thermogravimetry-Fourier Transform Infrared Spectrometry Research Articles

Influence of biomass on coal slime combustion characteristics based on TG-FTIR, principal component analysis, and artificial neural network

The development and utilization of solid waste is an effective way to solve the severe environmental and energy crisis. In this study, Thermogravimetry - Fourier transform infrared spectrometry (TG-FTIR) was used to carry out the co-combustion experiment of coal slime and rice husk under different mixing ratios. With the increase of the mass percentage of rice husk in the sample, the initial ignition temperature and burnout of the sample decreased, and the comprehensive combustion performance improved gradually. The dominant reaction in the co-combustion of coal slime and rice husk was determined by statistical method. When the mass percentage of rice husk in the mixture is between 30 and 90 %, it can inhibit the release of NOx and SO2. Taking Kissinger-Akahira-Sunose method as an example, the calculated average activation energies of coal slime and rice husk combustion are 105.66 and 148.93 kJ/mol respectively. With the increase of the mixing ratio of rice husk in the blend, the combustion mechanism of the sample changed. Finally, the mean absolute error, root mean square error and determination coefficient of the artificial neural network model are 0.52697, 0.67866 and 0.99941 respectively.

Synthesis of LDHs Based on Fly-Ash and Its Influence on the Flame Retardant Properties of EVA/LDHs Composites.

Fly-ash, a kind of large solid waste in energy industry, has brought about serious environmental problems and safety consequences. No efficient way has been found yet to deal with it worldwide. The focus of contemporary research are mainly placed on the reuse of aluminum and iron, but with a low utilization rate less than 30%. Having destroyed the ecological balance, fly-ash has become a challenge drawing the attention of people in the solid waste industry. In this paper, a smoke-suppressant and flame-retardant layered double hydroxide (LDH) featuring Mg-Al-Fe ternary was successfully synthesized by fly-ash after coprecipitation. XRD results presented LDHs successful synthesis. Then, exploration on the flame retarding properties of LDHs in composites composed by ethylene vinyl acetate (hereinafter referred to as EVA)/LDHs was carried out by UL-94, limiting oxygen index (LOI), cone calorimeter (CCT), smoke density (SDT), and thermogravimetry-Fourier transform infrared spectrometry (TG-IR) tests. UL testing results showed that most of the samples had a vertical combustion rating of V-0. LOI results showed the highest LOI value of ELDH-1, amounting to as high as 28.5 ± 0.1 while CCT results showed that the rate of heat releasing, mass loss, and smoke production of composite materials were decreased significantly compared with corresponding data of pure EVA. The ELDH-1 sample displayed the lowest peaks of heat release rate (pHRR) value of 178.4 ± 12.8 Kw·m−2 and the lowest total heat release (THR) value of 114.5 ± 0.35 KJ·m−2. Then, SDT indicated that under respective ignition and non-ignition conditions, all composite materials present a good smoke suppression performance. Additionally, digital photographs after CCT demonstrated that EVA/LDHs composites could enhance the formation of compact charred layers, and prevent their splitting, which effectively prevent the underlying materials from burning. Finally, TG-IR findings showed that compared with pure EVA, EVA/LDHs composites also achieved a higher-level thermal stability.

Preparation of heat resistant boron-containing phenyl silicone oil and its initial degradation mechanism in air

Boron-containing phenyl silicone oil (BCPSO) with terminal boronic hydroxyl groups was synthesized by acid-catalyzed balance condensation polymerization using phenylboric acid, dimethyldichlorosilane and diphenyldichlorosilane as raw materials. The structure of BCPSO was characterized by 1H, 13C and 29Si nuclear magnetic resonance (NMR) and Fourier transform infrared spectrometry (FTIR). The thermal degradation behavior of BCPSO was tested by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) analysis. The TG-FTIR results indicated that thermal decomposition of BCPSO had significant hysteresis over that of phenyl silicone oil. The empty electron orbital of boron atom could accept electron of peroxide free radical to generate conjugation effect at initial degradation stage of BCPSO, and this phenomenon was confirmed by 11B NMR, FTIR and Raman spectroscopies. As a result, temporarily stable intermediate was formed which increased the heat resistant of BCPSO.

Pyrolysis of Biomass: The Effect of Lipids During Protein Pyrolysis by Thermogravimetry Fourier Transform Infrared Spectrometry

With the excessive use of fossil fuels, the search for new energy sources has become urgent. Biomass pyrolysis has attracted attention; however, its development has been restricted by the formation of NOx precursors, which result mainly from protein pyrolysis. In addition, the effect of lipids on this process is not clear presently. We extracted proteins and lipids from chlorella and sewage sludge to investigate the thermal decomposition characteristics, thermodynamic properties, kinetic parameters, and reaction mechanisms of protein and protein with lipids. Two model-free methods (Flynn–Wall–Ozawa (FWO) and Friedman (FM)) were used to calculate the kinetic energy. Between 150 and 600 ℃, the average activation energy (E) of sludge protein was 73.63 kJ/mol (FM) or 72.53 kJ/mol (FWO), whereas with lipids, it was 129.19 kJ/mol (FM) or 124.55 kJ/mol (FWO), indicating that lipids restrict the pyrolysis of sludge protein. There was no significant difference between E of chlorella protein and chlorella protein with lipids. Moreover, the release of NOx precursors (NH3 and HCN) was measured by Fourier transform infrared spectrometry linked to thermogravimetry. The proteins in sludge and chlorella released less NH3 under the influence of lipids, however, the formation of HCN was affected slightly. Finally, amino acids and palmitic acids were selected as model compounds to reduce the influence of complex biomass components. The main purpose of analyzing the influence of lipids on protein pyrolysis is to provide a reliable reference for the regulation of protein pyrolysis, considering its production of NOx precursors.

Development of Biodegradable Flame-Retardant Bamboo Charcoal Composites, Part II: Thermal Degradation, Gas Phase, and Elemental Analyses.

Bamboo charcoal (BC) and aluminum hypophosphite (AHP) singly and in combination were investigated as flame-retardant fillers for polylactic acid (PLA). A set of BC/PLA/AHP composites were prepared by melt-blending and tested for thermal and flame-retardancy properties in Part I. Here, in Part II, the results for differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), X-ray diffraction (XRD), and X-ray photoelectron analysis (XPS) are presented. The fillers either singly or together promoted earlier initial thermal degradation of the surface of BC/PLA/AHP composites, with a carbon residue rate up to 40.3%, providing a protective layer of char. Additionally, BC promotes heterogeneous nucleation of PLA, while AHP improves the mechanical properties and machinability. Gaseous combustion products CO, aromatic compounds, and carbonyl groups were significantly suppressed in only the BC-PLA composite, but not pure PLA or the BC/PLA/AHP system. The flame-retardant effects of AHP and BC-AHP co-addition combine effective gas-phase and condensed-phase surface phenomena that provide a heat and oxygen barrier, protecting the inner matrix. While it generated much CO2 and smoke during combustion, it is not yet clear whether BC addition on its own contributes any significant gas phase protection for PLA.

Synthesis of LDHs using red mud and bittern and its influence on the flame retardant properties of EVA/LDHs composites

Red mud (RM) is one kind of basic solid waste produced from aluminum industry. RM is usually stored by the method of land stockpiling, which has caused serious environmental and safety issues. Bittern, a by-product of salt manufacture, is abundant in China. But the utilization rate is low, less than 20%. The disposal of waste bittern has become a challenge that attracts much attention in water industry. In this article, Mg/Al/Fe layered double hydroxides (Mg/Al/Fe-LDHs) were synthesized using the above two wastes by a coprecipitation method and characterized by X-ray diffraction (XRD) and scanning electron microscopy. The XRD results showed that LDHs were successfully synthesized. Then, the flame-retardant properties and thermal properties of Mg/Al/Fe-LDHs in ethylene vinyl acetate (EVA)/LDHs composites had been tested by cone calorimeter test (CCT), limiting oxygen index (LOI), smoke density test (SDT), and thermogravimetry–Fourier transform infrared spectrometry (TG-FTIR). The CCT results showed that the heat release rate (HRR) of the EVA/LDHs composites significantly decreased in comparison with that of pure EVA, and EVA2 sample showed the lowest peak value of HRR value of 204.59 kW m−2. The LOI results showed that EVA3 had a highest LOI value of 28.3% in all the samples. The SDT test indicated that Mg/Al/Fe-LDHs were beneficial to the smoke suppression performance of EVA composites. TG-IR results showed that EVA/LDHs composites had better thermal stability than EVA.

Slow pyrolysis characteristics of bamboo subfamily evaluated through kinetics and evolved gases analysis

The objective of this study is to investigate the pyrolysis and kinetic characteristics of three varieties of the bamboo subfamily via thermogravimetry/Fourier transform infrared spectrometry (TG-FTIR) coupling technologies. The pyrolysis process can be divided into three stages of dehydration, volatilization, and carbonization. TG-FTIR analysis revealed that evolved gas is constituted by CO2, CO, CH4, H2O, NO, NO2, formic acid, HCN, and CO functional groups as major pyrolysis products. The kinetic parameters of pyrolysis were calculated using model-free methods of distributed activation energy (DAEM). With an increase in conversion, the activation energy of each bamboo subfamily exhibited distinct variations. The average values of activation energy for moso bamboo, bambusa multiplex, and black bamboo determined by DAEM were 201.59, 220.49, and 224.47 kJ/mol, respectively. Results of thermodynamic and kinetic analysis indicate that the bamboo subfamily shows great potential as an alternative fuel by pyrolysis.

Improving the flame retardancy of ethylene vinyl acetate composites by incorporating layered double hydroxides based on Bayer red mud

AbstractNowadays, reducing the hazards of bayer red mud (BRM) is an important research direction in the fields of environmental and safety. In this article, Mg/Al/Fe ternary layered double hydroxides (Mg/Al/Fe-LDHs) were synthesized successfully by a co-precipitation method based on introducing Mg2+ into the BRM suspension. The thermogravimetric analysis (TGA) results showed that the decomposition rate of LDHs is higher than that of BRM, which indicates that LDHs can absorb more heat than BRM during the decomposition process. Subsequently, BRM and LDHs were added into the ethylene vinyl acetate (EVA) to investigate its effects on reducing flammability of the composites. The cone calorimeter test (CCT) results demonstrated that 50 wt% LDH-B can make the peak value of HRR (PHRR) decrease from 1694.8 kW/m2 (EVA) to 199.2 kW/m2 (ELDH2). The smoke density test (SDT) results showed that the luminous flux of ELDH2 is nearly 95% at the end of test with a pilot flame, which is much higher than that of EVA and EBRM. The thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) results confirmed that LDHs can improve the thermal stability of composites and reduce the production of some toxic gases. Compared with BRM, the improved flame retardancy of Mg/Al/Fe-LDHs is ascribed to the introduction of Mg2+, which offering an enhanced catalytic carbonization capability, as well as the physical barrier effect of char residue layer catalyzed by the lamellar LDHs

Preparation of LDHs Based on Bittern and Its Flame Retardant Properties in EVA/LDHs Composites

Bittern, as a byproduct of salt manufacture, is abundant in China. The researches and developments for seawater bittern have mainly focused on the reuse of magnesium, calcium, lithium, and boron. However, the utilization rate is less than 20%. The large amount of unused bittern has become a challenge that attracts much attention in academic and industry areas. In this paper, three kinds of layered double hydroxides (LDHs) were synthesized from bittern using a coprecipitation method and characterized by X-ray diffraction (XRD). The XRD results showed that the three kinds of LDHs(MgAl-LDHs, MgFe-LDHs and MgAlFe-LDHs) were successfully synthesized. Then, the flame retardant properties and thermal properties of the three LDHs in ethylene vinyl acetate (EVA)/LDHs composites had been tested by cone calorimeter test (CCT), limiting oxygen index (LOI), smoke density test (SDT), and thermogravimetry-Fourier transform infrared spectrometry (TG-IR). The CCT results showed that the heat release rate (HRR) of all three kinds of EVA/LDHs composites significantly decreased compared with that of pure EVA, and the EVA/MgAl-LDHs composites had the lowest PHRR value of 222.65 kW/m2. The LOI results showed that EVA/MgAl-LDHs composites had the highest LOI value of 29.8%. The SDT results indicated that MgAl-LDHs were beneficial to smoke suppression. TG-IR results showed that EVA/MgAl-LDHs composites had a better thermal stability.

Thermal Stability and Flame Retardancy of Polypropylene Composites Containing Siloxane-Silsesquioxane Resins.

A novel group of silsesquioxane derivatives, which are siloxane-silsesquioxane resins (S4SQ), was for the first time examined as possible flame retardants in polypropylene (PP) materials. Thermal stability of the PP/S4SQ composites compared to the S4SQ resins and neat PP was estimated using thermogravimetric (TG) analysis under nitrogen and in air atmosphere. The effects of the non-functionalized and n-alkyl-functionalized siloxane-silsesquioxane resins on thermostability and flame retardancy of PP materials were also evaluated by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and by cone calorimeter tests. The results revealed that the functionalized S4SQ resins may form a continuous ceramic layer on the material surface during its combustion, which improves both thermal stability and flame retardancy of the PP materials. This beneficial effect was observed especially when small amounts of the S4SQ fillers were applied. The performed analyses allowed us to propose a possible mechanism for the degradation of the siloxane-silsesquioxane resins, as well as to explain their possible role during the combustion of the PP/S4SQ composites.

Vacuum Residue Thermal Cracking: Product Yield Determination and Characterization Using Thermogravimetry–Fourier Transform Infrared Spectrometry and a Fluidized Bed Reactor

To make full use of heavy oil by thermochemical conversion, the thermal behaviors of vacuum residue (VR) were investigated first by thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR) and then via a laboratory-scale fluidized bed reactor (FBR). The TG–FTIR results showed that the changes in the absorbance of volatiles during thermal cracking were consistent with the weight loss in the derivative thermogravimetric curve. The dynamic information about the release profiles of the typical gaseous products such as CO, CO2, CH4, C2H4, light aromatics, and aliphatic olefins revealed the cleavage of varied structures and functional groups of VR at different temperatures. Moreover, the peaks for the maximum releasing rate on the evolving profiles of gaseous products became narrower and sharper, and the yield at maximum releasing rate for the gaseous species increased with increasing the heating rate. The pyrolysis experiments in a FBR with silica sand as a heat carrier showed that alkenes were the d...

Effect of alkyl-disubstituted ureido silanes with different alkyl chain structures on tracking resistance property of addition-cure liquid silicone rubber

Ureido silane is considered to be a novel tracking resistance additive for effectively improving the tracking resistance property of addition-cure liquid silicone rubber (ALSR). In this work, a series of alkyl-disubstituted ureido silanes (ADUSs) with different alkyl chain structures were synthesized by the transetherification of allyl alcohol (AA) and alkyl-disubstituted ureido siloxanes from the nucleophilic addition between alkyl-disubstituted amides and 3-isocyanatopropyltriethoxysilane (ICPES). The effect of ADUSs with different alkyl chain structures on the tracking resistance property of ALSR was investigated by inclined plane test (IPT), thermogravimetry analysis (TGA), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and energy dispersive spectroscopy (EDS). The results showed that ADUSs could effectively improve the tracking resistance property of ALSR, especially for (γ-diisopropylureidopropyl) allyloxyethoxysilane (DIPUPAS), (γ-dibutylureidopropyl) allyloxyethoxysilane (DBUPAS) and (γ-diisobutylureidopropyl) allyloxyethoxysilane (DIBUPAS). ALSR incorporated with DIPUPAS, DBUPAS and DIBUPAS passed the inclined plane test (IPT) at the alternating voltage of 4.5 kV and the average erosion mass was only 3.8%, 3.4% and 4.4% of the virgin ALSR, respectively. TGA and TG-FTIR results revealed that DIPUPAS, DBUPAS and DIBUPAS could also effectively improve the thermal stability of ALSR. Accompanying with the weakened oxidation reactions of methyl groups in molecular chains, the formed cyclic oligomers decreased. Meanwhile, the release of methane and cross-linking reaction of the silicone rubber chains were enhanced, leading to the increase of residue under high temperature and the formation of a ceramic barrier layer to protect the silicone rubber matrix. EDS results showed that the carbon content in ceramic barrier layer decreased, which was beneficial to prohibit the development of tracking.

Preparation of mesoporous silica-LDHs system and its coordinated flame-retardant effect on EVA

This paper mainly studies synergistic flame-retardant effects and smoke suppression properties of mesoporous silica-LDHs system on the ethylene-vinyl acetate copolymer (EVA). The mesoporous silica-LDHs/EVA composites were prepared based on EVA as resin matrix, mesoporous silica-LDHs as flame-retardant composites. The flame-retardant and thermal degradation properties of the composites were characterized by limiting oxygen index (LOI), cone calorimeter test, scanning smoke density test (SDT), electronic microscopy (SEM) and thermogravimetry–Fourier transform infrared spectrometry (TG-IR) analysis. Remarkably, addition of certain amount of mesoporous silica-LDHs could evidently increase LOI values. The heat release rate and the total heat release of the composites were much lower than of pure EVA. The SDT results showed that the composites containing mesoporous silica-LDHs produced less smoke than pure EVA for a period of time. The morphologies and structures of the residues, revealed by SEM, ascertained that the formed char layers on the composites were denser than that of the LDHs/EVA composites. Mesoporous silica in the material can help smoke suppression. TG-IR data reveal that the incorporation of mesoporous silica-LDHs promoted the release of H2O, and CO2, meanwhile reduced harmful gases release.

Investigation of the tracking and erosion resistance of cured liquid silicone rubber containing ureido-modified MQ silicone resin

Ureido-modified MQ silicone resin (DIPUPES-MQ) was prepared by the hydrolytic condensation of tetraethoxysilane (TEOS), (γ-diisopropylureidopropyl) triethoxysilane (DIPUPES), hexamethyldisiloxane and divinyltetramethyldisiloxane. Subsequently, DIPUPES-MQ was employed to improve the resistance to tracking and erosion of addition-cure liquid silicone rubber (ALSR), and it showed that DIPUPES-MQ could significantly enhance the tracking and erosion resistance as well as the mechanical properties of the ALSR. When the content of DIPUPES-MQ was 3.75 phr, all the test samples passed the inclined plane tracking and erosion (IP) test at 4.5 kV. The thermogravimetry (TG), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and FTIR results showed that the striking enhancement in the tracking and erosion resistance of the ALSR was probably ascribed to the decomposition of the ureido groups. In the pyrolysis process, the ureido groups of DIPUPES-MQ could generate isocyanic acid to hinder the “unzipping” depolymerization through reacting with Si-OH groups, so that the amount of cyclic dimethylsiloxanes inducing intense and continuous dry-band arcs was decreased.

Thermal degradation and combustion behavior of novel intumescent flame retardant polypropylene with N-alkoxy hindered amine

How to effectively improve the flame retardancy of polypropylene (PP) is one of the key problems needed to be resolved to promote its development and application. In this work, an efficient synergist—N-alkoxy hindered amine (NOR116) was combined with a novel intumescent flame retardant (IFR, i.e., ammonium polyphosphate/silicone-containing macromolecular charring agent) to flame-retard PP. The effects of NOR116 on the thermal degradation and combustion behavior of the PP/IFR composites were investigated. It was found that a small amount of NOR116 could effectively improve the flame retardancy and thermal stability of the composites. When the content of NOR116 was 0.3wt%, the limiting oxygen index (LOI) value of the composite was increased from 35.0% to 42.5%, and the vertical burning (UL-94) test reached a V-0 rating. Meanwhile, the heat release rate (HRR), total heat release (THR), average mass loss rate (av-MLR) and smoke production rate (SPR) of the composite were also significantly reduced. Thermogravimetric analysis (TGA), Thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDXS) and Laser Raman Spectroscopy (LRS) results revealed that NOR116 could change the thermal degradation of the PP/IFR composites, and promote the charring performance of IFR at lower temperature and enhance the quantity and quality of the intumescent char at high temperature. The possible synergistic mechanism between NOR116 and IFR in PP was also discussed.

Synergistic effect and mechanism of platinum catalyst and nitrogen-containing silane on the thermal stability of silicone rubber

Platinum (Pt) catalyst and nitrogen-containing silane (NS) were introduced to improve the thermal stability of silicone rubber. The effects of Pt and NS on thermal stability and degradation mechanism of silicone rubber were investigated by thermogravimetry (TG), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDXS) and Fourier transform infrared spectrometry (FTIR). A significant synergism was found between Pt and NS for improving the thermal stability of silicone rubber. When 6.67ppm of Pt and 1.4 phr of NS were introduced, the temperature of 10% and 20% weight loss under nitrogen atmosphere were respectively increased by 36°C and 119°C. Meanwhile, the residue weight at 900°C was doubled to 68% in the presence of Pt/NS. The synergistic mechanism might be that the nitrogen atom coordinated with Pt and improved the catalytic efficiency of Pt. Additionally, NS preserved the catalytic activity of Pt under air atmosphere. Hence, Pt/NS efficiently catalyzed thermal crosslinking and suppressed degradation of silicone chains. Moreover, it revealed that the presence of Pt/NS protected silicone chains from oxidation. Thus, the unzipping depolymerization by silanol groups was reduced significantly.

Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and 1H nuclear magnetic resonance spectrometry (1H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31°C and 60°C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800°C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization.

Preparation and characterization of novel carbon dioxide adsorbents based on polyethylenimine-modified Halloysite nanotubes

New nano-sized carbon dioxide (CO2) adsorbents based on Halloysite nanotubes impregnated with polyethylenimine (PEI) were designed and synthesized, which were excellent adsorbents for the capture of CO2 at room temperature and had relatively high CO2 adsorption capacity. The prepared adsorbents were characterized by various techniques such as Fourier transform infrared spectrometry, gel permeation chromatography, dynamic light scattering, thermogravimetry, thermogravimetry-Fourier transform-infrared spectrometry, scanning electron microscopy and transmission electron microscopy. The adsorption characteristics and capacity were studied at room temperature, the highest CO2 adsorption capacity of 156.6 mg/g-PEI was obtained and the optimal adsorption capacity can reach a maximum value of 54.8 mg/g-adsorbent. The experiment indicated that this kind of adsorbent has a high stability at 80°C and PEI-impregnated adsorbents showed good reversibility and stability during cyclic adsorption–regeneration tests.

Effect of urea-containing anti-tracking additive on the tracking and erosion resistance of addition-cure liquid silicone rubber

Three novel urea-containing anti-tracking additives were prepared and used to enhance the tracking and erosion resistance of addition-cure liquid silicone rubber (ALSR). The suppression effect and mechanism of the additives on tracking and erosion were investigated by the inclined plane (IP) test, thermogravimetry (TG) and thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR). It was found that the anti-tracking additives not only significantly improved the tracking and erosion resistance but also enhanced the mechanical properties of the ALSR. When using 2 phr of the anti-tracking additive, all the ALSR samples could pass the 4.5 kV level in the IP test. This might be mainly attributed to the arc-quenching capability of the urea group and the formation of a ceramic barrier to protect the underlying materials from further degradation during the dry band arcing. The TG and TG-FTIR results revealed that the urea-containing anti-tracking additives could prevent the radical decomposition of the ALSR below 400 °C. Hence, it considerably improved the initial thermal degradation stability of the ALSR and prolonged the time to track.

Effect of Polyborosiloxane on the Flame Retardancy and Thermal Degradation of Intumescent Flame Retardant Polypropylene

A novel synergistic flame retardant agent containing boron and silicon, namely polyborosiloxane (PBSil), was prepared via the condensation reaction of boric acid (BA), tetraethoxysilane (TEOS), and octamethyl cyclotetrasiloxane (OMCTS). The obtained PBSil was then combined with an intumescent flame retardant (IFR) to flame retard polypropylene (PP), and the effects of PBSil on the flame retardancy and thermal degradation of the PP/IFR composite were investigated. It was found that PBSil could improve the compatibility between the IFR and the PP matrix, thereby improving the mechanical properties of the composite. Compared with zinc borate, zeolite, and nano-silica, PBSil showed much better flame retardancy and smoke suppression in the PP/IFR composite. When the content of PBSil was 3.0 wt%, the limiting oxygen index (LOI) value of the flame retardant PP was increased from 29.0% to 35.0%, and the UL-94 rating was improved from V-1 to V-0 rating. Simultaneously, the heat release rate (HRR) and smoke production rate (SPR) of the composite were decreased dramatically. The thermogravimetric (TG) analysis, Fourier transform infrared (FTIR), and thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) results showed that, PBSil could enhance the thermostability of the IFR, and promote the char formation. Furthermore, the compactness and thermostability of the intumescent char were significantly improved, contributing to the improvement of the flame retardancy of the composite.