Influence of char-forming lignin in combination with aluminium phosphinate on thermal stability and combustion properties of polyamide 11 blends

Polyamide 11 (PA) blends based on char-forming industrial lignin and aluminum phosphinate (AlP) were prepared to improve flame retardant (FR) properties using a green and eco-friendly approach. This study investigates the thermal degradation and combustion behavior of PA blends prepared by using AlP in combination with two different types of industrial lignins (i.e., kraft lignin (DL) and lignosulphonate lignin (LL). Thermogravimetric (TG) analysis showed that ternary blends containing LL and AlP developed higher char residue up to 10.7 wt% upon decomposition in inert atmospheres. The combination of lignin and AlP increases the thermal stability by shifting the initial decomposition temperature (T_5%) and temperature at maximum decomposition (T_max) to a higher temperature range, attributed to the stabilization of decomposition products. Furthermore, combustion behavior studied by cone calorimeter (forced combustion) and pyrolysis combustion flow calorimeter (PCFC) tests presented a significant reduction in the peak of heat release rate (PHRR) and total heat release (THR). It was found that LL and AlP-containing blends more effectively decreased fire parameters like PHRR and THR than that of DL and AlP-containing blends. The best interaction with reduced fire-retardant properties was obtained when 10 wt% loading of lignin (DL/LL) and AlP was used. The reduction in heat release parameters was mainly ascribed to the condensed phase mechanism by forming an efficient protective char layer, which acts as a barrier against heat and mass transfer between the condensed and the gas phases. Raman spectroscopy analysis also confirmed the formation of the protective graphitic layer in the condensed phase.     

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).     

亲脂化有机改性磷酸锆协效阻燃含磷共聚酯的机制探讨

将含磷共聚酯(P-co-PET)与亲脂化有机改性层状磷酸锆(OZrP)熔融共混制得复合树脂,通过热失重分析、锥形量热分析、拉曼光谱、扫描电镜研究了OZrP对P-co-PET热稳定性的影响及协效阻燃机制。研究表明:在P-co-PET中引入OZrP能够抑制热和质的传递,延缓降解,当OZrP质量分数为2%时,热释放速率峰值(PHRR)降低了9%,总的热释放量(THR)降低了14%;同时OZrP具有促进成炭,提高炭层稳定性和石墨化程度的作用,因而协效阻燃作用明显。     

Chemical modification of alkyd resin by a DOPO derivative and its flame retardancy

9,10‐Dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and its derivatives have been widely used as effective flame retardants. In this study, 6‐((bis(2‐hydroxyethyl) amino) methyl)‐6H‐dibe‐nzo[c,e][1,2]oxaphosphinine‐6‐oxide (DHDOPO) was synthesized from DOPO, paraformaldehyde, and diethanolamine, and subsequently used as a reactant for synthesis of flame retarded alkyd resin (FR‐ALK). Thermogravimetric analysis (TGA) showed that DHDOPO had relatively high thermal stability and would not decompose at synthesis temperature of ALK. The thermal stability and flame retardancy of ALKs were improved by introduction of DHDOPO. As the mass fraction of phosphorus in FR‐ALK increased the decomposition temperature, the char yield in TGA experiments, the fire residue, and time to ignition in cone calorimeter tests increased, and peak heat release rate (PHRR) and total heat release (THR) decreased. Compared with the non‐flame retarded ALK the PHRR and THR values of FR‐ALK containing 2.5 wt % phosphorus decreased, respectively, by 43.1% and 58.5%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45643.     

Synergistic flame retardant interplay of phosphorus containing flame retardants with aluminum trihydrate depending on the specific surface area in unsaturated polyester resin

The influence of the specific surface area of aluminum trihydrate (ATH) on the synergism to different phosphorus-based flame retardants (FRs) in unsaturated polyester (UP) resin was investigated. Flammability and thermal stability of UP composites were evaluated with UL-94 vertical burning, thermogravimetric analysis, and cone calorimetry. The morphology of char residues was examined via scanning electron microscopy (SEM). An interaction between crystalline ATH (4.5 m² g⁻¹) and aluminum hypophosphite (AHP) or zinc diethylphosphinate (DEPZn) was observed. When 37 wt % ATH and 8 wt % AHP or DEPZn were incorporated, samples passed V-0 in UL-94 tests. Furthermore, peak of heat release rate (PHRR) and total heat release (THR) were reduced by introduction of phosphorus containing FRs compared to a formulation containing solely crystalline ATH. The incorporation of amorphous ATH (300 m² g⁻¹) leaded to lower UL-94 ratings, using the same amount of AHP or DEPZn. In comparison to crystalline ATH, an addition of phosphorus containing FRs did not lead to a decrease of PHRR and THR for amorphous ATH. SEM of the residues showed that the combination of crystalline ATH with phosphorus species having hydrogen/carbon rich environment formed a dense and tough layer. The combination of crystalline ATH with phosphorus species providing oxygen rich environment gives fragile residues. An incorporation of amorphous ATH leaded to a fragile residue as well. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47270.     

Fire performance and post‐fire mechanical properties of polymer composites coated with hybrid carbon nanofiber paper

In this study, glass fiber reinforced polyester composites were coated with carbon nanofiber/clay/ammonium polyphosphate (CCA) paper and carbon nanofiber/exfoliated graphite nanoplatelets/ammonium polyphosphate (CXA) paper. The composites were exposed to a heat flux of 35 kW/m² during the cone calorimeter testing. The testing results showed a significant reduction in both heat release rates and mass loss rates. The peak heat release rate (PHRR) of CCA and CXA composite samples in the major decomposition period are 23 and 34% lower than the control sample, respectively. The time to reach the PHRR for the CCA and CXA composite samples are ～ 125% longer than the control sample. After the composite samples were exposed to heat for different time periods, their post‐fire mechanical properties were determined by three‐point bending testing. The three‐point bending testing results show that the composite samples coated with such hybrid papers exhibit more than 20% improvement in mechanical resistance at early stages of combustion. The mechanism of hybrid carbon nanofiber paper protecting the underlying laminated composites is discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of a nanoclay/triphenyl phosphate hybrid system on the fire retardancy of polycarbonate/acrylonitrile–butadiene–styrene blend

The effect of a hybrid system of nanoclay and triphenyl phosphate (TPP) on the fire retardancy of a polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) blend was examined in this study. The nanoclay in the polymers decreased the peak heat release rates (PHRRs) with no significant effect on the ease of ignition and times to extinguishment. Improvements in the flame retardancy were observed only when nanoparticles were used with conventional flame‐retardant (FR) additives. Thermogravimetric analysis (TGA), cone calorimetry, and limited oxygen index (LOI)/UL 94 (Underwriters Laboratory) testing were used to investigate the thermal degradation, fire behavior, and flammability of the materials. The results show that when we used a combination of TPP and nanoclay as an FR system, degradation of the polymer blends was reduced as the TGA curves shifted to higher temperatures. PHRR in cone calorimetry testing decreased from 1032 kW/m² for the PC/ABS blend to 300 kW/m² for the PC/ABS/(12% TPP–2% nanoclay) sample, and the LOI increased from 23 to 35%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(methyl methacrylate)/montmorillonite nanocomposites prepared with a novel reactive phosphorus–nitrogen‐containing monomer of N‐(2‐(5,5‐dimethyl‐1,3,2‐dioxaphosphinyl‐2‐ylamino)ethyl)‐ acrylamide and its thermal and flame retardant properties

A novel reactive phosphorus–nitrogen‐containing monomer, N‐(2‐(5,5‐dimethyl‐1,3,2‐dioxaphosphinyl‐2‐ylamino)ethyl)‐acrylamide (DPEAA), was synthesize and characterized. Flame retardant poly(methyl methacrylate)/organic‐modified montmorillonite (PMMA‐DPEAA/OMMT) nanocomposites were prepared by in situ polymerization by incorporating methyl methacrylate, DPEAA, and OMMT. The results from X‐ray diffraction and transmission electron microscopy (TEM) showed that exfoliated PMMA‐DPEAA/OMMT nanocomposites were formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis, cone calorimeter, and limiting oxygen index (LOI) tests. The synergistic effect of DPEAA and montmorillonite improved thermal stability and reduced significantly the flammability [including peak heat release rates (PHRR), total heat release, average mass loss rate, etc.]. The PHRR of PMMA‐DPEAA/OMMT was reduced by about 40% compared with pure PMMA. The LOI value of PMMA‐DPEAA/OMMT reached 27.3%. The morphology and composition of residues generated after cone calorimeter tests were investigated by scanning electronic microscopy (SEM), TEM, and energy dispersive X‐ray (EDX). The SEM and TEM images showed that a compact, dense, and uniform intumescent char was formed for PMMA‐DPEAA/OMMT nanocomposites after combustion. The results of EDX confirmed that the carbon content of the char for PMMA‐DPEAA/OMMT nanocomposites increased obviously by the synergistic effect of DPEAA and montmorillonite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Correlations between pyrolysis combustion flow calorimetry and conventional flammability tests with halogen‐free flame retardant polyolefin compounds

Seven halogen‐free flame retardant (FR) compounds were evaluated using pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry. Performance of wires coated with the compounds was evaluated using industry standard flame tests. The results suggest that time to peak heat release rate (PHRR) and total heat released (THR) in cone calorimetry (and THR and temperature at PHRR in PCFC) be given more attention in FR compound evaluation. Results were analyzed using flame spread theory. As predicted, the lateral flame spread velocity was independent of PHRR and heat release capacity. However, no angular dependence of flame spread velocity was observed. Thus, the thermal theory of ignition and flame spread, which assumes that ignition at the flame front occurs at a particular flame and ignition temperature, provides little insight into the performance of the compounds. However, results are consistent with a heat release rate greater than about 66kW/m² during flame propagation for sustained ignition of insulated wires containing mineral fillers, in agreement with a critical heat release rate criterion for burning. Mineral fillers can reduce heat release rate below the threshold value by lowering the flaming combustion efficiency and fuel content. A rapid screening procedure using PCFC is suggested by logistic regression of the binary (burn/no‐burn) results. Copyright © 2008 John Wiley & Sons, Ltd.     

Three in one: β‐cyclodextrin,nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

A new halogen‐free flame retardant was developed by integrating β‐cyclodextrin, triazin ring, and nanohydroxyapatite (BSDH) into a hybrid system. A β‐cyclodextrin was grafted to a commercially available SABO®STAB UV94 via an aromatic deanhydrate. The BSDH was prepared in situ in the presence of β‐cyclodextrin‐grafted nitrogen‐rich precursor. The resulting hybrid was applied as a flame retardant for poly(lactic acid) (PLA) and compared for performance with ammonium polyphosphate (APP). PLA composites containing BSDH and APP, individually or simultaneously, were examined for thermal degradation and flammability by TGA, cone calorimeter, and pyrolysis‐combustion flow calorimetry. TGA results confirmed enhancement of thermal stability of PLA with assistance of BSDH compared to APP. The gases evolved during thermal degradation were assessed by a thermogravimetric analysis and Fourier infrared spectroscopy device. APP revealed catalytic effect to initiate PLA degradation, while BSDH continued to release some gases at elevated temperatures. The flame retardancy of PLA/APP/BSDH blend containing only 10 wt.% of additives was significantly improved. In cone calorimetric tests, a significant fall in peak of heat release rate was observed for this sample, 49% more than that of neat PLA, which was indicative of more gas and condensed phase reflected in more char residue. The corresponding PLA/APP sample, however, showed 17% improvement, as compared to neat PLA. Also, total heat release rate of PLA/APP/BSDH was 45 MJ.m^?2, whereas those of PLA and PLA/APP were 89 and 65 MJ.m^?2, respectively. BSDH and APP showed a synergistic effect on improving the flame retardancy of PLA composites.     

ZnO/MoO3/Al(OH)3阻燃聚丙烯材料的制备及性能

采用水热法制备了一维材料ZnO和MoO_3纳米线(nanowires,NWs),并通过SEM和XRD对纳米线的形貌和结构进行了表征。将一维纳米线和纳米氢氧化铝(ATH)与聚丙烯(PP)熔融共混制备了ZnO/MoO_3/Al(OH)_3/PP复合材料(NWs/ATH/PP)。利用TGA、极限氧指数(LOI)测定仪和锥形量热仪(CCT)表征了复合材料的热稳定性和燃烧性能,利用万能材料试验机测试了复合材料的力学性能。结果表明:当添加质量分数3.75%ZnO纳米线、质量分数3.25%MoO_3纳米线和质量分数21.00%纳米ATH时,NWs/ATH/PP复合材料的初始分解温度较纯PP增加了17.8℃,残重率为24.6%,峰值热释放速率(PHRR)和总热释放量(THR)分别下降了54.3%和25.7%,LOI提高7.1%。SEM结果显示:NWs/ATH/PP的残炭表面致密、连续且平整。     

Mechanical,thermal properties,and flame retardancy of PC/ultrafine octaphenyl‐POSS composites

Composites of ultrafine polyhedral oligomeric octaphenyl silsesquioxane (OPS) and polycarbonate (PC) were prepared by melt blending. The mechanical and thermal properties of the composites were characterized by tensile and flexural tests, impact test, differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). Rheological properties of these melts were tested by torque rheometer. The flame retardancy of the composites was tested by limiting oxygen index (LOI), the vertical burning (UL‐94), and cone calorimeter test. The char residue was characterized by scanning electron microscope (SEM) and ATR‐FTIR spectrum. Furthermore, the dispersion of OPS particles in the PC matrix was evidenced by SEM. The results indicate that the glass transition temperatures (T_g) and torque of the composites decrease with increasing OPS loading. The onset decomposition temperatures of composites are lower than that of PC. The LOI value and UL‐94 rating of the PC/OPS composites increase with increasing loading of OPS. When OPS loading reaches 6 wt %, the LOI value is 33.8%, UL‐94 (1.6 mm) V‐0 rating is obtained, and peak heat release rate (PHRR) decreases from 570 to 292 kJ m^?2. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The flame retardant behaviors and synergistic effect of expandable graphite and dimethyl methylphosphonate in rigid polyurethane foams

A series of flame‐retardant rigid polyurethane foams (RPUFs) containing dimethyl methylphosphonate (DMMP) and expandable graphite (EG) were prepared by box‐foaming. The RPUFs were characterized by thermogravimetric analysis (TGA), the limiting oxygen index (LOI), cone calorimeter, and scanning electron microscope (SEM). The decomposition process of DMMP was investigated by Pyrolysis‐Gas Chromatography/Mass Spectroscopy (Py‐GC/MS). Accordingly, their flame retardant behaviors and mechanism were also discussed. The results show that the DMMP/EG system can linearly enhance the LOI value from 19.2% of the pure RPUF to 33.0% of RPUFs containing 16 wt% flame retardant. In addition, the DMMP/EG system also remarkably increases yields of the residual char and drastically decreases the peak value of heat release rate (PHRR), heat release rate (HRR), total heat release (THR), total smoke release (TSR), and the yields of CO (COY). In the flame retardant RPUFs, when the matrix is ignited, the flame retardant DMMP should be decomposed to gaseous PO₂ fragments, which can inhibit free radical chain reaction of flammable alkyl free radical from the decomposed matrix; whereas the flame retardant EG can rapidly expand and form loose and worm‐like expanding graphite char layer accordingly, which can hinder the heat transmission to the inner matrix and reduce decomposing velocity of matrix. After the combination of the two flame retardant effects, the DMMP/EG flame retardant system provides the matrix with better flame retardant effects than one of them does. Namely, it shows excellent gas‐condensed bi‐phase synergistic effect. POLYM. COMPOS., 35:301–309, 2014. © 2013 Society of Plastics Engineers     

Expandable graphite's versatility and synergy with carbon black and ammonium polyphosphate in improving antistatic and fire‐retardant properties of wood flour/polypropylene composites

This study investigated the antistatic and fire‐retardant properties of wood flour/polypropylene composites consisting of carbon black (CB), ammonium polyphosphate (APP), and expandable graphite (EG) through resistance meter measurement, cone calorimetry (CONE), thermogravimetric analysis (TGA), and scanning electron microscopy. Antistatic property testing confirmed a positive effect between CB and EG on discharging electrostatic charge. Electrostatic charge was thus considered able to be conducted between CB particles through EG, which acted as a bridge in the CB/EG ‐ treated composites. The results of CONE tests showed that EG significantly reduced the smoke release of the wood plastic composites (WPCs), including total smoke release (TSR), average specific extinction area (SEA), and production of carbon monoxide. During the WPCs burning process, a compound of EG and APP showed synergistic effects which decreased heat release and fixed the residual char. TGA results demonstrated that combining EG with APP, as opposed to using EG only, effectively increased the residual mass and decreases the initial thermal decomposition temperature of the WPCs. Addition of APP caused the wood flour char by catalyzing at a lower temperature, moreover, EG and APP displayed good synergistic effects on fire inhibition and smoke suppression. POLYM. COMPOS., 38:767–773, 2017. © 2015 Society of Plastics Engineers     

Investigation on flammability of rigid polyurethane foam‐mineral fillers composite

This study investigates the incorporation of castor oil–based rigid polyurethane foam with mineral fillers feldspar or kaolinite clay in order to enhance the mechanical, thermal, and flame retardant properties. Influence of mineral fillers on the mechanical strength was characterized by compressive strength and flexural strength measurement. Thermogravimetric analysis (TGA) was performed to diagnose the changes in thermal properties, while cone calorimeter test was performed to ascertain the flame retardancy of the mineral filler–incorporated rigid polyurethane foam composites. Results showed that the foams incorporated with mineral filler demonstrated up to 182% increase in compressive strength and 351% increase in flexural strength. Thermal stability of these composite foams was also found to be enhanced on the incorporation of kaolinite clay filler with an increase in 5% weight loss temperature (T_5%) from 192°C to 260°C. Furthermore, peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), and total smoke release (TSR) were also found to decreased on the incorporation of mineral filler in the rigid polyurethane foam. So mineral fillers are ascertained as a potential filler to enhance the mechanical, thermal, and flame retardant behaviors of bio‐based rigid polyurethane foam composites.     

Effect of a novel phosphorus‐containing compound on the flame retardancy and thermal degradation of intumescent flame retardant polypropylene

A novel flame retardant, tetra(5,5‐dimethyl‐1,3‐ dioxaphosphorinanyl‐2‐oxy) neopentane (DOPNP), was synthesized successfully, and its structure was characterized by FT‐IR, ¹H NMR, and ³¹P NMR. The thermogravimetric analysis (TGA) results demonstrate that DOPNP showed a good char‐forming ability. Its initial decomposition temperature was 236.4°C based on 1% mass loss, and its char residue was 41.2 wt % at 600°C, and 22.9 wt % at 800°C, respectively. The flame retardancy and thermal degradation behavior of novel intumescent flame‐retardant polypropylene (IFR‐PP) composites containing DOPNP were investigated using limiting oxygen index (LOI), UL‐94 test, TGA, cone calorimeter (CONE) test, and scanning electron microscopy (SEM). The results demonstrate that DOPNP effectively raised LOI value of IFR‐PP. When the loading of IFR was 30 wt %, LOI of IFR‐PP reached 31.3%, and it passed UL‐94 V‐0. TGA results show that DOPNP made the thermal decomposition of IFR‐PP take place in advance; reduced the thermal decomposition rate and raised the residual char amount. CONE results show that DOPNP could effectively decrease the heat release rate peak of IFR‐PP. A continuous and compact char layer observed from the SEM further proved the flame retardance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Flame-retardant properties and synergistic effect of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber composites

The flammability behaviors of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber (APP/Al[OH]₃/mica/SiR) ceramifying composites containing APP, Al[OH]₃, and mica are investigated by cone calorimeter test. The thermal degradation and the synergistic effect of APP/Al(OH)₃/mica/SiR composites are investigated by thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. APP/Al(OH)₃/mica/SiR composites with 25 wt% of APP, 20 wt% of Al(OH)₃, 25 wt% of mica, and 30 wt% SiR presents a much lower total heat release, the value of peak heat release rate (PHRR), the maximum average heat release rate, the longest time to ignition, and time to the PHRR (t_PHRR), compared with the flame-retardant properties from composites with filler of APP and mica or APP and Al(OH)₃ alone. The results indicate that there is an excellent synergism in APP, Al(OH)₃, and mica, which endows APP/Al(OH)₃/mica/SiR composites with both good flame retardancy and fire prevention. The study on the synergism effect between fire prevention and flame retardancy of APP/Al(OH)₃/mica/SiR composites indicates that compounds containing P-O-Al are formed due to the reaction between APP and Al(OH)₃ during combustion in the early stage and a coherent, dense, and sealed structure is formed due to the reaction in mica, phosphates, and the thermal decomposition products of SiR during combustion in the later stage.     

Combustion behavior characterization of major crops through cone calorimeter

Induced by extremely inflammable characteristic, fire accidents worldwide of crops frequently occur and give rise to loss of life and personal injury. Given this problem, combustion behavior characterization of four major crops was investigated by cone calorimeter. Results confirmed the less quantity of crops needed longer time to be ignited. Meanwhile, the linear relation between the inverse square of time to ignition and heat flux of crops was found. For heat release rate (HRR), it was demonstrated that more quantity of crops prolonged the heat release process. For instance, with heat flux of 50 kW/m², HRR values of 100 and 50 g soybean at 400 seconds were 212 and 40 kW/m². Besides, peak values of HRR (PHRR) were close with different mass, especially for corn. Interestingly, compared to less quantity, more quantity crops were harder to be ignited at same heat flux. In addition to soybean, PHRR and total heat release (THR) of crops was gradually increased with the increasing heat flux. Meanwhile, THR values of 100 g crops were lower than double THR of 50 g crops. The investigation of combustion behavior characteristic could guide the safety storage of crops, thus avoiding the occurrence of crops fire hazards.     

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 of tris(2‐hydroxyethyl) isocyanurate homopolymer and its application in intumescent flame retarded polypropylene

A macromolecular homopolymer (named as Homo‐THEIC) was synthesized through self‐etherification of tris(2‐hydroxyethyl) isocyanurate (THEIC) molecules and used as charring agent. Its chemical structure was characterized by FTIR and ¹³C‐NMR. The charring agent was mixed with ammonium polyphosphate (APP) and applied in flame retarded polypropylene (PP). Results of UL‐94, LOI, and cone calorimeter test showed that the LOI of flame retarded PP can reach 32.8% and UL‐94 V‐0 rating can be achieved at 30 wt % loading. The heat release rate and smoke production rate during the combustion of PP were substantially reduced. TGA results indicated that the synergistic effect between APP and Homo‐THEIC existed and the addition of intumescent flame retardant (IFR) dramatically enhanced the thermal stability of PP. According to the results of TGA, SEM, TG‐FTIR, FTIR, and Raman, the char forming process of IFR can be separated into three stages: the formation of viscous phosphate ester (T _onset?330 °C), the expanding process along with the decomposition of phosphate ester and the release of a large amount of gases (330–480 °C), and the final formation of graphitic‐like char without any expanding feature (480–670 °C). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44663.