CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yue Zhu,Ronghua Yu,Shengda Wang,Haiping Xing,Jian Qiu,Jie Liu,Tao Tang
A rare charring behaviour was found during the combustion of polycarbonate (PC) composites containing polyborosiloxane (PBS), in which a highly intumescent char layer with core–shell structure was formed. Particularly the core–shell structure is composed of an outer porous structure and an inner lamellar structure, which can effectively isolate external heat radiation and limit the diffusion of degradation products and oxygen. PC/PBS-X composites with 2 wt% PBS-X showed excellent flame retardancy without compromising mechanical properties, including passing the UL-94 V-0 rating and increasing the limiting oxygen index (LOI) to 31.2%. Compared to PC , the peak heat release rate (pHRR) and peak smoke production rate (pSPR) in the case of PC/PBS-1 composites were reduced by 63.2% and 45.5%, respectively. The mechanism for promoting the flame retardancy of PC by PBS-X was studied. The results showed that the PBS decomposed to form linear polysiloxane oligomer with terminal Si-H bond (L-PDMS-H), which reacted with the degraded products of PC to quickly form intumescent char layer with core–shell structure during the combustion. This is the reason why to PBS presented the striking effect on improving flame retardancy of PC.
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Ni Kang,Xulong Ma,Yonghang Zhang,Ou Zhao,Yang Min,Wei Zhao,Daming Ban
The intrinsic flammability and high smoke production are two major defects that epoxy resin (EP) must overcome during the practical application. However, few current studies have acknowledged in both fire resistance and smoke suppression performance, which is vitally interrelated with quality of char layers. Herein, a P/S-containing compounds (PODSE) was prepared via esterification and then supplemented with ammonium polyphosphate (APP) to develop an intumescent flame retardant for heightening the strength of char. With 20 wt% PODSE/APP, the peak of smoke produce rate (pSPR) and total smoke production (TSP) of EP3 reduced by 88.1 % and 87.0 %, respectively, indicative of superior smoke suppression performance. It attained a limited oxygen index (LOI) value of 40.0 % with V-0 rating during vertical burning test (UL-94) and the char residues at 700 °C increased from 15.8 % to 29.9 % compared with pure EP. More importantly, in order to figure out the reason for such highly-improved performance, the residual chars after cone calorimeter (CC) test were comprehensively investigated. The result showed that the internal chars of the samples modified by PODSE/APP exhibited honeycomb-like structure instead of irregular network structure of the one modified with single PODSE, endowing the char layers with higher expanded ratio and strength, which responded to excellent insulation effect. This finding provided theoretical and experimental basis for further exploration of P/S synergistic intumescent flame retardant.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2019
·
IF 1.911
Shouwu Yu,Shujuan Xiao,Zewen Zhao,Xiaowen Huo,Junfu Wei
Dipentaerythritol (DPER), 4, 4′-diphenylmethanediisocyanate (MDI) and melamine (MEL) are used as raw materials to microencapsulate ammonium polyphosphate (MAPP) in situ polymerization. The MAPP is characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). The results show that the coating operation can effectively improve water resistance of ammonium polyphosphate (APP), and MAPP has higher residual rate than that of APP after combustion. The flame retardant action of MAPP and APP in polypropylene (PP) is investigated by the limited oxygen index (LOI), vertical burning test (UL-94), TGA, SEM, and cone calorimeter test (CCT). The LOI value of the PP/MAPP composite at the same loading is higher than that of PP/APP composite. UL 94 ratings of PP/MAPP composites are raised to V-0 at 20 wt% loading. The results of CCT also show that MAPP is more efficient than APP. The morphological structures observed by digital photos and SEM demonstrated that MAPP could be promoted to form the continuous and compact intumescent char layer. The flame retardant mechanism of PP/MAPP is also discussed.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2018
·Vol. 40
·期 6
·2244-2257
·
IF 1.943
Lingfeng Xu,Xinwen Tan,Ruijie Xu,Jiayi Xie,Caihong Lei
Molybdenum disulfide (MoS 2 ) with two-dimensional (2D) lamellar structure was functionalized with melamine-cyanuric acid (MCA) hybrids via a facile way. A core-shell composite particle (MoMA) was obtained. Acting as one kind of synergistic flame retardant, it was mixed with traditional intumescent flame retardant (IFR) to prepare the flame retardant poly(lactic acid) composites by melt blending. UL-94 V-0 rating and LOI value of 29.8% for PLA composites were achieved while the total amount of flame retardants was 12 wt%, with the optimal weight ratio of IFR to MoMA 3:1. The inclusion of MoMA can enhance the amount of char residue and suppress the pyrolysis rate. The thermal degradation kinetic studies indicated that more pyrolysis conversion energy was needed. Finally, the investigation of char residue further confirmed that the addition of MoMA can improve the continuity and thermal stability of intumescent char layer and promote its graphitization degree. The condensed phase mechanism was mainly responsible for the improved flame retardant performance. This work suggests a novel strategy for improving flame retardant performance of PLA by combination of MoMA with IFR. The mechanical properties were studied as well. POLYM. COMPOS., 40:2244–2257, 2019. © 2018 Society of Plastics Engineers
研究领域:
材料科学
·
高分子化学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2024
·Vol. 14
·期 2
·162
·
IF 2.9
Qiuchen Zhang,Qin Wang,Yan Li,Ziang Li,Shuang Liu
This study examined the effect of ultralow concentrations of three types of graphene oxide (GO) flakes on the fire resistance of water-based intumescent coatings, which are used widely as fire protectants for steel structures. The fire resistance of the coatings was assessed using a small-scale fireproof testing furnace, and their elemental compositions, oxidation states, and char-layer microstructures were analysed using Thermal Gravimetric analyzer (TG), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM)SEM, and X-Ray Photoelectron Spectroscopy (XPS)XPS, and the reaction mechanisms were revealed. The results show that three types of GO with different sizes and thicknesses all have the ability to enhance the fire-resistance performance of intumescent coatings at different extremely low dosages (0.001%–0.002%), with a maximum increase of 20% compared to that of the blank. Compared with small GO flakes, large GO flakes more effectively enhanced the fire resistance of coatings. The mechanism of enhancement of GO is attributed to two factors. On the one hand, although the presence of GO did not affect the type of final product of intumescent coatings, it affected the proportion of products. After adding GO, the production of titanium pyrophosphate increased, leading to an increase in the strength of the char layer. On the other hand, the microstructure of the char layer of the intumescent coating added with GO has been improved, leading to a significant improvement in the fire-resistance performance. When the dosage was greater than 0.002%, GO tended to agglomerate, which diminished its ability to enhance the fire resistance of coatings. Agglomerated GO can also leaded to a deterioration in the crystal structure of titanium pyrophosphate, thereby affecting the strength of the char layer.Keywords:graphene oxide;fire resistance;intumescent coating;ultralow concentrations;char layer
研究领域:
材料科学
·
消防工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yubin Huang,Saihua Jiang,Runcan Liang,Ping Sun,Yun Hai,Lei Zhang
The use of intumescent flame-retardant (IFR) coatings is one of the most highly effective methods for polymeric materials to improve their fire safety. However, organic IFR coatings show “negative effect” in a large amount of heat and smoke release during the char-forming process. Developing nanocomposite coatings that can reduce their “negative effect” and simultaneously enhance the barrier effect of fireproof char layer is particularly desirable. Herein, a novel UV-curable IFR/MXene nanocomposite coating was developed by incorporation of surface-modified MXene nanosheets in the IFR coating system, and then constructed on the surface of rigid polyurethane (RPU) foam to fabricate coated RPU foams via spray-coating and UV-cured process. The IFR/MXene coated RPU foams show a fast self-extinguished behavior and a remarked decrease in heat and smoke production, indicating the great improvement of RPU fire safety in building. The fireproof layers combined with expanded char and MXene jammed networks generated rapidly during combustion can serve as physical shield to effectively delay the release of heat and volatile products, protecting the underlying substrate from further burning. Moreover, the mechanical properties and dispersion are enhanced due to the co-cross-linking networks between the IFR coating and MXene nanosheets. As a new member of the 2D nanomaterials, MXene nanosheets have potential to be a new choice for developing high-performance nanocomposite coating for polymers to reduce their risk of fire hazard.
研究领域:
材料科学
·
消防安全
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Zhijing Wang,Yinfeng Liu,Juan Li
In this paper, four kinds of nitrogenous bases, adenine (A), guanine (G), cytosine (C), and uracil (U), were used as biobased gas sources to regulate the efficiency of an intumescent flame retardant (IFR) in polypropylene (PP). The flame retardant properties of PP composites were evaluated by using the limiting oxygen index (LOI), the vertical burning (UL-94) test, an infrared thermal imager, etc. The thermal degradation behaviors and char morphology were studied by using thermogravimetric analysis (TGA) and scanning electron microscopy. It is found that U and C play great roles in improving the flame retardancy of PP/IFR composites. The PP sample containing 17 wt % IFR and 1 wt % U (or C) achieves the UL-94 V0 rating without melt-dripping and has a LOI value of >27.9%, while the samples with equal amounts of A or G are not classified in the UL-94 test. TGA results showed that U (or C) can react with an IFR, but the interaction between A (or G) and an IFR is weak. U (or C) accelerates the formation of char and regulates its space structure at the right content. They induce the formation of a cellular and intumescent char layer that decreases the surface temperature quickly after ignition and protects the underlying resin from flame, thus improving the efficiency of PP/IFR composites.
研究领域:
材料科学
·
生物学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Li Zhang,Shouxiang Gao,Shiya Wang,Yan Xia,Bingtao Wang,Yingke Zhu,Jinquan Chen,Zhenghong Guo,Zhengping Fang,Juan Li
Flame retardancy and thermal conductivity are contradictory usually. In this paper, furan and vinyl groups were grafted on the surface of aluminum oxide (Al 2 O 3 ) and aluminum nitride (AlN), respectively; carbon nanotubes (CNTs) were assembled on the surface of aluminum diethylphosphonate (ADP) to construct ADP@CNTs; they were used to regulate the flame retardancy and thermal conductivity of epoxy (EP). With the incorporation of 50 wt% modified Al 2 O 3 /AlN and 6.5 wt% ADP@CNTs, the thermal conductivity of EP composites is improved to 0.706 W/m·K, which is 188 % more than that of EP, meanwhile the UL-94 V-0 rating is achieved. The furan ring of Al 2 O 3 and vinyl of AlN can perform the Diels-Alder reaction to form a thermally conductive network, thus the heat can be carried away and the ignition time can be prolonged at the early stage of combustion; while a multi-hierarchical char layer is formed based on these inorganic fillers and ADP after ignition, which breaks the thermal conductive pathway and prevents the heat from transferring resulting in good flame-retardant properties of EP composites. It provides a novel perspective and solution for satisfied flame retardancy of EP composites with high thermal conductivity.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 32
·50804
·
IF 3.125
Hao Zhang,Liwei Yan,Yuan Wang,Shengtai Zhou,Mei Liang,Huawei Zou,Yang Chen
The ablative properties of epoxy modified silicone rubber composites filled with zinc borate (ZB) and aluminum hypophosphite (AHP) were studied. The decomposition of the added fillers and covering connection of residual on the substrate contribute to the improvement of heat insulation. The ablation test shows that the formation of a dense char layer with certain strength is key to improving the ablative properties. The optimal ablative performance is achieved when the concentration of ZB and AHP is 10 and 5 phr, respectively. Under such circumstances, the linear ablation rate is as low as 0.032 mm/s, which is about 61% lower than the pure silicone rubber. Furthermore, the structure and composition of the formed char layer were analyzed using X-ray diffraction analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy.
研究领域:
材料科学
·
热防护工程
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 11
·7355-7372
·
IF 5.044
Guo Yingbin,Xiao Mengyuan,Ren Yuanlin,Liu Yansong,Wang Yang,Guo Xun,Liu Xiaohui
A novel effective halogen-free flame retardant (FR) rich in phosphorus (P) and nitrogen (N) was synthesized via Mannich and esterification reaction of ethanolamine, glyoxal, phosphoric acid and urea, and used for the preparation of durable flame retardant lyocell fabric (FR-lyocell). Its chemical structure was characterized by Fourier transform infrared spectra, 1 H and 31 P nuclear magnetic resonance spectra. Inductively coupled plasma emission spectrometry and elemental analysis were conducted to test the phosphorous, carbon and nitrogen contents. The results confirmed that the FR was successfully synthesized and grafted on the lyocell fabric via firm P–O–C covalent bonds. The limiting oxygen index of the FR-lyocell treated with 30 wt% flame retardant finishing solution is 44.6%, demonstrating high efficiency flame retardancy. The thermo-gravimetric analysis indicated that FR-lyocell degraded preferentially than that of the control sample and the char residue was 38.8 wt% at 800 °C in N 2 atmosphere. In addition, the cone calorimeter test revealed that FR-lyocell could not be ignited and the peak of heat release rate was much lower than that of original specimen. Furthermore, the char residue of FR-lyocell is compact and the I D / I G value is 0.771, exhibiting a super degree of carbonization. Moreover, TG-IR result revealed that FR played dual flame-retardant effect in the gaseous and condensed phases. The flame retardant finishing has a negligible impact on the mechanical properties of the fibers. In summary, FR-lyocell exhibits excellent flame retardancy and superior char forming capability, which is suitable for the preparation of flame retardant lyocell fibers. Graphic abstract
研究领域:
材料科学
·
纺织工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 3
·1-10
·
IF 2.8
Jiang Yuanping,Liu Lian,He Guohang,Shang Ning,Xie Yingying,Han Huan,Ma Mingyang,Li Xiang
A flame retardant precursor named DTDO, which contains phosphorus, nitrogen and silicon, was synthesized and grafted to graphene oxide (GO) to prepare functional graphene oxide (FGO), which was further applied to prepare a crosslinked organic/inorganic hybrid intumescent flame retardant (FGOS) through in situ sol gel process. 3 wt% loading of FGOS can reduce the combustion parameters of inflammable epoxy resin (EP) obviously, such as the heat release rate (28.1% reduction), smoke production rate (19.6% reduction), and average mass loss rate (61.2% reduction). The EP/FGOS-3 sample shows a LOI value of 29.1% and passes UL-94 and V-0 flammability rating, and the char residue increased from 0.3% to 8.5%. The results indicates a significant enhanced flame retardancy of EP, phosphorus, nitrogen, silicon, and GO in FGOS promoted the forming of a compact and porous char layer, thus to prevent further combustion and improve the flame retardancy of EP.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 5
·1304
·
IF 5
Feiyue Wang,Jiahao Liao,Miaotian Long,Long Yan,Mengtao Cai
A unique hybridized intumescent flame retardant named reduced-graphene-oxide-modified ammonium polyphosphate (RGO-APP) was successfully synthesized via the simple hydrothermal method and reduced process. Then, the obtained RGO-APP was applied in epoxy resin (EP) for flame retardancy reinforcement. The addition of RGO-APP results in a significant reduction in heat release and smoke production from the EP, which is attributed to EP/RGO-APP producing a more compact and intumescent char against the heat transfer and combustible decomposition, thus enhancing the fire safety of EP, as confirmed by char residue analysis. Especially, the EP containing 15 wt% RGO-APP acquires a limiting oxygen index (LOI) value of 35.8% and shows a 83.6% reduction in peak heat release rate and a 74.3% reduction in peak smoke production rate compared with those of pure EP. The tensile test exhibits that the presence of RGO-APP favors the enhancement in tensile strength and elastic modulus of EP due to the good compatibility between flame retardant and epoxy matrix, as supported by differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analyses. This work provides a new strategy for the modification of APP, thus facilitating a promising application in polymeric materials.Keywords:epoxy resin;ammonium polyphosphate;graphene oxide;flame retardancy;char formation
研究领域:
材料科学
·
高分子化学
·
消防安全工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）