Effects of zinc borate and microcapsulated red phosphorus on mechanical properties and flame retardancy of polypropylene/magnesium hydroxide composites

In this paper, the mechanical properties and flame retardancy of zinc borate (ZB) and microcapsulated red phosphorus (MRP) with modified magnesium hydroxide (MH) in flame-retardant polypropylene (PP) were studied by mechanical properties test, UL-94 test, and thermogravimetric analysis (TGA). The crystallization behaviors of the composites were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The addition of ZB could improve tensile strength and elongation at break of PP/MH composite. The MRP powders had a little effect on the mechanical properties of the PP composites. DSC results showed the addition of ZB and MRP weakened the heterogeneous nucleation effect of MH on PP. The addition of ZB and MRP had a great effect on the flammability of the PP/MH/EG composites. The thermal stability of PP/MH/ZB and PP/MH/ZB/MRP composites was better than that of PP/MH composite.     

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     

PP/SEBS/MH复合材料的制备及其性能研究

采用极限氧指数（LOI）和热重分析（TGA）研究了聚丙烯（PP）/氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）/氢氧化镁（MH）复合材料的阻燃性能和热降解行为;探讨了SEBS和MH分别对PP/SEBS共混体系和PP/SEBS/MH复合材料力学性能和熔体流动速率的影响。结果表明：PP/SEBS/MH复合材料的力学性能和加工流动性能随着MH的质量分数增加而降低;复合材料高温下的热稳定性得到提高,MH分解吸热降低材料的热降解速率;MH以吸热方式在凝缩相和气相中发挥阻燃作用,复合材料阻燃性能得到提高,当MH的质量分数为60%时,LOI可达26.3%。     

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.     

Synthesis of a novel oligomeric intumescent flame retardant and its application in polypropylene

A novel oligomeric phosphorous‐nitrogen containing intumescent flame retardant, poly (4,4‐diamino diphenyl methane‐O‐bicycli pentaerythritol phosphate‐phosphate) (PDBPP), was synthesized and characterized. Thermal stability and flammability properties of polypropylene (PP)/PDBPP composites with various PDBPP loading were investigated by thermogravimetric analysis (TGA), limited oxygen index (LOI), and cone calorimeter, respectively. The results showed that the incorporation of PDBPP could improve both the thermal stability and flame retardancy of PP considerably. PP/30%PDBPP system had a LOI value of 28 and its peak heat release rate was reduced by 60% relative to pure PP. Infrared spectrum and field emission scanning electron microscope measurements revealed that PDBPP and PP/PDBPP composites would form a continuous multicellular char layer containing phosphoric acid when exposed to elevated temperature. It was suggested that the very char layer was responsible for the enhanced thermal stability and improved flame retardancy. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Kinetics of thermo-oxidative degradation of zinc borate/microcapsulated red phosphorus with magnesium hydroxide in flame retarded polypropylene composites

The flammability and the thermo-oxidative degradation kinetics of zinc borate (ZB) and microcapsulated red phosphorus (MRP) with magnesium hydroxide (MH) in flame-retardant polypropylene (PP) composites were studied by limiting oxygen index (LOI), TGA, and FTIR spectroscopy. The results show that ZB/MRP is a good synergist for improving the flame retardancy of the PP composites. The Kissinger and Flynn-Wall-Ozawa methods were used to determine the activation energy (E) for degradation of PP composites. The results from the TGA curves indicate that the thermal stability of PP/MH/ZB and PP/MH/ZB/MRP composites is better than that of PP/MH composites. The kinetic results show that the values of E for degradation of PP/MH/ZB/MRP composites is much higher than those of PP/MH and PP/MH/ZB composites. The FTIR spectra data show that the incorporation of MH improves the thermo-oxidative stability of PP, especially for PP/MH composites with suitable content of MRP at higher temperatures. These data indicate that the synergistic flame retardants used in this work have a great effect on the mechanisms of pyrolysis and combustion of PP/MH composites.     

有机化坡缕石黏土-膨胀型阻燃聚丙烯复合材料的制备及性能

制备了优异阻燃性能(LOI36%)兼具良好力学性能的膨胀型阻燃聚丙烯复合材料OPGS/PA-APP/PP。将有机化坡缕石黏土引入到哌嗪-多聚磷酸铵(PA-APP)膨胀型阻燃(IFR)聚丙烯(PP)复合材料中,通过极限氧指数(LOI)、垂直燃烧(UL-94)、热重分析法(TGA)、扫描电子显微镜(SEM)、通用电子万能试验机研究了有机化坡缕石黏土添加量对PA-APP阻燃聚丙烯复合材料阻燃性能和力学性能的影响。结果表明,添加质量分数为2%的有机化坡缕石黏土提高了该复合材料的阻燃性能和力学性能。此外,所制备样品经垂直燃烧测试可达到阻燃V-0级别。实验证明,有机化坡缕石黏土在膨胀型阻燃聚丙烯复合材料中具有明显的协效阻燃作用。     

Effects of magnesium hydroxide and its surface modification on crystallization and rheological behaviors of polypropylene

In this article, polypropylene composites filled with magnesium hydroxide (PP filled with MH) were prepared in corotating twin-screw extruder. The effects of MH particles content and types of treatment agents on the crystallization and melting behaviors, crystal structure, and rheological properties of PP/MH composites were studied by differential scanning calorimetry (DSC), a wide-angle X-ray diffraction, and dynamic rheological measurements. The DSC results show that MH particles act as a good heterogeneous nucleation effect on PP. Surface treatment of MH weakens its heterogeneous nucleation effect. The nucleating efficiency of MH on PP is found to depend strongly on its content and type of treatment agents. The dynamic rheological behaviors of MH filled PP is found that the complex viscosity (η*) increases with increasing MH content, whereas with increasing filler concentration the network structure becomes the prevailing process, which raises the η* values, especially at the low frequency zone. The η* values of the composites, however, decrease with the addition of various treatment agents. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

Synergistic effects of expandable graphite with magnesium hydroxide on the flame retardancy and thermal properties of polypropylene

In this study, the flammability characterization and synergistic effects of different particle size of expandable graphite (EG) with modified magnesium hydroxide (MH) in flame‐retardant polypropylene (PP) composites were studied by limiting oxygen index (LOI), UL‐94 test, thermogravimetric analysis (TGA), and fourier transform infrared (FTIR) spectroscopy. The results showed that the particle size of EG had a great effect on the flammability of the PP/MH/EG composites. The EG2 with smaller particle size could apparently increase the LOI value and improved the UL‐94 flammability properties rating of the PP composites. The data obtained from the TGA and FTIR curves indicated that the thermo‐oxidative stability of PP/MH/EG composites increased with decreasing particle size of EG. And the smaller the particle size of EG, the higher the residues of the composite. POLYM. ENG. SCI., 47:1756–1760, 2007. © 2007 Society of Plastics Engineers     

PP无卤阻燃复合材料性能研究

采用双辊塑炼机制备了不同组分的聚丙烯(PP)无卤阻燃复合材料。利用差示扫描量热仪(DSC)、偏光显微镜(POM)和扫描电子显微镜(SEM)研究了Mg(OH)2、乙烯-辛烯共聚物(POE)、相容剂PP-g-MAH对PP无卤阻燃复合材料的热行为、结晶形态和微观结构的影响。结果表明:Mg(OH)2和POE两种成核剂的异相成核作用提高了共混物中PP的结晶温度和结晶速率;Mg(OH)2的加入使球晶颗粒变得细小且有碎晶产生;POE大分子链使PP分子链的扩散和堆积受阻,阻碍了晶粒的生长,从而导致PP/Mg(OH)2/POE复合材料结晶度的降低。PP-g-MAH的加入可以提高PP与Mg(OH)2的界面相容性,当PP/Mg(OH)2/POE/PP-g-MAH的配比为80/100/20/2时,PP无卤阻燃复合材料可以同时拥有良好的力学性能和阻燃性能。     

Flammability and mechanical properties of wood flour‐filled polypropylene composites

Polypropylene (PP) composites filled with wood flour (WF) were prepared with a twin‐screw extruder and an injection‐molding machine. Three types of ecologically friendly flame retardants (FRs) based on ammonium polyphosphate were used to improve the FR properties of the composites. The flame retardancy of the PP/WF composites was characterized with thermogravimetric analysis (TGA), vertical burn testing (UL94‐V), and limiting oxygen index (LOI) measurements. The TGA data showed that all three types of FRs could enhance the thermal stability of the PP/WF/FR systems at high temperatures and effectively increase the char residue formation. The FRs could effectively reduce the flammability of the PP/WF/FR composites by achieving V‐0 UL94‐V classification. The increased LOI also showed that the flammability of the PP/WF/FR composites was reduced with the addition of FRs. The mechanical property study revealed that, with the incorporation of FRs, the tensile strength and flexural strength were decreased, but the tensile and flexural moduli were increased in all cases. The presence of maleic anhydride grafted polypropylene (MAPP) resulted in an improvement of the filler–matrix bonding between the WF/intumescent FR and PP, and this consequently enhanced the overall mechanical properties of the composites. Morphological studies carried out with scanning electron microscopy revealed clear evidence that the adhesion at the interfacial region was enhanced with the addition of MAPP to the PP/WF/FR composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of boron‐containing materials on the flammability and thermal degradation of polyamide 6 composites containing melamine

Three different boron‐containing substances—zinc borate (ZnB), borophosphate (BPO₄), and a boron‐ and silicon‐containing oligomer (BSi)—were used to improve the flame retardancy of melamine in a polyamide 6 (PA‐6) matrix. The combustion and thermal degradation characteristics of PA‐6 composites were investigated with the limiting oxygen index (LOI), the UL‐94 standard, thermogravimetric analysis (TGA)/Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). A slight increase was seen in the LOI values of a sample containing BSi (1 wt %). BPO₄ at high loadings showed a V0 rating (indicating the best flame retardancy) and slightly lower LOI values in comparison with samples with only melamine. For ZnB and BSi, glassy film and char formation decreased the dripping rate and sublimation of melamine, and this led to low LOIs. According to the TGA–FTIR results, the addition of boron compounds did not change the decomposition product distribution of melamine and PA‐6. The addition of boron compounds affected the flame retardancy by physical means. The TGA data showed that boron compounds and melamine reduced the decomposition temperature of PA‐6. According to the DSC data, the inclusion of boron compounds increased the onset temperature of sublimation of melamine and also affected the flame retardancy negatively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

膨胀型阻燃剂在聚丙烯中的应用研究

使用磷酸、季戊四醇、三聚氰胺合成了一种膨胀型阻燃剂。采用热重分析（TGA）、红外光谱分析（FTIR）、氧指数晨6定和垂直燃烧实验，研究了所合成的膨胀型阻燃剂对聚丙烯的阻燃作用。与普通的膨胀型阻燃剂和包覆型膨胀阻燃剂的对比研究表明，该阻燃剂对聚．丙烯的阻燃性能优良，达到相同的阻燃效果（聚丙烯氧指数达到34％）时，用量较其它两种膨胀型阻燃剂明显减少。抗析出和防湖性能较其它两种膨胀型阻燃剂也有明显改善。     

苯基聚硅氧烷微胶囊化聚磷酸铵的制备及其在PP中阻燃性能研究

采用苯基三甲氧基硅烷为前驱体,通过溶胶凝胶法制备出苯基聚硅氧烷微胶囊化聚磷酸铵（MAPP）。将MAPP作为阻燃剂,季戊四醇（PER）作为成炭剂,制备阻燃聚丙烯（PP）。用傅里叶红外光谱、扫描电子显微镜、能谱仪及热重分析仪对MAPP进行表征。结果表明,聚磷酸铵（APP）被苯基聚硅氧烷成功包覆;较之APP,MAPP的热稳定性和疏水性显著提高;MAPP的阻燃性能优于APP,PP/MAPP/PER复合材料达到V-0级别;阻燃剂及成炭剂的加入对PP的结晶行为有促进作用。     

Experimental investigation of flame retardancy and mechanical properties of APP/EG/TPU multilayer composites prepared by microlayer coextrusion technology

In this paper, ammonium polyphosphate(APP)/expandable graphite(EG)/thermoplastic polyurethane (TPU) composites were prepared by microlayer coextrusion technology, APP and EG fillers had good synergistic flame retardancy and excellent dispersion in TPU matrix, which greatly improved the flame retardancy and mechanical properties of multilayer composites. The dispersion of APP and EG in TPU was characterized by using SEM, the flame retardancy of composites was characterized by using UL94 and LOI, the thermal stability of composites was characterized by using TGA and DTG, and tensile test was used to characterized the mechanical properties of composites. SEM showed that the microlayer coextrusion technology significantly improved the dispersion of APP and EG in TPU. As showed by the experimental results, the vertical combustion level of ordinary blended composites reached V-2 after adding only one kind of filler either APP or EG, and the vertical combustion level of ordinary blended composites reached V-0 with APP and EG applied together, while the vertical combustion level of microlayer coextruded composites all reached V-0 when the total addition of APP and EG was 15%. In particular, the LOI value of microlayer coextruded composites was 30.9%, while the LOI value of ordinary blended composites only was 27.9% when APP: EG = 1: 1. At this time, the flame retardancy level of APP/EG/TPU composites was the best. In addition, the thermal stability and mechanical properties of microlayer coextruded composites were far superior to ordinary blended composites. In conclusion, the synergistic flame retardancy of APP and EG fillers and the dispersion of APP and EG fillers in TPU matrix played a significant role in enhancing flame retardancy and mechanical properties.     

Effects of ammonium polyphosphate and triphenyl phosphate on the flame retardancy,thermal, and mechanical properties of glass fiber–reinforced PLA/PC composites

The purpose of this study is to increase of the flammability properties of the glass fiber (GF)–reinforced poly (lactic acid)/polycarbonate (PLA/PC) composites. Ammonium polyphosphate (APP) and triphenyl phosphate (TPP) were used as flame retardants that are including the organic phosphor to increase flame retardancy of GF‐reinforced composites. APP, TPP, and APP‐TPP mixture flame retardant including composites were prepared by using extrusion and injection molding methods. The properties of the composites were determined by the tensile test, limiting oxygen index (LOI), differential scanning calorimetry (DSC), and heat release rate (HRR) test. The minimum T_g value was observed for the TPP including PLA/PC composites in DSC analysis. The highest tensile strength was observed in GF‐reinforced PLA/PC composites. In the LOI test, GF including composite was burned with the lowest concentration of oxygen, and burning time was the longest of this composite. However, the shortest burning time was obtained by using the mixture flame retardant system. The flame retardancy properties of GF‐reinforced PLA/PC composite was improved by using mixture flame retardant. When analyzed the results of HRR, time to ignition (TTI), and mass loss rate together, the best value was obtained for the composite including APP.     

Influence of Maleic Anhydride Grafted Ethylene-Vinyl Acetate Copolymer as a Compatibilizer on Combustion and Thermal Stability Properties of Magnesium Hydroxide Flame-Retardant Ethylene Propylene Diene Terpolymer Composites

New halogen-free, flame-retardant ethylene propylene diene terpolymer (EPDM)/organically modified magnesium hydroxide (MH) composites have been prepared via melt compounding method, using maleic anhydride grafted ethylene-vinyl acetate copolymer (MAH-g-EVA) as a compatibilizer. Influence of MAH-g-EVA on the fire and thermal properties of the composites are investigated by means of LOI, UL94 vertical burning, cone calorimeter tests, thermogravimetric analysis (TGA), real time fourier-transform infrared spectroscopy (RTFTIR) and environmental scanning electron microscopy (ESEM). The results show that MAH-g-EVA plays a positive role in improving the flame retardancy and thermal stability of the composites.     

NPM阻燃聚丙烯的研究

通过氧指数(LOI)、水平燃烧(HB)、热重分析(TGA)、扫描电镜(SEM)和红外(IR)等表征方法,研究了单组分膨胀型阻燃剂新戊二醇磷酸脂三聚氰胺盐(NPM)阻燃PP体系的阻燃性能、燃烧炭层结构及阻燃机理,评价了NPM的添加量对体系物理性能的影响。结果表明:PP/NPM(100/30)体系的氧指数为26．8%,600℃时的成炭率为8．30%,NPM显著提高了体系的热稳定性。     

Surface photografting: New application for flame retardant finishing of polyamide6.6 (PA6.6) fabric

Surface photografting modification with maleic anhydride (MAn) under UV irradiation in association with a post reaction with triethanolamine has been used to improve the flame retardancy of polyamide6.6 (PA6.6) fabric in this study. The effects of irradiation time and monomer concentration on the fabric surface grafting were investigated. The flame retardancy and thermal decomposition behavior of the samples were characterized by limiting oxygen index test (LOI), thermogravimetric analysis (TGA), and differential scanning calorimetric (DSC), and the results indicate that flame retardancy of the treated PA6.6 fabric samples has been significantly improved. The chemical structures of the treated samples' surface were characterized by attenuated total reflection infrared spectroscopy (ATR‐FTIR), and the possible photochemical mechanisms were discussed. It is suggested that this could be the first time to use photografting technology to enhance the flame retardancy of PA6.6 fabric. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011