Maximum Thermal Decomposition Rate Research Articles

Fabrication of nickel phytate modified bio-based polyol rigid polyurethane foam with enhanced compression-resistant and improved flame-retardant

A bio-based flame retardant nickel phytate (PA-Ni) was synthesized and combined with soybean oil-based polyol (SO) to create a green rigid polyurethane foam (RPUF) with enhanced compressive strength, good thermal stability and flame retardant. The results showed that the RPUF-SO2/Ni3 with 3 wt% PA-Ni had the highest initial and termination temperature, maximum thermal decomposition rate temperature and carbon residue, and better thermal stability. Its limiting oxygen index was increased by 2.6% compared with RPUF-SO2 without PA-Ni added, and the peak heat release rate (PHRR) and total heat release rate (THR) were reduced by 14.92% and 19.92%, respectively. In addition, RPUF-SO2/Ni3 had the lowest Ds under the conditions of flame (18.90) and flameless (22.41), and had the best smoke suppression effect. And the compressive strength of RPUF-SO/Ni3 was significantly enhanced by the addition of PA-Ni. The results show that the improvement of flame retardancy of RPUF is mainly the result of the combined effect of gas-phase and condensed-phase flame retardancy, among which the flame retardancy of RPUF-SO/Ni3 was the best. The current findings offer a practical way to produce green and low-carbon RPUF as well as promising prospects for the material's safe application.

Optimization of ultrasonic conditions for improving the characteristics of corn starch-glycyrrhiza polysaccharide composite to prepare enhanced quality lycopene inclusion complex

In this study, based on response surface optimization of ultrasound pre-treatment conditions for encapsulating lycopene, the corn starch-glycyrrhiza polysaccharide composite (US-CS-GP) was used to prepare a novel lycopene inclusion complex (US-CS-GP-Lyc). Ultrasound treatment (575 W, 25 kHz) at 35 °C for 25 min significantly enhanced the rheological and starch properties of US-CS-GP, facilitating the preparation of US-CS-GP-Lyc with an encapsulation efficiency of 76.12 ± 1.76 %. In addition, the crystalline structure, thermal properties, and microstructure of the obtained lycopene inclusion complex were significantly improved and showed excellent antioxidant activity and storage stability. The US-CS-GP-Lyc exhibited a V-type crystal structure, enhanced lycopene loading capacity, and reduced crystalline regions due to increased amorphous regions, as well as superior thermal properties, including a lower maximum thermal decomposition rate and a higher maximum decomposition temperature. Furthermore, its smooth surface with dense pores provides enhanced space and protection for lycopene loading. Moreover, the US-CS-GP-Lyc displayed the highest DPPH scavenging rate (92.20 %) and enhanced stability under light and prolonged storage. These findings indicate that ultrasonic pretreatment can boost electrostatic forces and hydrogen bonding between corn starch and glycyrrhiza polysaccharide, enhance composite properties, and improve lycopene encapsulation, which may provide a scientific basis for the application of ultrasound technology in the refined processing of starch-polysaccharides composite products.

Effect on thermal, mechanical, and biodegradable properties of plasma‐treated fish scale powder/linear low‐density polyethylene polymer composite films

AbstractIn the present work, we report the effect of low‐temperature plasma treatment on thermal, mechanical, and biodegradable properties of polymer composite blown films prepared from carp fish scale powder (CFSP) and linear low‐density polyethylene (LLDPE). The CFSP was melt compounded with LLDPE using a filament extruder to prepare 1, 2, and 3 wt.% of CFSP in LLDPE polymer composite filaments. These filaments were further pelletized and extruded into blown films. The blown films extruded with 1, 2, and 3 wt.% of CFSP in LLDPE were tested for thermal and mechanical properties. It was observed that the tensile strength decreased with the increased loading content of CFSP, and 1% CFSP/LLDPE exhibited the highest tensile strength. To study the effect of low‐temperature plasma treatment, 1% CFSP/LLDP polymer composite with high tensile strength was plasma treated with O2 and SF6 gas before blow film extrusion. The 1% CFSP/LLDPE/SF6‐extruded blown films showed increased thermal decomposition, crystallinity, tensile strength, and modulus. This may be due to the effect of crosslinking by the plasma treatment. The maximum thermal decomposition rate, crystallinity %, tensile strength, and modulus obtained for 1% CFSP/LLDPE/SF6 film were 500.02°C, 35.79, 6.32 MPa, and 0.023 GPa, respectively. Furthermore, the biodegradability study on CFSP/LLDPE films buried in natural soil for 90 days was analyzed using x‐ray fluorescence. The study showed an increase in phosphorus and calcium mass percent in the soil. This is due to the decomposition of the hydroxyapatite present in the CFSP/LLDPE biocomposite.

Strong Thermo-tolerant Silicone-Modified Waterborne Polyurethane/Polyimide Pressure-Sensitive Adhesive.

A waterborne polyurethane pressure-sensitive adhesive (WPUPSA) has the advantages of low pollution and good viscoelasticity. However, its poor thermo-tolerance limits its application in the field of high temperatures. Hence, a novel silicone-modified strong thermo-tolerant waterborne polyurethane/polyimide pressure-sensitive adhesive is developed as a way to remedy this problem. The single-chain structure of waterborne polyurethane (WPU) is transformed into a network structure by introducing the three-position network structure to increase the cohesive energy and heat resistance of the WPUPSA. Meanwhile, the primary chain of waterborne polyurethane (WPU) is modified by the reaction between pyromellitic dianhydride (PMDA) and isophorone diisocyanate (IPDI) to include an imide ring and a benzene ring with more stable structures and heat resistance. Characterization results of the prepared WPUPSA show that the thermo-tolerance index of the WPUPSA increases by 15.2% and the room temperature 180° peel strength and shear resistance of the WPUPSA increase by 80.9 and 231.8%, respectively. Meanwhile, the temperature corresponding to the maximum thermal decomposition rate of the samples is improved. More importantly, at 80 and 100 °C, the 180° peel strength and shear resistance of the modified samples are stronger than those of the unmodified samples. In addition, the energy storage modulus of WPUPSAs is also greater than the loss and increases with the increase of the frequency. Viscoelasticity dominates in the samples. This will provide new insight for the development of WPUPSAs in the field of high-temperature resistance.

Preparation and Properties of Phenolic Epoxy Modified Silicone Resin

Phenolic epoxy resin (F51) was first reacted with silane coupling agent (3-aminopropyl)triethoxysilane (KH550) to form a silanized phenolic epoxy resin (SPER); then the SPER was copolymerized with methylphenyl silicone resin (MPS) to synthesize phenolic epoxy modified silicone copolymer (PEMSC). The chemical structure of the PEMSC was characterized by FT-IR. The results of tensile strength and shear strength measurements indicated that the successful introduction of F51 significantly improved the mechanical and adhesive properties of the PEMSC; compared with the PEMSC with 10 phr of F51 added, the tensile strength and shear strength of the PEMSC with 40 phr increased by 8.5 and 3.5 times respectively. The TGA and DTGA analysis showed that the initial thermal decomposition temperature and the residual weight of PEMSC at 800 °C decreased compared to MPS, but the temperature corresponding to the maximum thermal decomposition rate in the second stage increased. Qualitative analysis was conducted on the decomposition products of PEMSC using gas chromatography coupled with mass spectrometry (GC-MS). The results showed that the relative content of aromatic hydrocarbons and their derivatives in the decomposition products of PEMSC was 64.11%, and the relative content of cyclic trimers and higher cyclomers was 20.41%.

Biomass intumescent flame retardant polyacrylonitrile composite: flame retardancy, smoke suppression and recycling

A fully biomass intumescent flame retardant (IFR) system was fabricated by combining the reaction product ([email protected]) of phytic acid (PA) and hydrolyzed silk (HS) with potato starch (PS), which was then blended with polyacrylonitrile (PAN) to obtain flame retardant PAN (FR-PAN). The tensile strength and elongation at break for PAN-10%[email protected]/5%PS sample increased by 18.8% and 86.3%. The peak heat release rate (PHRR) and peak smoke production rate (PSPR) decreased by 54.8% and 79.3% respectively, exhibiting excellent flame retardant and smoke suppression performance. Furthermore, the PAN-10%[email protected]/5%PS sample was carbonized to prepare FR-PAN Char (FRPC), which was then used for cellulose and polyvinyl alcohol (PVA) modification. The maximum thermal decomposition rate and PHRR of modified cellulose and PVA were significantly reduced, showing the improved fire safety. This work not only prepared an eco-friendly fully biomass flame retardant PAN composite, but also realized the successful recycling of waste flame retardant PAN materials.

Functionalized magnesium hydroxide with zinc borate and 3‐aminopropyltriethoxysilane for enhanced flame retardant and smoke suppressant properties of epoxy resins

AbstractTo improve the fire safety of epoxy resins (EP), a composite with magnesium hydroxide loaded zinc borate (MH@ZBO) was obtained using a heterogeneous deposition method, and then 3‐aminopropyltriethoxysilane (APES) was grafted onto the surface of MH@ZBO to produce an organic–inorganic hybrid (MH@ZBO‐APES). Subsequently, the EP composite with added MH@ZBO‐APES was prepared and its thermal properties and fire safety were evaluated. The results showed that the glass transition temperatures of the EP/MH@30ZBO‐10APES composite are improved, and the maximum thermal decomposition rate decreased, and the samples exhibited favorable thermal stability and flame‐retarding performance (flame retardancy index: 2.40; LOI: 33%). The enhanced fire safety was a result of two factors. On one hand, the endothermic decomposition of MH and ZBO and the physical barrier of their decomposition products, the catalytic carbonization function of ZBO, the synergistic flame retardation of APES, and its improvement in dispersion to form a denser carbon layer, which plays a role in fire retardation and smoke suppression in the condensed phase. On the other hand, water vapor produced by the decomposition of MH and ZBO, as well as incombustible gas produced by the degradation of APES, are vital in the gas phase.

Curing Behavior of UV-Initiated Surface-Modified Nano-TiO2/Epoxy Resin Prepolymers and the Properties of Cured Composites.

Nano-titanium dioxides (nano-TiO2) surface modified with isopropyl tri(dioctylpyrophosphate) titanate (NDZ-201), a titanate coupling agent, and 3-glycidoxypropyltrimethoxysilane (KH-560), a silane coupling agent, were separately mixed with bisphenol A epoxy resin (DEGBA) prepolymer and then cured using a UV-normal temperature synergistic curing process. Then, the isothermal curing process of the system was investigated by differential scanning calorimetry (DSC). The relationship between the organization structures, mechanical properties, and heat resistance properties of the cured composites and material formulation was studied, and the DSC results showed that the addition of nano-TiO2 reduced the curing reaction rate constant k1 and increased the k2 of the prepolymer, while the activation energy of the curing reaction after UV irradiation Ea1 decreased, and the activation energy in the middle and later periods Ea2 increased. The characterization results of the composite material showed that nano-TiO2 as a scattering agent reduced the photoinitiation efficiency of UV light, and due to its obvious agglomeration tendency in the epoxy resin, the mechanical properties of the composite material were poor. The dispersibility of the coupling-agent-modified nano-TiO2 in the epoxy resin was greatly enhanced, and the mechanical and heat resistance properties of the composite material improved remarkably. The comparison results of the two coupling agents showed that NDZ-201 had better performance in increasing the impact strength by 6.8% (minimum value, the same below) and the maximum thermal decomposition rate temperature by 4.88 °C of the composite, while KH-560 improved the tensile strength by 7.3% and the glass transition temperature (Tg) by 3.34 °C of the composite.

Characterization of historical leather bookbindings by various thermal methods (TG/MS, Py-GC/MS, and micro-DSC) and FTIR-ATR spectroscopy

The goal of this study was to obtain information about the thermal stability, composition and molecular structure of four historical leather bookbindings dated between the 17th and 19th century and to identify correlations between their thermal, structural and chemical properties and deterioration mechanisms by using thermal analysis and decomposition methods (TG/MS, micro-DSC, Py-GC/MS), and infrared spectroscopy (FTIR-ATR). The TG/MS study revealed that the maximum thermal decomposition rate of the historical samples depended on the deterioration degree of leather. Micro-DSC was applied to determine the collagen population profile, i.e., “leather-like”, “parchment-like”, or “gelatin-like” behavior, which characterizes the deterioration pattern of the samples. The historical samples have higher amount of adsorbed water compared with the modern leather indicating their higher polarity. The significantly higher yield of carbon dioxide during the pyrolysis of historical leathers demonstrates that leather underwent various oxidation processes over time. The smaller yield of the pyrolysis products attributed to vegetable tannins detected in the chromatograms of historical leathers was related to the degradation of tannins (i.e., de-tanning), while the higher amount of 2-pyrrolidone and succinimide confirmed the oxidation of proline and hydroxyproline amino acid residues in the historical leathers. Leather de-tanning and collagen gelatinization were clearly evidenced by both micro-DSC and FTIR-ATR.

Preparation and research of epoxy modified by carboxyl-terminated polybutylene adipate at room temperature.

In this study, carboxyl-terminated polybutylene adipate (CTPBA) was used to modify epoxy resin, and the modified epoxy resin was cured by a room temperature rapid curing agent (T-31). The effects of CTPBA modification on bonding properties and mechanical properties of epoxy resin adhesive at room temperature were carefully studied. Epoxy-terminated prepolymer was synthesized by pre-polymerization and its structure was characterized. Compared with the addition method of direct blending, the bonding properties and mechanical properties of pre-polymerized epoxy resin adhesive were significantly better. Compared with unmodified epoxy resin, CTPBA modification significantly improved the bonding strength. Furthermore, with the increase of CTPBA content, the shear strength of the material increased first and then decreased, and reached the maximum when the addition amount was 40 phr. This shows that the tensile strength of the material decreased with the increase of CTPBA content, and the elongation at break increased with the increase of CTPBA content. Dynamic mechanical analyzer (DMA) test results showed that the addition of CTPBA reduced the glass transition temperature, but broadened the damping temperature range. TG analysis showed that the thermal stability of the modified epoxy resin was good, and compared with pure epoxy resin, the initial temperature of thermal weight loss and the maximum thermal decomposition rate decreased, but the overall thermal stability was not significantly different. In summary, CTPBA modification of epoxy resin is expected to improve the comprehensive mechanical properties at room temperature.

Simultaneously improving the thermal stability, mechanical properties and flame retardancy of epoxy resin by a phosphorus/nitrogen/sulfur-containing reactive flame retardant

In order to broaden the application field of epoxy resin (EP), it is significant to heighten the fire safety without deteriorating the comprehensive performance. A high-efficiency reactive phosphorus/nitrogen/sulfur flame retardant (SAD) derived from 2-Thenaldehyde, 9,10-dihydro-9-oxa-10-phosphaphenanthrene10-oxide (DOPO) and 3-amino-1H-1,2,4-triazole (ATA) was designed, acting as the co-curing agent for DGEBA/DDM system. Fourier transform infrared (FTIR) spectra and nuclear magnetic resonance (NMR) were used to confirmed the chemical structure of SAD. Besides, the glass transition temperature (Tg) was gradually increased from 150.4 ℃ for EP to 156.9 ℃ for EP-7.5 and the maximum thermal decomposition rate was decreased after the introduction of SAD. The samples exhibited excellent thermal stability. Meanwhile, SAD promoted cross-linking reaction during curing process. Compared with EP, EP-5 (phosphorus content was 0.39 wt%) reached V-0 rating in vertical burning (UL-94) test and acquired a remarkable enhancement from 25.7% to 34.7% in the limited oxygen index (LOI) value, an obvious blowing out effect occurred when the samples burned. Furthermore, from the data of cone calorimeter (CC) tests, there was a reduction of 19.1% and 16.6% for EP-7.5′s the total heat release (THR) and the peak heat release rate (PHRR) compared with EP. And the analysis of char residue and incomplete combustion products indicated that SAD displayed bi-phase flame-retardant effect. It is very meaningful that the mechanical properties of materials were slightly enhanced after the introduction of SAD. The results showed that SAD has a broad prospect in practical application.

Evidence of overpressure at the base of huge landslide

Overpressuring from generation of CO2 gas caused by thermal decomposition of basal carbonates can raise pore-fluid pressure and reduce friction during landsliding. We used thermogravimetry and dilatometry to determine the evidence of raised pore-fluid pressure from carbonate thermal decomposition at the base of the 2009 Jiweishan landslide. Results from thermal expansion experiments showed that the rock undergoes expansion and thermal fracture. At a heating rate of 20°C/min, the coefficient of linear thermal expansion increased sharply at 807.3 °C and reached a maximum of 36.6×10−6 °C −1 at 827.3 °C. DTG data show that the temperature of the maximum thermal decomposition rate of calcite is 852.5°C. The evidence showed that CO2 gas can produce great pressure during the rapid sliding process of Jiweishan landslide, and it is conducive to reduce the effective normal load. In addition, thermal fracture may be a explanation for the ultra-low friction during the rapid sliding by reducing the strength of the rock at the sliding surface and making it more easily entrained.

Improved thermal stability and heat-aging resistance of silicone rubber via incorporation of UiO-66-NH2

The metal-organic frameworks (MOFs) as emerging materials have attracted worldwide attention. In this study, a novel strategy by blending classic MOFs material UiO-66-NH2 to efficiently enhance the thermal stability and thermal aging resistance of silicone rubber (SR) was proposed. The experimental results indicated that very low dosage (0.25–1.5 part) of UiO-66-NH2 addition could effectively increase the thermal-oxidative stability of SR, which was proved by that the values of T5 (temperature at 5% weight loss) and Tm (the maximum thermal decomposition rate temperature) of SR were greatly increased by 43.4 °C and 97.9 °C, respectively. Moreover, the retention rate of elongation at break and tensile strength of SR with 1.5 part UiO-66-NH2 could remain about 72% and 57% after 288 h treatment in 210 °C. The possible heat resistance mechanism was explored by processing torque (PT) and thermogravimetry-mass spectrometry (TG-MS), whose results suggested that even very low addition of UiO-66-NH2 could efficiently inhibit degradation of SR chains and obstruct heat transfer due to its low thermal conductivity. This study provided a novel strategy to enhance thermal stability of rubber materials, and might open up new filed for polymer material processing.

Study on preparation and properties of PVC/NBR/PVC-g-PMMA composite film

In this paper, the graft copolymer PVC-g-PMMA composed of PVC main chain and PMMA side chain is synthesized by atom transfer radical polymerization. And it is added to the polyvinyl chloride/nitrile rubber (PVC/NBR) to prepare the PVC/NBR/PVC-g-PMMA composite film. The effects of PVC-g-PMMA on the mechanical properties, heat-resistant oxygen aging properties and thermal stability of PVC/NBR composite film are investigated. The mechanical performance test results show that after adding PVC-g-PMMA, the mechanical properties of the PVC/NBR composite film is improved. The tensile strength increases by 20.13%, and the elongation at break increases by 14.28%. The test results of heat-resistant oxygen aging performance indicate that after 96 hours of aging, the tensile strength of the PVC/NBR/PVC-g-PMMA composite film increases by 4.88% compared with the PVC/NBR composite film. The thermal stability test results illustrate that after adding PVC-g-PMMA, the residual weight of the PVC/NBR composite film increases by 0.7%, and the maximum thermal decomposition rate reduces by 0.12%/°C. It shows that PVC-g-PMMA not only improves the mechanical properties, thermal stability and aging resistance of PVC/NBR composites, but also enhances the market competitiveness of PVC/NBR composites. It expands the application of PVC/NBR composite materials in the field of decoration and protective coatings.

Experimental Study on Optimization of Phosphogypsum Suspension Decomposition Conditions under Double Catalysis.

Phosphogypsum (PG) is not only a solid waste discharged from the phosphate fertilizer industry, but also a valuable resource. After high-temperature heat treatment, it can be decomposed into SO2 and CaO; the former can be used to produce sulfuric acid, and the latter can be used as building materials. In this paper, the catalytic thermal decomposition conditions of phosphogypsum were optimized, and the effects of the reaction temperature, reaction atmosphere, reaction time and carbon powder content on the decomposition of phosphogypsum were studied. The research shows that the synergistic effect of carbon powder and CO reducing atmosphere can effectively reduce the decomposition temperature of phosphogypsum. According to the results of the orthogonal test under simulated suspended laboratory conditions, the factors affecting the decomposition rate of phosphogypsum are temperature, time, atmosphere and carbon powder content in turn, and the factors affecting the desulfurization rate are time, temperature, atmosphere and carbon powder content in turn. Under laboratory conditions, the highest decomposition rate and desulfurization rate of phosphogypsum are 97.73% and 97.2%, and the corresponding reaction conditions are as follows: calcination temperature is 1180 °C, calcination time is 15 min, carbon powder content is 4%, and CO concentration is 6%. The results of thermal analysis of phosphogypsum at different temperature rising rates show that the higher the temperature rising rate, the higher the initial temperature of decomposition reaction and the temperature of maximum thermal decomposition rate, but the increase in the temperature rising rate will not reduce the decomposition rate of phosphogypsum.

Кинетические параметры процесса термического разложения нанопорошка гидроксида кобальта при изотермических условиях

The paper focuses on the kinetic parameters of synthesizing Co3O4 nano-powder by thermal decomposition of hydroxide Co(OH)2 under isothermal conditions. The thermal decomposition of Co(OH)2 nano-powder under isothermal conditions was carried out in a tube furnace in the temperature range from 150 to 200 °C. Findings of research show that the thermal decomposition rate constant at 200 °C is approximately 2.7 times higher than that at 150 °C. Accordingly, for 80 min of thermal decomposition, the process accelerates 1.8 times. The activation energy of this process is approximately 33 kJ/mol, which indicates a mixed reaction mode. The study shows that Co3O4 nanoparticles obtained at the temperature of the maximum thermal decomposition rate, i.e. 180 °C, mainly consist of elongated ovoid and acicular aggregates with an average particle value of 47 nm and the length of up to 200 nm.

Realization of reversible thermochromic polydiacetylene through silica nanoparticle surface modification

AbstractThe novel functionalized poly(silanization alcoholamine diacetylene)/silica nanoparticles (poly(SiDGADA)/SiO2 nanoparticles) have been achieved for reversible thermochromism. The silanized alcoholamine diacetylenic monomer (SiDGADA) is condensed with the hydroxyl group of SiO2 nanoparticle via hydrolysis of the SiDGADA siloxy group, followed by fixation after being polymerized upon UV light stimulation. The maximum thermal decomposition rate of the SiDGADA/SiO2 nanoparticles is 0.65%/°C at 460°C, while the maximum thermal decomposition rate of the SiDGADA is 1.92%/°C at 400°C. Poly(SiDGADA)/SiO2 nanoparticles appears a blue phase after photo polymerization and exhibits a distinctive red phase at the discoloration temperature of 65°C, which is 5°C higher than that of the pure poly(SiDGADA). It shows excellent reversible thermochromic properties, undergoing stable reciprocal blue‐to‐red conversion from 25 to 65°C, and returning to bluish violet after cooling. The extension of the SiDGADA alkyl chain length with formation of the covalent bond, to promote the interaction between the alkyl chains of polydiacetylene (PDA). This work provides a strategy to effectively improve the reversibility of thermochromic PDA.

Kinetics Model Reconstruction for Multistep Overlapping Thermal Decomposition of Ammonium Perchlorate with and without the Copper Oxide Compound Catalyst

ABSTRACT The effects of copper oxide compound catalyst (Cu-O) on various stages of ammonium perchlorate (AP) thermal decomposition were investigated by TG. The results show that the thermal decomposition rate at the low-temperature section increases and the temperature at the maximum thermal decomposition rate (Tm ) appears at 571 K when the Cu-O catalyst was added. The Tm at the high-temperature section is reduced from 660 K to 606 K. The thermal decomposition activation energy (Ea ) of the whole process shows that the Ea of pure AP is significantly higher than that of AP+Cu-O when α > 0.25. According to the Gaussian peak-fit, the thermal decomposition of pure AP and AP+Cu-O can be divided into four stages. The Ea of each stage shows that the Cu-O catalyst has a significant catalytic effect on the first three stages of AP thermal decomposition, but has almost no catalytic effect on the fourth stage. According to the Coats-Redfern (CR) and masterplot method, the four stages of pure AP and AP+Cu-O are consistent with the n-order reaction F model and the Avrami-Eroféev (AE) model. Finally, the mechanism function reconstruction of four stages for pure AP and AP+Cu-O is completed by Arrhenius equation and kinetics compensation effect.

Flame Retardancy of Epoxy Resin/β-cyclodextrin@Resorcinol Bisdiphenylphosphate Inclusion Composites

In order to improve the efficiency of β-CD, the inclusion complex of β-CD and resorcinol bisdiphenylphosphate (RDP) (β-CD@RDP) was prepared, which β-CD was as the host component and RDP was as the guest. The structure and thermal stability property of β-CD@RDP was also characterized. EP/β-CD@ RDP composites were prepared by adding β-CD@RDP into EP matrix. The results of thermogravimetric test showed that the flame retardant systems could effectively increase the corresponding temperature of EP matrix to reach the maximum thermal decomposition rate, and exhibited good char-forming property. When the amount of β-CD@RDP in EP was 20wt%, the limiting oxygen index (LOI) value of EP was increased to 26.5% from 19.8%, and the vertical burning test (UL-94) reached V-1 level. The cone calorimeter test indicated that 20wt% loading in EP could reduce the peak of heat release rate (PHRR) and the total heat release (THR) of EP by 94.7% and 93.4% respectively, and the peak of smoke production rate (PSPR) and the total smoke production (TSP) was reduced by 16.7% and 22.2%, respectively. Therefore, the addition of β-CD@RDP could reduce the fire risk of EP effectively.

Preparation of piperazine cyanurate by hydrogen‐bonding self‐assembly reaction and its application in intumescent flame‐retardant polypropylene composites

Piperazine cyanurate (PCA) is designed and synthesized via hydrogen‐bonding self‐assembly reactions between piperazine and cyanuric acid. Chemical structure and morphology of PCA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The prepared PCA is combined with ammonium polyphosphate (APP) to prepare flame‐retardant polypropylene (PP) composites. Thermostability, flammability, and combustion characteristics of PP composites are analyzed. The maximum thermal decomposition rate of flame‐retarded PP composites has an apparent reduction compared with that of pure PP, and obvious char is left for this intumescent flame retardant (IFR) system of APP and PCA. A high limiting oxygen index value and UL‐94 V‐0 rating are achieved with addition of APP and PCA. In cone calorimetry test, heat and smoke releases of PP are significantly decreased by this IFR system. Gaseous decomposition products during the thermal decomposition of flame‐retardant composites are studied. Chemical structure and morphology of char residues are analyzed. The results illustrate that APP and PCA have a superb synergistic action in the aspect of improvement in fire safety of PP. A possible flame‐retardant mechanism is concluded to reveal the synergism between APP and PCA.