Thermal oxidative degradation kinetics of PP and PP/mg (OH)2 flame‐retardant composites

The thermal stability and thermal oxidative degradation kinetics of polypropylene (PP) and flame‐retardant PP composites filled with untreated and treated magnesium hydroxide (MH) in air were studied by thermogravimetric analysis (TGA). The effect of the heating rate in dynamic measurements (5°C–30°C/min) on kinetic parameters such as activation energy was also investigated. The Kissinger and Flynn–Wall–Ozawa methods were used to determine the apparent activation energy for the degradation of neat PP and flame‐retardant PP composites. The results of TGA showed that the addition of untreated or treated MH improved the thermal oxidative stability of PP in air. The kinetic results showed that the apparent activation energy for degradation of flame‐retardant PP composites was much higher than that of neat PP, suggesting that the flame retardant used in this work had a great effect on the mechanisms of pyrolysis and combustion of PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1978–1984, 2007     

Studies on Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Hemp fabric, one of the most flammable materials, was treated with compounds containing different kinds of elements that contribute to flame retardation. For a study of flame retardation from the standpoint of thermal degradation, the samples were subjected to thermogravimetry (TG) and differential thermal analysis (DTA) in air from ambient temperature to 600℃. The apparent activation energy (Ea) is evaluated by Broido's method at different stages of thermal degradation to observe the variation of Ea in the process of thermal degradation. Flame retardation of samples was determined by limiting oxygen index (LOI) to find the effects of the different compounds on flammability and the thermal degradation of the hemp fabric. The composition of the chars was studied by the IR spectra to obtain information concerning the thermal degradation mechanism. Compared with flammable hemp, the hemp fabric treated with flame retardants showed a higher LOI but lower Ea and decomposition temperatures, which indicated that some compounds make the hemp fabric decompose at lower temperatures, resulting in less flammable products.     

Flame retardation and thermal degradation of flame‐retarded polypropylene composites containing melamine phosphate and pentaerythritol phosphate

The flame retardation of polypropylene (PP) composites containing melamine phosphate (MP) and pentaerythritol phosphate (PEPA) was characterized by limiting oxygen index (LOI) and UL 94. The morphology of the char obtained from the combustion of the composites was studied by scanning electron microscopy (SEM). The thermal degradation of the composites was investigated using thermogravimetric (TG) analysis and real‐time Fourier transform infrared (RTFTIR) spectroscopy. It has been found that the PP composites containing only MP do not show good flame retardancy even at 40% additive level. Compared with the PP/MP binary composites, all the LOI values of the PP/MP/PEPA ternary composites at the same additive loading increase, and UL 94 ratings of the ternary composites at suitable MP/PEPA ratios are raised to V‐0 from no rating (PP/MP). The TG and RTFTIR studies indicate that the interaction occurs among MP, PEPA and PP. Copyright © 2008 John Wiley & Sons, Ltd.     

Mg（OH）2/包覆红磷对阻燃聚丙烯性能的影响

研究了Mg（OH）2和Mg（OH）／包覆红磷复配阻燃聚丙烯的性能及阻燃剂的阻燃机理,对阻燃聚丙烯进行力学性能测试、阻燃性测试．用扫描电镜二次电子成像分析试样的拉伸断口。结果表明：Mg（OH）／包覆红磷复配物比Mg（OH）2阻燃的聚丙烯的阻燃效果要好,但阻燃聚丙烯力学性能下降幅度大。     

The flame retardancy and mechanical properties of jute/polypropylene composites enhanced by ammonium polyphosphate/polypropylene powder

Surface flame retarded jute/polypropylene composites (J/P/A) were prepared via a modified strategy: the mixture of PP and APP powder was spread over the surface of jute/PP nonwoven felts, and then transformed into the flame retarded layer by the hot pressing process. The flame retardancy and thermal properties of composites were analyzed by limit oxygen index (LOI), horizontal burning rate (HBR), thermogravimetric analyses (TGA), and differential scanning calorimetry (DSC). We demonstrated that the flame retardancy and mechanical properties of composites was significantly improved compared with those obtained by presoaking the nonwoven fiber felts in flame retardant (FR) solvent before hot pressing. The mechanism of thermal degradation of jute fiber and flame‐retardant mechanism of composites were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43889.     

无卤阻燃永久抗静电GFPP材料研制

以玻纤增强聚丙烯(GFPP)为基体,加入无卤阻燃剂FR–1420、永久抗静电剂P–22制备复合材料,考察了体系的阻燃性能、永久抗静电性能、力学性能和热稳定性能.结果表明,FR–1420单独添加20％时,可使GFPP阻燃等级达到UL–94 V0级;P–22单独添加20％,可使GFPP表面电阻率下降至1.4×108Ω.当阻...     

埃洛石复配阻燃剂对聚丙烯阻燃性能和力学性能的影响

用埃洛石、三聚氰胺作为阻燃剂,制备了无卤阻燃聚丙烯(PP)复合材料。通过氧指数(OI)、垂直燃烧、万能力学仪、扫描电镜分析研究了埃洛石复配阻燃剂对PP阻燃性能、力学性能的影响。结果表明:埃洛石复配阻燃剂可使PP复合材料通过UL94燃烧性能测试,在提高材料OI的同时,保持了其优良的力学性能。     

Effects of nanofiber treatments on the properties of vapor‐grown carbon fiber reinforced polymer composites

Vapor‐grown carbon fibers (VGCFs) were exposed to a series of chemical treatments and to electrochemical deposition of copper to modify their surface conditions and alter their electrical properties. The fibers were then mixed with polypropylene using a Banbury‐type mixer obtaining composites up to 5 wt % VGCFs. Rheological, electrical, and mechanical properties were evaluated and compared to unfilled polypropylene processed in a similar manner. The composites made with HNO₃‐treated VGCFs showed a lower electrical resistivity compared to the untreated samples. The composites containing VGCFs subjected to the copper electrodeposition process showed the lowest resistivity with no change in the mechanical properties. Changes in rheological properties demonstrated the effects of varying surface conditions of the VGCFs. Microscopic analysis of these composites showed a heterogeneous distribution of VGCFs forming an interconnected network with the presence of copper on the surface of the VGCFs and in the matrix. Both the interconnected network and the presence of copper led to a lower percolation threshold than those seen in a previous work where high dispersion was sought. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2527–2534, 2003     

三聚氯化磷腈微胶囊阻燃剂/聚丙烯复合材料的性能研究

Microcapsulated chlorocyclophosphazenes were synthesized,and then microcapsulated chlorocyclo- phosphazene/polypropylene（PP）composites were prepared.The results showed that microcapsulated chlorocyclo- phosphazene had good high thermal stability through thermogravimetric analysis（TGA）.The flammability and mechanical properties of microcapsulated chlorocyclophosphazene/polypropylene composites were investigated by limiting oxygen index experiment,UL 94V flame retardancy test,cone calorimetry,tensile experiment,and impact test,respectively.It was shown that the microcapsulated chlorocyclophosphazene/PP composites had better tensile strength,impact strength,flame retardant properties and smoke suppress properties compared with chlorocyclo- phosphazene/PP composites.     

硅油及钛白粉在聚丙烯膨胀阻燃中的应用研究

选用一种含有聚磷酸铵的高效膨胀型阻燃剂（SR-50A）与聚丙烯（PP）和不同含量的苯基硅油和钛白粉通过挤出造粒法制备了膨胀型阻燃母粒,将其与PP注塑成阻燃复合材料,利用极限氧指数测试仪等对阻燃复合材料的燃烧性能进行测试。结果表明,复合材料中膨胀型阻燃母粒含量为20 %（质量分数,下同）,苯基硅油的添加量为0.17 %时,极限氧指数值提高到35.6 %;钛白粉的添加量为1 %时,极限氧指数值提高到35.1 %,垂直燃烧等级（UL 94）均能达到V-0级;苯基硅油的加入可促进阻燃剂在阻燃初始阶段的分解,降低了复合材料的热分解速率,钛白粉的加入可促进基体成炭。     

Structure and properties of polypropylene composites filled with magnesium hydroxide

Silane and silicone oil modified superfine magnesium hydroxide (MH) was filled into polypropylene (PP) as a flame retardant. The PP and flame‐retarded PP composites were studied for their mechanical properties and rheological behaviors by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), limiting oxygen index (LOI), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that the addition of MH improved flame retardancy of PP/MH composites, but seriously deteriorated mechanical properties of the composites. Surface treatment of MH could significantly improve tensile and impact strength of PP/MH composite because of its enhanced interfacial adhesion between MH and PP matrix. DSC results showed that MH had heterogeneous nucleation effect on PP. Surface treatment of MH weakened its heterogeneous nucleation effect. POM results showed that the dispersion of MH particles played an important role in the crystalline morphology and spherulite size of PP crystals. TGA indicated that MH greatly enhanced the thermal stability of PP. The introduction of treatment agent further improved the thermal oxidative stability of the composite. According to LOI, silane‐treated MH greatly enhanced flame retardancy of PP/MH composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4943–4951, 2006     

Effect of Phosphorus-Containing Fire-Retardant Systems on Fireproofing and Processing Indexes of Polypropylene

The thermal stability of polypropylene composites containing the microencapsulated ammonium salt of methylphosphonic acid amide and copper-zinc-boron compounds as a fire retardant was investigated. It was shown that incorporation of dizinc hexaborate increases the thermal stability period (MFI of 15 min) in comparison to this index for the composite containing a fire retardant alone (MFI of 2 min), which is due to slowing of decomposition of the fire retardant. It was found that dizinc hexaborate alters thermooxidative degradation of polypropylene containing microencapsulated methylphosphonic acid amide ammonium salt by decreasing the temperature and maximum rate of decomposition. The number of gaseous compounds liberated in thermooxidative decomposition of the composite is much lower than for the initial polypropylene.     

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

Detrimental physical and mechanical properties are common problems 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 nanotubes (HNTs) and montmorillonite (MMT) nanoclay) on the flame and mechanical properties in an intumescent ammonium polyphosphate (APP)-based polypropylene (PP)/kenaf composite system. 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 nanocomposites. An increase in the decomposition temperature was observed under thermogravimetric analysis (TGA), with the presence of HNT. However, MMT tends to lower the maximum decomposition temperature under inert atmosphere. The flammability 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.     

Improving the flame retardancy of polypropylene by nano metal–organic frameworks and bioethanol coproduct

In this work, a novel flame retardant system based on nano zeolitic imidazolate framework‐8 (ZIF‐8) and the distiller's dried grains with solubles (DDGS) without traditional flame retardants has been designed and blended with polypropylene (PP) to prepare the green flame retarded composites. The influences of nano ZIF‐8 and DDGS on mechanical properties and flame retardancy of PP are studied. The results indicate that combination of nano ZIF‐8 and DDGS improves the mechanical properties of PP, and the tensile strength of the composites containing 29 wt% of DDGS and 1 wt% of nano ZIF‐8 reaches 34.0 MPa compared with 24.7 MPa of pure PP. The limiting oxygen index (LOI) of the composites containing 27 wt% DDGS and 3 wt% of nano ZIF‐8 is about 25.0% compared with 17.5% of pure PP. Besides, its horizontal burning velocity also decreases significantly. The char residues after burning of the PP composites are analyzed, and the mechanism is discussed in detail.     

一种三嗪阻燃剂对玻纤增强PET体系性能的影响

比较了新型阻燃剂无析出阻燃剂A和十溴联苯醚对玻纤增强聚对苯二甲酸乙二醇酯（PET）体系的阻燃和力学性能的影响以及阻燃剂在体系中的抗析出性能。结果表明，两种阻燃剂对体系性能的贡献几乎一样，但无析出阻燃剂A具有良好的抗析出性。借助扫描电镜（SEM）对体系的微观结构的分析发现无析出阻燃剂A在PET基体中分散均匀，颗粒尺寸小而一致。在不同工程塑料中加入无析出阻燃剂A后发现，PET体系的阻燃性能明显高于而力学性能则大大低于PBT和尼龙体系，这在很大程度上是由于无析出阻燃剂A体系使PET树脂摩尔质量降低所致。此外，还讨论了玻纤对十溴联苯醚阻燃PET的影响。适当提高玻纤的加入量，不仅可以提高体系的力学性能，还可以改善其阻燃性能。     

High-efficiency ammonium polyphosphate intumescent encapsulated polypropylene flame retardant

The flame retardant polypropylene containing the micro-envelope core-shell structure flame retardant, which encapsulated ammonium polyphosphate into melamine-formaldehyde resin and sodium silicate through in situ polymerization was prepared with polyamide 6, added as a carbon-forming agent. The composition of ammonium polyphosphate, encapsulated ammonium polyphosphate with melamine-formaldehyde resin and the micro-envelope core-shell structure flame retardant were characterized. The fire safety and thermal stability were investigated and showed an improvement including limiting oxygen index, thermogravimetric analysis, vertical burning tests, and microscale combustion calorimeter. The burned compounds were also studied to confirm the burning mechanism. The results showed the flame retardant performance had been greatly improved, while polyamide 6 had better char-forming effect. Besides, the water solubility of flame retardants and their influence on the mechanical properties of polypropylene were also investigated. The results on the effects of additives demonstrated a high efficiency flame retardant to polypropylene. A core-shell flame retardant that sodium silicate and melamine-formaldehyde resin-coated ammonium polyphosphate had been constructed. The effect of the built flame retardant system on the combustion performance of polypropylene was studied from the mechanism and performance. The LOI of the most flame retardant polypropylene reached 28.6%, and UL-94 reached the V-0 level.     

Effects of Zinc Phytate on Flame Retardancy and Thermal Degradation Behaviors of Intumescent Flame-retardant Polypropylene

In this paper, zinc phytate was prepared and used as a synergist in intumescent flame-retarded polypropylene composites. The results showed that the polypropylene composites with 17?wt% intumescent flame retardant and 2?wt% zinc phytate have a limiting oxygen index 29.2 and achieve the UL-94?V-0 rating. Moreover, the peak heat release rate of the polypropylene composites decreases from 374 to 275?kW/m². Real-time Fourier-transform infrared spectroscopy showed that the zinc phytate delays the emission of carbon dioxide indicating that zinc phytate slows the degradation of polypropylene which regulates the suitability of intumescent flame-retardant system in polypropylene.     

磷–氮系膨胀型阻燃剂改性玻纤增强聚丙烯

采用双螺杆挤出机共混的方法制备了磷–氮系膨胀型阻燃剂与玻璃纤维改性聚丙烯(PP)的共混物,通过垂直燃烧、扫描电子显微镜表征、力学性能测试、氧化诱导期和热重分析等研究了改性体系的阻燃性能、力学性能和热稳定性等。结果表明,磷–氮系膨胀型阻燃剂SS–111提高了玻纤增强PP的阻燃性能,当阻燃剂添加量超过30%后,垂直燃烧等级达到UL94 V–0级;由于玻纤的增强作用,复合体系随阻燃剂SS–111添加量的增大,除弯曲弹性模量较未添加时有600~700 MPa的提高外,其他力学性能变化不大;阻燃剂还使复合体系的氧化诱导期延长,高温氮气条件下,阻燃剂提前分解形成阻隔层减缓了PP的热分解,体系热稳定性提高。     

氢氧化镧对聚丙烯膨胀阻燃体系性能影响

采用燃烧性能测试、热重分析、扫描电镜和力学性能测试等手段,分别研究了氢氧化镧对聚丙烯/磷酸密胺盐/季戊四醇(PP/MP/PER)复合材料阻燃性能和力学性能的影响。结果表明,添加氢氧化镧的PP/MP/PER复合材料的垂直燃烧指数均达到V0级别,当氢氧化镧添加量为0.5 %（质量分数,下同）时,复合材料的极限氧指数可达33.0 %,说明氢氧化镧能在一定程度上提高了PP的阻燃性能,是一种有效的阻燃协效剂。这可能是因为膨胀阻燃PP体系在燃烧过程中,氢氧化镧可与膨胀型阻燃剂反应形成网状结构、提高体系黏度,促进体系形成致密的炭层,提高体系的残炭量。研究还表明,在膨胀阻燃PP体系引入适量的氢氧化镧可在一定程度上提高体系的力学性能。     

纳米改性氢氧化铝在PBT中的阻燃应用

首次采用纳米改性氢氧化铝（CG-ATH）对对苯二甲酸丁二醇酯（PBT）进行阻燃研究,考察了纳米（CG—ATH）的填充量对PBT／CG—ATH复合材料力学性能以及燃烧性能的影响。实验结果表明,随着CG-ATH填充量的增加,复合材料的拉伸强度、断裂伸长率和冲击强度都呈先上升后下降的趋势,在纳米CG-ATH填充量为5％时,冲击强度、断裂伸长率达到最大值,分别为5．0kJ／m^2和15．9％;在CG—ATH填充量达到15％时．拉伸强度达到最大值58．2MPa。纳米CG—ATH具有提高氧指数、降低分解速度的作用,但其分解产物具有促使炭残余物分解的负面作用。