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How to Reduce the Flammability of Plastics and Textiles through Surface Treatments: Recent Advances

by

Giulio Malucelli

Coatings 2022, 12(10), 1563; https://doi.org/10.3390/coatings12101563 - 17 Oct 2022

Viewed by 751

Abstract

The high flammability of plastics, polymer composites, textiles, and foams represents a severe and stringent issue that significantly limits their use in all those sectors, where resistance to a flame or an irradiative heat flux is mandatory [...] Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

Research

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Open AccessArticle

Development of Multifunctional Flame-Retardant Gel Coatings for Automotive Applications

by

Zsófia Kovács

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Ákos Pomázi

and

Andrea Toldy

Coatings 2023, 13(2), 345; https://doi.org/10.3390/coatings13020345 - 02 Feb 2023

Cited by 2 | Viewed by 1182

Abstract

Due to strict safety regulations, the automotive industry requires an effective reduction of flammability in polymer components. Flame retardants are usually added to the polymer matrix, affecting the viscosity of the matrix. Another possible solution is the application of coatings containing flame retardants, [...] Read more.

Due to strict safety regulations, the automotive industry requires an effective reduction of flammability in polymer components. Flame retardants are usually added to the polymer matrix, affecting the viscosity of the matrix. Another possible solution is the application of coatings containing flame retardants, which can additionally ensure good surface quality and protection against external influences. In our research, the flammability of reference and flame retarded gelcoat base materials was investigated using oxygen index (LOI), UL-94, and mass loss type cone calorimetry (MLC) tests. Based on the flammability tests, the best results were obtained with the gelcoat formulation containing 15%P ammonium polyphosphate (APP) and the mixed formulation containing 5%P APP and 5%P resorcinol bis(diphenyl phosphate) (RDP), with a 55% and 64% reduction in the total heat release compared to the reference gelcoat, respectively. The two best-performing coatings were applied to polypropylene (PP) samples. 15%P APP reduced the peak heat release rate of PP by 89% compared to the reference. The gelcoat formulation containing 15%P APP was applied to polyurethane (PUR) automotive components, where the coating reduced the maximum heat release rate by 53% and shifted the time to peak heat release rate by 447 s. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

New Transparent Flame-Retardant (FR) Coatings Based on Epoxy-Aluminum Hypophosphite Nanocomposites

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Coatings 2023, 13(1), 140; https://doi.org/10.3390/coatings13010140 - 10 Jan 2023

Cited by 3 | Viewed by 1277

Abstract

The present study investigated the flame-retardant (FR) effect of transparent epoxy coating containing aluminum hypophosphite (AHP) nanoparticles (NPs) on polylactic acid (PLA) sheets used as a typical model of combustible polymeric material. First, AHP NPs (≤60 nm) were prepared by a specific two-stage [...] Read more.

The present study investigated the flame-retardant (FR) effect of transparent epoxy coating containing aluminum hypophosphite (AHP) nanoparticles (NPs) on polylactic acid (PLA) sheets used as a typical model of combustible polymeric material. First, AHP NPs (≤60 nm) were prepared by a specific two-stage wet milling process and deeply analyzed (morphology, thermal/mechanisms of degradation under nitrogen and air). The thermal properties of epoxy–AHP nanocomposites were compared with the pristine epoxy resin. The addition of AHP NPs into epoxy resin accelerated thermal degradation of the coating, thereby increasing the amount of char residue. The application of blank epoxy coating on the surface of PLA plate slightly made PLA more ignitable, without any reduction in the peak of heat release rate (pHRR). The decrease of time to ignition (TTI) was more important in the presence of AHP NPs due to their reactivity toward epoxy resin. Epoxy coating containing 15 wt.% AHP NPs showed the most significant reduction in pHRR as the result of the formation of a homogenous char layer. Further increase of AHP NPs content up to 20 wt.% did not end in any further enhancement, as a consequence of structural cracks observed in the coating that prevent the formation of an effective char. The coated samples remained transparent, promisingly paving the way to appropriate decorative flame-retardant coatings. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

Design and Performance Evaluation of Flame Retardant and Thermally Insulated Material-Integrated Multi-Functional Thermoplastic Corrugated Sandwich Panels

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Coatings 2022, 12(11), 1719; https://doi.org/10.3390/coatings12111719 - 10 Nov 2022

Viewed by 708

Abstract

Multifunctional composite panels for flame retardant and thermal insulation have not yet been studied. In the current study, we prepared sandwich sheets by using continuous glass fiber flame retardant polypropylene prepreg tape and compared the thermal insulation properties of different fillings. Corrugated sandwich [...] Read more.

Multifunctional composite panels for flame retardant and thermal insulation have not yet been studied. In the current study, we prepared sandwich sheets by using continuous glass fiber flame retardant polypropylene prepreg tape and compared the thermal insulation properties of different fillings. Corrugated sandwich panels, featuring a corrugated space filled with different materials, were prepared and their thermal and mechanical properties are tested and verified. Determining the two structural parameters that have the greatest influence on the heat transfer performance of corrugated sandwich panels has important guiding significance for the structural design of corrugated panels. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

Flame Retardancy Performance of Continuous Glass-Fiber-Reinforced Polypropylene Halogen-Free Flame-Retardant Prepreg

by

Yiliang Sun

,

Jingwen Li

and

Hongfu Li

Coatings 2022, 12(7), 976; https://doi.org/10.3390/coatings12070976 - 09 Jul 2022

Viewed by 1804

Abstract

Thermoplastic resin matrix has a high melt viscosity, which is difficult to impregnate with fibers. The addition of flame retardant will further increase the viscosity of the melt and increase the difficulty of impregnation. It is possible to reduce the effect of flame [...] Read more.

Thermoplastic resin matrix has a high melt viscosity, which is difficult to impregnate with fibers. The addition of flame retardant will further increase the viscosity of the melt and increase the difficulty of impregnation. It is possible to reduce the effect of flame retardant on melt viscosity by adding high-flow polypropylene. In this study, the effect of adding flame retardant on the impregnation quality of prepreg tape was investigated. By adding high-flow polypropylene to improve the melt viscosity of flame-retardant-modified polypropylene, continuous glass-fiber-reinforced polypropylene flame-retardant prepreg tape was successfully prepared. Intumescent flame retardant (IFR) was added at 20 wt%, 25 wt%, 30 wt% of the polypropylene matrixes, which were prepared by melt impregnation. The composites were analyzed with thermogravimetric analysis, limiting oxygen index testing, UL-94 flame retardancy testing, cone calorimeter testing (CCT) and scanning electron microscopy. Tests involving the flame retardant showed that when the added amount of flame retardant reached 25%, the UL-94 flame retardancy grade reached V0. Compared with the CCT sample heating data, taking economic considerations into account, 25 wt% IFR addition was the most suitable. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

Case Study on Fire Resistance of Sandwiches for Means of Transport

by

Pavel Koštial

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Zora Koštialová Jančíková

and

Robert Frischer

Coatings 2021, 11(2), 207; https://doi.org/10.3390/coatings11020207 - 11 Feb 2021

Cited by 5 | Viewed by 1480

Abstract

These days there are undeniably unique materials that, however, must also meet demanding safety requirements. In the case of vehicles, these are undoubtedly excellent fire protection characteristics. The aim of the work is to experimentally verify the proposed material compositions for long-term heat [...] Read more.

These days there are undeniably unique materials that, however, must also meet demanding safety requirements. In the case of vehicles, these are undoubtedly excellent fire protection characteristics. The aim of the work is to experimentally verify the proposed material compositions for long-term heat loads and the effect of thickness, the number of laminating layers (prepregs) as well as structures with different types of cores (primarily honeycomb made of Nomex paper type T722 of different densities, aluminum honeycomb and PET foam) and composite coating based on a glass-reinforced phenolic matrix. The selected materials are suitable candidates for intelligent sandwich structures, usable especially for interior cladding applications in the industry for the production of means of public transport (e.g., train units, trams, buses, hybrid vehicles). Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

Influence of Magnesium Aluminate Nanoparticles on Epoxy-Based Intumescent Flame Retardation Coating System

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Murefah Mana AL-Anazy

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Ahmad A. Ifseisi

Coatings 2020, 10(10), 968; https://doi.org/10.3390/coatings10100968 - 12 Oct 2020

Cited by 6 | Viewed by 2020

Abstract

Ethylenediamine modified ammonium polyphosphate (EDA-MAPP) and charring-foaming agents (CFA) were prepared using a simple chemical method and further used to make intumescent flame retardant coatings based on epoxy resin. The content of MAPP and CFA was fixed at a ratio of 2:1. Nanoparticles [...] Read more.

Ethylenediamine modified ammonium polyphosphate (EDA-MAPP) and charring-foaming agents (CFA) were prepared using a simple chemical method and further used to make intumescent flame retardant coatings based on epoxy resin. The content of MAPP and CFA was fixed at a ratio of 2:1. Nanoparticles of magnesium aluminate (MgAl₂O₄ NPs) have been introduced into the flame retardant coating formulation in various quantities to evaluate the promotional action of MgAl₂O₄ NPs with a flame retardant coating system. The promotional action of MgAl₂O₄ NPs on the flame retardant coating formulation was studied using a vertical burning test (UL-94V), limiting oxygen index (LOI), thermogravimetric analysis (TGA) and Fourier transform infra-red spectroscopy (FTIR). The UL-94V results indicated that the addition of MgAl₂O₄ effectively increased flame retardancy and met the V-0 rating at each concentration. The TGA results revealed that the incorporation of MgAl₂O₄ NPs at each concentration effectively increased the thermal stability of the flame retardant coating system. Cone-calorimeter experiments show that MgAl₂O₄ NPs effectively decreased peak heat release rate (PHRR) and total heat release (THR). The FTIR results indicated that MgAl₂O₄ NPs can react with MAPP and generate a dense char layer that prevents the transfer of oxygen and heat. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessArticle

Improved Thermal Processing of Polylactic Acid/Oxidized Starch Composites and Flame-Retardant Behavior of Intumescent Non-Wovens

by

Muhammad Maqsood

and

Gunnar Seide

Coatings 2020, 10(3), 291; https://doi.org/10.3390/coatings10030291 - 20 Mar 2020

Cited by 10 | Viewed by 3019

Abstract

Thermoplastic processing and spinning of native starch is very challenging due to (a) the linear and branched polymers (amylose and amylopectin) present in its structure and (b) the presence of inter-and-intramolecular hydrogen bond linkages in its macromolecules that restrict the molecular chain mobility. [...] Read more.

Thermoplastic processing and spinning of native starch is very challenging due to (a) the linear and branched polymers (amylose and amylopectin) present in its structure and (b) the presence of inter-and-intramolecular hydrogen bond linkages in its macromolecules that restrict the molecular chain mobility. Therefore, in this study, oxidized starch (OS) (obtained after oxidation of native starch with sodium perborate) was melt-blended with polylactic acid (PLA) polymer to prepare PLA/OS blends that were then mixed together with ammonium polyphosphate (APP), a halogen-free flame retardant (FR) used as acid donor in intumescent formulations on twin-screw extruder to prepare PLA/OS/APP composites. OS with different concentrations also served as bio-based carbonic source in intumescent formulations. PLA/OS/APP composites were melt spun to multifilament fibers on pilot scale melt-spinning machine and their crystallinity and mechanical properties were optimized by varying spinning parameters. The crystallinity of the fibers was studied by differential scanning calorimetry and thermal stabilities were analyzed by thermogravimetric analysis. Scanning electron microscopy was used to investigate the surface morphology and dispersion of the additives in the fibers. Needle-punched non-woven fabrics from as prepared melt-spun PLA/OS/APP fibers were developed and their fire properties such as heat release rate, total heat release, time to ignition, residual mass % etc. by cone calorimetry test were measured. It was found that PLA/OS/APP composites can be melt spun to multifilament fibers and non-woven flame-retardant fabrics produced thereof can be used in industrial FR applications. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Review

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Open AccessReview

Sol-Gel and Layer-by-Layer Coatings for Flame-Retardant Cotton Fabrics: Recent Advances

by

Giulio Malucelli

Coatings 2020, 10(4), 333; https://doi.org/10.3390/coatings10040333 - 01 Apr 2020

Cited by 27 | Viewed by 4164

Abstract

Surface-engineered coatings for the fire protection of cotton are being increasing used thanks to the ease of application of the coatings and their effectiveness in preventing flame propagation and improving resistance to irradiative heat flux exposure. Two main approaches have been extensively investigated, [...] Read more.

Surface-engineered coatings for the fire protection of cotton are being increasing used thanks to the ease of application of the coatings and their effectiveness in preventing flame propagation and improving resistance to irradiative heat flux exposure. Two main approaches have been extensively investigated, namely sol-gel derived coatings and layer-by-layer assemblies. These approaches are both capable of providing treated fabrics with outstanding flame-retardant features. Notwithstanding, according to the composition of the sol-gel recipes and the type of deposited layers, it is possible to design multifunctional (for example hydrophobic and electrically conductive) treatments. This review aims at discussing recent advances with respect to both strategies, highlighting current limitations, open challenges, and possible advances. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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Open AccessReview

Multifunctional Gelcoats for Fiber Reinforced Composites

by

Ákos Pomázi

and

Andrea Toldy

Coatings 2019, 9(3), 173; https://doi.org/10.3390/coatings9030173 - 06 Mar 2019

Cited by 19 | Viewed by 5869

Abstract

Achieving special features in polymer composites, such as flame retardancy and thermal and electrical conductivity, often requires the application of different additives, which might negatively affect other properties of the polymer matrix and the composite structure. Furthermore, the application of solid additives in [...] Read more.

Achieving special features in polymer composites, such as flame retardancy and thermal and electrical conductivity, often requires the application of different additives, which might negatively affect other properties of the polymer matrix and the composite structure. Furthermore, the application of solid additives in composites produced by liquid transfer moulding can lead to the filtration of the additive by the reinforcement, which causes a non-uniform particle distribution and an uneven performance. An evident solution to address these issues is to apply the additives in a separate layer on the surface of the composite. As in many applications, gelcoats are used to reach appropriate surface quality, a reasonable progression in the composite industry is the development of multifunctional gelcoats. In this article, after a short introduction to gelcoats and their main base materials (unsaturated polyester, epoxy, and others) multifunctional gelcoats are discussed according to their functionality, in particular water resistance, electric conductivity and flame retardancy. Classical and novel gelcoat preparation methods (application by brush and/or roller, spraying, UV-curing, in-mould gelcoating), as well as common defects that occur during gelcoating are discussed. Finally, the testing methods of multifunctional gelcoats are outlined. Full article

(This article belongs to the Special Issue Flame Retardant Coatings for Plastics and Textiles)

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