In situ polymerization of flame retardant modification polyamide 6,6 with 2-carboxy ethyl (phenyl) phosphinic acid

A novel halogen-free flame retardant copolyamide 6,6 (FR-PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2-carboxy ethyl (phenyl) phosphinic acid (CEPPA). The elemental composition and chemical structure of FR-PA66 were characterized by energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and ¹³C Nuclear magnetic resonance spectrometer. The flame retardancy, thermal stability, and morphology of char residues were also investigated by the limiting oxygen index (LOI), UL 94 test, thermogravimetric analysis, and scanning electron microscopy. The results showed that FR-PA66 samples had much better flame retardancy and char formation ability than pure PA66 after the flame retardant modification. The LOI values were increased from 24.0 to 28.0% by adding 6 wt % of CEPPA and all FR-PA66 samples were rated as V-0 rating in UL-94 test. Furthermore, the thermal stability analysis indicated that in situ polymerization with CEPPA effectively decreased the initial decomposition temperature and increased the amount of char residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48687.     

Investigation on effects of aluminum and magnesium hypophosphites on flame retardancy and thermal degradation of polyamide 6

Two hypophosphites, aluminum hypophosphite (AlHP) and magnesium hypophosphite (MgHP), were applied to obtain flame retardant polyamide 6 (FR-PA6) composites. UL-94 and limiting oxygen index results indicated that AlHP contributed both good flame retardance and antidripping ability for PA6, while MgHP did not. Based on thermogravimetric analysis (TGA), AlHP and MgHP presented the different thermal degradation behavior. That is, the quick decomposition of AlHP took place at lower temperature than that of MgHP. AlHP promoted the early thermal degradation of PA6 and formed more char residue. The thermal decomposition mechanisms of AlHP and MgHP in nitrogen or air were suggested. Scanning electron microscope and X-ray photoelectron spectroscopy indicated that in the existence of AlHP, the morphological structures of char residue were more homogenous, and compact, and more char residue was formed. These results well illustrated the difference of the flame retardancy between AlHP and MgHP. Mechanical properties of PA6/AlHP and PA6/MgHP were also obtained. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

成炭剂和分子筛协同MPP对PA6的阻燃性研究

将聚磷酸三聚氰胺(MPP)作为阻燃剂阻燃PA6,研究了高效成炭(剂CFA)和4A分子筛对MPP阻燃PA6性能的影响,并通过热失重分(析TGA)对材料进行了表征。结果表明:CFA和4A分子筛对MPP具有协效阻燃作用,加速了PA6阻燃时的成炭化学反应,改善了炭层结构。当阻燃体系中添加26%的MPP、4%的CFA和2%的4A分子筛时P,A6的氧指数可达到35%,垂直燃烧通过UL94 V—1级。     

硼酸锌对氮磷协效阻燃玻纤增强尼龙66性能的影响

为提高三聚氰胺聚磷酸盐(MPP)和二乙基次膦酸盐(OP)协效阻燃玻纤(GF)增强尼龙66(PA66)的综合性能,引入少量的无机阻燃剂硼酸锌(ZB)作为协效剂,系统研究了不同添加量的ZB对阻燃材料的阻燃性能、热稳定性、力学性能和白度的影响。结果表明,当MPP和OP的总添加量为15%,复配0.5%的ZB时,阻燃GF增强PA66的垂直燃烧阻燃等级达到UL94 V–0级,且热释放总量由MPP/OP体系的15.4 k J/g降为13.7 k J/g;ZB的引入促进了连续、致密炭层的形成,增强了凝聚相阻燃;ZB增强了阻燃材料的热稳定性,ZB复配量为1.0%的阻燃材料的初始降解温度提高到了301℃,有效避免了加工过程中的降解;当ZB添加量为1.0%时,阻燃材料的拉伸强度和缺口冲击强度分别为100.9 MPa和4.22 k J/m~2,均优于未添加阻燃剂的纯GF增强PA66;同时,样品的白度得到了明显提升,有利于阻燃GF增强PA66的工业化应用。     

阻燃聚酰胺的研究

本文对含阻燃剂的聚酰胺6进行了熔体流变性能、极限氧指数、热失重和力学性能的研究。加入阻燃剂后,熔体粘度稍有增加,非牛顿指数均为0.81,熔体粘流活化能变大(58.5kJ/mol)。极限氧指数值随阻燃剂加入而线性增加可达到26％以上,阻燃剂具有协同效应。阻燃聚酰胺6纤维的力学性能有所降低。     

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。     

聚磷酸三聚氰胺对玻纤增强PA66的膨胀阻燃作用

采用自制的新型膨胀型阻燃剂——聚磷酸三聚氰胺(MPP)对玻纤增强PA66进行阻燃,以氧指数和垂直燃烧(UL94)评价了其阻燃作用;以热失重测定了材料的热分解性能;以扫描电镜观察了材料残炭的结构;并探讨了MPP阻燃玻纤增强PA66的阻燃机理。试验表明,单一MPP对玻纤增强PA66有良好的阻燃效果,当添加25％时,阻燃材料的氧指数为38,0％,达到UL94V-0级;MPP参与了玻纤增强PA66的降解过程,在材料表面形成了致密的隔热、隔氧的泡沫炭层。     

Intumescent flame retardation of melamine‐modified montmorillonite on polyamide 6: Enhancement of condense phase and flame retardance

Melamine‐modified montmorillonite (MA‐MMT) was prepared via cation exchange. The intercalation behavior was investigated by Fourier transform infrared spectrometer (FT‐IR), X‐ray photoelectron spectroscopy (XPS), and X‐ray diffraction (XRD). The results showed that the d‐spacing value increased from 1.25 nm for Na‐montmorillonite (Na⁺MMT) to 1.53 nm for MA‐MMT. Different kinds of montmorillonite combined with melamine pyrophosphate (MPP) were used to prepare flame‐retardant polyamide 6 (FR‐PA6). Flame retardance of FR‐PA6 samples was investigated by limiting oxygen index (LOI), UL‐94 vertical burning method, and cone calorimeter test. Morphology and component of char residues for FR‐PA6 were investigated by scanning electron microscope (SEM) and XPS. It was found that MA‐MMT/MPP system contributed both excellent flame retardance and anti‐dripping ability for PA6. MA‐MMT particles can fill flaws of char residues and strengthen the char layer, leading to form more intumescent char layer. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Influence of polyamide 6 as a charring agent on the flame retardancy,thermal, and mechanical properties of polypropylene composites

In this work, polyamide 6 (PA6) as a charring agent has been used in combination with thermoplastic polyurethane (TPU)‐microencapsulated ammonium polyphosphate (MTAPP) forming intumescent flame retardants (IFRs) which applies in polypropylene (PP). The effects of the IFRs on the flame retardancy, morphology of char layers, water resistance, thermal properties and mechanical properties of flame‐retardant PP composites are investigated by limiting oxygen index (LOI), UL‐94 test, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical properties test. The results show that the PP/MTAPP/PA6 composites exhibit much better flame‐retardant performances than the PP/MTAPP composites. The higher LOI values and UL‐94 V‐2 of the PP/MTAPP composites with suitable amount of PA6 are obtained, which is attributed to the thick and compact char layer structure evidenced by SEM. The results from TGA and DSC demonstrate that the introduction of PA6 into PP/MTAPP composites has a great effect on the thermal stability and crystallization behaviors of the composites. Furthermore, the mechanical properties of PP/MTAPP/PA6 composites are also improved greatly due to the presence of PA6 as a charring agent. POLYM. ENG. SCI., 55:1355–1360, 2015. © 2015 Society of Plastics Engineers     

Flame retardancy and mechanical properties of polyamide 6 with melamine polyphosphate and ionic liquid surfactant‐treated montmorillonite

The mechanical properties and inflammability of polyamide 6 (PA6) nanocomposites incorporated with Montmorillonite organoclay (MMT) modified with thermal stable ionic liquid surfactants were investigated. The compatibility between ionic liquid‐treated MMT and PA6 matrix was improved and the intercalation morphology was achieved, which resulted in the increaseof tensile modulus. However, the addition of organo‐MMTs alone did not improve the inflammability of the PA6 nanocomposite, because of strong melt‐dripping behavior of PA6 matrix. Addition of auxiliary melamine polyphosphate (MPP) intumescent flame retardant to the nanocomposite prevented the melt dripping and enhanced inflammability performance. The enhanced inflammability of PA6/organoclay/MPP nanocomposites was attributed to the synergistic effect between imidazolium or phosphonium organo‐MMTs and intumescent flame retardant MPP. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40648.     

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。     

Ionic liquid modified graphene oxide for enhanced flame retardancy and mechanical properties of epoxy resin

In this work, to improve its dispersion and flame retardancy, graphene oxide (GO) was functionalized by silane coupling agent KH550 and 1-butyl-3-methylimidazole hexafluorophosphate (PF₆-ILs), and characteristics of the PF₆-ILs@GO was obtained by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Then, the synergistic flame retardant of GO or PF₆-ILs@GO and melamine pyrophosphate (MPP) were applied for epoxy resin (EP) materials. Specifically, the limiting oxygen index (LOI) value of EP with 0.1 wt% PF₆-ILs@GO was increased to 29.2% from 27.5% of EP/MPP composites, and the UL-94 test reached the V-0 rating. The CCT results showed that the total heat release (THR) and total smoke release (TSP) of EP/MPP/PF₆-ILs@GO composites were significantly 24.4% and 53.4% lower than that of EP/MPP composites. Besides, the thermal behavior investigated by TGA indicated that the char-forming effect of GO and PF₆-ILs@GO was great, the residual char of EP/MPP/PF₆-ILs@GO composites was as high as 19.5% at 700°C, and its thermal stability was higher than that of EP/MPP composites. On the other hand, the tensile strength of EP/MPP/GO and EP/MPP/PF₆-ILs@GO composites were increased by 15.6% and 28.3% compared with EP/MPP composites. According to SEM analysis, the EP/MPP/GO composites formed a good protective char layer, which can effectively improve flame retardancy of EP. This research represents a new method of flame retardant modified GO to improve the flame retardancy and mechanical properties of polymers.     

Synergistic effect of melamine polyphosphate with macromolecular charring agent novolac in wollastonite filled PA66

In this article, macromolecular charring agent linear novolac (NA) was served as a synergist with nitrogen‐phosphorous flame retardant melamine polyphosphate (MPP) for the flame‐resistance of wollastonite (WT) filled polyamide 66 (PA66). The investigations showed that MPP/NA system possessed obvious synergistic effects by increasing the charring rate and amount, therefore, showing much higher flame retardancy than the filled PA66 flame retarded with MPP alone. The corresponding char layer structure of MPP/WT/PA66 and MPP/NA/WT/PA66 was investigated and their difference was analyzed. In addition, as a multifunctional additive, NA could act as a compatibilizer and lubricant in the system, and endowed the material with improved mechanical performance and processability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The investigation on the flame retardancy mechanism of nitrogen flame retardant melamine cyanurate in polyamide 6

Melamine cyanurate (MCA) flame retardant polyamide 6 (PA6) shows good flame retardancy, but the corresponding mechanisms have not been completely understood. In this paper, Fourier transform infrared spectra (FTIR), elemental analysis (EA), scanning electronmicroscope (SEM), energy dispersive scanning (EDS), thermogravimeric analysis (TGA) and pyrolysis-gas chromatogram-mass spectrometer (Py-GC-MS) were conducted to investigate the processes including melt-drip phase, gaseous phase and condensed phase of MCA/PA6 system. Compared with original PA6, it is found that MCA flame retardant PA6 mainly undergoes predominant weak bond-breakage degradation forming oligomers rather than oxidative degradation producing low-boiling point fuel as original PA6 does. The produced oligomers can accelerate the formation of the melt drips which effectively removes the combustion heat and latent fuel, also the self-condensation of these oligomers is advantageous to form stable cross-linking structure, thus greatly consolidating the char layer.     

ZnO对PP/MPP/PEPA膨胀阻燃体系的协同作用

以ZnO为阻燃协效剂,采用多聚磷酸蜜胺(MPP)和笼状季戊四醇磷酸酯(PEPA)复配阻燃剂,制备了具有良好阻燃性能的无卤阻燃PP。研究了ZnO用量对PP阻燃性能和协效作用的影响。结果表明:添加少量的ZnO即可显著提高PP的阻燃性能。当MPP、PEPA和ZnO添加量分别为12%、8%和1%时,阻燃PP的氧指数高达29.5%。TGA、FTIR分析和体式显微镜观测结果表明:添加ZnO可以催化MPP/PEPA间的酯化反应,促进体系成炭,形成更致密的炭层,从而提高材料的阻燃性能。     

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.     

MPP无卤阻燃聚丙烯纤维的辐照改性研究

采用自制季戊四醇螺环磷酸酯双蜜胺盐(MPP)无卤阻燃剂与聚丙烯(PP)进行共混纺丝,制备了无卤阻燃PP纤维,采用低能电子辐照对无卤阻燃PP纤维进行改性,并对MPP的结构、PP纤维的力学性能及阻燃性能进行了表征。结果表明:自制MPP为预期结构;随着MPP含量的增加,PP纤维的极限氧指数(LOI)增大,但其断裂强度有所下降;MPP质量分数为8%时,纤维断裂强度为6.02 cN/dtex,LOI为24.5%;随低能电子辐照量的增大,MPP质量分数8%的阻燃PP纤维的LOI大幅度增加;当电子辐照量为200 kGy时,阻燃PP纤维的LOI为33.8%,断裂强度为3.08 cN/dtex,起始分解温度和残炭率比纯PP纤维均有较大幅度增加,燃烧形成连续致密的炭层。     

Melamine polyphosphate/silicon‐modified phenolic resin flame retardant glass fiber reinforced polyamide‐6

The halogen‐free flame retardance of glass fiber reinforced polyamide‐6 (PA6) is an everlastingly challenge due to well‐known wick effect. In this research, a novel system composed of a nitrogen–phosphorous flame retardant, melamine polyphosphate combined with a macromolecular charring agent, silicon‐modified phenolic resin (SPR), was employed to flame‐retard glass fiber reinforced PA6. It exhibited obvious synergistic effect between the two components at a proper ratio range. The flame retardance of the composites can be remarkably improved due to the increased amount and improved thermal stability of the produced char. The flame resistance tests indicated that the synergism system with an optimized ratio achieved V0 (1.6 mm) rating of UL94, 25.2% of Limited Oxygen Index, and only 338.2 W/g of the heat release peak rate. The corresponding synergistic mechanisms were investigated by the characterizations including the thermal gravimetric analysis, carbonation test, and the char morphology observation. It confirmed that the introduced SPR could accelerate the carbonation of PA6 resin, which was in favor of the construction of denser and more continuous charring structure. In addition, the flame retardant materials also indicated the acceptable mechanical properties, showing the advantages in the overall performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

酚醛树脂基新戊二醇磷酸酯阻燃剂的合成及其性能研究

通过用新戊二醇磷酰氯对线型酚醛树脂(PF)酚羟基实行磷酰化封端处理,制备了线型PF基新戊二醇磷酸酯(NDMPP)阻燃剂,将其应用于阻燃PA6。采用核磁共振氢谱(1H NMR)、核磁共振磷谱(31P NMR)和傅立叶变换红外光谱(FTIR)表征了NDMPP的结构,采用热重(TG)分析研究其热分解行为,采用极限氧指数(LOI)和UL 94测试其阻燃PA6材料的阻燃性能,采用万能材料试验机和冲击试验机测试阻燃材料的力学性能。1H NMR,31P NMR和FTIR结果表明,线型PF中大约82%的羟基被磷酰化,NDMPP中的磷含量约为11.9%。TG分析结果表明,NDMPP阻燃剂在氮气气氛下起始分解温度超过250℃,600℃的残炭率达到43.5%,显示出良好的热稳定性。当NDMPP质量分数为25%时,其阻燃的PA6达到UL 94 V–0等级,LOI达到33.4%,而拉伸强度、缺口冲击强度、弯曲强度和弯曲弹性模量分别为纯PA6的76%,41%,72%和71%。     

无卤膨胀阻燃PP/PA6合金性能研究

研究了以聚磷酸铵（APP）、三聚氰胺（MA）和层状复合金属氢氧化物（LDH）复配得到的膨胀阻燃剂（IFR）对聚丙烯／尼龙6（PP／PA6）合金性能的影响，分析了不同阻燃体系对PP／PA6合金的阻燃性能、力学性能、热性能和微观形态的影响。结果表明，当APP／MA／LDH为21．0／7．5／1．5（质量比）时，PP／PA6合金具有较好的阻燃性能并能保持较高的力学性能。LDH可以提高阻燃材料的热稳定性和残炭量，而且SEM照片显示炭层微观形态为“面包”状的膨松状。