9% and 71.0%, the char residuals amount increased by 84.3% and 41.6%, and the average CO2 yield decreased by 55.4% and 55.0%, respectively. It is worth nothing that the mechanical properties increased, especially the flexural strength increased by 36.0% and 38.4%, respectively. The results indicated that DOPO and CS had important synergistic effects for simultaneous increase both the flame retardancy and mechanical properties of EP composites.

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Synergistic effects of metal hydroxides and fumed nanosilica as fire retardants for polyethylene

Flame Retardancy and Thermal Stability of Materials ◽

10.1515/flret-2019-0004 ◽

2019 ◽

Vol 2 (1) ◽

pp. 30-48

Author(s):

Giulia Fredi ◽

Andrea Dorigato ◽

Luca Fambri ◽

José-Marie Lopez-Cuesta ◽

Alessandro Pegoretti

Keyword(s):

Mechanical Properties ◽

Synergistic Effect ◽

Silica Nanoparticles ◽

Synergistic Effects ◽

Metal Hydroxide ◽

Flow Index ◽

Fire Performance ◽

Cone Calorimetry ◽

Neat Polymer ◽

Limiting Oxygen Index

AbstractThis work aims to study the synergistic effect of aluminum/magnesium hydroxide microfillers and organomodified fumed silica nanoparticles as flame retardants (FRs) for linear low-density polyethylene (LLDPE), and to select the best composition to produce a fire-resistant polyethylene-based single-polymer composite. The fillers were added to LLDPE at different concentrations, and the prepared composites were characterized to investigate the individual and combined effects of the fillers on the thermo-oxidation resistance and the fire performance, as well as the microstructural, physical, thermal and mechanical properties. Both filler types were homogeneously distributed in the matrix, with the formation of a network of silica nanoparticles at elevated loadings. Melt flow index (MFI) tests revealed that the fluidity of the material was not considerably impaired upon metal hydroxide introduction, while a heavy reduction of the MFI was detected for silica contents higher than 5 wt%. FRs introduction promoted a noticeable enhancement of the thermo-oxidative stability of the materials, as shown by thermogravimetric analysis (TGA) and onset oxidation temperature (OOT) tests, and superior thermal properties were measured on the samples combining micro- and nanofillers, thus evidencing synergistic effects. Tensile tests showed that the stiffening effect due to a high content of metal hydroxide microparticles was accompanied by a decrease in the strain at break, but nanosilica at low concentration contributed to preserve the ultimate mechanical properties of the neat polymer. The fire performance of the samples with optimized compositions, evaluated through limiting oxygen index (LOI) and cone calorimetry tests, was strongly enhanced with respect to that of the neat LLDPE, and also these tests highlighted the synergistic effect between micro- and nanofillers, as well as an interesting correlation between fire parameters and viscosity.

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Effects of Combining Graphene Nanoplatelet and Phosphorous Flame Retardant as Additives on Mechanical Properties and Flame Retardancy of Epoxy Nanocomposite

Polymers ◽

10.3390/polym12102349 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2349

Author(s):

Woranan Netkueakul ◽

Beatrice Fischer ◽

Christian Walder ◽

Frank Nüesch ◽

Marcel Rees ◽

...

Keyword(s):

Mechanical Properties ◽

Flame Retardant ◽

Epoxy Resin ◽

Flame Retardancy ◽

Crosslinking Density ◽

Milling Process ◽

Structure Property ◽

Cone Calorimetry ◽

Graphene Nanoplatelet ◽

Phosphorous Flame Retardant

The effects of combining 0.1–5 wt % graphene nanoplatelet (GNP) and 3–30 wt % phosphorous flame retardant, 9,10- dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as fillers in epoxy polymer on the mechanical, flame retardancy, and electrical properties of the epoxy nanocomposites was investigated. GNP was homogeneously dispersed into the epoxy matrix using a solvent-free three-roll milling process, while DOPO was incorporated into the epoxy resin by mechanical stirring at elevated temperature. The incorporation of DOPO reduced the crosslinking density of the epoxy resin. When using polyetheramine as a hardener, the structural rigidity effect of DOPO overshadowed the crosslinking effect and governed the flexural moduli of epoxy/DOPO resins. The flexural moduli of the nanocomposites were improved by adding GNP up to 5 wt % and DOPO up to 30 wt %, whereas the flexural strengths deteriorated when the GNP and DOPO loading were higher than 1 wt % and 10 wt %, respectively. Limited by the adverse effects on mechanical property, the loading combinations of GNP and DOPO within the range of 0–1 wt % and 0–10 wt %, respectively, in epoxy resin were further studied. Flame retardancy index (FRI), which depended on three parameters obtained from cone calorimetry, was considered to evaluate the flame retardancy of the epoxy composites. DOPO showed better performance than GNP as the flame retardant additive, while combining DOPO and GNP could further improve FRI to some extent. With the combination of 0.5 wt % GNP and 10 wt % DOPO, improvement in both mechanical properties and flame retardant efficiency of the nanocomposite was observed. Such a combination did not affect the electrical conductivity of the nanocomposites since the percolation threshold was at 1.6 wt % GNP. Our results enhance the understanding of the structure–property relationship of additive-filled epoxy resin composites and serve as a property constraining guidance for the composite manufacturing.

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Flammability and thermal properties of cotton fabrics modified with a novel flame retardant containing triazine and phosphorus components

Textile Research Journal ◽

10.1177/0040517516652349 ◽

2016 ◽

Vol 87 (11) ◽

pp. 1367-1376 ◽

Cited By ~ 20

Author(s):

Chaohong Dong ◽

Zhou Lu ◽

Peng Wang ◽

Ping Zhu ◽

Xuechao Li ◽

...

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Cotton Fabric ◽

Flame Retardancy ◽

Decomposition Temperature ◽

Cotton Fabrics ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Untreated Cotton ◽

Index Value

A novel formaldehyde-free flame retardant containing phosphorus and dichlorotriazine components (CTAP) for cotton fabrics was synthesized. As an active group, the dichlorotriazine could react with cotton fabric via covalent reaction. The addition of 20.7 wt% CTAP into the cotton fabric obtained a high limiting oxygen index value of 31.5%, which was 13.5% higher than the pure cotton fabric. The results of heat release rate, total heat release and effective heat combustion indicated that CTAP effectively imparted flame retardancy to cotton fabric by the cone calorimetry test. With respect to the untreated cotton fabrics, the treated cotton fabrics degraded at lower decomposition temperature and form a consistent and compact char layer, which could be observed by thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Compared to the untreated cotton fabrics, CTAP performed an effective role in flame retardancy for treated cotton fabrics. Meanwhile, it stimulated the formation of char and promoted the thermal stability of treated cotton fabrics during combustion.

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The synergistic flame retardancy of modified expandable graphite and metal hydroxides on HDPE/EVA composites

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705720925137 ◽

2020 ◽

pp. 089270572092513

Author(s):

Xincheng Guo ◽

Nian Liu ◽

Lingtong Li ◽

Zhuyu Bai ◽

Xiaolang Chen ◽

...

Keyword(s):

Heat Release ◽

Flame Retardancy ◽

Synergistic Effects ◽

Zinc Borate ◽

Expandable Graphite ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Limiting Oxygen Index ◽

Cone Calorimeter Test ◽

Ul 94

In this article, the flammable behaviors and synergistic effects of modified expanded graphite (MEG) with zinc borate (ZB) on flame-retardant high-density polyethylene/ethylene vinyl acetate (HDPE/EVA) composites containing magnesium hydroxide (MH) and aluminum hydroxide (ATH) are investigated by the Underwriters Laboratories-94 (UL-94) test, limiting oxygen index (LOI), cone calorimeter test (CCT), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), differential scanning calorimetry, and tensile tests. The LOI, UL-94, and CCT results show that the synergistic effect of MEG and ZB can improve the flame retardancy of the composites. With the addition of ZB and MEG, the LOI value increases, and the UL-94 reaches the V-0 rating. The heat release rate and total heat release decrease, respectively. The data obtained from the TGA indicate that the synergistic effects of ZB with MEG increase the decomposition temperature when 2 phr ZB and 8 phr MEG are added into the composites. The data from FTIR show that HMEG8 and HMEG10 composites produce phosphate at high temperatures, which promotes the formation of stable and compact charred layer. All the results show that ZB and MEG have positive synergistic effects on HDPE/EVA composites containing MH and ATH. However, ZB and MEG play a negative role in the tensile properties of the HDPE/EVA composites.

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Investigation of nickel ammonia phosphate with different morphologies as a new high-efficiency flame retardant for epoxy resin

High Performance Polymers ◽

10.1177/0954008319867369 ◽

2019 ◽

Vol 32 (4) ◽

pp. 359-370 ◽

Cited By ~ 1

Author(s):

Weiwei Zhang ◽

Hongjuan Wu ◽

Weihua Meng ◽

Jiahe Li ◽

Yumeng Cui ◽

...

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Flame Retardancy ◽

Photoelectron Spectroscopy ◽

High Efficiency ◽

Ammonium Phosphate ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

X Ray ◽

The Matrix

Nanowires, nanosheets, and microflowers of nickel ammonium phosphate (NiNH4PO4·H2O) were synthesized by a mixed solvothermal method and used to improve the flame retardancy of epoxy resin (EP). The solvent concentration and surfactant content were found to play a key role in nucleation and growth of NiNH4PO4·H2O. The structure of NiNH4PO4·H2O was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The flame retardancy, thermostability, mechanical properties, and flame retardancy mechanism of EP/NiNH4PO4·H2O composites were analyzed using the limiting oxygen index (LOI), cone calorimetry (Cone), mechanical property tests, thermogravimetric analysis, and thermogravimetric–Fourier transform infrared spectroscopy. The results indicated that NiNH4PO4·H2O has proper thermal stability and greatly improves the flame retardancy of EP. The nanosheets outperformed the other morphologies; the EP/5% NiNH4PO4·H2O nanosheets have an LOI of 35.2%, which exceeds that of pure EP (24.7%). Furthermore, Cone showed that these nanosheets have the lowest peak heat release rate and peak smoke production rate, which are 69.1% and 36.5% lower than those of pure EP, respectively. NiNH4PO4·H2O can promote the formation of a stable char layer and release nonflammable gases, thus protecting the matrix by preventing heat and oxygen transfer and reducing the concentration of combustible gas. NiNH4PO4·H2O is expected to serve as a new high-efficiency flame retardant for EP.

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Construction of a Phytic Acid–Silica System in Wood for Highly Efficient Flame Retardancy and Smoke Suppression

Materials ◽

10.3390/ma14154164 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4164

Author(s):

Zhuoran Chen ◽

Shaodi Zhang ◽

Mengyi Ding ◽

Mingzhi Wang ◽

Xing Xu

Keyword(s):

Heat Release ◽

Phytic Acid ◽

Hybrid System ◽

Flame Retardancy ◽

Smoke Suppression ◽

Char Residue ◽

Cone Calorimetry ◽

Silica Network ◽

Limiting Oxygen Index ◽

Degradation Rates

The intrinsic flammability of wood restricts its application in various fields. In this study, we constructed a phytic acid (PA)–silica hybrid system in wood by a vacuum-pressure impregnation process to improve its flame retardancy and smoke suppression. The system was derived from a simple mixture of PA and silica sol. Fourier transform infrared spectroscopy (FTIR) indicated an incorporation of the PA molecules into the silica network. Thermogravimetric (TG) analysis showed that the system greatly enhanced the char yield of wood from 1.5% to 32.1% (in air) and the thermal degradation rates were decreased. The limiting oxygen index (LOI) of the PA/silica-nanosol-treated wood was 47.3%. Cone calorimetry test (CCT) was conducted, which revealed large reductions in the heat release rate and smoke production rate. The appearance of the second heat release peak was delayed, indicating the enhanced thermal stability of the char residue. The mechanism underlying flame retardancy was analyzed by field-emission scanning electron microscope coupled with energy-dispersive spectroscopy (SEM-EDS), FTIR, and TG-FTIR. The improved flame retardancy and smoke-suppression property of the wood are mainly attributed to the formation of an intact and coherent char residue with crosslinked structures, which can protect against the transfer of heat and mass (flammable gases, smoke) during burning. Moreover, the hybrid system did not significantly alter the mechanical properties of wood, such as compressive strength and hardness. This approach can be extended to fabricate other phosphorus and silicon materials for enhancing the fire safety of wood.

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Mechanical Properties and Flame Retardancy of Epoxy Resin/Nanoclay/Multiwalled Carbon Nanotube Nanocomposites

Journal of Chemistry ◽

10.1155/2019/3105205 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Tuan Anh Nguyen ◽

Quang Tung Nguyen ◽

Trong Phuc Bach

Keyword(s):

Mechanical Properties ◽

Carbon Nanotube ◽

Epoxy Resin ◽

Flame Retardancy ◽

Multiwalled Carbon Nanotube ◽

Multiwalled Carbon ◽

Limiting Oxygen Index ◽

Mechanical Stirring ◽

Flame Retardant Properties ◽

Index Value

This paper reports the improvement of the mechanical properties and flame retardant properties of epoxy Epikote 240/nanoclay I.30E/multiwalled carbon nanotube nanocomposite prepared by mechanical stirring method combined with ultrasonic vibration, nanoclay I.30E content (1; 2; 3 wt.%) and content of MWNT (0.01; 0.02; 0.03 wt.%). When burned, MWCNT reduces degradation speed of epoxy Epikote 240 resin and increases the char yield, and nanoclay acts as an energy storage medium to hinder the heat transfer in epoxy resin. The limiting oxygen index value and UL94 test indicated improvement of flame retardancy of the nanocomposites. The results exhibit the potentiality of these based epoxy Epikote 240 resin/nanoclay I.30E/MWCNTs nanocomposites for multifaceted advanced applications. These fillers can produce environmental friendly products with high thermal and mechanical properties.

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Improving the flame retardancy and thermal property of organotitanate-modified epoxy resin for electronic application via a simple method

High Performance Polymers ◽

10.1177/0954008317749019 ◽

2017 ◽

Vol 31 (1) ◽

pp. 12-23 ◽

Cited By ~ 4

Author(s):

Birong Zeng ◽

Li Yang ◽

Jinmei Chen ◽

Xinyu Liu ◽

Haiyang Wu ◽

...

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Thermal Property ◽

Heat Release ◽

Flame Retardancy ◽

Synergistic Effects ◽

Mechanical And Thermal Properties ◽

Simple Method ◽

Limiting Oxygen Index

The development of halogen-free epoxy resins (EPs) has become a major concern in the field of electronic packaging materials because flame retardants containing halogen release toxic chemicals during combustion. In this article, a type of modified EP possessing multiple functionalities, including high flame retardancy and thermal property as well as low hygroscopicity, was prepared via a simple method by taking advantage of synergistic effects of organotitanate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The mechanical and thermal properties of the as-prepared EP/titanium (Ti)/DOPO system were characterized by dynamic mechanical analysis, glass transition temperature, differential scanning calorimetry, and so on. The results showed that the incorporation of organotitanate and DOPO into EP can not only enhance the decomposition temperature and residual char but also increase the glass transition temperature and limiting oxygen index (LOI) value. The EP/Ti/DOPO system reached UL94 V-0 rating with an LOI of 34.7%. Compared to pure epoxy, the peak heat release rate, heat release capacity, and total heat release of EP/Ti/DOPO were decreased by 33.3%, 35.1%, and 16.7%, respectively.

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Poly(diallyldimethylammonium) and polyphosphate polyelectrolyte complex as flame retardant for char-forming epoxy resins

Journal of Fire Sciences ◽

10.1177/0734904120911722 ◽

2020 ◽

Vol 38 (4) ◽

pp. 333-347

Author(s):

Lichen Zhang ◽

Deqi Yi ◽

Jianwei Hao

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Epoxy Resin ◽

Epoxy Resins ◽

Polyelectrolyte Complex ◽

Oxygen Index ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Smoke Production ◽

Ul 94

The flame retardant poly(diallyldimethylammonium) and polyphosphate polyelectrolyte complex and the curing agent m-Phenylenediamine were blended into diglycidyl ether of bisphenol A (DGEBA)-type epoxy resin to prepare flame-retardant epoxy resin thermosets. The effects of poly(diallyldimethylammonium) and polyphosphate on fire retardancy and thermal degradation behavior of epoxy resins (EP)/poly(diallyldimethylammonium) and polyphosphate composites were tested by Limiting Oxygen Index, UL-94, cone calorimeter tests, and thermogravimetric analysis and compared with pure EP. The results showed that the Limiting Oxygen Index value of EP/poly(diallyldimethylammonium) and polyphosphate composite could reach 31.9%, and UL-94 V-0 rating at 10 wt% poly(diallyldimethylammonium) and polyphosphate loading. Meanwhile the cone calorimetry peak heat release rate and total heat release were reduced up to 55.2% and 21.8%, respectively; smoke production rate and total smoke production were also declined significantly, compared with those of pure epoxy resins. Poly(diallyldimethylammonium) and polyphosphate played a very good flame-retardant effect on epoxy resins.

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Influence of Zirconium Oxide on Thermal Degradation and Flame Retardancy of Viscose Fibers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.884-885.73 ◽

2014 ◽

Vol 884-885 ◽

pp. 73-77

Author(s):

Cui Cui Song ◽

Quan Ji ◽

Chun Xia Li ◽

Feng Yu Quan ◽

Yan Zhi Xia

Keyword(s):

Thermogravimetric Analysis ◽

Thermal Degradation ◽

Heat Release ◽

Flame Retardancy ◽

Zirconium Oxide ◽

Cellulose Fiber ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Viscose Fibers ◽

Spinning Combustion

We have investigated the effect of zirconium oxide on the thermal degradation and flame retardancy of viscose fibers. ZrO2/cellulose fiber was prepared by wet spinning. Combustion behaviour and flammability were assessed using the limiting oxygen index (LOI) and thermogravimetric analysis from ambient temperature to 800°C and cone calorimetry. LOI results showed that the ZrO2 increased the LOI of viscose fiber from 20% to 26%, which showed that ZrO2 particles had a positive effect on cellulose flame-retardancy. Results from thermogravimetric analysis (TG) indicated that the ZrO2/cellulose fibers produced greater quantities of residues than viscose fibers. The combustion residues were examined using the scanning electron microscopy, indicating that ZrO2/cellulose fiber produced consistent, thick residues. Cone calorimetry indicated that heat release rate and total heat release values of ZrO2/cellulose fiber were less than those of viscose fibers.

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