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Richard A Horrocks - One of the best experts on this subject based on the ideXlab platform.
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effect of different compatibilisers on nanoclay dispersion thermal stability and burning behavior of polypropylene nanoclay blends
Journal of Applied Polymer Science, 2008Co-Authors: Baljinder K Kandola, B J Hunt, Paul Joseph, John R. Ebdon, Richard A Horrocks, Sheng Zhang, G Smart, Richard T Hull, Andy CookAbstract:The combustion behaviour of polystyrene flame retarded by the incorporation of phosphorus-containing compounds has been studied by LOI and cone calorimetry. Both 'reactive' and 'additive' approaches to the incorporation of the phosphorus have been applied and assessed. The data obtained show that the reactive approach results in enhanced Char Formation during combustion due to a condensed phase mechanism. Flame retardation by the additive systems occurred exclusively in the vapour phase via both chemical and physical interactions. The main advantage of the reactive approach was the maintenance of the physical and chemical properties similar to those of the homopolymer. The phosphorus environment was also a significant factor in terms of the level of flame retardance achieved. Phosphonate species were more effective than were phosphate species.
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Char Formation in polyamides nylons 6 and 6 6 and wool keratin phosphorylated by polyol phosphoryl chlorides
Textile Research Journal, 2004Co-Authors: Richard A Horrocks, Sheng ZhangAbstract:Polyamides (nylon 6 and 6.6) phosphorylated by spirocyclic pentaerythritol phosphoryl chloride (SPDPC), cyclic 1,3-propanediol phosphoryl chloride (CPPC), and cyclic 2,2- diethyl-1,3-propanediol ph...
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enhancing polymer Char Formation by reaction with phosphorylated polyols 1 cellulose
Polymer, 2001Co-Authors: Richard A HorrocksAbstract:Abstract The use of polyol phosphonyl chlorides or phosphochloridates as phosphorylating agents for cellulose is considered as means of introducing a Char-forming centre in association with an acid-generating moiety into a functional polymer which itself is potentially Char-forming. The specific polyol phosphonyl chloride used, spirocyclic pentaerythritol di(phosphonyl chloride) or diphosphochloridate (SPDPC) is shown to be able to substitute into cellulose (as cotton) in the presence of a suitable solvent (DMF) and base (pyridine and sodium hydroxide) at levels commensurate with phosphorus concentrations up to 2.5% (w/w). This is equivalent to phosphorylation yields of up to 22.7%. The efficiency of phosphorylation is dependent upon reaction temperature and SPDPC: cotton mass ratios. Highest yields occur when reactions are carried out at respective mass ratios of 4:1 (almost equivalent to a molar ratio of an anhydroglucopyranose repeat: 1/2 SPDPC molecule) at 160°C for 2 h. Thermogravimetric analysis of SPDPC-phosphorylated cellulose shows enhanced Char Formation over the range 400–740°C with respect to untreated cotton cellulose. Scanning electron microscopy shows Chars to be well-defined and quite resistant to oxidation as the temperature rises above 600°C in air.
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Char Formation in flame retarded fibre intumescent combinations part v exploring different fibre intumescent combinations
Fire and Materials, 2001Co-Authors: Baljinder K Kandola, Richard A Horrocks, Samuel HorrocksAbstract:Previous research work in our laboratory has indicated that the efficiency of certain flame-retardant fibres can be further enhanced if certain interactive intumescents are dispersed on their surfaces. In our previously reported work we have successfully observed interactions between certain commercially available flame-retardant cellulosic and regenerated cellulose (viscose) fibres and two melamine and phosphoric acid-based intumescent systems. In the present work we have explored the use of other intumescent systems-melamine cyanurate, melamine borate, melamine oxalate, melamine pyrophosphate and an inorganic silicate-based intumescent, Cylatherm. Two non-cellulosic fibres-the novoloid (Kynol) and melamine-formaldehyde (Basofil) were also explored in combination with different intumescent systems. These systems were studied by thermal analytical techniques to observe any possible interaction between FR fibre and intumescent components. Of these intumescents, only melamine borate and melamine pyrophosphate showed interactions with flame retardant cellulosic fibres and both Kynol and Basofil indicated Char interactive tendencies with some of the phosphorus-containing intumescents.
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scanning electron microscopic studies of wool intumescent Char Formation
Polymer International, 2000Co-Authors: Philip J Davies, Richard A Horrocks, Mohsen MiraftabAbstract:Thermal analytical studies of synthesized mixtures of powdered wool, wool/flame retardant viscose blended fibre/intumescent combinations and intumescent-coated fabrics have shown previously that while enhanced volatilization occurs during Char Formation below 400°C, the Chars formed show higher-than-expected oxidative resistance up to temperatures beyond 700°C. In this paper, scanning electron microscopy has been used to study these interactions and show that over the temperature range 250-450 °C, Charred residues from wool-containing samples coated with intumescent and without intumescent exhibit significant changes in wool fibre morphology. Wool fibres first appear first to swell and then develop an axial defect. Further swelling occurs to yield a swollen 'pod-like' morphology at higher temperatures, and splitting of the cuticle along the axial defect allows the largely liquid degraded wool keratin interior to escape and wet neighbouring surfaces. The presence of intumescent flame retardant appeared to inhibit the rupture of the wool cuticular membrane, possibly via enhanced crosslinking of the keratinous protein accompanied by enhanced volatile Formation in the 250-350°C region. The subsequent rupture stage (>350°C) enables the intumescent to act upon the emerging liquefied pyrolysing keratin core of the fibres, providing a second high volatilization stage to accompany complex Char Formation with adjacent cellulosic fibres.
Shiro Saka - One of the best experts on this subject based on the ideXlab platform.
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pyrolysis of cellulose in aromatic solvents reactivity product yield and Char morphology
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Takashi Nomura, Haruo Kawamoto, Shiro SakaAbstract:Abstract Aromatic solvents are known to stabilize levoglucosan (1,6-anhydro-β- d -glucopyranose), the major pyrolysis intermediate of cellulose, against thermal degradation including Char Formation. In this article, pyrolysis of cellulose, a crystalline component of biomass, was investigated in the aromatic solvents 1,3-diphenoxybenzene, diphenyl sulfide, and benzophenone under nitrogen at 280 °C. Thermal degradation of cellulose (Whatman filter paper) was markedly delayed in the aromatic solvents and gave thin film-like Char after the removal of unreacted cellulose through hydrolysis. The yields of levoglucosan and 5-hydroxymethylfurfural were greatly enhanced in the aromatic solvents. These observations are discussed at the molecular level in terms of the interactions of cellulose crystallites and the pyrolysis products with the aromatic solvents. A possible Char Formation mechanism via 5-hydroxymethylfurfural involving the ultrastructure of the cell wall is also discussed. This study provides insight into the molecular-based cellulose pyrolysis mechanisms and efficient and selective thermochemical production of bio-based materials and chemicals.
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complete inhibition of Char Formation from cellulose in fast pyrolysis with aromatic substance
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Taeko Shoji, Haruo Kawamoto, Shiro SakaAbstract:Abstract Aromatic substances stabilize levoglucosan and other monomeric glycosides by solvation against thermal decomposition including Char Formation. We applied this stabilization to inhibit Char Formation from cellulose, a crystalline polysacCharide. Cellulose was heated with various types of aromatic substances in a heating mantle (slow pyrolysis) or by inserting a sample in a ceramic boat into a furnace preheated to 700 °C under a nitrogen flow (fast pyrolysis). As a result, only fast pyrolysis in aromatic substances with polar substituents (>C O or N ) and high boiling points >400 °C completely inhibited the Char Formation. By the NMR analysis, the major product was identified to be levoglucosan (LG), and the selectivity increased in the presence of aromatic substances probably due to the stabilization of LG in the molten products produced from cellulose fast pyrolysis. The phscicochemical properties required for aromatic substance are discussed with the nature of the cellulose crystallite surface and its decomposition temperature.
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role of methoxyl group in Char Formation from lignin related compounds
Journal of Analytical and Applied Pyrolysis, 2009Co-Authors: Takashi Hosoya, Haruo Kawamoto, Shiro SakaAbstract:Abstract Although Char Formation from lignin is an important process in wood pyrolysis, the molecular mechanism has not been clarified yet. In this study, the vapor-phase Char Formation of various lignin-related compounds was studied under the pyrolysis conditions of N 2 /600 °C/80 s. The methoxyl groups were found necessary for Char Formation. Interestingly, ethoxyl group was not effective in such Char Formation. Guaiacol and 2-ethoxyphenol gave pyrocatechol (formed through thermal homolysis of the O–R bonds) and the ether-rearranged products ( o -cresol, 2-ethylphenol, xanthenes and 2,3-benzofuran). The latter products are likely formed via an o -quinone methide intermediate, initiated from the H-abstraction of the phenolic hydroxyl groups. 2-Ethoxyphenol gave larger amounts of 2,3-benzofuran and less xanthenes and Char than guaiacol, with yields of other products similar. Such reactivity difference is explainable with the different reactivities of the o -quinone methide intermediates. Based on the results, o -quinone methide is proposed as an important intermediate for lignin Char Formation during pyrolysis.
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Influence of neutral inorganic chlorides on primary and secondary Char Formation from cellulose
Journal of Wood Science, 2008Co-Authors: Haruo Kawamoto, Daisuke Yamamoto, Shiro SakaAbstract:The influence of various alkali and alkaline earth metal chlorides (LiCl, NaCl, KCl, MgCl_2, and CaCl_2) on primary and secondary Char Formation from cellulose was studied at 400°C. Secondary Char was formed through carbonization of the volatile products. All chlorides increased the primary Char yield while decreasing the secondary Char Formation, and this situation was promoted in the order of alkaline earth Mg, Ca, alkali Li > alkali Na, K. Levoglucosan yield also decreased along with the secondary Char yield. These results indicate that the reduced Formation of volatile levoglucosan was related to the decreasing yield of secondary Char. A model experiment at 250°C revealed that these chlorides, especially the two alkaline earth metals, had catalytic action on the polymerization of levoglucosan, which serves to reduce the Formation of volatile levoglucosan.
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cellulose hemicellulose and cellulose lignin interactions in wood pyrolysis at gasification temperature
Journal of Analytical and Applied Pyrolysis, 2007Co-Authors: Takashi Hosoya, Haruo Kawamoto, Shiro SakaAbstract:Abstract Cellulose–hemicellulose and cellulose–lignin interactions during pyrolysis at gasification temperature (800 °C) were investigated with various cellulose samples mixed with hemicellulose (glucomannan or xylan) or milled wood lignin. Significant interactions were observed in cellulose–lignin pyrolysis; lignin inhibited the thermal polymerization of levoglucosan formed from cellulose and enhanced the Formation of the low molecular weight products from cellulose with reduced yield of Char fraction; cellulose reduced the secondary Char Formation from lignin and enhanced the Formation of some lignin-derived products including guaiacol, 4-methyl-guaiacol and 4-vinyl-guaiacol. Comparatively weak interactions were also observed in cellulose–hemicellulose pyrolysis. Finally, factors influencing the wood pyrolysis at gasification temperature are discussed.
Wei Ke - One of the best experts on this subject based on the ideXlab platform.
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effect of acrylic polymer and nanocomposite with nano sio2 on thermal degradation and fire resistance of app dper mel coating
Polymer Degradation and Stability, 2006Co-Authors: Zhenyu Wang, Wei KeAbstract:Acrylic nanocomposite and flame retardant coatings with different acrylic polymers were prepared. The effect of molecular structure and molecular weight of acrylic resins and nanocomposite with nano-SiO2 on the interaction and Char Formation of ammonium polyphosphate-dipentaerythritol-melamine (APP-DPER-MEL) coating was investigated using differential thermal analysis (DTA), thermogravimetry (TG), Limiting Oxygen Index (LOI), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and fire protection test. The interaction of APP, DPER, MEL and 3F-I acrylic resin led to the Formation of intumescent coherent Char at 300-450 degrees C. Owing to low molecular weight and lack of benzene rings, F-963 acrylic resin decomposed at lower temperature than APP, and hence their endothermic interaction was destroyed. The well-distributed nano-SiO2 particles in acrylic nanocomposite could modify Char Formation and anti-oxidation of Char structure at high temperature. It is noted that the fire protection properties of nanocoating with acrylic nanocomposite were better than those of flame retardant coatings with conventional acrylic resins. (c) 2006 Elsevier Ltd. All rights reserved.
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influence of nano ldhs on Char Formation and fire resistant properties of flame retardant coating
Progress in Organic Coatings, 2005Co-Authors: Zhenyu Wang, Wei KeAbstract:Flame-retardant nano-coatings were prepared by adding flame-retardant nano-concentrates to APP/PER/EN coating. Dispersion morphology and stability principle of nano-size magnesium aluminum-layered double hydroxides (nano-LDHs) have been studied by using transmission electron microscopy (TEM). Relation of added amount of nano-concentrates in flame-retardant coating to flame-retardant properties for APP/PER/EN system has been studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), thermogravimetry (IG) and fire protection test. It was indicated that nano-LDHs could catalyze the esterification reaction between ammonium polyphosphate and pentaerythritol, and IPN network formed by nano-size thermal-decomposed products of LDH could efficiently enhance Char Formation and structure of Char layer. Only specific content (1.5%) of nano-LDHs in flame-retardant coating could efficiently improve its Char layer structure and fire-resistant properties. Nano-LDHs (1.5%) greatly improve mechanical properties (bonding strength, bending resistance and resistance to freeze-thaw cycle) of flame-retardant coating. (c) 2005 Elsevier B.V. All rights reserved.
Bin Li - One of the best experts on this subject based on the ideXlab platform.
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effect of a novel Charring foaming agent on flame retardancy and thermal degradation of intumescent flame retardant polypropylene
Polymer Degradation and Stability, 2006Co-Authors: Bin Li, Miaojun XuAbstract:Abstract A new triazine polymer was synthesized by using cyanuric chloride, ethanolamine and ethylenediamine as raw materials. It is used both as a Charring agent and as a foaming agent in intumescent flame retardants, designated as Charring–foaming agent (CFA). Effect of CFA on flame retardancy, thermal degradation and mechanical properties of intumescent flame retardant polypropylene (PP) system (IFR–PP system) has been investigated. The results demonstrated that the intumescent flame retardant (IFR) consisting of CFA, APP and Zeolite 4A is very effective in flame retardancy of PP. It was found that when the weight ratio of CFA to APP is 1:2, that is, the components of the IFR are 64 wt% APP, 32 wt% CFA and 4 wt% Zeolite 4A, the IFR presents the most effective flame retardancy in PP systems. LOI value of IFR–PP reaches 37.0, when the IFR loading is 25 wt% in PP. It was also found that when the IFR loading is only 18 wt% in PP, the flame retardancy of IFR–PP can still pass V-0 rating, and its LOI value reaches 30.2. TGA data obtained in pure nitrogen demonstrated that CFA has a good ability of Char Formation itself, and CFA shows a high initial temperature of the thermal degradation. The Char residue of CFA can reach 35.7 wt% at 700 °C. APP could effectively promote the Char Formation of the APP–CFA system. The Char residue reaches 39.7 wt% at 700 °C, while it is 19.5% based on calculation. The IFR can change the thermal degradation behaviour of PP, enhance T max of the decomposition peak of PP, and promote PP to form Char, based upon the results of the calculation and the experiment. This is attributed to the fact that endothermic reactions took place in IFR Charring process and the Char layer formed by IFR prevented heat from transferring into inside of IFR–PP system. TGA results further explained the effective flame retardancy of the IFR containing CFA.
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investigation of mechanical property flame retardancy and thermal degradation of lldpe wood fibre composites
Polymer Degradation and Stability, 2004Co-Authors: Bin Li, Jinmei HeAbstract:The mechanical properties, flame retardancy and thermal degradation of linear low density polyethylene (LLDPE)–wood-fibre composites have been investigated. LLDPE–wood-fibre composites were prepared on a two-roll machine. Maleated polyethylene (MPE) was used to improve the mechanical properties of LLDPE–wood-fibre composites. Ammonium polyphosphate (APP) and the mixtures of APP, melamine phosphate (MP) or pentaerythritol (PER) were used as flame retardants. The experimental results demonstrated that MPE enhanced tensile strength and Izod impact of LLDPE–wood-fibre composites, which is in agreement with literature. APP influenced Izod impact of LLDPE–wood-fibre composites, while it scarcely affected tensile strength. It was found that PER could clearly decrease both tensile strength and Izod impact of LLDPE–wood-fibre composites. This is attributed to PER being involved in esterification reactions between wood-fibre and MPE. According to LOI obtained from this work, APP is an effective flame retardant for LLDPE–wood-fibre composites. It was also found that wood-fibre obviously influenced the thermal degradation behaviour of LLDPE. Wood-fibre made the rapid thermal degradation of LLDPE take place earlier, while APP thermally stabilized LLDPE in LLDPE–wood-fibre composite based upon the temperature (Tmax) at maximum peak of the thermal degradation. APP decreased initial temperature (Tinitial) of thermal degradation, and promoted Char Formation of the composite. It is suggested that APP can catalyze esterification, dehydration and Char Formation of wood fibre.
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the study of flame retardants on thermal degradation and Charring process of manchurian ash lignin in the condensed phase
Polymer Degradation and Stability, 2001Co-Authors: Jian Li, Bin Li, Xiucheng Zhang, Renzhou SuAbstract:Abstract Dioxane lignin was isolated from manchurian ash by means of Pepper's method. The thermal degradation and Charring of the manchurian ash treated with ammonium polyphosphate, ammonium dihydrogen or boric acid in the condensed phase were investigated by the combination of XPS, FTIR and TGA. TGA results under pure nitrogen showed that the flame retardants reduced the initial temperature of thermal degradation of the lignin and promoted Char Formation compared with the control sample. XPS data obtained in high vacuum showed that an increase of C1s and C1s (C–C) intensity, a decrease of C1s (C–O) intensity and a decrease of C1s binding energy were promoted by the flame retardants. FTIR data of Char residue showed that flame retardants reduced the relative absorbance of the C–O group and enhanced the relative absorbance of C–H vibration in aromatic ring and of aromatic ring vibration. No increase of the CO group vibration was observed. The results from XPS, FTIR and TGA demonstrate that the flame retardants catalyzed the cleavage of C–O bonds in the lignin to form a highly conjugated system and promoted crosslinking and Char Formation. Ammonium polyphosphate and ammonium dihydrogen phosphate were more effective in Char forming than was boric acid.
Sheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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the preparation of a bisphenol a epoxy resin based ammonium polyphosphate ester and its effect on the Char Formation of fire resistant transparent coating
Progress in Organic Coatings, 2019Co-Authors: Xuelian Liu, Jia Guo, Jun Sun, Weihua Feng, Wei Liu, Sheng ZhangAbstract:Abstract This work reports the synthesis of an effective Charring agent (ammonium polyphosphate ester (BAPPE)) and its application in preparing intumescent transparent fire resistive coatings. Bisphenol A epoxy resin reacted with diethanol amine to produce a waterborne epoxy resin (WEP), and then WEP was further reacted with orthophosphoric acid (PA) and urea (U) to obtain BAPPE. The chemical structure of BAPPE was confirmed by FT-IR and 1H NMR. Transparent fire resistive coating containing BAPPE and melamine urea formaldehyde (MUF) resin was prepared. The thermal gravimetric analysis showed that BAPPE could enhance Char Formation of the coating in the temperature range of 320–800 ℃. The flammability evaluation by simulated big panel method, smoke density test, and cone calorimeter (CONE) indicated that the presence of BAPPE significantly increased the fire resistant time, suppressed the smoke release amount, and remarkably reduced the peak heat release rate (pHRR) to 6.6 kW/m2. It was proved BAPPE could act as a three sources integrated reactive flame retardant in transparent coating. It is proposed that BAPPE can form cross-linking networks with MUF, thus enhancing the Char Formation upon heating and improving the fire resistance of the coating.
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intercalation of phosphotungstic acid into layered double hydroxides by reconstruction method and its application in intumescent flame retardant poly lactic acid composites
Polymer Degradation and Stability, 2018Co-Authors: Sheng Zhang, Yongxin Yan, Wenjia Wang, Jun SunAbstract:Abstract Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative Charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were Characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0 wt% IFR and 2.0 wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m2 of neat PLA to 40.1 kW/m2. Thermogravimetric analysis showed that both the thermal stability and the Char Formation were enhanced. The Char morphology observation revealed that PWA-LDH was beneficial to form dense and compact Char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the Char Formation and enhancing the fire resistance.
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flammability and thermal degradation of poly lactic acid polycarbonate alloys containing a phosphazene derivative and trisilanollsobutyl poss
Polymer, 2015Co-Authors: Peng Jiang, Jun Sun, Sheng Zhang, Serge Bourbigot, Sophie Duquesne, Mathilde CasettaAbstract:Abstracts This work reports our recent efforts on improving the flame retardancy and thermal stability of biodegradable poly (lactic acid) (PLA) which is usually produced from corn and sugar beets. Hexa-(phosphaphenanthrene-methyl-(p-hydrobenzal)-amino-phenoxyl)-cyclotriphosphazene (HPHAPC) was synthesized by the classic Kabachnik-Fields reaction, and was then incorporated into PLA/polycarbonate (PC) alloys by melt blending. The flammability evaluation by limiting oxygen index (LOI), vertically burning (UL-94) and cone calorimeter tests has indicated that the LOI value can reach up to 31.5 and UL-94 grade can pass V-0 by the presence of only 3 wt% HPHAPC and 3 wt% polyhedral oligomeric silsesquioxane (POSS). The thermal behavior Characterization by thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) shows that the Char Formation of PLA/PC alloys can be significantly enhanced by the presence of HPHAPC/POSS. The evolved gas of the alloys was analyzed by Fourier transform infrared spectroscopy-TGA (FTIR-TGA) and pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Char morphology was observed by scanning electronic microscopy (SEM). It is demonstrated that HPHAPC can react with POSS during processing to form an intumescent Char structure. It is proposed that the degradation products of HPHAPC/POSS can capture free radicals in the gas phase and enhance Char Formation in the condensed phase.
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effect of different compatibilisers on nanoclay dispersion thermal stability and burning behavior of polypropylene nanoclay blends
Journal of Applied Polymer Science, 2008Co-Authors: Baljinder K Kandola, B J Hunt, Paul Joseph, John R. Ebdon, Richard A Horrocks, Sheng Zhang, G Smart, Richard T Hull, Andy CookAbstract:The combustion behaviour of polystyrene flame retarded by the incorporation of phosphorus-containing compounds has been studied by LOI and cone calorimetry. Both 'reactive' and 'additive' approaches to the incorporation of the phosphorus have been applied and assessed. The data obtained show that the reactive approach results in enhanced Char Formation during combustion due to a condensed phase mechanism. Flame retardation by the additive systems occurred exclusively in the vapour phase via both chemical and physical interactions. The main advantage of the reactive approach was the maintenance of the physical and chemical properties similar to those of the homopolymer. The phosphorus environment was also a significant factor in terms of the level of flame retardance achieved. Phosphonate species were more effective than were phosphate species.
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Char Formation in polyamides nylons 6 and 6 6 and wool keratin phosphorylated by polyol phosphoryl chlorides
Textile Research Journal, 2004Co-Authors: Richard A Horrocks, Sheng ZhangAbstract:Polyamides (nylon 6 and 6.6) phosphorylated by spirocyclic pentaerythritol phosphoryl chloride (SPDPC), cyclic 1,3-propanediol phosphoryl chloride (CPPC), and cyclic 2,2- diethyl-1,3-propanediol ph...