卡拉胶-纳米氢氧化铝协同阻燃天然橡胶

将BaCl2分级的k型卡拉胶(KC)和纳米氢氧化铝〔Al(OH)3〕构成的协同阻燃体系添加到天然橡胶(NR)中制备KC-Al(OH)3/NR复合材料。通过TG、极限氧指数(LOI)、锥形量热(CCT)以及SEM考察了不同质量比的KC和Al(OH)3对复合材料力学性能和阻燃性能的影响。结果表明,当KC与Al(OH)3以1∶1的质量比加入到NR时,KC-Al(OH)3/NR复合材料的热稳定性、阻燃性能最优,复合材料的LOI达到25%。与纯天然橡胶相比,复合材料总热释放量(THR)、热释放速率峰值(pHRR)、总烟释放量(TSP)和平均质量损失率(AMLR)分别降低了12%、65%、23%和62%。相比于单独添加Al(OH)3体系,复合材料拉伸强度和断裂伸长率分别增加了11%和17%。     

壳聚糖包覆三聚磷酸钠微胶囊-可膨胀石墨协同阻燃天然/杜仲橡胶

以三聚磷酸钠（STPP）为芯材，壳聚糖（CS）为壁材，通过离子凝胶法成功制备阻燃微胶囊CS@STPP。采用扫描电镜（SEM）、傅里叶红外光谱（FTIR）对所制备的微胶囊的表面形貌、化学结构进行表征。将CS@STPP与EG以一定比例添加到天然（NR）/杜仲（EUG）并用橡胶中，探究CS@STPP与可膨胀石墨（EG）之间的协同作用对NR/EUG并用橡胶阻燃性能影响。采用极限氧指数（LOI）、垂直燃烧测试（UL-94）、锥形量热（CCT）等测试手段对FRBR阻燃性能进行分析。结果表明FRBR的燃烧性能显著降低，LOI值达到28.4%，UL-94达到V-0等级，最大热释放速率下降30%。     

A novel bio-based charcoal-forming agent based on chitosan and phytate@Mg to improve the flame retardancy of poly(lactic acid)

A novel bio-based carbon forming agent (Mg@PA-CS) containing P and N elements was were synthesized using the complexation characteristics of chitosan (CS) and phytate (PA). The flame retardant behavior of poly(lactic acid) (PLA)/Mg@PA-CS/APP composites (addition of 20 wt% of different ratios of Mg@PA-CS and APP to polylactic acid composites) were investigated by the limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetry test (CCT), and thermogravimetric analysis (TGA). Due to the biphasic flame retardant and synergistic effect, since the 20 wt% flame retardant system (Mg@PA-CS:APP = 1:2), PLA composites passed the UL-94 test V-0 rating, reached 34% LOI value. The peak heat release rate (PHRR) and total heat release rate (THR) were reduced to 1/2 of the pure PLA, char residue could be as high as 11.49% at 800°C. Moreover, the flame-retardant mechanism of PLA composites during thermal decomposition was analyzed using a scanning electron microscope (SEM) and the coupling techniques of TGA linked with FT-IR (TG-FTIR).     

有机磷/硼杂化小分子阻燃改性环氧树脂

从二苯基次膦酰氯和苯基磷酰二氯出发,分别合成了含单个苯硼酸基团和含两个苯硼酸基团的两种有机磷/硼杂化小分子（缩写为：DPC-1B和PDS-2B）。两种杂化小分子与环氧树脂有着良好的相容性并可参与环氧固化,在比较低的添加量下便有较高的机械强度和优异的阻燃性能,且保持环氧的透明度。DPC-1B和PDS-2B添加量为2%（质量）时,复合材料氧指数从25.7%分别提高到了31.8%和31.5%,热释放速率峰值分别降低了26.5%与21.8%,UL-94阻燃等级均达到了V-0级。改性环氧树脂燃烧后的残炭分析表明,炭层外部连续紧密,内部多蓬松,硼磷共同作用形成致密炭层,隔绝热质传递,从而达到阻燃效果。     

Synergistic flame retardant effects of Fe-OMMT with LDH in EVA/LDH composites

Abstract

The synergistic effects of Fe organic modified montmorillonite (Fe-OMMT) with layered double hydroxides (LDHs) in ethylene vinyl acetate copolymer/LDH (EVA/LDH) composites have been studied using thermal analysis [thermogravimetric analysis (TGA)], limiting oxygen index (LOI), UL-94 test and cone calorimeter test (CCT). The results showed that the addition of a given amount of Fe-OMMT apparently increased the LOI value and the rating in the UL-94 test. The results from the LOI and UL-94 tests show that Fe-OMMT can act as flame retardant synergistic agents in EVA/LDH composites. The CCT data indicated that the addition of Fe-OMMT in the EVA/LDH system can greatly reduce the heat release rate. The TGA data show that Fe-OMMT, as an excellent flame retardant synergist of LDH, cannot increase the thermal degradation temperature and the charred residues.     

In-situ growth of layered double hydroxide on montmorillonite nanosheets to improve the flame retardant performance of ABS resin

Layered double hydroxide (LDH) is a widely used flame retardant in polymer materials; however, the poor dispersion due to its high hydrophilic nature results in disappointing thermal stability and fire safety. In this work, LDH was in-situ grown on the disordered montmorillonite (MMT) nanosheets to obtain the hybrid of LDH and MMT nanosheets (LDH@MMT, simplified as LM). Various techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscope were used to characterize the microstructure of LM. In addition, the acrylonitrile-butadiene-styrene (ABS) composite containing LM and intumescent flame retardant (IFR) was prepared, and its mechanical and flame-retardant properties were also measured. The characterization results demonstrate that the LM exhibits a periodically alternating layered structure. The Limiting Oxygen Index (LOI) of the ABS composite reaches 27.2% with a V-0 rating in the UL-94 vertical burning test, while its flexural strength and tensile strength decrease by only 17.82% and 13.45%, respectively. Furthermore, the heat release rate, total heat release, smoke production rate, and carbon monoxide production rate of the ABS composite present a significant decline in cone calorimeter tests compared with those of pure ABS. The results further indicate that the hybridization could effectively improve the flame-retardant performance of ABS composites and perform lesser impacts on their mechanical properties.     

一种新型次膦酸盐阻燃PA6的制备及其阻燃性能

采用新型阻燃荆苯基次膦酸铝和MC复配阻燃体系对玻纤增强PA6进行阻燃改性.通过热失重分析研究了引入阻燃剂对PA6热分解过程的影响;通过氧指数和垂直燃烧测试研究PA6复合体系的阻燃性能.结果表明:当阻燃剂添加量为18%时,玻纤含量为30%的改性PA6的氧指数和垂直燃烧测试分别达到32%和V-0级.     

O–VMT和二乙基次磷酸铝对PBT/GF的阻燃作用

研究了有机蛭石(O–VMT)和二乙基次磷酸铝(ADP)对玻纤(GF)增强聚对苯二甲酸丁二酯(PBT)(PBT/GF)的阻燃作用,对复合材料的极限氧指数(LOI)和UL94阻燃等级进行测试,并用热失重和锥形量热仪进行分析。结果发现,ADP可以很好阻燃PBT/GF,加入19%的ADP,复合材料的LOI为33.5%,阻燃达到UL941.6 mm V–0级,相对PBT/GF,其点燃时间、火灾性能指数(FPI)有所提高,热释放速率峰值(PHRR)、平均热释放速率(AHRR)、总热释放量(THR)及总生烟量(TSR)有所降低。同时加入15%的ADP和2%的O–VMT,复合材料的PHRR,AHRR,THR和TSR相对单独添加17%ADP的材料,分别降低12.8%,9.5%,4.5%和15.9%,FPI提高15.4%,LOI和UL94阻燃也对应提高,O–VMT和ADP在PBT/GF中有协同阻燃作用。     

Synthesis and characterization of bio-based intumescent flame retardant and its application in polyurethane

A novel bio-based P-N containing intumescent flame retardant melamine starch phytate (PSTM) was prepared via the reaction of phytic acid starch ester with melamine and characterized by Fourier transform infrared, scanning electron microscopy and thermogravimetric analysis (TGA). The effects of PSTM on thermal properties and flammability of rigid polyurethane (PU) foams were analyzed by TGA, limit oxygen index (LOI), vertical burning tests (UL-94) and cone calorimeter measurement. The TGA results demonstrated that the thermal stabilities of PU/PSTM foam at high temperature was enhanced with the increasing additive amount of PSTM. The results showed that PU foam with 30 php PSTM (PU/PSTM-30%) observed an LOI value of 25.9 and a UL-94 rating of V-0. Cone calorimetry data showed that peak heat release rate, total heat release and smoke production rate of PU/PSTM-30% were distinctly lower than that of pure PU. Further experimental results demonstrated that PSTM promotes well charring of PU which could protect the foam from combustion. This work developed a novel bio-based intumescent flame retardant by suing phytic acid and starch as the acid source and carbon source, respectively, which is of great significance to the preparation of environmental-friendly flame retardants.     

PBT/TPU/DOPO-MA阻燃复合材料的制备及性能

通过使用9,10-二氢-9-氧杂-10-磷朵菲-10-氧化物（DOPO）和马来酸酐反应合成制备DOPO衍生物阻燃剂DOPO-MA,并且其结构使用傅里叶红外光谱分析（FTIR）和核磁共振氢谱分析（¹H NMR）技术进行表征。将阻燃剂与聚对苯二甲酸丁二醇酯（PBT）和热塑性聚氨酯（TPU）熔融共混以制备PBT/TPU/DOPO-MA阻燃复合材料。通过运用锥形量热、UL-94、极限氧指数（LOI）、热重分析（TGA）、差热分析（DSC）和力学测试,研究了阻燃剂对复合材料的性能影响。测试结果表明,PBT/TPU/DOPO-MA复合材料具有良好的阻燃性能,加入10％DOPO-MA后,LOI从23.2增加到31.6,可达到UL-94 V-1等级,热释放率峰值（PHRR）和最大成热辐射速率（MAHRE）值降低;热重分析测试结果表明,添加DOPO-MA可以使得阻燃复合材料的热稳定性有显著的提高,当加入10％DOPO-MA后,残炭量可从6.87增加到14.36。此外,随着DOPO-MA含量的增加,阻燃复合材料的结晶度可得到一定的提高。     

EG与IFR复合阻燃ABS的动态燃烧性和协同效应

将可膨胀石墨(EG)与P-N型膨胀阻燃剂(IFR)复合阻燃丙烯腈-丁二烯-苯乙烯共聚物(ABS)树脂,阻燃剂添加量为20%(质量分数,下同),通过极限氧指数(LOI)仪、垂直燃烧测试(UL-94)仪、锥形量热(CONE)仪和扫描电镜(SEM)研究了EG与IFR复合阻燃ABS的协同效应。结果表明,EG/IFR质量比为1/1为最佳配比,阻燃ABS的LOI达到29%,UL-94为V-0级;EG与IFR复合阻燃ABS,表现出一定的协同作用;通过SEM观察ABS/EG/IFR试样燃烧后样品发现,EG与IFR起到协同阻燃作用。     

Effect of phosphorus–nitrogen compound on flame retardancy and mechanical properties of polylactic acid

A phosphorus-nitrogen flame retardant (PN) was synthesized by using cytosine and diphenylphosphinic chloride. The flame retardancy and thermal stability of polylactic acid (PLA)/PN composites were investigated by the UL-94 vertical burning test, limited oxygen index (LOI), cone calorimeter test, and thermogravimetric analysis. The PN performs efficiently on improving the flame retardancy of PLA. The PLA composite achieves the UL-94 V-0 rating and its LOI increases to 30.4 vol% by adding 0.5 wt% PN. The flame retardant mechanism analysis showed that PN catalyzes the degradation of PLA to improve the flame retardancy by melting-away mode. Meanwhile PN reduces the release of flammable gasses during thermal degradation of PLA by promoting the transesterification of PLA, which is helpful for extinguishing flame. Moreover, triglycidyl isocyanurate (TGIC) was used as a micro-crosslinking agent to reduce the loss of mechanical properties of PLA/PN composites caused by degradation. Adding 0.1 wt% TGIC and 1.0 wt% PN into PLA, the tensile strength and elongation at break of PLA/PN are increased to the same level as that of PLA. Therefore, PLA with excellent comprehensive performance can be obtained.     

磷氮阻燃剂/协效剂对PA9T的阻燃性、热稳定性的影响

探究二乙基次磷酸铝(ADP)、三聚氰胺聚磷酸盐(MPP)及不同协效剂(勃姆石、无水硼酸锌(ZnB)、锡酸锌、三氧化钼)对PA9T阻燃性能的影响,且定量分析阻燃体系的分散性,同时分析阻燃体系的阻燃机理。结果表明:当m(ADP)∶m(MPP)=2∶1,PA9T/ADP/MPP的LOI值为38.5%,UL-94达到V-0级,阻燃效果最佳。PA9T/13.3%ADP/6.7%MPP的实际残炭率高于理论残炭率,表明ADP/MPP的引入促使PA9T在凝聚相交联成炭。协效剂对PA9T阻燃性能的影响程度排序为:ZnB>三氧化钼>锡酸锌>勃姆石。PA9T/FR/ZnB复合材料的烟气释放最低,燃烧后碳氢化合物的释放量显著降低,CO₂释放量提高。复合材料燃烧后形成连续、致密的炭层,且炭层中存在磷酸类物质、碳氧化物及铝氧化物等,具有典型的凝聚相阻燃机理。     

Use of a combination of phosphorous-containing epoxy resin and silica fillers for development of flame retardant thermoset polymer composites

In this paper, we report a method of preparation of ambient temperature curable phosphorous containing epoxy resin-based composites and their flame retardant behavior. The phosphorous containing resin, prepared by reacting the epoxy resin with 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), shows higher limiting oxygen index (LOI) in the cured state compared to the pure epoxy network. The LOI value is further enhanced due to the incorporation of phosphorous-containing silica, although the same remains unchanged when pure silica is added. The composites made with phosphorous-containing resin and pure silica exhibits UL-94 V-1 class rating whereas the same made with phosphorous-containing silica offers V-0 rating under UL-94 classification. This observation clearly indicates that the performance is enhanced when phosphorous in incorporated in the resin as well as in the inorganic reinforcing filler.     

Effects of platinum compounds/superfine aluminum hydroxide/ultrafine calcium carbonate on the flame retardation and smoke suppression of silicone foams

Environmentally friendly, flame-retardant, and relatively low-density (0.25–0.31 g cm⁻³) silicone foams (SiFs) were successfully obtained through dehydrogenation at room temperature (RT = 25.0 °C). Moreover, a flame-retardant system for SiFs was obtained through a synergistic combination of platinum (Pt) compounds, superfine aluminum hydroxide (ATH), and ultrafine calcium carbonate (CC). The smoke suppression, flame retardance, mechanical properties, and thermal stability of SiFs with Pt compounds, ATH, and CC were tested using the limited oxygen index (LOI), UL-94 test, smoke density test, cone calorimeter, and thermogravimetry–Fourier transform infrared spectroscopy. With only 0.6 wt % Pt compounds, the pure SiF achieved the UL-94-V1 rating (3 mm thick), had an LOI value of 29.6%, and the maximum smoke density (MSD) was 6.5%. After adding ATH and CC, SiF composites could achieve the UL-94-V0 rating (3 mm thick), the LOI increase to 35.2%, and MSD decrease by 45%. Furthermore, the SiF with 0.6 wt % Pt compounds, 15.0 wt % ATH, and 15.0 wt % CC exhibited the optimal comprehensive properties for smoke suppression, flame retardance, mechanical performance, and thermal stability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47679.     

Combustion Behavior and Thermal Oxidative Degradation of EVA Containing Intumescent Flame Retardant

Microencapsulated ammonium polyphosphate (VAPP) with poly(vinyl alcohol)- melamine-formaldehyde (VMF) shell was introduced in ethylene vinyl acetate copolymer (EVA) to improve its flame retardancy. Due to the presence of VMF shell, VAPP shows better compatibility, flame retardancy and water resistance compared with ammonium polyphosphate (APP) in EVA. The flammability of EVA and its flame-retarded composites was studied by LOI, UL-94 and cone calorimeter. The composite containing 40 wt% VAPP can pass V-0 in UL-94 test, and hot water treatment shows few effects on its LOI value and UL-94 rating. The cone results indicated that the use of VAPP in EVA can significantly decrease heat release rate and total heat release compared with APP. To understand the mechanism of action of VAPP, dynamic FTIR experiments were carried out on EVA and EVA/VAPP composites. Based on above studies, the flame retardant mechanism of VAPP in EVA composite is discussed.     

Influence of expandable graphite on flame retardancy and thermal stability property of unsaturated polyester resins/organic magnesium hydroxide composites

An eco-friendly flame retardant unsaturated polyester resin (UPR) material was prepared by combination organic magnesium hydroxide (OMH) and expandable graphite (EG). Different from direct addition of magnesium hydroxide (MH) in UPR matrix-like traditional method, OMH as a reactive monomer participates in the polycondensation reaction of UPR was more effective in improving the compatibility of flame retardant with matrix. Interestingly, the flame retardant UPR composites exhibited a more satisfactory flame retardant effect when a certain amount of 8 wt % EG was added into UPR/OMH matrix because of the synergistic effect between OMH and EG, resulted in the limited oxygen index from 21.7 to 28.5% and UL-94 test passed V-0 rating. Moreover, the peak heat release rate, total heat release, and smoke production rate of flame retardant UPR composites significantly reduced. The excellent flame retardancy was due to the formation of a dense and continuous carbon layer in the later stages of combustion. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47881.     

Preparation of aluminum diethyl hypophosphite intercalation-modified montmorillonite AlPi-MMT and its effect on the flame retardancy and smoke suppression of thermoplastic polyester elastomer

An aluminum diethyl hypophosphite intercalation-modified montmorillonite flame retardant (AlPi-MMT) is successfully prepared and characterized by FT-IR, SEM, and X-ray diffraction. It is found that thermoplastic polyester elastomer (TPEE) composites incorporating 15 wt% AlPi-MMT flame retardant exhibited better char formation and flame retardant properties compared to those incorporating 15 wt% (4:1, w:w) AlPi and MMT. And the char residual of TPEE/AlPi-MMT at 700°C is 16.17%, which is higher than that of TPEE/AlPi-MMT at 13.94%. and the former can pass UL-94 V-0 rating test while the latter can only pass UL-94 V-1 rating test. Afterwards, the combustion performance of TPEE composites is characterized, and it is found that the heat release and smoke release of TPEE/AlPi-MMT are greatly reduced compared with those of pure TPEE and TPEE/AlPi/MMT, which is a flame retardant and smoke suppressant TPEE composite. Finally, by analyzing the residual char morphology and elements of TPEE composites after combustion, the mechanism of the flame retardant AlPi-MMT to promote char formation and flame retardancy is demonstrated.     

Synthesis of a novel microcapsule flame retardant and flame-retardant property of its composites with poly (ethylene terephthalate)

A novel halogen-free microcapsule flame retardant, carbon microspheres coated with magnesium hydroxide microcapsule and polyethylene terephthalate (PET) (MMH@CMSs) were synthesized. Then, the prepared MMH@CMSs were introduced into PET resin to prepare MH@CMSs/PET composites. The morphology and structure of MMH@CMSs were characterized by SEM, TEM and FTIR, which showed that an organic shell layer of PET as capsule wall was coated on the surface of MH@CMSs. The prepared MMH@CMSs/PET reached the LOI of 27.4 with only 1wt.% MMH@CMSs, and UL94 test results showed that MMH@CMSs/PET reached UL94 V-0 rating when the dosage of MMH@CMSs was over 1.5wt.%. Tensile properties results showed that the microcapsule treatment of MH@CMSs significantly improved the mechanical properties of the composite, and the tensile strength of 1wt.% MMH@CMSs/PET increased by 83.9% compared with 1wt.% MH@CMSs/PET. The flame retardant mechanism was studied by cone calorimeter measurement, TGA, TGA-FTIR, SEM and FTIR. The results disclosed that MMH@CMSs enhanced the thermal stability of PET in air, and promoted PET to form a dense and continuous protective char layer that effectively blocked heat transfer and combustible gas release.     

Synergistic effect of intumescent flame retardant and zinc borate on linear low-density polyethylene

A series of novel intumescent flame retardant (IFR) based on melamine, neopentyl glycol, and aluminum diethylphosphinate were prepared and tested. In addition, the synergistic effect of the novel IFR and zinc borate (ZB) on the flame retardancy of LLDPE composites was investigated. The structures of novel IFR and ZB were characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The limiting oxygen index (LOI) increased from 19.3% for the pure LLDPE to 27% for the 25 wt% IFR/5 wt% ZB composites and the composites achieved the desired V-0 rating in the UL-94 test. Thermogravimetric analysis showed that the addition of IFR/ZB reduced the pyrolysis rate of the LLDPE composites at high temperatures and increased the amount of the char residues, and the char residue of LLDPE-5 reached 12.1 wt% at 700°C. Cone calorimetry (CCT) data showed that the peak of total heat release, heat release rate, and fire growth index were comparatively reduced, indicating that the addition of IFR/ZB decreased the fire hazard of LLDPE composites. The formation of a compact and thermally stable char layer on the surfaces of LLDPE composites was revealed from the scanning electrone microscopy images and digital photographs of the char residue after the CCT tests.