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.     

Fire retardant mechanism of PA66 modified by a “trinity” reactive flame retardant

A “trinity” reactive flame retardant (TRFR) was successfully synthesized from pentaerythritol, phosphorus oxychloride (POC), and p-aminobenzoic acid in two steps. The flame retardant polyamide 66 (PA66) was prepared by polymerizing TRFR with PA66 salt; the structural changes during the heating process, the morphology, and composition after combustion of flame retardant PA66 were analyzed. Fourier transform infrared, scanning electron microscopy, and Raman analysis results showed that the TRFR structure on flame retardant PA66 decomposed at the temperature of 25–550 °C, forming compounds containing phosphorus, carbon, and nitrogen, respectively. These compounds promoted the dehydration of the combustion surface to form char, increased the char formation rate, and produced nonflammable gases, resulting in a dense, porous, noncombustible carbon layer. The carbon layer may isolate oxygen and heat, thereby preventing the polymer from sustainability of combustion. When the TRFR salt content was 3%, TRFR flame retardant PA66 has excellent flame retardancy with limited oxygen index value of 29 and UL94 of V-0 rating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47488.     

微胶囊化红磷阻燃剂的制备及其在玻纤增强尼龙66中的应用

为克服红磷直接应用于玻纤增强尼龙66中的缺点,研究了用原位聚合法制备微胶囊红磷的工艺,测试了样品的吸湿性以及表面包覆性能,并研究了其用于玻纤增强尼龙66的阻燃性能和力学性能。结果表明,制得的微胶囊化红磷应用于玻纤增强尼龙66中,不仅具有优良的阻燃性能(FV 0级),而且力学性能比单独应用红磷有所提高,加工工艺性能有较大幅度的提高。     

Evaluation of nonconventional additives as fire retardants on polyamide 6,6: Phosphorous‐based master batch, α‐zirconium dihydrogen phosphate,and β‐cyclodextrin based nanosponges

The influence of new types of additives, such as halogen‐ and antimony‐free flame‐retardant master batches based on phosphorus, α‐zirconium dihydrogen phosphate, and β‐cyclodextrin nanosponges, on the flame retardancy of polyamide 6,6 (PA6,6) by means of cone calorimetry and limiting oxygen index (LOI) tests was investigated. A significant decrease of the heat release rate, depending by the type of additive used, was observed. Furthermore, with the consideration that the life safety during the fire could be improved by a decrease in the fire hazard, a decrease in the quantity of the smoke and its toxicity, depending also on the type of additive, was revealed. With regard to the LOI test, neat PA6,6 showed a slight increase in the LOI value in comparison with the PA6,6 composites. However, all of the PA6,6/composites showed a slower burning velocity and antidripping effects at oxygen concentrations corresponding to the LOI value. To understand the flame‐retardancy mechanism of these novel PA6,6 composites, we thoroughly investigated their thermal decomposition behavior and microstructure/elemental analysis by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy. Furthermore, the combustion behavior of these novel PA6,6 composites was compared with that of conventional nanofillers (e.g., modified montmorillonite clay and carbon nanotubes). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

高含量玻璃纤维增强阻燃聚酰胺材料的制备与性能

采用双螺杆挤出机制备了聚酰胺6(PA6)/50%（质量分数,下同）玻璃纤维（GF）、PA66/50%GF、PA56/50%GF 3种高含量GF增强阻燃PA复合材料,对比研究了红磷、溴系、磷氮3种阻燃体系下复合材料的力学性能、阻燃性能和激光打标性能。结果表明,不同阻燃体系对复合材料的力学性能有明显影响,吸水平衡后,PA66复合材料的力学性能保持率最高;PA56复合材料在3种阻燃体系中均表现出比PA6、PA66复合材料更好的阻燃性能;红外激光和紫外激光的打标效果存在明显不同,而在阻燃体系和激光光源相同的条件下,PA6、PA66和PA56 3种PA复合材料的激光打标效果没有明显差异。     

Fire and thermal properties of PA 66 resin treated with poly‐N‐aniline‐phenyl phosphamide as a flame retardant

In this study, a halogen‐free phosphorous‐nitrogen synergistic flame retardant, poly‐N‐aniline‐phenyl phosphamide (PDPPD), was synthesized. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis data confirmed the structure of PDPPD. The essential FR PA66 was polymerized with PA66 pre‐polymer and PDPPD pre‐polymer, prepared from PDPPD and adipic acid. The limit oxygen index and UL‐94 test results of FR PA66 reached 28% and V‐0, respectively, when the contents of PDPPD pre‐polymer were 4.5 wt%. The thermo‐gravimetric and differential scanning calorimetry results demonstrated that the initial decomposition temperature of FR PA66 was 43 °C lower than that of pristine PA66 from 385 to 342 °C; however, the peak decomposition temperature was 36 °C higher than that of pure PA66 from 437 to 473 °C, when the contents of PDPPD pre‐polymer reached 4.5 wt%. Flame retardant mechanism was studied by cone calorimeter testing and SEM‐EDX, confirming that the heat release rate (HRR), total heat release (THR), and total smoke product (TSP) decreased slightly, and PDPPD followed the gas phase flame retardant mechanism. Copyright © 2016 John Wiley & Sons, Ltd.     

ZnS as fire retardant in plasticised PVC

The flame retardant effect of zinc sulphide (ZnS) in plasticised poly(vinyl chloride) (PVC‐P) materials was investigated. PVC‐P containing different combinations of additives such as 5% ZnS, 5% of antimony oxide (Sb₂O₃) and 5% of mixtures based on Sb₂O₃ and ZnS were compared. The thermal degradation and the combustion behaviour were studied using thermogravimetry (TG), coupled with FTIR (TG–FTIR) or with mass spectroscopy (TG–MS), and a cone calorimeter, respectively. A detailed and unambiguous understanding of the decomposition and release of the pyrolysis products was obtained using both TG–MS and TG–FTIR. The influence of ZnS, Sb₂O₃ and the corresponding mixtures on the thermal decomposition of PVC‐P was demonstrated. Synergism was observed for the combination of the two additives. The combustion behaviour (time to ignition, heat release, smoke production, mass loss, CO production) was monitored versus external heat fluxes between 30 and 75 kW m^?2 with the cone calorimeter. Adding 5% of ZnS has no significant influence on the fire behaviour of PVC‐P materials beyond a dilution effect, whereas Sb₂O₃ works as an effective fire retardant. Synergism of ZnS and Sb₂O₃ allows the possibility of replacing half of Sb₂O₃ by ZnS to reach equivalent fire retardancy. © 2002 Society of Chemical Industry     

Flame-retardant behavior and protective layer effect of phosphazene-triazine bi-group flame retardant on polycarbonate

A series of flame-retardant polycarbonate (PC) composites with different ratios of phosphazene-triazine bi-group flame retardant (A3) were prepared. The flame retardant performance and thermal stability of PC/A3 composites were characterized by LOI, UL 94 vertical burning test, cone calorimetry test and TG. Results show that when the addition of A3 is 13.5%, the PC/A3 composite can pass UL94 V-0 level with a LOI value of 29.3% and reduce the peak heat release rate by 47.5% during the combustion. TG results show that adding 5% A3 can increase the initial decomposition temperature of the PC by 7°C in nitrogen and 9°C in air. Investigation of the morphology and chemical structure of char residue demonstrates that A3 promotes the formation of more complete and compact char residue which acts as physical barriers to inhibit the transfer of heat and oxygen, resulting the good flame retardant properties. The analysis of gaseous pyrolysis product reveals that A3 also exerts a flame-retardant effect in gas phase by releasing PO· free radicals.     

次磷酸盐⁃环四硅氧烷双基化合物复配二乙基次磷酸铝对PA6的阻燃性能研究

将次磷酸盐?环四硅氧烷双基化合物（MVC?AlPi）与二乙基次磷酸铝（AlPi）复配阻燃聚酰胺6（PA6）。目的是考察外加的富磷酸铝化合物中磷酸铝基团和环四硅氧烷基团之间的配比对PA6阻燃效率的影响。结果表明, PA6/8.8 %AlPi/2.2 %MVC?AlPi具有协同屏障效应,可使复合材料的极限氧指数（LOI）值提高到31.5 %,并通过UL 94 V?0级别。相比于纯PA6,PA6/8.8 %AlPi/2.2 %MVC?AlPi的热释放速率峰值（PHRR）降幅近50 %、总热释放量（THR）也降低了15 %,PA6/8.8 %AlPi/2.2 %MVC?AlPi的残炭率虽略低于11 %MVC?AlPi,却形成了内层坚硬,外层类陶瓷化的双层炭层结构,MVC?AlPi、AlPi与PA6的相互作用可以锁定更多P、C碎片,促进由含硅富磷残渣组成的屏障保护炭层的形成。在阻燃剂添加总量不变的情况下,通过调节各组分的比例,发挥出更好的协同阻燃效果。     

硅锡协同阻燃尼龙6

采用氯化亚锡(SnCl2)/聚氨丙基苯基倍半硅氧烷(PAPSQ)复合阻燃剂阻燃改性尼龙6(PA6)。测定了阻燃PA6的氧指数(LOI),利用锥形量热仪测定了阻燃PA6的释热速率、总释热量、有效燃烧热等多种阻燃参数,并用扫描电镜(SEM)观察了阻燃PA6残炭的形貌。实验表明,当SnCl2用量为4%,PAPSQ用量为1%时,PA6的LOI为31%,PA6的释热速率、总释热量和有效燃烧热均明显下降,PAPSQ对SnCl2有协同阻燃效果。     

锥形量热法研究木质素基膨胀型阻燃剂对环氧树脂阻燃抑烟效果

以来自自然界储量第二的木质素作为膨胀型阻燃剂的基体,通过接枝氮、磷元素成功合成碳源、酸源、气源三位一体的木质素基膨胀型阻燃剂(Lig?T),实现了良好的阻燃性能.将Lig?T按照不同含量添加到环氧树脂(EP)中制备EP/Lig?T复合材料,以锥形量热测试考察复合材料的热稳定性能和阻燃性能,并重点考察复合材料在接近真实火...     

低烟无卤阻燃HIPS的研究

采用熔融法制备包括有机蒙脱土（OMMT）、红磷（RP）和酚醛树脂（PFR）体系的阻燃高抗冲聚苯乙烯（HIPS）复合材料，用基于耗氧原理的锥形量热仪研究复合材料的阻燃性能，用扫描电子显微镜观察了复合材料燃烧残余物的微观结构形态。结果表明，与纯HIPS相比，制备的HIPS／OMMT复合阻燃材料阻燃性能有所提高，但提高幅度有限；与HIPS／OMMT复合阻燃材料相比，添加RP和PFR的阻燃RP／PFR／HIPS／OMMT复合材料的热释放速率及其峰值、质量损失速率和生烟速率等燃烧性能参数继续降低，且火灾性能指数大幅提高，表现出低烟和高效的阻燃特点。     

阻燃增强增韧尼龙66的制备及工艺研究

以十溴二苯醚和氮磷复合物为阻燃剂,以玻璃纤维为增强剂,加入自制增韧剂,制备了阻燃增强增韧尼龙(PA)66材料,并对其阻燃性能和力学性能进行了表征,研究了加工工艺对改性PA66材料性能的影响。     

聚乳酸/苯基次膦酸铈复合材料的制备及性能

采用简单方法合成苯基次膦酸铈(CeP),并将其作为阻燃剂加入聚乳酸(PLA)中,通过熔融共混技术制备聚乳酸/苯基次膦酸铈(PLA/CeP)复合材料。通过热重(TG)、极限氧指数(LOI)、UL-94垂直燃烧(UL-94)、微型量热(MCC)研究复合材料的热稳定性、阻燃性能和燃烧性能。通过阻燃测试发现,CeP能够提高复合材料阻燃性能,PLA/CeP20极限氧指数能达到24.3%并通过UL-94 V-2级别。热重分析的结果表明,CeP显著提高了PLA/CeP复合材料初始分解温度和成炭率。MCC测试结果表明,CeP能明显降低PLA/CeP复合材料火灾危险性。PLA/CeP20热释放速率峰值(PHRR)和总热释放(THR)分别为397 W/g和13.6 kJ/g,与纯聚乳酸相比,分别下降了13.9%和28.0%。因此,苯基次磷酸铈对聚乳酸具有良好的阻燃效果。     

Synergistic Flame Retardant Effect of Organic Phosphorus–Nitrogen and Inorganic Boron Flame Retardant on Polyethylene

In this study, to develop an organic/inorganic synergistic flame retardant, organic phosphorus–nitrogen flame retardant 6,6-(((sulfonylbis(4,1-phenylene)) bis(azanediyl))bis(thiophen-2-ylmethylene))bis(6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO-N) and inorganic boron flame retardant zinc borate (ZB) were selected. The flame retardant properties of polyethylene (PE) containing ZB/DOPO-N were investigated. PE/20%ZB/10%DOPO-N had better thermal stability and flame retardant properties. The limiting oxygen index of PE/20%ZB/10%DOPO-N reached 24.6%, and UL 94 V-0 rating was attained. The peak heat release rate, total heat release, average effective heat combustion, and fire growth index of PE/20%ZB/10%DOPO-N were lower than when ZB and DOPO-N were added separately. In addition, the flame retardant mechanism was investigated using scanning electron microscopy, X-ray diffraction, energy dispersive X-ray, and Fourier transform infrared spectroscopy. ZB/DOPO-N simultaneously exerted condensed phase and gas phase flame retardant effect. POLYM. ENG. SCI., 60: 414–422, 2019. © 2019 Society of Plastics Engineers     

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。     

Heat propagation in thermally conductive polymers of PA6 and hexagonal boron nitride

Thermally conductive polymers offer new possibilities for the heat dissipation in electric and electronic components, for example, by a three‐dimensional shaping of the heat sinks. To face safety regulations, improved fire performance of those components is required. In contrast to unfilled polymers, those materials exhibit an entirely different thermal behavior. To investigate the flammability, a phosphorus flame retardant was incorporated into thermally conductive composites of polyamide 6 and hexagonal boron nitride. The flame retardant decreased the thermal conductivity only slightly. However, the burning behavior changed significantly, due to a different heat propagation, which was investigated using a thermographic camera. An optimum content of hexagonal boron nitride for a sufficient thermal conductivity and fire performance was found between 20 and 30 vol%. The improvement of the fire performance was due to a faster heat release out of the pyrolysis zone and an earlier decomposition of the flame retardant. For higher contents of hexagonal boron nitride, the heat was spread faster within the part, promoting an earlier ignition and increasing the decomposition rate of the flame retardant.     

赤磷阻燃剂母料在热塑性工程塑料中的应用

以自制赤磷母料作为工程塑料ＰＡ６,ＰＡ６６,ＰＥＴ,ＰＥＴ的阻燃剂,对不同的阻燃复合材料进行相应的力学性能、电性能和阻燃性能比较。结果表明,赤磷母料阻燃的工程塑料具有较高的力学性能和电性能,尤其是具有较高的相比漏电起良指数值。     

无卤阻燃SBR的阻燃性能及热失重行为

利用锥形量热仪(CONE)和热失重分析(TG)研究了化学膨胀阻燃剂(IFR)、氢氧化铝/红磷(Al(OH)3/P)及二者复合阻燃SBR的阻燃性能及热失重行为。结果表明,阻燃剂用量为40份,聚磷酸铵(APP)与季戊四醇(PER)质量比为3∶1时,SBR/APP/PER的热释放速率及生烟速率均大幅度下降,阻燃效果较好;Al(OH)3与P质量比为26∶14时,可有效降低SBR/Al(OH)3/P的热释放速率,但生烟速率较大;将APP/PER∶Al(OH)3/P=1∶1复配,SBR/IFR/Al(OH)3/P的热释放速率和生烟速率没有进一步改善,协同效应不明显。热失重研究表明,空气气氛下,试样SBR/IFR/Al(OH)3/P在300~500℃时,Al(OH)3/P反应使得SBR分解速度下降;在500~800℃时,APP与PER形成炭层,有效地起到隔热隔氧的作用,从而抑制炭黑的分解;两者复合使用,使阻燃SBR分解速度降低,热稳定性提高。     

无卤阻燃增强PA66的研制及其应用

以包覆红磷和三聚氰胺氰尿酸(MCA)作为协效阻燃剂,玻璃纤维作为增强体系,加入增容剂和其它添加剂,制备了一种无卤阻燃增强尼龙(PA)66材料.从阻燃性能、热性能、力学性能等方面表征两种阻燃剂的协效作用;探讨了增容剂的加入对复合体系性能的影响.结果表明,当PA66增强料、包覆红磷、MCA、增容剂的质量比为100∶15∶5∶6时,复合材料具有较好的阻燃性能和力学性能.该材料已广泛应用于电子、电器领域.