Synergistic Flame Retardant Effect of Ammonium Polyphosphate and Aluminum Hydroxide on Polyurethane

The flame-retardant properties of polyurethane(PU)containing ammonium polyphosphate(APP)and aluminum hydroxide(ATH)were investigated.Moreover,the flame retardant performance was investigated through thermogravimetric analysis,limiting oxygen index(LOI),vertical combustion(UL 94),and cone calorimeter.When 15 wt%APP and 5 wt%ATH were added together,the PU/15%APP/5%ATH sample shows better thermal stability and flame-retardant properties.When 15 wt%APP and 5 wt%ATH were added together,the LOI value of the PU/15%APP/5%ATH sample was 30.5%,and UL 94 V-0 rating was attained.Compared with PU,the peak heat release rate(PHRR),total heat release(THR),and average effective heat combustion(av-EHC)of the PU/15%APP/5%ATH sample decreased by 43.1%,21.0%,and 29.4%,respectively.In addition,the flame-retardant mechanism was investigated through cone calorimeter.The APP/ATH addition simultaneously exerted condensed phase and gas phase flame retardant effects.APP and ATH have synergistic flame retardant properties.

A biobased flame retardant towards improvement of flame retardancy and mechanical property of ethylene vinyl acetate

A new biobased flame retardant(MHPA)with remarkable compatibility was synthesized via a facile and low-cost neutralization reaction of magnesium hydroxide(MH)and phytic acid(PA).By blending the prepared MHPA into ethylene vinyl acetate(EVA),the fire retardancy,smoke suppression and mechanical properties of the composites were significantly improved.When 50 wt%of MH was added into EVA matrix,the value of limiting oxygen index(LOI)reached 26.1%.Whereas,when 10 wt%MH in the EVA composites(with initial 50 wt%MH)was replaced by MHPA,the resulted EVA composites had a LOI value of 30.8%,indicating high efficiency of addition of MHPA to improve flame retardancy.Moreover,the heat release rate(HRR)and total smoke production(TSP)of the EVA composites reduced by 54.4%and 27.6%,respectively,suggesting that incorporation of MHPA could effectively hinder rapid degradation of EVA composites during burning process.The fire-retardant mechanism may reside in that the MHPA combined with MH can present the excellent carbonization and expansion effects.This study illustrates that the biobased MHPA has a broad application prospect to develop flame-retardant EVA composites.

A Novel Bio-Based Zirconium Phosphonate as a Flame Retardant and Smoke Suppressant for Epoxy Resin

Although epoxy resin has been widely used in various fields,it still suffers from some problems including brittleness and flammability.In this study,a new phosphonic acid,N,N-bis(phosphomethyl)glycine(GDMP),was prepared by Mannich reaction with bio-based glycine and then a novel layered zirconium phosphonate(ZrGDMP)was synthesized using GDMP and zirconyl chloride hydrate as reactants.The chemical structure of ZrGDMP was well characterized by 1 H and 31P NMR,SEM,XRD and XPS.The effect of ZrGDMP on the flame retardancy,smoke suppression,strengthening and toughening performances of the epoxy matrix was investigated and evaluated.TGA results indicated that compared with pure EP,ZrGDMP-EP composites showed higher char yield due to the catalytic charring effect of ZrGDMP.The pure EP exhibited high flammability,while ZrGDMP-EP composites possessed excellent thermal stability and remarkable fire resistance.The PHRR,THR,and TSP values of 3wt%ZrGDMP-EP were obviously declined by 39.6%,40.2%,and 24.9%compared to these of pure EP.Moreover,the tensile and impact tests implied that the addition of ZrGDMP can significantly reinforce the toughness as well as the strength of EP in terms of higher impact strength(24.8 kJ/m^(2))and tensile strength(57.7 MPa),which was mainly contributed to the uniform dispersion of ZrGDMP within the EP matrix.

Steam Exploded Peanut Shell Fiber as the Filler in the Rigid Polyurethane Foams

In this study,steam exploded peanut shell fibers(SE-PSFs)were utilized to fabricate with rigid polyurethane foam(RPUF)in order to improve sound absorption performance and hydrothermal weather resistance.Optimized method of SE treatment,RPUF preparation and flame retardant treatment were selected to prepare SE-PSF/RPUF composites in this experiment.Physical and mechanical properties including density,water absorption capacity,thickness swelling rate,compressive strength,thermal conductivity and average sound absorption coefficient of SE-PSF/RPUF were investigated and compared with the control(PRUF).The results showed that the density,water absorption capacity,thickness swelling rate and thermal conductivity showed an increasing trend with the increase of SE-PSFs content.The strength of the composite material showed a downward trend with the increase of the SE-PSFs content.The average sound absorption coefficient of the SE-PSFs/RPUF compared with PRUF significant increased,and the average sound absorption coefficient of the SE-PSFs/RPUF with SE-PSFs 40%was 0.47.The study getted the best ratio of flame retardants for 10%EG and 3%DMMP.The oxygen index was 35.56 vol%.

Thermal Degradation, Flame Retardance and Mechanical Properties of Thermoplastic Polyurethane Composites Based on Aluminum Hypophosphite

Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limiting oxygen index （LOI）, vertical burning test （UL-94）, thermogravimetric analysis （TGA）, cone calorimeter （CC） test, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM） and tensile test. TPU containing 30 wt% of AP could reach a V-0 rating in the UL-94 test, and its LOI value was 30.2. TGA tests revealed that AP enhanced the formation of residual chars at high temperatures, and slightly affected the thermal stability of TPU at high temperatures. The combustion tests indicated that AP affected the burning behavior of TPU. The peak of heat release rate （PHRR）, total heat release （THR） and mass loss rate （MLR） greatly reduced due to the incorporation of AP. The tensile test results showed that both the tensile strength and the elongation at break slightly decreased with the addition of AP. The digital photos and SEM micrographs vitrified that AP facilitated the formation of more compact intumescent char layer. Based on these results mentioned above, the flame-retarding mechanism of AP was discussed. Both the self-charring during the decomposing process of AP and its facilitation to the charring of TPU led to the great improvement in the flame retardancy of TPU.

Recent advances in constructing new type of epoxy resin flame retardant system using ammonium polyphosphate

In recent years,research has focused heavily on the investigation of functionalized ammonium polyphosphate(APP)flame retardants to improve the fire safety of epoxy resins(EP).The reason for this is the dual nature of APP's performance in fire protection of EP.This article provides a comprehensive overview of the advances in the use of functionalized APP flame retardants to improve the fire resistance of EP materials.It then presents the improvement of the modification of the functionalized APP flame retardants in terms of the hydrophobicity,compatibility and catalytic ability of the flame retardants,as well as the effects on the fire resistance,heat resistance,smoke reduction and mechanical properties of the EP composites.After the summary and comparison of the relevant studies,it is clear that the functionalized APP flame retardants can effectively improve the fire safety of EP composites and offset the adverse effects of APP in EP flame retardant applications.In addition,APP flame retardants can obtain various excellent functions through the use of materials with different properties,and the interaction between APP and materials can also lead to more efficient fire protection.However,the current problem is to find ways to streamline the process and minimise the costs associated with functionalized APP flame retardants,as well as to use them effectively in industrial production.We hope that this review can provide valuable hints and insights for the practical application of functionalized APP in EP and perspectives for future research.

Flame Retardant and Mechanical Properties of Wood Powders/PE Composites

The influence law of ammonium polyphosphate(APP) and coupling agents on the mechanical properties and flame retardant properties of wood powder/PE composites were studied by mechanical test and limited oxygen index(LOI) test. The experimental results show that the LOI of composites increased from 18.7%to 26.5%when the content of APP flame retardant was 30%,however the mechanical properties decreased.The maleic anhydride graft PP,titanate and silane coupling agent were used to improve mechanical properties of composites and it was implied that titanate and silane coupling agent can improve the mechanical properties of composites obviously.The limited oxygen index of wood powder/PE composites reached 27.5% when the content of titanate was 2%. Thermogravimetric analysis(TGA) shows that APP promoted charring and increased the amounts of char,thus protecting the inner matrix and increased the amount of residual char at higher temperature. The titanate coupling agent further increased the charring formed and strengthened the thermal stability,so obviously increased the flame retardant of composites.

Boosting fire safety and mechanical performance of thermoplastic polyurethane by the face-to-face two-dimensional phosphorene/MXene architecture

Black phosphorus(BP), as one of the most promising fillers for flame retarding polymer, has been seriously limited in practical application, due to the agglomeration and poor structural stability challenges.Here, the BP was modified by MXene and polydopamine(PDA) via ultrasonication and dopamine modification strategy to improve the structural stability and dispersibility in the matrix. Then, the obtained(BP-MXene@PDA) nanohybrid was employed to promote the mechanical performance, thermal stability,and flame retardancy of thermoplastic polyurethane elastomer(TPU). The resultant TPU composite containing 2 wt.% of BP1-MXene2@PDA showed a 19.2% improvement in the tensile strength and a 13.8%increase in the elongation at break compared to those of the pure TPU. The thermogravimetric analysis suggested that BP-MXene@PDA clearly enhances the thermal stability of TPU composites. Furthermore,the introduction of the BP-MXene@PDA nanohybrids could considerably improve the flame retardancy of TPU composite, i.e., 64.2% and 27.3% decrease in peak heat release rate and total heat release, respectively. The flame-retardant mechanisms of TPU/BP-MXene@PDA in the gas phase and condensed phase were investigated systematically. This work provides a novel strategy to simultaneously enhance the fire safety and mechanical properties of TPU, thus expanding its industrial applications.

Novel wood-plastic composite fabricated via modified steel slag:Preparation,mechanical and flammability properties

A novel method was developed to enhance the utilization rate of steel slag(SS).Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane(KH550),we obtained modified SS(MSS),which was used to prepare MSS/wood-plastic composites(MSS/WPCs)by replacing talcum powder(TP).The composites were fabricated through melting blending and hot pressing.Their mechanical and combustion properties,which comprise heat release,smoke release,and thermal stability,were systematically investigated.MSS can improve the mechanical strength of the composites through grafting reactions between wood powder and thermoplastics.Notably,MSS/WPC#50(16wt%MSS)with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive performance.Compared with those of WPC#0 without MSS,the tensile,flexural,and impact strengths of MSS/WPC#50 were increased by 18.5%,12.8%,and 18.0%,respectively.Moreover,the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%,the highest vertical burning rating at the V-1 level,and the lowest horizontal burning rate at 44.2 mm/min.The formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#50.However,the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties,possibly due to the weak grafting caused by SS powder agglomeration.These findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

PRELIMINARY STUDIES ON STRUCTURES AND PROPERTIES OF WATER-RETENTIVE, FLAME-RETARDANT ACRYLIC FIBERS

The blend fibers of acrylonitrile-vinylidene chloride-sodium methallysulfonate copolymer(AN-VDC-SMAS) and cellulose acetate (CA) with various blend ratios were investigated bymeans of SEM, DDV, WAXD, etc. The results show that AN-VDC-SMAS and CA areincompatibale; the numerous microvoids in the blend fiber resulted from the phase seperationcan remarkably improve the water absorbability and the dyeing behavior but hardly influencethe mechanical properties. On the other hand, the crystal structure of the continuous phaseAN-VDC-SMAS is not influnced by the dispersed phase CA.

Surface decoration of Halloysite nanotubes with POSS for fire-safe thermoplastic polyurethane nanocomposites

Halloysite nanotubes(HNTs)have been considered as a promising flame retardant fillers for polymers.In this work,the polyhedral oligomericsilsesquioxane(POSS)containing amino group was covalently grafted on the surface of HNTs with 3-(2,3-epoxypropoxy)propytrimethoxysilane as a chemical bridge.The POSS modified HNTs(HNTs-POSS)dispersed uniformly in the thermoplastic polyurethane(TPU)matrix and endowed TPU nanocomposites with enhanced tensile properties and fire safety.Cone calorimeter tests revealed that the introduction of 2 wt%HNTs-POSS to TPU matrix remarkably reduced the peak of heat release rate(PHRR)and total heat release(THR)by 60.0%and 18.3%,respectively.In addition,the peak CO production rate and total smoke release(TSR)could be significantly suppressed by the addition of HNTsPOSS.The well dispersed HNTs in combination with the ceramified silicon network from the thermal decomposition of POSS contributed to the formation of a continuous and compact char layer,exhibiting a tortuous effect by inhibiting heat diffusion and evaporation of volatile gaseous.In addition,the released crystal water from HNTs could dilute the combustible volatiles and then decline the combustion intensity.The tensile tests demonstrated that introduction of 2 wt%HNTs-POSS would enhance the maximum stress of TPU nanocomposite with a slight decrease of elongation at break.The combination of HNTs and POSS through the construction of effective interfacial interactions provides a feasible way to effectively enhance the fire safety of TPU nanocomposites without scarifying ductility.

高性能有机硅灌封胶的制备与性能研究

以端乙烯基硅油(1000 mPa·s)和侧乙烯基硅油(500 mPa·s)复配为基体树脂,含氢硅油为固化剂,乙烯基硅烷偶联剂为增黏剂,乙烯基MQ树脂和气相白炭黑为补强材料,氢氧化镁和硅系阻燃剂(FCA-107)为阻燃填料,成功制备了一款具有无卤阻燃特性及优异力学性能和电气绝缘性能的有机硅灌封胶,并研究了硅油复配比例、各填料添加量对有机硅灌封胶性能的影响。结果表明:当端乙烯基硅油与侧乙烯基硅油的复配比例为5∶5,乙烯基硅烷偶联剂质量分数为3%,气相白炭黑质量分数为4%,乙烯基MQ树脂质量分数为30%,复配阻燃剂质量分数为20%时,有机硅灌封胶的综合性能达到最佳,其混合黏度为1842 mPa·s,拉伸强度为2.83 MPa,断裂伸长率为51.3%,拉伸剪切强度为2.12MPa,阻燃性能(UL 94)达到V-0级,电气强度达到24.3 kV/mm,体积电阻率为3.8×10^(15)Ω·cm,制备的有机硅灌封胶可以满足电子元器件的发展要求。

APP/ZB协效阻燃发泡木塑复合材料性能研究

为了拓宽发泡木塑复合材料(FWPC)的功能性,以沙柳木粉、高密度聚乙烯(PE-HD)为主要原料,纳米炭黑(Nano-CB)为导电填料,聚磷酸铵(APP)和硼酸锌(ZB)作为阻燃剂和抑烟成分进行复配,采用发泡工艺和模压法制备阻燃抗静电型发泡木塑复合材料。研究APP/ZB协效阻燃剂质量比对FWPC力学性能、阻燃抑烟性能及热稳定性能的影响。结果表明:当APP/ZB总加入量为20%,质量比为4∶1时,FWPC的各项性能相对较优,静曲强度、弹性模量、拉伸强度和冲击强度分别为30.11MPa、2636MPa、14.65MPa和3.72kJ/m^(2),氧指数达27.3%,属难燃级别;与单独加APP时相比,力学性能降低,烟释放速总量降低11.93%,CO产率峰值和平均CO产率分别降低80.6%和49.3%,总失重率从63.53%降至61.42%,热稳定性能提高;FWPC燃烧后炭层表面凹凸不平,复合材料的阻燃和抑烟性能得到提升。

植酸/茶多酚整理棉织物的阻燃及防紫外线性能

为解决棉织物易燃烧和抗紫外线性能差的问题,提高其使用安全性,采用浸轧和喷涂结合的方法,通过植酸(PA)和茶多酚(Tea)协同作用制备了阻燃/抗紫外线棉织物,并研究了其阻燃、防紫外线、拉伸以及透气性性能。结果表明:质量分数2.5%的PA和25 g/L的Tea复合整理的棉织物,其质量增加率仅为13.3%,而极限氧指数LOI值从原棉织物的17.5%提高到30.4%,离火自熄;PA/Tea整理棉织物与原棉织物相比,不仅热释放速率峰值(PHRR)下降了78.2%,其总热释放量(THR)和热释放能力(HRC)也分别下降了70.8%和78.3%,这意味着PA/Tea整理棉织物可以降低火灾放热强度,阻碍火焰快速传播;整理后的棉织物对UVB和UVC区域的紫外线具有良好的吸收性能,在实现阻燃和防紫外线功能的同时,保留了85.1%以上的透气性。

降活型防火聚脲涂层改性聚氨酯可控膨胀材料研究

为提高聚氨酯可控膨胀材料的耐火性能与力学性能,通过分子设计,在聚脲合成中引入降活胺扩链剂和低活性异氰酸酯组分调控聚脲涂层(PUA)的反应速度及力学性能,并与新型淀粉基磷酸酯蜜胺盐阻燃剂(SPM)复配,在聚氨酯可控膨胀材料(PUF)表面制备了降活型防火聚脲涂层,通过极限氧指数、垂直燃烧法以及抗压抗折测试等手段研究了降活型防火聚脲涂层改性聚氨酯可控膨胀材料的耐火性能及力学性能。结果表明:改性可控膨胀材料PU/PUA10S可通过UL-94测试,达到V-0等级,锥形量热测试显示其具有良好的耐火效果。与纯聚氨酯可控膨胀材料相比,PU/PUA10S的力学性能得到了明显提升,其抗压强度从3.4 MPa提高到5.0 MPa,抗折强度从2.5 MPa提高到3.4 MPa,可作为抢修抢建、应急防护等领域的表面增强耐火防护材料。

阻燃水性聚氨酯的制备及对涤纶织物涂层研究

以阻燃聚酯多元醇为磷源对水性聚氨酯阻燃改性,并对改性的阻燃水性聚氨酯乳液、膜及其涂层涤纶织物进行性能表征。结果表明,改性引入的阻燃聚酯多元醇已完全参与了对水性聚氨酯的阻燃改性;当含磷量低于5%时,阻燃水性聚氨酯乳液呈半透明至乳白色,粒径低于100 nm,离心稳定性较好;随着含磷量的增加,阻燃水性聚氨酯膜的吸水率、力学性能及裂解温度有所降低,质量残存率有所上升;含磷量为3%时,其涂层涤纶织物已达到难燃级别;分析认为:利用阻燃水性聚氨酯涂层涤纶织物进行阻燃整理具有可行性。

Boron nitride silicone rubber composite foam with low dielectric and high thermal conductivity

Silicone rubber(SR)is widely used in the field of electronic packaging because of its low dielectric properties.In this work,the porosity of the SR was improved,and the dielectric constant of the SR foam was reduced by adding expanded microspheres(EM).Then,the thermal conductivity of the system was improved by combining the modified boron nitride(f-BN).The results showed that after the f-BN was added,the dielectric constant and dielectric loss were much lower than those of pure SR.Micron-sized modified boron nitride(f-mBN)improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride(f-nBN),but f-nBN improved the volume resistivity,tensile strength,and thermal stability of the SR better than f-mBN.When the mass ratio of f-mBN and fnBN is 2:1,the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^(-1)·K^(-1),which is 6.5 times that before the addition.The heat release rate and fire growth index are the lowest,and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN.

A strategy to synthesize phosphorus-containing nickel phyllosilicate whiskers to enhance the flame retardancy of epoxy composites with excellent mechanical and dry-friction properties

To enhance the fire safety and wear resistance of epoxy,phosphorus-containing nickel phyllosilicate whiskers(FP-NiPS)were synthesized using a facile hydrothermal technology,with 9,10-dihydro-9-oxa-10-phosphaphenanthrene as the organic modifier.The impacts of FP-NiPS on the thermal stability,flame retardancy,and mechanical and tribological properties of EP composites were explored.The findings demonstrated that 5 wt%FP-NiPS elevated the limiting oxygen index of the EP composite from 23.8%to 28.4%,achieving a V-0 rating during vertical burning tests.FP-NiPS could enhance the thermal stability of epoxy resin(EP)and facilitate the development of a dense and continuous carbon layer,thereby significantly improving the fire safety of the EP composites.The FP-NiPS led to an 8.2%increase in the tensile strength and a 38.8%increase in the elastic modulus of the EP composite,showing outstanding mechanical properties.Furthermore,FP-NiPS showed remarkable potential in enhancing the wear resistance of EP.The wear rate of 1 wt%FP-NiPS is 2.34×10^(−5) mm^(3)·N^(−1)·m^(−1),a decrease of 66.7%compared to EP.This work provides a novel promising modification method to enhance the fire safety,mechanical and wear resistance properties of EP.

可膨胀石墨/硅橡胶泡沫材料制备及其阻燃性能研究

硅橡胶材料兼具有机材料柔韧性和无机材料的热稳定性,已经在各个领域取得了显著的增长。通过低温法制备了具有优异阻燃性能、较好力学性能、低成本、泡孔结构丰富的可膨胀石墨(EG)/硅橡胶泡沫复合材料,其可有效提高硅橡胶泡沫的阻燃性能。结果表明:添加10%EG可以提高硅橡胶泡沫的拉伸强度、断裂伸长率和硬度等力学性能指标,同时硅橡胶泡沫的密度增加,回弹性有所降低。锥型量热仪(CCT)测试表明,EG的添加有助于延迟点火时间(TTI),降低热释放速率(HRR)和总热释放量(THR)等参数,且有助于提高抑烟性能。适量添加EG可以改善硅橡胶泡沫的热稳定性,过量会导致产生“飞灰”现象。这些特征结合在一起预示着EG/硅橡胶泡沫复合材料由于出色的阻燃性质可在阻燃材料领域得到广泛的应用。

阻燃纤维/不锈钢纤维混纺纱线的力学性能分析

为探讨混纺比对纱线性能的影响,测试分析了5种不同混纺比的阻燃腈纶(A)/阻燃黏胶(R)/不锈钢纤维(G)(A90/G10、A70/R20/G10、A45/R45/G10、A20/R70/G10、R90/G10)混纺纱线的力学性能。结果表明:混纺纱线的拉伸断裂性能、弹性、蠕变性能、耐磨性能、扭转性能和弯曲性能随阻燃腈纶纤维混纺比的增加而提升;A45/R45/G10混纺纱线的疲劳性能较差,A90/G10混纺纱线的疲劳性能较好;在较大压力下,A70/R20/G10和R90/G10混纺纱线的压缩性能较好,在较小压力下,A20/R70/G10混纺纱线的压缩性能较好。