Recent developments in fire-retardant thermoset resins using inorganic-organic hybrid flame retardants

Abstract Inorganic-organic hybrid modifiers have attracted attention of scholars worldwide because they combine the advantages of both different components and provide a way for modifying the structure and properties of polymeric materials. The article describes and investigates a positive effect of reduced flammability of thermoset resins resulting from the use of nanocomposites containing new inorganic-organic hybrid flame retardants (FRs) that combine conventional phosphorous/nitrogen modifiers interacting with nanofillers. The impact of these inhibitors on the level of flammability of thermoset resin compositions was defined by determining the value of limiting oxygen index, thermogravimetric and cone calorimeter analysis of thermal destruction processes. Morphology of composites was assessed using a scanning microscope and an analysis of actual scanning electron micrographic images. The analysis of thermal decomposition of the materials under examination confirmed flammability reducing properties of the inorganic-organic hybrid FR used, and a synergist to generate integrated flame retarding effect was observed between conventional modifiers and nanofillers, in particular carbon nanofillers: expandable graphite, graphene and graphene oxide. The inorganic-organic hybrid FR will provide a new solution to efficient FR polymeric materials.

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Cyclodextrins and Cyclodextrin Derivatives as Green Char Promoters in Flame Retardants Formulations for Polymeric Materials. A Review

Polymers ◽

10.3390/polym11040664 ◽

2019 ◽

Vol 11 (4) ◽

pp. 664 ◽

Cited By ~ 4

Author(s):

Maria Paola Luda ◽

Marco Zanetti

Keyword(s):

Flame Retardants ◽

Environmental Concern ◽

Fire Retardant ◽

Polymeric Materials ◽

Poly Lactic Acid ◽

Mechanical Resistance ◽

Self Healing ◽

Cyclodextrin Derivatives ◽

The Matrix ◽

Fire Retardance

Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their most common applications (i.e., electronic and construction, to mention some). Recently, it has been reported that cyclodextrin (CD) and cyclodextrin derivatives are beginning to be introduced into Intumescent Fire Retardant (IFR) formulations in place of pentaerythritol, which is used in IFRs that are currently on the market. Since IFRs are of less environmental concern than their hazardous halogen containing counterparts, the use of natural origin compounds in IFRs provides a way to comply with green chemistry issues. BCD and BCD derivatives presence in IFR mixtures promotes a higher yield of blowing gases and char when polymeric materials undergo combustion. Both processes play important roles in intumescence. The key rule to obtain in insulating compact char is the good dispersion of the nanoparticles in the matrix, which can be achieved by functionalizing nanoparticles with BCD derivatives. Moreover, CD derivatives are attractive because of their nanosized structure and their ability to form inclusion complexes with many compounds used as FR components, reducing their release to the environment during their shelf life of FR items. Often, fire retardance performed by BCD and BCD derivatives accompanies other relevant properties, such as improved mechanical resistance, washability resistance, self healing ability, thermal conductivity, etc. The application of CD fire retardant additives in many polymers, such as poly(lactic acid), poly(propylene), poly(vinyl acetate), poly(methyl methacrylate), linear low density poly(ethylene), polyamides, and polyesters are comprehensively reviewed here.

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Self-Extinguishing Resin Transfer Molding Composites Using Non-Fire-Retardant Epoxy Resin

Materials ◽

10.3390/ma11122554 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2554 ◽

Cited By ~ 3

Author(s):

Zhi Geng ◽

Shuaishuai Yang ◽

Lianwang Zhang ◽

Zhenzhen Huang ◽

Qichao Pan ◽

...

Keyword(s):

Flame Retardant ◽

Flame Retardants ◽

Resin Transfer Molding ◽

Fire Retardant ◽

Functional Materials ◽

Building Blocks ◽

Fire Retardancy ◽

Limiting Oxygen Index ◽

Transfer Molding ◽

Halogen Free

Introducing fire-retardant additives or building blocks into resins is a widely adopted method used for improving the fire retardancy of epoxy composites. However, the increase in viscosity and the presence of insoluble additives accompanied by resin modification remain challenges for resin transfer molding (RTM) processing. We developed a robust approach for fabricating self-extinguishing RTM composites using unmodified and flammable resins. To avoid the effects on resin fluidity and processing, we loaded the flame retardant into tackifiers instead of resins. We found that the halogen-free flame retardant, a microencapsulated red phosphorus (MRP) additive, was enriched on fabric surfaces, which endowed the composites with excellent fire retardancy. The composites showed a 79.2% increase in the limiting oxygen index, a 29.2% reduction in heat release during combustion, and could self-extinguish within two seconds after ignition. Almost no effect on the mechanical properties was observed. This approach is simple, inexpensive, and basically applicable to all resins for fabricating RTM composites. This approach adapts insoluble flame retardants to RTM processing. We envision that this approach could be extended to load other functions (radar absorbing, conductivity, etc.) into RTM composites, broadening the application of RTM processing in the field of advanced functional materials.

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New Production Route of Magnesium Hydroxide and Related Environmental Impact

Sustainability ◽

10.3390/su12218822 ◽

2020 ◽

Vol 12 (21) ◽

pp. 8822

Author(s):

Andrzej Jarosinski ◽

Piotr Radomski ◽

Lukasz Lelek ◽

Joanna Kulczycka

Keyword(s):

Environmental Impact ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Magnesium Hydroxide ◽

Flame Retardants ◽

Polymeric Materials ◽

New Production ◽

Constant Flow Rate ◽

The Impact

The paper presents research on a method of obtaining magnesium hydroxide from magnesium sulphate salts and NaOH. In order to acquire the desired and controlled properties, the method of precipitating in aqueous solutions by introducing a NaOH solution into a solution of MgSO4 has been applied. To get as stable a product as possible with graining, the introduction of NaOH takes place at a constant flow rate. In order to identify the environmental impact of the developed process, a life cycle assessment (LCA) has been made. The use of the proposed method for the synthesis of Mg(OH)2 incorporating washing with 25% ammonia solution and acetone enabled a product with a high specific surface area. The Mg(OH)2 obtained was characterised by a higher specific surface area than commercially available magnesium hydroxides that are used as additives for flame retardants in polymeric materials. This allows the material to be used as an anti-pyrogen for a wider group of polymeric materials. For the LCA analysis, two scenarios were assumed, from which the basic one included recovery of ammonia and acetone. The environmental analysis carried out confirmed the validity of this assumption, as it was stated that the main part of the impact was connected with the supply chain for the process examined.

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Preparation and Characterization of Excellent Flame Retarded Rigid Polyurethane Foams

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.374-377.1563 ◽

2011 ◽

Vol 374-377 ◽

pp. 1563-1566

Author(s):

An Zhen Zhang ◽

Yi He Zhang

Keyword(s):

Flame Retardant ◽

Flame Retardants ◽

Polyurethane Foams ◽

Expandable Graphite ◽

Dimethyl Methylphosphonate ◽

Limiting Oxygen Index ◽

Rigid Polyurethane Foams ◽

Foaming Process ◽

Flame Retarded

Rigid polyurethane foams were excellent thermal insulation materials with widely used, which was highly flammable at the same time. In order to obtain safe application, flame retarded polyurethane foams were needed. In this paper, series flame retarded rigid polyurethane foams were prepared with loading different flame retardants such as ammonium polyphosphate, expandable graphite, red phosphorus, Tri (2-chloroethyl) phosphate and dimethyl methylphosphonate. The effects of flame retardants on the foaming-process and flame retardant property of the rigid polyurethane foams were investigated by otary viscometer and limiting oxygen index. The results showed that the combination of solid and liquid flame retardants was necessary to improve the flame retardant and different flame retardants played synergistic roles in rigid polyurethane foams. The limiting oxygen indexes of the foams could be up to 30wt% and 29.6% with 25wt% solid flame retardants and 10wt% liquid retardants, respectively.

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Effects of Aluminum Hydroxide and Layered Double Hydroxide on Asphalt Fire Resistance

Materials ◽

10.3390/ma11101939 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1939 ◽

Cited By ~ 10

Author(s):

Menglin Li ◽

Ling Pang ◽

Meizhu Chen ◽

Jun Xie ◽

Quantao Liu

Keyword(s):

Carbon Monoxide ◽

Layered Double Hydroxide ◽

Aluminum Hydroxide ◽

Fire Resistance ◽

Flame Retardants ◽

Synergistic Effects ◽

Combined System ◽

Limiting Oxygen Index ◽

Double Hydroxide ◽

The Impact

When a fire occurs in a tunnel, the instantaneous high temperature and smoke cause great danger to people. Therefore, the asphalt pavement material in the tunnel must have sufficient fire resistance. In this study, the effects of aluminum hydroxide and layered double hydroxide on the fire resistance of styrene-butadiene-styrene (SBS) polymer-modified asphalt was investigated. The fire resistance of the asphalt was evaluated by using a limiting oxygen index (LOI). The impact of aluminum hydroxide (ATH), layered double hydroxide (LDHs), and mixed flame retardant (MFR) on LOI was studied. The synergistic fire resistance mechanism of ATH and LDHs in asphalt binder was analyzed by using an integrated thermal analyzer‒mass spectrometry combined system (TG-DSC-MS) and Fourier transform infrared spectrometer (FTIR). The experimental results indicated that the main active temperature range of these flame retardants was 221–483 °C. The main components of smoke were methane, hydroxyl, water, carbon monoxide, aldehyde, carbon dioxide, etc. The addition of flame retardants could inhibit the production of methane, carbon monoxide, and aldehyde. Moreover, due to the good synergistic effects of ATH and LDHs, 20 wt % MFR had the best fire resistance.

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Effects of nitrogen-phosphorus flame retardants in different forms on the performance of slim-type medium-density fiberboard

BioResources ◽

10.15376/biores.12.4.8014-8029 ◽

2017 ◽

Vol 12 (4) ◽

pp. 8014-8029

Author(s):

Bin Xu ◽

Weidong Li ◽

Daowu Tu ◽

Zhinan Wu ◽

Changjie Song

Keyword(s):

Flame Retardants ◽

Mechanical Performance ◽

Orthogonal Design ◽

Medium Density Fiberboard ◽

Wood Fiber ◽

Fire Retardant ◽

National Standard ◽

Medium Density ◽

Scanning Calorimetry ◽

Limiting Oxygen Index

An orthogonal design was used to optimize the process of making slim medium-density fiberboard modified by a nitrogen-phosphorous series of flame retardants. Mechanical performance was the evaluating criterion. Subsequently, the combustion performances of each type of flame retardant, including in states solid, liquid, and their combination with a ratio of 1:1, were investigated to clarify the corresponding fire-retardant mechanism. The results showed that only physical bonding was responsible for connecting the wood fiber with the retardants, according to the Fourier transform infrared spectrum. Catalytic charring, flame retardancy, and the thermal insulation of three types of retardant were solidified by the results of a cone calorimeter (CONE) analysis, thermogravimetric (TG) analysis, and differential scanning calorimetry (DSC), and the mixture of solid and liquid was demonstrated as the primary choice. It was also found that after the mixture of the solid and liquid retardant was added, the limiting oxygen index of the board reached 43.3%, and it met the requirements of the B1 Class in the Chinese National Standard GB/T8624-2012 (2012).

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Synergistic Effect of APP and TBC Fire-Retardants on the Physico-Mechanical Properties of Strandboard

Materials ◽

10.3390/ma15020435 ◽

2022 ◽

Vol 15 (2) ◽

pp. 435

Author(s):

Feiyu Tian ◽

Deliang Xu ◽

Xinwu Xu

Keyword(s):

Mechanical Properties ◽

Flame Retardants ◽

Oxygen Index ◽

Fire Retardant ◽

Modulus Of Rupture ◽

Fire Retardancy ◽

Thickness Swelling ◽

Cone Calorimetry ◽

Limiting Oxygen Index ◽

Polymeric Diphenylmethane Diisocyanate

This study explored the feasibility of fabricating fire-retardant strandboard with low mechanical properties deterioration to the physico-mechanical properties. A hybrid fire-retardant system of ammonium polyphosphate (APP) and 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione (TBC) was investigated. Thermogravimetric analysis results show that both APP and TBC enhance the thermal stability and incombustibility of wood strands. An infrared spectrum was applied to investigate the effect of flame retardants on the curing behaviors of polymeric diphenylmethane diisocyanate (PMDI) resin. Based on the results of limiting oxygen index (LOI) and Cone calorimetry (CONE), APP and TBC both lead to a higher fire retardancy to strandboard. It is worth mentioning that the two flame retardants lead to evidently differential influences on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), and water-soaking thickness swelling (TS) properties of strandboard. Hence, a hybrid flame retardant is prominent in manufacturing strandboard with both good fire retardant and satisfying physico-mechanical properties.

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Towards the use of acrylic acid graft-copolymerized plant biofiber in sustainable fortified composites: Manufacturing and characterization

e-Polymers ◽

10.1515/epoly-2021-0080 ◽

2021 ◽

Vol 21 (1) ◽

pp. 881-896

Author(s):

Ashvinder K. Rana ◽

Vijay Kumar Thakur ◽

Amar S. Singha

Keyword(s):

Mechanical Properties ◽

Acrylic Acid ◽

Moisture Absorption ◽

Oxygen Index ◽

Polymeric Materials ◽

Dielectric Strength ◽

Differential Scanning Calorimetric ◽

Limiting Oxygen Index ◽

Particle Form ◽

The Impact

Abstract In this study, the impact of particle form of the Cannabis indica plant biofibers and the fiber’s surface tailoring on the physical, thermal, dielectric, and mechanical properties of unsaturated polyester composite specimens manufactured utilizing nonconventional materials were investigated. The mechanical properties such as compressive, flexural, and tensile strengths of the composite specimens were noticed to increase after functionalization of biofiber with acrylic acid and maximum enhancement was found at 20% of biofiber sacking. The physical characterization was concentrated on the assurance of the dielectric constant, dielectric strength, dielectric loss, moisture absorption, chemical resistance, percentage of swelling, limiting oxygen index, and biodegradation of polymer composites under red soil. An increase in dielectric strength from 28 to 29 kV, limiting oxygen index values from 19% to 23%, and moisture/water absorption behavior was noted for resulted bio-composites after surface tailoring of biofiber. To assess the deterioration of the polymeric materials with the temperature, differential scanning calorimetric and the thermogravimetric tests were carried out and enhancement in thermal stability was noted after fortification of polyester composites with functionalized biofiber.

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Flame Retardant Paraffin-Based Shape-Stabilized Phase Change Material via Expandable Graphite-Based Flame-Retardant Coating

Molecules ◽

10.3390/molecules25102408 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2408 ◽

Cited By ~ 1

Author(s):

Ling Xu ◽

Xuan Liu ◽

Rui Yang

Keyword(s):

Phase Change ◽

Flame Retardant ◽

Phase Change Material ◽

Flame Retardants ◽

Fire Risk ◽

Moderate Temperature ◽

Expandable Graphite ◽

Limiting Oxygen Index ◽

Thermal Energy Storage Material ◽

Change Material

Shape-stabilized phase change material (SSPCM) is a promising thermal energy storage material in energy-saving buildings. However, its flammability leads to a fire risk. The conventional bulk addition method has a limited flame-retardant effect. Herein, a series of surface coatings with various flame retardants were introduced to improve flame retardance of SSPCM. The results showed that all of the coatings had flame-retardant effects on SSPCM; In particular, the EG coating performed the best: the horizontal burning time was the longest, the limiting oxygen index was above 30%, the V0 classification was obtained, the peak heat release rate was sharply decreased from 1137.0 to 392.5 kW/m2 and the burning process was prolonged with the least total smoke production. The flame-retardant mechanism was discussed. As paraffin easily evaporated from the SSPCM at a moderate temperature, it caused flames. After being surface coated, the EG-based coatings first hindered the volatilization of paraffin at a moderate temperature, then expanded and formed thick porous carbon layers at a high temperature to block the transfer of combustibles, oxygen and heat between the bulk and the environment. Therefore, the surface coating strategy achieved a desirable flame-retardant level with fewer flame retardants.

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Synthesis of a Novel Spirocyclic Inflatable Flame Retardant and Its Application in Epoxy Composites

Polymers ◽

10.3390/polym12112534 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2534 ◽

Cited By ~ 1

Author(s):

Kunpeng Song ◽

Yinjie Wang ◽

Fang Ruan ◽

Weiwei Yang ◽

Jiping Liu

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Flame Retardants ◽

Phenyl Group ◽

Polymeric Materials ◽

Polymer Materials ◽

Epoxy Composites ◽

Limiting Oxygen Index ◽

Cone Calorimeter Test ◽

Low Efficiency

Derivatives of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro-[5,5]undecane-3,9-dioxide (SPDPC) are of increasing interest as flame retardants for polymeric materials. In addition, SPDPC is also an important intermediate for the preparation of intumescent flame retardants (IFRs). However, low efficiency and undesirable dispersion are two major problems that seriously restrain the application of IFRs as appropriate flame retardants for polymer materials. Usually, the functionalization or modification of SPDPC is crucial to acquiring high-performance polymer composites. Here, a small molecule spirocyclic flame retardant diphenylimidazole spirocyclic pentaerythritol bisphosphonate (PIPC) was successfully prepared through the substitution reaction between previously synthesized intermediate SPDPC and 2-phenylimidazole (PIM). Phenyl group and imidazole group were uniformly anchored on the molecular structure of SPDPC. This kind of more uniform distribution of flame retardant groups within the epoxy matrix resulted in a synergistic flame retardant effect and enhanced the strength of char layers to the epoxy composites, when compared to the unmodified epoxy. The sample reached a limiting oxygen index (LOI) of 29.7% and passed with a V-0 rating in the UL 94 test with the incorporation of only 5 wt% of as-prepared flame retardant PIPC. Moreover, its peak of heat release rate (pHRR) and total heat release (THR) decreased by 41.15% and 21.64% in a cone calorimeter test, respectively. Furthermore, the addition of PIPC has only slightly impacted the mechanical properties of epoxy composites with a low loading.

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