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     

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     

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     

A study of the flame‐retardant properties of polypropylene/Al(OH)3/Mg(OH)2 composites

Polymeric materials are used extensively, but their applications are limited because many of them are flammable. Therefore ways to make them flame retardant have received much attention. In this work, polypropylene (PP) was used as the matrix resin, aluminium hydroxide (Al(OH)₃) and magnesium hydroxide (Mg(OH)₂) as flame‐retardant additives and zinc borate (ZB) as a flame‐retardant synergist. PP/Al(OH)₃/Mg(OH)₂ and PP/Al(OH)₃/Mg(OH)₂/ZB flame‐retardant composites were prepared with a twin‐screw extruder. The flame‐retardant properties, i.e. oxygen index (OI), burning velocity and smoke density, of the composites were measured. The results showed that OI increased with an increase of the filler content and decreased with an increase of the filler particle diameter. The burning velocity decreased with an increase of the filler content, while it first increased and then decreased with an increase of the filler particle diameter. The smoke density decreased with an increase of the filler content and increased with an increase of the filler particle diameter. There was a flame‐retardant synergy between Al(OH)₃/Mg(OH)₂ and ZB in the composites, and the smoke suppression effect was marked when ZB was added. Copyright © 2009 Society of Chemical Industry     

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     

ZnO/MoO3/Al(OH)3阻燃聚丙烯材料的制备及性能

采用水热法制备了一维材料ZnO和MoO_3纳米线(nanowires,NWs),并通过SEM和XRD对纳米线的形貌和结构进行了表征。将一维纳米线和纳米氢氧化铝(ATH)与聚丙烯(PP)熔融共混制备了ZnO/MoO_3/Al(OH)_3/PP复合材料(NWs/ATH/PP)。利用TGA、极限氧指数(LOI)测定仪和锥形量热仪(CCT)表征了复合材料的热稳定性和燃烧性能,利用万能材料试验机测试了复合材料的力学性能。结果表明:当添加质量分数3.75%ZnO纳米线、质量分数3.25%MoO_3纳米线和质量分数21.00%纳米ATH时,NWs/ATH/PP复合材料的初始分解温度较纯PP增加了17.8℃,残重率为24.6%,峰值热释放速率(PHRR)和总热释放量(THR)分别下降了54.3%和25.7%,LOI提高7.1%。SEM结果显示:NWs/ATH/PP的残炭表面致密、连续且平整。     

超细Al(OH)3对PP球晶结构和性能的影响

分别用超细Al(OH)_3和普通Al(OH)_3填充聚丙烯(PP),研究了超细Al(OH)_3/PP和普通Al(OH)_3/PP体系的力学性能、熔体流动性、阻燃性能及其结晶的微观形态。结果表明,加入适量的超细Al(OH)_3对PP具有增韧效应;超细Al(OH)_3能使PP球晶显著细化;与普通Al(OH)3/PP相比,超细Al(OH)_3/PP具有较好的抗冲击性能、拉伸性能和弯曲性能,但熔体流动性低。     

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     

丙烯酸改性卤锑阻燃PP的力学性能

在过氧化二异丙苯(DCF)存在或不存在条件下,制备了丙烯酸(AA)改性Sb2O3／聚丙烯(PP)母料、十溴联苯醚／PP母料及其相应的卤锑阻燃PP。研究了Sb2O3、十溴联苯醚和不同含量卤锑阻燃剂对PP力学性能的影响。结果表明,随Sb2O3含量增加,PP的拉伸和弯曲性能提高,缺口冲击强度降低。对于改性阻燃PP,无DCP时,加入AA有利于阻燃PP拉伸强度提高。但对其他力学性能影响不大。添加DCP提高了PP的弯曲强度。但AA用量高时,缺口冲击强度降低。AA改性阻燃PP的力学性能随着DCP用量增加而降低,尤其缺口冲击强度。退火处理使阻燃PP力学性能提高。     

Crystallization and melt behavior of Mg(OH)2/PP composites modified by functionalized polypropylene

The crystallization and melting behavior of Mg(OH)₂/PP composites modified by the addition of functionalized polypropylene (FPP) or acrylic acid (AA) and the formation of in situ FPP were investigated by DSC. The results indicated that addition of FPP increased the crystallization temperatures of PP because of the nucleation effect of FPP. The formation of in situ FPP resulted in a reduced crystallization rate, melting point, and degree of crystallization attributed to the decreased regularity of the PP chain. For Mg(OH)₂/PP composites, the addition of Mg(OH)₂ increased the crystallization temperatures of PP resulting from a heterogeneous nucleation effect of Mg(OH)₂. The addition of FPP into Mg(OH)₂/PP composites further enhanced the crystallization temperatures of PP. It is suggested that there is an activation of FPP to the heterogeneous nucleation effect on the Mg(OH)₂ surface. The addition of AA also increased the crystallization temperatures of PP in Mg(OH)₂/PP composites, although the crystallization temperature of PP was not influenced by the AA content, which is explained by the heterogeneous nucleation effect of the Mg(OH)₂ surface activated by FPP and AA. A synergistic effect on the crystallization of PP in Mg(OH)₂/PP composites further increased the crystallization temperatures of PP. However, The crystallization temperatures of Mg(OH)₂/PP composites modified by in situ FPP were lower than those of Mg(OH)₂/PP composites modified by addition of either FPP or AA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3610–3621, 2004     

高填充聚乙烯／氢氧化铝体系的交联改性

聚乙烯中大量填充氢氧化铝可有效地提高阻燃性能,但导致聚乙烯的力学性能明显下降。本文用过氧化二异丙苯（ＤＣＰ）对线型低密度聚乙烯／氢氧化铝（１００／１５０）体系进行交联,发现适开交联时,可同时提高体系的拉伸强度和断裂伸长率。顺丁橡胶与ＤＣＰ有协同作用。     

Fracture morphology of Mg(OH)2/polypropylene composites modified by functionalized polypropylene

The morphologies of the fracture surface under impact and flexural testing of Mg(OH)₂/Polypropylene (PP) composites and their modified composites were investigated by scanning electron microscopy. Experimental results indicated that addition of functionalized polypropylene (FPP) and acrylic acid (AA) and the formation of in situ FPP changed the fracture morphologies of Mg(OH)₂/PP composites. We believe that addition of these modifiers improved the interfacial interaction and enhanced the interface adhesion between the particle and the matrix in Mg(OH)₂/PP composites. The degree of improvement was more significant in Mg(OH)₂/PP composites modified by the formation of in situ FPP. At low Mg(OH)₂ content, 2 phr AA exhibited a marked effect, but at high Mg(OH)₂ content, 4 phr AA afforded good effect. Due to the improved interface adhesion by interface interactions the fracture mechanism transformed from interface debonded fracture into a matrix fracture. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2148–2159, 2003     

原位形成FPP偶联Al(OH)3/PP中的界面相互作用研究

制备低含量Al(OH)3填充PP复合材料[Al(OH)3/PP]，研究原位形成的官能团化聚丙烯（FPP）在Al(OH)3/PP中的结晶、熔融行为，结晶形态，以及与各组分间的相互作用。研究认为，在复合材料中存在Al(OH)3与FPP间的化学作用，FPP与PP的相容与共结晶作用，Al(OH)3表面异相诱导成核作用，FPP对Al(OH)3表面异相诱导成核作用的活化作用等，从而改善了Al(OH)3/PP的物理与力学性能。     

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。     

PP/针形纳米CaCO3复合材料的力学性能

用硬脂酸皂化改性针形纳米CaCO3表面后,将其与聚丙烯(PP)共混、挤出和注塑,制成PP／CaCO3纳米复合材料。与纯PP相比,填充针形纳米CaCO3的体积分数为4.21％时,PP体系的冲击强度和断裂伸长率分别提高了49％,339％,拉伸强度下降2．7％。改性后的纳米CaCO3与PP之间的界面作用与改性前相比有所减弱,冲击断面扫描电子显微镜照片显示,针形纳米CaCO3均匀地分散在PP基体中。偏光显微照片显示,针形纳米CaCO3对PP有明显的异相成核作用。     

Changes in morphology and properties by grafting reaction in PP/EOR/CaCO3 ternary composites

The phase morphology and mechanical properties of polypropylene (PP) composites containing ethylene–octene elastomer (EOR) and calcium carbonate (CaCO₃) filler were investigated by comparing the toughening effect of unmodified EOR with EOR grafted with maleic anhydride (EOR–MA). EORs of various MA contents were prepared by free‐radical grafting of MA onto the EOR backbone using a reactive extrusion process. The composite morphology was directly explored by scanning electron microscopy technique and indirectly explored by differential scanning calorimetry and dynamic mechanical analysis. Separate dispersion of the elastomer and filler particles was achieved by using unmodified EOR. Modification of EOR by maleic anhydride grafting resulted in encapsulation of the filler particles. The mechanical properties of the composites were found to depend mainly on composite morphology and composition and, to a lesser degree, on maleic anhydride concentration. The results of this study showed that when composites contained an equal or higher amount of elastomer relative to filler, a composite with a separate dispersion structure was preferred. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3557–3562, 2003     

甲醇分解铝酸钠溶液制备大颗粒氢氧化铝的工艺与表征

对甲醇分解NaAl(OH)4溶液制备大颗粒Al(OH)3进行了工艺研究,考察了分解温度、分子比(Na2O/Al2O3摩尔比)、Na2O浓度、硅量指数(Al2O3/SiO2质量比)、搅拌速度和甲醇用量对产品粒度和形貌的影响. 结果表明,在NaAl(OH)4溶液的Na2O浓度为180 g/L、分子比为1.5~1.6,硅量指数550以上及甲醇与NaAl(OH)4溶液等体积的优化条件下,控制分解温度60℃,可得到平均粒径达80 mm的球形Al(OH)3. 甲醇的加入改变了Al(OH)3生长基元的径向和轴向生长速率,甲醇量越大,径向生长速率越快,生长基元越薄. 当甲醇与NaAl(OH)4溶液体积比为1:1时,Al(OH)3生长基元的厚度在100 nm左右. 随分解温度升高,Al(OH)3由Bayerite型向Gibbsite型转变,热重-差热值与理论值吻合.     

氢氧化铝和氢氧化锶复合粉末的制备及热处理

采用活化铝-锶合金粉末水解反应制备氢氧化铝和氢氧化锶复合粉末，并在700℃下进行热处理，利用XRD，SEM，BET和TG—DTG等分析技术对复合粉末结构、性能及热处理进行研究。结果表明，铝-锶合金粉末水解反应产物为氢氧化铝和氢氧化锶的复合粉末，微观形貌为1～3μm片状小颗粒叠加的团聚颗粒，BET比表面积较大。达到45．2m^2／g。TG—DTG结果显示，在70～190℃，八水氢氧化锶中8个结晶水脱水，在190～650℃，氢氧化铝和氢氧化锶热分解。经700℃下热处理1h后，其相组成、微观形貌、BET比表面积都将发生较大的变化。     

Effects of the Treatment of Al(OH)3 by a Silane Coupling Agent on the Tensile Properties of PVC/Al(OH)3 Composite

The present work deals with the study of a composite based on poly(vinyl chloride) (PVC) and aluminum hydroxide (Al(OH)₃) which is treated with different concentrations of the silane coupling agent N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

The composites containing untreated Al(OH)₃ and those treated with the coupling agent were prepared by melt mixing using a two-roll mill.

Analysis of the treated filler by means of Fourier Transform Infrared spectroscopy (FTIR) showed the formation of oligoaminosilanes resulting from the condensation of the silane coupling agent.

The tensile properties of the PVC/Al(OH)₃ composite reflected the effect of the addition of the mineral filler and also the influence of the chemical treatment on the interfacial adhesion. The incorporation of aluminum hydroxide into PVC resulted in an increase of Young's modulus and the yield stress.

From the calculation of a parameter B which was used to quantify the state of adhesion between the polymeric matrix and the filler, it was concluded that the surface chemical treatment of the filler with the silane coupling agent leads to higher reinforcement as a result of the interfacial interactions developed between PVC and Al(OH)_3.     

氢氧化铝对有机硅电子灌封胶性能的影响

以端乙烯基硅油为基胶、含氢硅油为交联剂、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)为表面处理剂、Al(OH)3或Al(OH)3/铂络合物为阻燃剂,制备阻燃型有机硅电子灌封胶。研究结果表明:对Al(OH)3表面进行处理、降低其粒径、增加其含量、Al(OH)3/铂络合物并用等均有利于提升灌封胶的阻燃性能;当w(KH-570)=0.5%[相对于Al(OH)3质量而言]、Al(OH)3的平均粒径为2.6μm、m(5.0μmAl2O3):m[2.6μm Al(OH)3]=160:40和w(铂络合物)=0.002%(相对于基胶质量而言)时,可制得阻燃性优异的有机硅电子灌封胶。