Synergistic effect of MXene on the flame retardancy and thermal degradation of intumescent flame retardant biodegradable poly(lactic acid)composites

The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.

STUDY OF SYNERGISTIC FLAME RETARDANCY OF PHOSPHORUS AND BORON ON COTTON AND COTTON-PET BLENDS FBRICS

The fire retardancy effectiveness of mixtures formed from phosphorus-containing compound and boron-phosphorus-containing compound were examined utilizing limited oxygen index (LOI) and vertical test techniques. Phosphorus-boron systems in flame retardancy may show synergism and antagonism. The fire-retardancy effectiveness of boron-phosphorus-containing compounds are superior to the mixing systems of compounds which contain phosphorus or boron individully.

A NEW SYNERGIST FOR INTUMESCENT FLAME RETARDANT POLYPROPYLENE

The synergistic effects of silicotungstic acid (SiW12) as a catalyst in the phosphorus-nitrogen compounds AM-based intumescent flame-retardant (IFR) polypropylene (PP) were studied using the limiting oxygen index (LOI), the UL-94 test, thermogravimetric analysis (TGA), real time Fourier transform infrared (FTIR), laser Raman spectroscopy (LRS). The LOI data show that SiW12 added to PP/IFR systems has a synergistic FR effect with an IFR additive named AM. The TGA data show that SiW12 apparently increases the thermal stability of the PP/IFR systems at high temperature (T > 500degreesC). The FTIR results provide the positive evidence that IFR can improve the thermal stability of PP and SiW12 can induce a higher rate of formation of phosphoric acid and its derivatives. The LRS measurements provide useful information on the carbonaceous microstructures. In short, a suitable amount of SiW12 (1.5 wt%) exerts synergistic effects with the IFR by increasing the LOI value and the thermal stability at high temperature and promoting the formation of charred structures on the burning PP surface.

SYNERGISTIC EFFECTS OF LAYERED DOUBLE HYDROXIDE WITH PHOSPHORUS-NITROGEN INTUMESCENT FLAME RETARDANT IN PP/EPDM/IFR/LDH NANOCOMPOSITES

Synergistic effects of layered double hydroxide （LDH） with intumescent flame retardanct （IFR） of phosphorusnitrogen （NP） compound in the polypropylene/ethylene-propylene-diene/IFR/LDH （PP/EPDM/IFR/LDH） nanocomposites and related properties were studied by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, limiting oxygen index （LOI）, UL-94 test, cone calorimeter test （CCT） and thermo-gravimetric analysis （TGA）. The XRD and TEM results show that the intercalated and/or exfoliated nanocomposites can be obtained by direct melt-intercalation of PP/EPDM into modified LDH and that LDH can promote the IFR additive NP to disperse more homogeneously in the polymer matrix. The SEM results provide positive evidence that more compact charred layers can be obtained from the PP/EPDM/NP/LDH sample than those from the PP/EPDM/LDH and PP/EPDM/NP samples during burning. The LOI and UL-94 rating tests show that the synergetic effects of LDH with NP can effectively increase the flame retardant properties of the PP/EPDM/NP/LDH samples. The data from the CCT and TGA tests indicate that the PP/EPDM/NP/LDH samples apparently decrease the HRR and MLR values and thus enhance the flame retardant properties and have better thermal stability than the PP/EPDM/LDH and PP/EPDM/NP samples.

Synergistic Effects of Aluminum Hypophosphite on Intumescent Flame Retardant Polypropylene System

The effects of aluminum hypophosphite（AHP） as a synergistic agent on the flame retardancy and thermal degradation behavior of intumescent flame retardant polypropylene composites（PP/IFR） containing ammonium polyphosphate（APP） and triazine charring-foaming agent（CFA） were investigated by limiting oxygen index（LOI）, UL-94 measurement, thermogravimetric analysis（TGA）, cone calorimeter test（CONE）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. It was found that the combination of IFR with AHP exhibited an evident synergistic effect and enhanced the flame retardant efficiency for PP matrix. The specimens with the thickness of 0.8 mm can pass UL-94 V-0 rating and the LOI value reaches 33.5% based on the total loading of flame retardant of 24 wt%, and the optimum mass fraction of AHP/IFR is 1：6. The TGA data revealed that AHP could change the degradation behavior of IFR and PP/IFR system, enhance the thermal stability of the IFR and PP/IFR systems at high temperatures and promote the char residue formation. The CONE results revealed that IFR/AHP blends can efficiently reduce the combustion parameters of PP, such as heat release rate（HRR）, total heat release（THR）, smoke production rate（SPR） and so on. The morphological structures of char residue demonstrated that AHP is of benefit to the formation of a more compact and homogeneous char layer on the materials surface during burning. The analysis of XPS indicates that AHP may promote the formation of sufficient char on the materials surface and improve the flame retardant properties.

Novel phosphorus-silicon synergistic flame retardants:Synthesis and characterization

Three novel flame retardants containing both phosphorus and silicon elements in their structures,including[（1,1,3,3- tetramethyl-1,3-disiloxanediyl）di-2,1-ethanediyl]bis（diphenylphosphine oxide）（FR-1）,[（2,4,6,8-tetramethylcyclotetra-siloxane -2,4,6,8-tetrayl）tetra-2,1-ethanediyl]tetrakis[diphenylphosphine oxide]（FR-2） and 1,3,5,7,9,11,13,15-octakis（di-phenylphosphine oxide-2,1-ethanediyl）pentacyclo[9.5.1.1^（3,9）.l^（5,15）.1^（7,13）]octasiloxane（FR-3） were synthesized by a convenient pathway from the reaction of diphenylphosphine oxide（DPPO） and vinyl-terminated siloxanes under the catalysis of triethylborane. The chemical structures of the target compounds were confirmed by nuclear magnetic resonance（^1H NMR,^13C NMR,^29Si NMR and ^31P NMR）,matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF-MS） and Fourier transform infrared（FT IR） measurements.Thermogravimetric analysis（TGA） results indicated that the new flame retardants possessed good thermal stability both in nitrogen and in air.FR-3 containing polyhedral oligosilsesquioxanes（POSS） moiety exhibited the best thermal properties with a 10%weight loss temperature〉400℃ and a residual weight ratio〉39%at 700℃ .

Effect of MMT on Flame Retardancy of PLA/IFR/LDH Composites

Nano filler synergistic intumescent flame retardant(IFR)system is an effective way to improve the flame retardant properties of polymer.In this study,the effects of montmorillonite(MMT)on the flame retardant properties of polylactic acid/layered double hydroxides(PLA/LDH)and PLA/IFR/LDH were investigated.The results show that both LDH and LDH/IFR can reduce the peak heat release rate(HRR)of PLA and prolong the combustion time of PLA;When a proportionate MMT is introduced into PLA/LDH and PLA/IFR/LDH systems,respectively,MMT will not only affect the degradation process of PLA composites during combustion,but also the PLA composites can form a more stable carbon layer during combustion,which could decrease the peak HRR and prolong combustion time of PLA composite.Furthermore,when 0.5 wt%MMT is incorporated,the peak HRR of LDH/IFR/LDH composite is reduced by 16.17%and the combustion time is prolonged by about 70 s.This study can provide an opportunity to further optimize the properties of intumescent flame retardant polymer.

Study of thermal, flammability and mechanical properties of intumescent flame retardant PP/kenaf nanocomposites

Detrimental physical and mechanical properties are common pro-blems for composites when their flame retardancy is improved through filler additions.An increased interest of the synergistic nanoparticle addition to improve the flame retardancy of natural fiber composites is the aim of this work.The paper investigates the synergistic effect of two different nanoparticles(halloysite nano-tubes(HNTs)and montmorillonite(MMT)nanoclay)on the flame and mechanical properties in an intumescent ammonium poly-phosphate(APP)-based polypropylene(PP)/kenaf composite sys-tem.First,the nature of nanoparticle dispersion in PP through X-ray diffraction(XRD)and transmission electron microscopy(TEM)reveals that under twin screw compounding process,the partial exfoliation and intercalation have taken place within the nano-composites.An increase in the decomposition temperature was observed under thermogravimetric analysis(TGA),with the pre-sence of HNT.However,MMT tends to lower the maximum decomposition temperature under inert atmosphere.The flamm-ability analysis in an intumescent flame retardant(IFR)system shows that the suitable amount of high aspect ratio nanoparticles with their exfoliation characteristics effectively helps to reduce the sustained combustion.Even though,improved stiffness properties can be observed with the presence of increased filler content,particle agglomeration tends to reduce the mechanical strengths of these composites due to low compatibilization and crack propagation.

Performance of halogen-free flame retardant EVA/MH/LDH composites with nano-LDHs and MH

The flammability properties of three series of Ethylene-Vinyl Acetate/Magnesium Hydroxide/Layered Double Hydroxide(EVA/MH/LDH) composites as well as the flame retardance effect between LDH and the conventional flame retardant additive MH are investigated.In addition to acting as an insulating barrier,LDH assists the dispersion of MH particles in the EVA matrix,and promotes the formation of the char residues because of its abundant interlayer hydroxyl groups.Composites containing LDH show good flame retardancy in Cone and LOI testings.This means that the combustion properties of the composites have decreased,which may lessen the fire hazard when this materials are used.

Flame retardancy effect of surface-modified metal hydroxides on linear low density polyethylene

Metal hydroxides (MAH) consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1-2 were surface-modified by γ-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene (LLDPE) composite, filled with 50% (mass fraction) of MAH modified by 5.0% (mass fraction) of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.

白泥填料在膨胀阻燃环氧树脂中的协效阻燃和抑烟作用

为实现氨碱白泥的资源化利用,以氨碱白泥为原料,通过烘干、粉碎和表面改性制备白泥填料,并将其作为阻燃协效剂应用于膨胀阻燃环氧树脂,系统研究了白泥填料对膨胀阻燃环氧树脂的阻燃性能、抑烟性能和成炭能力的影响。结果表明,添加白泥填料能够显著降低膨胀阻燃环氧树脂的热释放和生烟量,表现出优异的协效阻燃和抑烟作用。当添加5%烷基化白泥填料时,阻燃和抑烟效率最高,峰值热释放速率和峰值生烟速率降低至234.6 kW/m^(2)和0.048 m^(2)/s,极限氧指数提高到30.5%。此外,白泥填料具有优异的协效成炭作用,添加5%烷基化白泥填料可以促进膨胀阻燃环氧树脂生成更多的芳香结构和含磷的交联结构,增强炭层的致密性和隔热隔质性,提高炭层质量,在700℃下残炭量达到24.5%。

原位生长的CNTs@MoS_(2)杂化物增强水性膨胀型防火涂料的耐火和隔热性能

目的设计并研制一种耐火和隔热性能突出的水性膨胀型防火涂料。方法以碳纳米管(CNTs)、四水合钼酸铵、十六烷基溴化铵(CTAB)、硫脲为原料,通过简单的一步水热法原位生长出一种新型的CNTs@MoS_(2)杂化物,并采用FT-IR、XRD、拉曼光谱、SEM等手段对复合杂化物进行表征。再将CNTs@MoS_(2)杂化物作为增效剂分散在水性膨胀型防火涂料(CNTs@MoS_(2)/WES)中,通过大板实验和涂层、炭焦层表面分析评价了涂层的耐火和隔热性能。结果与WES(膨胀倍率为3.90)、CNTs/WES涂层(膨胀倍率为6.04)、MoS_(2)/WES涂层(膨胀倍率为4.59)相比,CNTs@MoS_(2)/WES涂层具有最高的膨胀倍率(8.88)。CNTs@MoS_(2)/WES涂层所涂覆的钢板在燃烧40min后背面温度最低(133.3℃),这充分表明该涂层具有优异的隔热性能。结论制备的CNTs@MoS_(2)杂化物表现出稳定的网络交织结构,有效提高了它在涂料中的分散性能。此外,CNTs@MoS_(2)/WES涂层优异的耐火和隔热性能主要归因于:1)CNTs@MoS_(2)/WES涂层及其炭焦层具有更致密和完整的表面,阻隔了热量的传递;2)CNTs的添加增强了炭焦层的致密性,抑制了膨胀过程中产生的气体泄漏,提升了涂层膨胀倍率;3)MoS_(2)提高了膨胀层强度且促进了炭焦层的形成,减少了裂纹和孔隙的产生。

离子液体阻燃剂研究进展

离子液体是一种新型的绿色环保材料,在绿色溶剂、萃取介质以及催化等领域广泛应用,在阻燃方面的应用也逐渐崭露头角。本文介绍了离子液体的类型,制备方法,阐述了离子液体应用于阻燃方面的可行性,综述了离子液体在阻燃领域的研究进展,并对离子液体在阻燃领域的应用前景进行展望。

APP-MCA-CFA三元复配阻燃体系改性环氧树脂基玻璃纤维复合材料及性能研究

首次以聚磷酸铵(APP)为酸源和主阻燃剂,以高氮含量的三聚氰胺氰尿酸盐(MCA)为气源,以大分子型三嗪成炭剂(CFA)为炭源,组成APP-MCA-CFA三元复配阻燃剂体系。将其用于环氧树脂体系的阻燃改性,通过极限氧指数(LOI)、垂直燃烧等级、锥形量热、扫描电镜(SEM)、热失重分析(TG)和动态力学分析(DMA)等实验分析了它们之间的协同效应。结果表明:与单独使用APP阻燃剂相比,三元复配阻燃剂体系(20%APP-5%MCA-5%CFA,均为质量分数)表现出显著的协同阻燃效应,LOI值提升至62.0%,热释放速率峰值(PHRR)降低至401kW/m^(2),总热释放量(THR)下降至37.3MW/m^(2)。成炭分析结果表明,APP-MCA-CFA三元复配阻燃剂体系的引入使环氧树脂在高温下形成孔洞直径约5μm的形貌均一且规整的微米级膨胀炭层。DMA实验表明MCA和CFA可以通过粒子表面的胺基参与环氧固化反应,提高环氧固化交联密度,在一定程度抵消APP阻燃剂粉体加入导致的环氧机械性能下降。APP-MCA-CFA三元复配阻燃体系可用于环氧树脂基玻璃纤维复合材料的阻燃改性,垂直燃烧等级提升至UL-94 V0级,LOI值提升至66.3%。该研究为开发综合性能优异的阻燃环氧树脂基复合体系提供了一种简单易行的途径。

含硼/磷/氮阻燃元素的棉用阻燃剂的制备及其应用

随着全球环保意识的增强,开发环保型磷系阻燃剂取代有毒卤素阻燃剂成为阻燃剂行业的迫切需求,由于多元素协同阻燃剂具有更有效的阻燃性能,因此构建磷硼氮多元素交联型阻燃剂成为了一个具有创新性的研究方向。文中尝试了将硼酸和六氯磷腈等易得的原材料,在丙酮和水体系中合成了一种P-N-B协同阻燃的无卤棉用阻燃物,并对其性质进行了探究。结果表明,阻燃剂浓度为150 g/L,用氨水调节整理液pH值,烘焙温度为120℃,烘焙时间为6 min时,棉织物的残炭长度为5.4 cm,极限氧数值(LOI)提高至43.5%。

耐高温尼龙PA6T-66的阻燃改性研究

探究了二乙基次磷酸铝(OP1230)和二氧化硅(SiO2)复配使用对聚对苯二甲酰己二胺/己二酰己二胺(PA6T-66)树脂的阻燃协效作用。结果表明:OP1230的加入可显著提高材料的极限氧指数(LOI),当OP1230质量分数为6.0%时,材料的LOI从21.8%(未添加OP1230)提高至28.7%,且UL-94阻燃测试达到了V-2级。在此基础上,通过复配SiO2进一步提高材料阻燃性能。当SiO2质量分数为3.0%时,材料的LOI提高至29.4%,UL-94阻燃测试达到了V-0级。热氧降解和锥形量热数据也进一步证明OP1230和SiO2在PA6T-66阻燃体系中存在协效作用。

Influence of Beta-Cyclodextrin Functionalized Tin Phenylphosphonate on the Thermal Stability and Flame Retardancy of Epoxy Composites

To enhance the thermal stability and flame retardancy of epoxy resin(EP),beta-cyclodextrin(β-CD)is successfully introduced into the layered tin phenylphosphonate(SnPP),which is incorporated into EP matrix for preparing EP/β-CD@SnPP composites.The results indicate that the addition ofβ-CD@SnPP obviously improve the thermal stability and residual yield of EP composites at higher temperature.When the amount ofβ-CD@SnPP is only 4 wt%,EP/4β-CD@SnPP composites pass V-1 rating,and LOI value is up to 30.8%.Meanwhile,β-CD@SnPP effectively suppress the heat release and reduce the smoke production of EP/β-CD@SnPP composites in combustion,and the peak heat release rate(PHRR),total heat release(THR),smoke production rate(SPR)of EP/6β-CD@SnPP composites reduce by 28.4%,33.0%and 44.8%by comparison with those of pure EP.The good flame retardancy and smoke suppression are ascribed to the synergistic effect of excellent carbon-forming capability and fire retardancy ofβ-CD@SnPP.

改性氧化石墨烯对硬质聚氨酯泡沫的协效阻燃

硬质聚氨酯泡沫(RPUF)具有较好的隔热保温性能,但是,易燃烧,需要提高其阻燃性能。制备氧化石墨烯(GO)后,采用氧化锌(ZnO)对GO的分散性进行改性,复配阻燃剂,应用于RPUF的阻燃处理。利用锥形量热、氧指数、红外光谱、X射线衍射、透射电镜和热重,对其阻燃性能和阻燃机理进行研究。结果表明,ZnO成功负载于GO表面,同时改善了GO的分散性及热稳定性,FGO/RPUF阻燃复合材料的LOI为28.8,与纯RPUF(LOIRPUF=19.4)相比,提高了9.4,燃烧等级达到了V-0级;CO_(2)释放量、烟释放总量和热释放总量与GO/RPUF阻燃复合材料相比,分别降低了6.75%、7.64%和11.33%,残炭量提升了3.35%。加入GO后,“蠕虫状”的膨胀炭层更加致密、平整,阻燃性能得到提升。

环氧树脂中磷系阻燃剂协效体系的研究进展

近年来,出于环保等方面的考虑,一些卤系阻燃剂被逐渐淘汰,磷系阻燃剂作为卤系阻燃剂的替代品备受关注。然而,高效的磷系阻燃剂通常会在提高阻燃性能的同时产生更多的烟雾,因此需要与协效剂搭配使用。本文介绍了磷系阻燃剂在环氧树脂中的阻燃机理,综述了环氧树脂中磷系阻燃剂的协效体系的研究进展,包括无机协效剂、有机协效剂及有机-无机杂化协效剂等,并对环氧树脂体系中磷系阻燃剂的协效体系的未来发展趋势进行了展望。

角蛋白植酸涂层棉织物的协同阻燃效果

为了更好地推广生物质材料的阻燃应用,以角蛋白(WK)和植酸(PA)为阻燃剂,采用浸轧喷涂法对棉织物进行阻燃整理,研究两者对棉织物的协同阻燃效果。通过红外光谱仪、极限氧指数仪、热分析仪和微型燃烧量热仪等测试不同棉织物的燃烧性能。结果表明:随着整理次数的增加,WK/PA复配整理织物损毁长度减少,由30 cm下降至15 cm,最低4.5 cm;极限氧指数增大,由原来的18%增加到28.4%,最高到33.3%,且无续燃和阴燃发生,产生了较好的阻燃效果。认为:该方法可以有效解决棉织物的阴燃,为棉织物的阻燃改性提供了一种有效的解决方案。