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Thermal decomposition of ammonium polyphosphate into ammonia and ortho-phosphoric acid (a), Catalytic phosphorylation to produce phosphate esters (b), Dehydration of starch and formation of starch-based char structure (c).
Source publication
Starch, being a polyhydric compound with its natural charring ability, is an ideal candidate to serve as a carbonization agent in an intumescent system. This charring ability of starch, if accompanied by an acidic source, can generate an effective intumescent flame retardant (IFR) system, but the performance of starch-based composites in an IFR sys...
Contexts in source publication
Context 1
... the gas phase, the emission of carbon dioxide helped in dilution of the oxygen present in air together with the by-products that were ignited during decomposition of the materials, whereas the resultant char layer in the condensed phase protected the underlying polymeric material from further burning by restricting the free passage of radiant heat and oxygen. This mechanism of intumescence is shown in Figure 1. Polymers 2019, 11, x Figure 1. ...
Context 2
... mechanism of intumescence is shown in Figure 1. Polymers 2019, 11, x Figure 1. Thermal decomposition of ammonium polyphosphate into ammonia and ortho-phosphoric acid (a), Catalytic phosphorylation to produce phosphate esters (b), Dehydration of starch and formation of starch-based char structure (c). ...
Similar publications
Flame retardancy of polymers is a recurring obligation for many applications. The development trend of biobased materials is no exception to this rule, and solutions of flame retardants from agro-resources give an advantage. Lignin is produced as a waste by-product from some industries, and can be used in the intumescent formation development as a...
Citations
... Consequently, when the material is subjected to high temperatures, the PEEK 3D printed samples form a char that can act as a thermal and physical barrier, limiting heat conduction to the bulk of the polymer material and retarding decomposition. Similar trends have already been found in previous studies, including other polymer matrices [48]. ...
A strategy that is gaining momentum in several industrial sectors is metal replacement, which aims to find suitable alternatives for replacing metal components with lighter ones. One possible solution is represented by high-performance polymers (HPP), which are a family of materials with improved thermo-mechanical and functional properties, compared to commodity plastics. Additive manufacturing (AM) is revolutionizing the industrial world due to its high design freedom, dimensional accuracy, and shortened total production time. Thus, combining the use of HPP with AM technologies could lead to innovative results, which could offer new metal replacement solutions through redesign and new material properties. However, HPPs have some manufacturing limitations, for example, they require high processing temperatures, and some of them are subject to significant warping and deformation phenomena. This aspect is particularly significant for semi-crystalline polymers, as in the case of poly(ether-ether-ketone) (PEEK), which is affected by thermal gradients during 3D printing. In this research, an investigation was carried out on the Fused Filament Fabrication (FFF) of different 3D printed PEEK samples, evaluating the effect on final properties not only of various infill percentages (30%, 50%, 70%, and 100%) but also of two different heating treatments. In this regard, a traditional annealing in oven, post 3D printing, was compared to a direct annealing approach, performed during FFF. The mechanical performance of the samples was characterized through tensile and compression tests along with the thermal properties and the thermal stability. In addition, for all different cases, energy consumption was measured, to provide an indication of the sustainability of the presented approaches. The findings suggest that the direct annealing solution holds promise and merits further investigation to bridge knowledge gaps in this domain. This research contributed to advance the understanding of PEEK 3D printing by FFF and played a vital role in the practical implementation of metal replacement as a sustainable strategy across various industrial applications.
... 1,2 In recent history, intumescent fire retardants (IFRs) have begun to gain additional appeal as a potential solution to this issue. [3][4][5] Unlike a single-compound FR, IFRs function via a reaction between several components. These three primary components are nominally a carbon source, an acid source, and a blowing agent. ...
A novel intumescent fire‐retardant coating formulation has been developed by taking advantage of the inherent stability of large cyclic polyphenols (e.g., tannic acid) to remove the need for a dedicated blowing agent, specifically melamine. Cone calorimetry data indicate a lower fire growth rate (FIGRA) (5.0 ± 1.3 vs. 2.4 ± 0.7 kW m ⁻² s ⁻¹ ) upon removal of melamine. Total smoke release (TSR) increases following this removal (178 ± 21.4 vs. 305 ± 13.2 m ² m ⁻² ), which indicates the role of tannic acid in gas generation. Thermogravimetric analysis resulted in similar residue yield from the examined systems (36 ± 1.3% vs. 34 ± 1.7%) despite removal of a dedicated blowing agent. These results indicate that tannic acids multistep degradation allows it to behave as both a char forming and blowing agent in intumescent systems. The observed reduction of acid loading between the melamine‐tannin system and the melamine‐free composition (15.6% vs. 10.6% wt. ammonium polyphosphate, respectively) is also significant. Tannic acid occurs in agricultural waste products, which is encouraging for the pursuit of sustainable chemistry and addressing potential adverse health effects in humans combined with reducing the overall phosphorous loading.
Highlights
Melamine was removed from the intumescent without compromising stability.
The resulting intumescent char was stronger despite less expansion.
Tannic acid is attributed as both the charring and blowing agent.
The tannin‐based coating requires a lower acid loading for similar performance.
... However, the residual masses for G 35 (a), G 35 (b), and G 35 (c) were found to be 14.24%, 15.44%, and 10.65%, respectively ( Table 2). It has been reported that the starch possesses a natural charring ability due to its polyhydric nature [57]. The cassava bagasse used to synthesise the films consists of a reasonable amount of residual starch, which might have also contributed to the formation of char. ...
... The cassava bagasse used to synthesise the films consists of a reasonable amount of residual starch, which might have also contributed to the formation of char. Moreover, higher residual mass indicates higher amount of stabilised char formation [57,58]. Thereby the residual mass after the thermal decomposition of the studies films may indicate the efficiency of the plasticisation of starch granules with glycerol while resulting in more homogeneous and compatible films. ...
The utilisation of edible sources of starch such as corn, wheat, potato, and cassava has become the common approach to develop biodegradable food packaging. However, the future food security issue from the wide application of such edible starch sources has become a major concern. Consequently, exploring non-edible sources of starch for starch-based biodegradable food packaging and their property enhancement have become one of the common research interests. Although there has been a great potentials of synthesising biodegradable food packaging by direct utilisation of agro-industrial waste cassava bagasse, there have been very limited studies on this. In this context, the current study investigated the potential of developing biodegradable food packaging by directly using cassava bagasse as an alternative matrix. Two film-forming mixtures were prepared by incorporating glycerol (30% and 35%), powdered cassava bagasse and water. The films were hot-pressed at 60 °C, 100 °C, and 140 °C temperatures under 0.28 t pressure for 6 min. The best film-forming mixture and temperature combination was further tested with 0.42 t and 0.84 t pressures, followed by analysing their morphology, functional group availability and the thermal stability. Accordingly, application of 35% glycerol, with 100 °C, 0.42 t temperature and pressure, respectively, were found to be promising for film preparation. The absence of starch agglomerates in film surfaces with less defects suggested satisfactory dispersion and compatibility of starch granules and glycerol. The film prepared under 0.42 t exhibited slightly higher thermal stability. Synthesised prototypes of food packaging and the obtained characterisation results demonstrated the high feasibility of direct utilisation of cassava bagasse as an alternative, non-edible matrix to synthesise biodegradable food packaging.
... The thermal degradation behaviour of the sample is observed through the TGA curve plotted between weight of the sample and temperature. TGA curve is used to determine the thermal degradation temperature, rate of degradation, weight of residual sample and also the temperature at which maximum degradation occurs (Maqsood and Seide, 2019;Shankar and Rhim, 2017;Shi et al., 2014). ...
Food packaging has a considerable vital effect in preserving the food quality from any physico-chemical and environmental damage. The requirement of consumers and industry for improved quality food has resulted in the production of active and intelligent food packaging technology in recent years. Traditionally, plastic material is applied in the food industry owing to its extensive accessibility and excellent mechanical properties at a low cost. The rising environmental and health concern of plastic packaging waste has conducted to the introduction of eco-friendly materials. Bio-based polymer materials can be treated for the formation of biodegradable plastics. To succeed in this aim, biopolymers should be inexpensive, biodegradable, and richly accessible. Bioplastic packaging substances derived from sustainable biomass could be applied as a continuous replacement to petrochemically derived plastic substances. This chapter highlights the progress in biopolymer-developed packaging with considering active and intelligent packaging.KeywordsBiopolymersBlendsExtrusionSolvent castingElectrospinning3D PrintingLayer by layer
... The thermal degradation behaviour of the sample is observed through the TGA curve plotted between weight of the sample and temperature. TGA curve is used to determine the thermal degradation temperature, rate of degradation, weight of residual sample and also the temperature at which maximum degradation occurs (Maqsood and Seide, 2019;Shankar and Rhim, 2017;Shi et al., 2014). ...
Biopolymers’ production and application have been increased during the last decade all around the world. This rapid switch from conventional polymers to new biopolymers makes it essential to consider their characteristics deeply due to the correlation of physicochemical properties with biopolymers’ functional properties. Biopolymers are one of the few renewable materials appropriate for food packaging. However, nearly all of them have inferior properties that are not suggested for packaging without any modification. As a result, various techniques have been examined by scientists to achieve the required specific characteristics. Blending is one of the most widely used methods in this field. In this chapter, a short review of food packaging, different types of materials used for food packaging, and their properties are discussed. In the following, different kinds of biopolymers and their preparation techniques are summarized. The properties of each biopolymer blend are also emphasized. Finally, applications of biopolymer blends in food packaging are highlighted.KeywordsBio-based polymer materialsBioplasticEco-friendly materialsIntelligent packagingFood shelf life
... The thermal degradation behaviour of the sample is observed through the TGA curve plotted between weight of the sample and temperature. TGA curve is used to determine the thermal degradation temperature, rate of degradation, weight of residual sample and also the temperature at which maximum degradation occurs (Maqsood and Seide, 2019;Shankar and Rhim, 2017;Shi et al., 2014). ...
Plastic application is one of the crucial concerns due to the global environmental impact, and shifting to biodegradable food packaging would be a favorable option. This review aims to use biodegradable microbial-derived polymers in food packaging. The main criteria in food application are mechanical and thermal characteristics and water vapor gas transfer. Among materials, microbial polymers, polysaccharides, and polyhydroxyalkanoate are desirable in food packaging due to being biodegradable, having better physical properties, and lower O2 and CO2 permeability with no catalysts residue. This article focuses on microbial polysaccharides (e.g., bacterial cellulose) and polyhydroxyalkanoate in food packaging. The necessity of using biobased polymers in food packages is expressed in the introduction part. The application of the most common biopolymers is described. The biopolymers production, polyhydroxybutyrate-based nanocomposites, and some microbial polysaccharide (e.g., BC) properties in food packaging are also discussed. Moreover, some improvement issues of polyhydroxybutyrate and microbial polysaccharide (e.g., BC) properties are explained, and the nanotechnology impresses on improving the physical properties. Eventually, the article includes some possible future trends.KeywordsPoly(hydroxybutyrate)Poly(hydroxyalkanoate)Food packagingPropertiesModificationsNanoparticlesMicrobial polisaccharides and bacterial celulose
... Natural structures such as chitosan [3], lignin [4], cyclodextrin [5] and starch [6] contain polyhydroxy groups. They can be used as carbon sources for intumescent flame retardants (IFR) because they are cross-linked to carbon through esterification during combustion. ...
Due to environmental concerns, some of the conventional halogenated flame retardants have been banned. In this context, both the industrial and academics have made efforts to develop more eco-friendly and sustainable flame retardant materials. Among new flame retardants, bio-based groups have attracted plenty of attention. In this review, varied types of bio-based flame retardants are systematically described, including the structural characteristics, flame retardant behaviors, and an overview of flame retardant mechanism. Recent research progress on various bio-based materials such as flame retardants (e.g., chitosan, lignin, phytic acid, polydopamine, Tannic acid, β-cyclodextrin, etc.) applied to different polymers are adequately summarized. Finally, the opportunities and challenges for the future development of bio-based flame retardants are briefly outlooked.
... The char acts as a physical barrier to heat transfer to the combustible material's surface. Other than that, the char layer prevents oxygen from reaching the site of combustion [126]. As shown in Figure 6, the formation of char slows the rate of temperature increase on the surface above the char layer. ...
... This is parallel to char-forming flame retardants, which have many advantages over other systems because they emit less smoke and toxic gases. Moreover, the smoke produced is less corrosive, and the scrap can be disposed of easier after usage [126,128]. ...
This review provides an intensive overview of flame retardant coating systems. The occurrence of flame due to thermal degradation of the polymer substrate as a result of overheating is one of the major concerns. Hence, coating is the best solution to this problem as it prevents the substrate from igniting the flame. In this review, the descriptions of several classifications of coating and their relation to thermal degradation and flammability were discussed. The details of flame retardants and flame retardant coatings in terms of principles, types, mechanisms, and properties were explained as well. This overview imparted the importance of intumescent flame retardant coatings in preventing the spread of flame via the formation of a multicellular charred layer. Thus, the intended intumescence can reduce the risk of flame from inherently flammable materials used to maintain a high standard of living.
... The addition of the APP improved the limiting oxygen index from 19 to 31%. Further, starch can be used as a potential carbonization agent to produce the PLA (Maqsood and Seide, 2019). Park et al. (2017) discussed the application of the biopolymers-based composite for the medical applications. ...
The development of biopolymers has significantly touched each and every sphere of human life due to their eco friendliness and biodegradability. In recent decades, the production of biopolymers gained profound attention due to the serious environmental concerns and threat to the non-renewable resources. The increased use of synthetic plastic in biomedical and engineering applications stays as a major threat to environment when these xenobiotic enters the food chain and soil upon their careless discharge after use. The significant material properties of plastic has made it as an inevitable part in our day to day life, but the concern over the environment directs the research focus on searching and developing biopolymers and bio composites as sustainable alternatives for their synthetic counterparts. Biopolymers of commercial interest can be majorly produced intracellularly by microbes or can be extracted through chemical or biological methods from plant and animal based substrates. The potential candidates with high market value with specific reference to biomedical engineering and tissue engineering include as polyhydroxyalkanoates, cellulose, chitosan and chitin, hydroxyapatite, and pectin. Despite of having high degree of biocompatibility, the major hurdle that retracts their widespread use commercially is attributed to the cost of production. This can be tackled out by exploiting cheap raw materials like agro waste as substrate and by employing green approaches over solvent based conventional extraction methods. The reduction in the material properties of purified biopolymers restricts their wide spread application especially in the fabrication of thermoplastic blends. This can be resolved by production of bio composites with improved properties than their parent biopolymers. The current review focuses on the recent developments in biopolymer science especially with regard to its application in engineering majorly biomedical and tissue engineering. This study throws light on the biosynthetic pathways, extraction methods and applications of commercially important biopolymers. Furthermore the challenges, limitations and future prospects in the production and commercialization of biopolymers is briefly discussed in this review.
... The first method is based on various bio-based compounds, namely starch (ST), β-cyclodextrin, lignin, cellulose, DNA, phytic acid (PA), protein, chitosan (CS), vegetable oils, etc, which are used directly or in physical mixing with other components as efficient green FR additives because of their outstanding char-forming ability [5]. Maqsood et al [6] reported that LOI of PLA with 7 wt% ST and 20 wt% ammonium polyphosphate (APP) improved to 37.3 % and obtained a V-0 grade in UL-94 vertical burning test. Wang et al [7] studied that PLA containing 30 % IFR (microencapsulated ammonium polyphosphate (MCAPP) mixed with ST) composites could reach a V-0 classification in UL-94 vertical burning test with LOI value of 41.0 %. ...
In this work, the highly-efficient multifunctional bio-based fire retardant phenylphosphonic difurfurylamine (PPDF) was prepared successfully for poly(lactic acid) using furfurylamine and phenylphosphonic dichloride. Moreover, the structure of PPDF was analyzed by NMR, FTIR and MS. The fire safety, thermal, crystallization, rheological and mechanical properties of PLA/PPDF compounds were systematically tested by LOI, UL94, cone calorimeter test, TGA, DSC, polarizing optical microscope, rheometer, DMA and tensile properties. Surprisingly, only a very small loading of 0.8 wt% loading of bio-fire retardant PPDF could increase the LOI value of PLA from 19.0 % to 30.0 % and achieve V-0 rating in UL-94 vertical burning test. Moreover, PPDF not only reduced the molecular entanglement and viscosity of PLA but also acted as a nucleating agent to increase crystallinity and crystallization rate of PLA matrix. More importantly, in the gas phase phosphorus, the PLA/PPDF compounds based on highly reactive benzene, phosphorus, phosphooxygen and phosphooxygen benzene radicals from the pyrolysis of PPDF had a highly-efficient fire safety. In the condensed phase, a relative stable residual char layer played a secondary role in a barrier. Thus, the total heat release and ignition time of PLA/PPDF compounds were evidently declined by 8.3 % and 10 s with only 0.8 wt% of PPDF loading.
