Melt density and volume flow rate of polypropylene/Al(OH)3/Mg(OH)2 flame retardant composites

Polypropylene (PP) flame retardant composites filled with aluminum hydroxide (Al(OH)₃), magnesium hydroxide (Mg(OH)₂) as well as zinc borate (ZB) were prepared with a twin‐screw extruder. The melt volume flow rate (MVR) and density of the composites were measured by means of a melt flow rate instrument under experimental conditions with temperature of 180°C and load varying from 2.16 to 5 kg, to identify the effects of the particle size and content. The results showed that MVR of the composites decreased with an increase of the filler weigh fraction (?_f) when ?_f was more than 10 phr. The MVR decreased first and then increased with an increase of the filler diameter (d). The melt density (ρ_m) of the composites increased linearly with an increase of ?_f and decreased linearly with the increase of d. In addition, the ρ_m increased with an increase of load. Under the same experimental conditions, the MVR decreased slightly while the ρ_m increased somewhat with addition of ZB for the PP/Al(OH)₃/Mg(OH)₂ composite systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

PP/AI(OH)_3/Mg(OH)_2复合材料阻燃性能研究

制备了PP(聚丙烯)/Al(OH)_3/Mg(OH)_2/硼酸锌和PP/Al(OH)_3/Mg(OH)_2阻燃复合材料,并测定了复合材料的氧指数(OI)、水平燃烧速度和烟密度。结果表明,OI随着阻燃剂质量分数的增加而升高,随着粒径的增大而降低;燃烧速度随着阻燃剂用量的增加而下降,随着粒径的增大先升后降;烟密度随着阻燃剂用量的增加而降低,随着粒径的增大而增大;添加硼酸锌后具有显著的抑烟效果。     

PP/Al(OH)_3/Mg(OH)_2阻燃复合材料的流动性能

制备了PP/Al(OH)_3/Mg(OH)_2阻燃复合材料,利用熔体流动速率仪测定了复合材料的熔体体积流动速率(MVR),并计算出其密度。结果表明:MVR随着阻燃剂质量分数的增加而减小,随着阻燃剂粒径的增加先降后升;复合材料密度随阻燃剂用量的增加呈近似线性增加,随阻燃剂粒径的增加呈近似线性降低,随着载荷的增加而提高。     

Melt shear viscosity of PP/Al(OH)3/Mg(OH)2 flame retardant composites at high extrusion rates

The melt apparent shear viscosity (η_a) of polypropylene (PP) composites filled with aluminum hydroxide [Al(OH)₃] and magnesium hydroxide [Mg(OH)₂] was measured by means of a capillary rheometer under experimental conditions of temperature ranging from 180 to 200°C and apparent shear rate varying from 10 to 2 × 10³ s⁻¹, to identify the effects of the filler particle content and size on the melt viscosity. The results showed that the melt shear flow of the composites obeyed the power law and presented pseudoplastic behavior. The dependence of η_a on temperature was consistent with the Arrhenius equation. The sensitivity of η_a for the composite melts to temperature was greater than that of the unfilled PP, and weakened with increasing apparent shear rate. The η_a increased linearly with an increase of the weigh fraction of the flame retardant, especially in the low apparent shear rate region. The η_a of the composites decreased slightly with an increase of particle size of flame retardant. Moreover, the variation for the η_a with particle size of flame retardant was much less than with apparent shear rate under these test conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of nitrogen–phosphorus fire retardant blended with Mg(OH)2/Al(OH)3 and nano‐SiO2 on fire‐retardant behavior and hygroscopicity of poplar

The aim of the study was to screen any possible synergistic effects related to the combination of nitrogen–phosphorus fire retardant and Mg(OH)₂/Al(OH)_3. This combination is used to improve fire performance, especially smoke suppression of poplar through ultrasonic wave impregnation after microwave treatment. In this study, nano‐SiO₂ was used to impregnate poplar treated with nitrogen–phosphorus fire retardant and form a hydrophobic layer on wood cells in order to improve hygroscopicity and reduce water uptake. Cone tests and thermal analysis showed that poplar treated with blended fire retardant had improved behavior. Results show that a 20% and 25% nitrogen–phosphorus fire‐retardant solution (blended by adding 10% Mg(OH)₂/Al(OH)₃ based on the dry weight of nitrogen–phosphorus fire retardant) was more effective for smoke suppression. The heat release rate, total heat release, and total smoke production of a 25% nitrogen–phosphorus fire‐retardant solution blended by adding 10% Mg(OH)₂/Al(OH)₃ showed significant reduction. The char residual yield showed a marked increase to 35.5%. Fourier transform infrared analysis suggested a –CH₂–Si–CH₂– and Si–O–C stretching vibration in nano‐SiO₂ treated poplar, which greatly decreased the hygroscopicity of fire‐retardant‐treated poplar. Copyright © 2014 John Wiley & Sons, Ltd.     

Heat resistant properties of PP/Al(OH)<Subscript>3</Subscript>/Mg(OH)<Subscript>2</Subscript> flame retardant composites

Vicat softening point temperature (T _V) and heat deflection temperature (T _d) are important parameters for characterization of heat resistant properties of polymeric materials. PP/Al(OH)₃/Mg(OH)₂ flame retardant composites were prepared using a twin-screw extruder, and the T _V and T _d of the composites were measured. The results showed that the T _V and T _d increased nonlinearly with an addition of the weight percentage of the flame retardant additives except for individual data points, while the T _V and T _d decreased with increasing the filler particle size when the content of flame retardant additives was constant. Under the same conditions, filling small amount of zinc borate into the composites might improve the heat resistant properties of the composite systems. Moreover, the morphology of the impact fracture surface of the specimens was observed by means of scanning electron microscope to understand the dispersion and distribution of the filler particles in the PP matrix.     

Thermal behavior and flame retardancy of flexible poly(vinyl chloride) treated with Al(OH)3 and ZnO

Al(OH)₃ as flame retardant and smoke suppressant for flexible poly(vinyl chloride) was evaluated alone and with ZnO, using thermal analytical techniques, limiting oxygen index and smoke density rating tests. The thermal behavior and flammability of the samples treated with Al(OH)₃ and ZnO were studied by differential thermal analysis and thermogravimetric analysis. The activation energy was calculated by using the Vyazovkin model‐free kinetic and Kissinger methods. The results showed that the flame‐retardant and smoke‐suppressant properties of the samples treated with Al(OH)₃ and ZnO were related to the content of ZnO and the thermal effect during the process of thermal degradation of the samples. Copyright © 2005 Society of Chemical Industry     

超微细改性Al(OH)3填充LDPE/EVA的研究

Al(OH）3是LDPE／EVA主要的阻燃，消烟填充剂。研究了不同粒度，表面处理及填充量的Al(OH）3对LDPE／EVA的氧指数（OI），烟密度等级（SDR）和物理机械性能的影响。     

Mg(OH)_2阻燃热塑性聚烯烃弹性体的研究

采用5种表面处理剂对氢氧化镁(Mg(OH)2)进行表面改性,并以热塑性聚烯烃弹性体(TPO)为基体树脂,制备了TPO/Mg(OH)2阻燃材料。通过氧指数(OI)、垂直燃烧和拉伸性能测试,研究了表面处理剂的种类、Mg(OH)2用量和粒径等对TPO/Mg(OH)2阻燃材料燃烧性能和力学性能的影响。OI测试结果表明,钛酸酯改性的粒径为2μm的Mg(OH)2使体系的OI达27.8%;改性Mg(OH)2用量为70份时成为难燃材料。垂直燃烧测试结果表明,100份改性Mg(OH)2使材料的燃烧等级达到FV-0级,无法引燃。力学性能测试结果表明,钛酸酯改性的粒径为2μm的Mg(OH)2使材料保持较高的应变;70份的Mg(OH)2使阻燃材料的拉伸屈服应力和拉伸断裂应力达到最大值。     

氢氧化铝在丁苯橡胶中的阻燃性研究

研究了不同品种无机阻燃剂在丁苯橡胶中的氧指数(OD值及其有关性能。结果表明，单用A1(OH)3时OI值比较高，燃烧时没有可见的烟雾，随Al(OH)3用量提高OI值上升，当用量达12O份时，OI值达27。以Al5l改性Al(OH)3 ，未能提高OI值，物理机械性能稍有改善。Al(OH)3粒径微细化能有效提高OI及物理机械性能。     

PP/Al(OH)_3/Mg(OH)_2复合材料的导热性能

制备了PP（聚丙烯）/Al(OH)₃/Mg(OH)₂导热复合材料,并用稳态平板导热系数测试仪在不同测试温度下测定该复合材料的导热系数。结果表明,加入Al(OH)₃和Mg(OH)₂使PP导热系数提高。复合材料的导热系数随着填料含量的增加而非线性提高,随着测试温度的升高而非线性提高,随着填料粒径的增大而非线性增大。     

超微细Mg(OH)2复合阻燃改性PP-R的研究

研制了超微细Mg(OH)2和少量的十溴联苯醚复配阻燃剂与无规共聚聚丙烯(PP-R)的填充共混复合材料,研究了复配阻燃剂的用量和硅烷偶联剂对复合材料力学性能和阻燃性能的影响。结果表明,复配阻燃剂用量的增加对材料拉伸强度有较明显的影响,用量在10份左右时缺口冲击强度达到最大;用硅烷偶联剂处理的填料可改善复合材料的各项性能。复配阻燃剂显著提高了复合材料的阻燃性能,在用量为15份时,氧指数达到27％;用量超过20份,垂直燃烧性为FV-1级。微量发烟。     

Physical and mechanical properties of Al(OH)3/polypropylene composites modified by in situ‐functionalized polypropylene

Al(OH)₃/polypropylene (PP) composites modified by in situ‐functionalized polypropylene (FPP) were prepared by a one‐step melt‐extrusion process. The effect of in situ FPP on the crystallization and melting behavior, melt‐flow index, limiting oxygen index, thermal degradation, mechanical properties, and fracture morphology of Al(OH)₃/PP composites was studied. Formation of in situ FPP resulted in a decreased crystallization temperature and melting point of PP in the composites, an increased melt‐flow index, and improved tensile and flexural strengths of Al(OH)₃/PP composites, whereas the thermal degradation behavior and limiting oxygen index was not been influenced. The impact strength of the Al(OH)₃/PP composites modified by in situ FPP depended upon the content of the initiator, dicumyl peroxide, and the monomer, acrylic acid. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2850–2857, 2002; DOI 10.1002/app.10269     

Mechanical properties and fracture morphology of Al(OH)3/polypropylene composites modified by PP grafting with acrylic acid

Al(OH)₃/polypropylene (PP) composites modified by polypropylene grafted with acrylic acid (FPP) were prepared by melt extrusion. Effect of PP grafting with acrylic acid on mechanical properties and fracture morphology of Al(OH)₃/polypropylene composites were investigated. Although incorporation of Al(OH)₃ reduced the mechanical properties of PP, addition of FPP increased the mechanical properties of Al(OH)₃/PP composites. It is suggested that addition of FPP improve the dispersion of Al(OH)₃ and the interfacial interaction between filler and matrix. Mechanical properties of Al(OH)₃/FPP/PP composites depend on the grafting rate and the content of FPP. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2617–2623, 2001     

有机硅在无卤阻燃EVA中的应用

有机硅作为ＥＶＡ－Ｍｇ（ＯＨ）２阻燃体系的加工助剂,降低了挤出加工时的扭矩。同时又量一种良好的分散剂,根高Ｍｇ（ＯＨ）２在ＥＶＡ中的分散性,从而使ＥＶＡ／Ｍｇ（ＯＨ）２的力学性能降低和;另外,有机硅又是阻燃协效剂,能有效地提高ＥＶＡ／Ｍｇ（ＯＨ）２阻燃体系的氧指数,其机理是含硅高聚物在燃烧时,硅残留在凝聚相中,形成玻璃态的炭化人而阻止热和物质的传播。     

Flammability and mechanical properties of Al(OH)3 and BaSO4 filled polypropylene

The flammability and mechanical properties of Al(OH)₃/BaSO₄/polypropylene (PP) composites were investigated. The flow, morphological, and thermal properties were also analyzed by melt flow index (MFI), Scanning electron microscopy (SEM), and Differential scanning calorimeter (DSC) studies, respectively. Total filler amount was fixed at 30 wt % to optimize physical characteristics of the composites. In addition to the flame retardant filler Al(OH)₃, BaSO₄ was used to balance the reduction in impact strength at high filler loadings. Substantial improvement in mechanical properties was achieved for 20 wt % Al(OH)₃ (i.e., 10 wt % BaSO₄) composition while maximum flammability resistance was obtained for 30 wt % Al(OH)₃ composite. SEM studies showed that the presence of aggregated Al(OH)₃ particles led to low interfacial adhesion between them and PP matrix ending up with decreased mechanical strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Interfacial interaction in AI(OH)3/polypropylene composites modified by insitu‐functionalized polypropylene

To investigate the interfacial interaction of AI(OH)₃/polypropylene (PP) composites modified by in situ‐functionalized polypropylene (FPP), AI(OH)₃/polypropylene (PP) composites containing a low AI(OH)₃ content, modified by in situ‐grafted acrylic acid, were prepared by a one‐step melt‐extrusion process. The effect of in situ FPP on the crystallization and melting behavior, crystalline morphology of the composites, and interfacial interaction between the filler and PP was investigated. The crystallization and melting behavior and crystalline morphology of PP in the composites depended upon the interfacial physical [heterogeneous nucleation of AI(OH)₃; cocrystallization and compabilitization of PP with in situ FPP] and the interfacial chemical interaction between both the components in the composites. FTIR results indicated that there exists a chemical reaction between AI(OH)₃ and in situ FPP. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 110–120, 2002; DOI 10.1002/app.10270     

Thermal properties and flame retardance of Al(OH)3/polypropylene composites modified by polypropylene grafting with acrylic acid

The effect of polypropylene grafting with acrylic acid, PP‐g‐AA (FPP), on crystallization and melting behavior, thermal degradation, and limiting oxygen index of Al(OH)₃/PP composites were investigated. The results indicated that crystallization temperature of PP shifted to high temperature with increasing content of Al(OH)₃ because of the interfacial heterogeneous nucleation of Al(OH)₃ and further increased by the addition of FPP and with increasing FPP content because of the improvement of the dispersion of Al(OH)₃ in PP matrix and the increase in the nucleating sites of Al(OH)₃. With adding Al(OH)₃ and increasing the content of Al(OH)₃, limiting oxygen index values of composites increased and further improved by adding FPP. This is attributed to the presence of an interfacial interaction between FPP and Al(OH)₃. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2679–2686, 2001     

Mechanical properties of Mg(OH)2/polypropylene composites modified by functionalized polypropylene

Modified Mg(OH)₂/polypropylene (PP) composites were prepared by the addition of functionalized polypropylene (FPP); and acrylic acid (AA) and by the formation of in situ FPP. The effects of the addition of FPP and AA and the formation of in situ FPP on the mechanical properties of Mg(OH)₂/PP composites were investigated. Experimental results indicated that the addition of Mg(OH)₂ markedly reduced the mechanical properties of PP. The extent of reduction in notch impact strength of PP was higher than that in flexural strength and tensile strength. However, tensile modulus and flexural modulus increased with increased Mg(OH)₂ content. The addition of FPP facilitated the improvement in the flexural strength and tensile strength of Mg(OH)₂/PP composites. The higher the Mg(OH)₂ content was, the more significant the effect of FPP was. The incorporation of AA resulted in further increased mechanical properties, in particular the flexural strength, tensile strength, and notch impact strength of Mg(OH)₂/PP composites containing high levels of Mg(OH)₂. It not only improved mechanical properties but also increased the flame retardance of Mg(OH)₂/PP composites. Although the mechanical properties of composites modified by the formation of in situ FPP were lower than those of composites modified by only the addition of AA in the absence of diamylperoxide, the mechanical properties did not decline with increased Mg(OH)₂ content. Moreover, the mechanical properties increased with increasing AA content. The addition of an oxidation resistant did not influence the mechanical properties of the modified Mg(OH)₂/PP composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2139–2147, 2003     

Effect of particle size on flame retardancy of Mg(OH)2‐filled ethylene vinyl acetate copolymer composites

Four kinds of magnesium hydroxide (Mg(OH)₂) with different particle sizes are chosen and mixed with ethylene vinyl acetate copolymer (EVA) to investigate the effect of particle size on the flame retardancy of composites, which is evaluated by limiting oxygen index (LOI) testing, horizontal fire testing, and cone calorimeter. When Mg(OH)₂ filling level changes from 35 to 70 wt %, the composites filled with nano‐Mg(OH)₂ do not always possess the best flame retardancy, and among the composites filled with micro‐Mg(OH)₂, the composites filled with 800 mesh Mg(OH)₂ show the best flame retardancy; however, the composites filled with 1250 mesh presents the worst one. So the effect of particle size on the flame retardancy of micro‐Mg(OH)₂‐filled EVA is not linear as expected. All the differences are thought to result from both particle size effect and distributive dispersion level of Mg(OH)₂. To prepare the composites with better mechanical properties and flame retardancy, authors suggested that Mg(OH)₂ of smaller size should be chosen as flame retardant, and good dispersion of Mg(OH)₂ particles also should be assured. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4461–4469, 2006