Structure‐property relationships of LLDPE—highly filled with aluminum hydroxide

The mechanical performance, rheological behavior, and phase morphology of linear low‐density polyethylene (LLDPE) highly loaded with aluminum hydroxide [Al(OH)₃] were investigated. It was found that titanate surface‐active agent and ethylene‐vinyl acetate copolymer (EVA) improve the processing and ductile properties of the composite remarkably but are accompanied by the deterioration of the tensile strength. Addition of vinyl triethoxy silane (VTEO) and dicumyl peroxide (DCP) improves the tensile strength of the composite because of the silane crosslinking structure introduced. A synergistic effect of interface modifying and silane crosslinking method in improving mechanical performance of the composite is presented. Phase morphology of the LLDPE/Al(OH)₃ composites was studied by means of scanning electron microscopy (SEM) technique. SEM micrographs indicate that a core‐shell type with Al(OH)₃ as a core and EVA as a shell is formed in the composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2485–2490, 2002     

Interface modification and characterization in linear low-density polyethylene highly loaded with aluminium hydroxide

Fire-retardant linear low-density polyethylene (LLDPE) composites were prepared by combining this polymer with uncoated and surface treated forms of aluminum hydroxide (Al(OH)₃). The poor toughness and ductility of polyethylene highly filled with Al(OH)₃ can be significantly improved by addition of a small amount of silicon oil. It is found that silicon oil improves elongation at break of the composite remarkably, but this is accompanied by the deterioration of tensile strength. Silane crosslinked polyethylene substituting for polyethylene as the matrix in Al(OH)₃-filled polyethylene improves the tensile strength of the composite. Fractured surface analysis and limiting oxygen index (LOI) of the composites were also studied. Possible mechanisms accounting for these effects are discussed.     

Effects of silicone oil and polymeric modifiers on the mechanical properties of highly filled LLDPE

The effects of coupling agents, silicone oil, and three types of polymeric modifiers on the mechanical properties of linear low density polyethylene (LLDPE) composites highly filled with aluminium hydroxide [Al(OH)₃] were studied. Polymeric modifiers that contain polar groups, such as silane‐grafted polyethylene (Si‐g‐PE) and acrylic‐acid‐grafted ethylene‐vinyl acetate copolymer (AA‐g‐EVA), improve the mechanical properties dramatically, while nonpolar modifiers improve them to some extent. When Al(OH)₃ was treated using a titanate coupling agent, the silicone oil increased the impact strength and elongation at break of the LLDPE/Al(OH)₃ composites. Introduction of a polymeric modifier containing polar groups destroys the beneficial effects of silicone oil on film mechanical properties, while the introduction of a nonpolar elastomeric polymeric modifier retains the high impact strength and elongation at break. SEM analyses provide the indirect evidence of the encapsulation of silicone oil around the filler. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 121–128, 2002     

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     

甲基丙烯酸对氢氧化铝填充丁苯橡胶性能的影响

将甲基丙烯酸（MAA）用作Al(OH）3填充丁苯橡胶（SBR）复合材料的添加剂，结果表明，在高填充Al(OH）3的SBR中加入MAA可以较大幅度地提高其过氧化物硫化胶的力学性能。当Al(OH）3用量为150份（质量份，下同）时，随着MAA用量增加，SBR硫化胶的邵尔A型硬度和定伸应力逐渐增大，拉伸强度和撕裂强度有较大幅度的提高，当MAA用量为20份时，随着Al(OH）3用量增加，SBR硫化胶的邵尔A型硬度、定伸应力和撕裂强度逐渐增大，拉伸强度在Al(OH）3填充量为25份时最大，大量填充Al(OH）3的SBR硫化胶的阻燃性能较好，氧指数受MAA用量的影响较小，该SBR硫化胶亦具有良好的热空气老化性能。     

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     

Performance evaluation of synthesized acrylic acid grafted polyethylene in aluminum hydroxide highly filled polyethylene composites

A polymeric agent acrylic acid grafted polyethylene (AAgPE) was synthesized and used as a coupling agent in aluminum hydroxide [Al(OH)₃] highly filled linear low‐density polyethylene (LLDPE) composite. It is found that AAgPE improves the interfacial adhesion between the filler and the polyethylene matrix, which results in good mechanical properties of the composite. Silicon oil is an effective additive for improving the impact strength, the elongation at break, and the rheological property of the filled composite, but it decreases the tensile strength remarkably. The combination of AAgPE and silicon oil can lead to good performance of the composite. Flammability properties and fracture surface morphologies of the composites through scanning electron microscopy were investigated. The relationship between mechanical properties and microstructure of the composites was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2544–2549, 2002     

基体接枝MAA改性Al(OH)3高填充LLDPE

研究了基体接枝甲基丙烯酸(MAA)对AI(OH)3填充线性低密度聚乙烯(LLDPE)力学性能的改善。接枝反应在密炼机中采用固相接枝方法进行。红外光谱分析表明在聚乙烯基体上进行了接枝反应。力学性能测试表明当AI(OH)3填充量较小时断裂强度和伸长率略有下降，而对于高填充量的复合材料，强度和伸长率得到了明显的改善。断面扫描电镜结果表明基体接枝改善了填料在复合材料中的分散状态。     

Evaluation of commercial Mg(OH)2, Al(OH)3 and TiO2 as antimicrobial additives in thermoplastic elastomers

Health concerns have driven the production of antimicrobial materials aimed at controlling the spread of diseases. Styrene-ethylene/butylene-styrene (SEBS)-based thermoplastic elastomers (TPE) incorporated with titanium dioxide (TiO₂), magnesium hydroxide (Mg(OH)₂) and aluminium hydroxide (Al(OH)₃) are one way to produce antimicrobial polymers. The purpose of this study is to characterise SEBS-based TPE compounds incorporated with TiO₂, Mg(OH)₂ and Al(OH)₃. The mechanical, optical and antimicrobial characteristics of TPE samples were investigated. The differences between the means in the mechanical properties of all loaded materials were not significant. The optical results show a reduction in polymer transparency, with total opacity after the incorporation of TiO₂. Among the additives tested, TiO₂ offered the best antimicrobial action. There was no fungal growth on the loaded TPE surface. The incorporation of TiO₂ in SEBS-based TPE materials may be used in the industry to develop antimicrobial products, which, when complemented with additional disinfection treatments, can contribute to public health.     

原位生成甲基丙烯酸铝对POE的补强

用氢氧化铝和甲基丙烯酸（MAA）经原位反应生成了甲基丙烯酸铝[Al（MAA）3],并将其作为补强剂用于补强聚烯烃热塑性弹性体（POE）,研究了过氧化二异丙苯（DCP）用量、Al（OH）3和MAA的物质的量比和Al（MAA）3理论生成量对POE硫化胶力学性能的影响。结果表明,当DCP用量为3份、Al（OH）3/MAA的物质的量比为1∶3时,原位生成Al（MAA）3能够显著地提高POE硫化胶的力学性能。随着Al（MAA）3理论生成量的增加,硫化胶的拉伸强度先增加后减少,当Al（MAA）3理论生成量为30份时,拉伸强度达到最大值为24.31 MPa,而扯断伸长率保持在500%以上。另外,Al（MAA）3补强的POE硫化胶还具有较好的耐热氧老化性能和较高的邵A硬度。     

Mechanical properties and microstructure of HDPE/AL(OH)3/silicone oil composite

The effect of surface modification on the mechanical properties and microstructure of the composites of high‐density polyethylene (HDPE), silicone oil, and aluminum hydroxide [Al(OH)₃] was investigated. The dispersion of silicone oil in the HDPE composites was studied by scanning electric microscope (SEM) and differential scanning calorimetry (DSC). In the HDPE/Al(OH)₃/silicone oil composites, two types of dispersion structure of silicone oil were observed resulting from different surface modifications. In the composites surface modified with titanate NDZ‐130, calcium stearate, or oleic acid, silicone oil encapsulates around Al(OH)₃ particles, and both the notched impact strength and the elongation at break are very high. However, in the composites surface modified with silane KH‐550 or silane‐g‐HDPE, silicone oil and Al(OH)₃ particles separately disperse in HDPE, and both the notched impact strength and the elongation at break are very low. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1896–1903, 2002     

Metal chelates as synergistic flame retardants for flexible PVC

The thermal degradation of flexible PVC treated with various metal chelates containing Cr, Al, Fe, Co, Ni, Cu, or Zn combined with two compounds, Al(OH)₃ and Mg(OH)₂, was studied by thermal analysis. Limiting Oxygen Index (LOI), Smoke Density Rating (SDR), and mechanical properties were investigated. The structure of the char formed after combustion of the PVC compounds was observed through scanning electron microscopy (SEM). The high LOI and char yield of flexible PVC treated with flame retardants showed that there was a good synergistic effect between Al(OH)₃, Mg(OH)₂, and metal chelates. J. VINYL. ADDIT. TECHNOL., 11:70–75, 2005. © 2005 Society of Plastics Engineers.     

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     

A comparative study of the lattice structure,optical band gap,electrical conductivity and polarization at different stages of the heat treatment of chemical routed Al(OH)3

Aluminium hydroxide (Al(OH)₃) was prepared by chemical reaction of the Al(NO₃)₃ in alkaline medium. The as-prepared powder was heated in the temperature range 250 °C to 1250 °C for studying the structural phase transformation at different stages of the heat treatment. The synchrotron x-ray diffraction patterns confirmed a structural transformation of Al(OH)₃ through different (Boehmite, γ, θ, δ, and α) polymorphic phases of Al₂O₃ on increasing the heat treatment temperature. The samples in Boehmite (γ-AlOOH) and α- Al₂O₃ phases showed Raman active modes, whereas the intermediate (meta-stable) multi-phased structure showed weak Raman active peaks. The analysis of UV–visible spectra of the samples indicated two optical band gap energy values in the high energy range 4.50–4.73 eV and low energy range 3.06–3.84 eV. The voltage dependence of current, capacitance and electrical polarization were recorded to study electrical properties in heat treated samples. The capacitance value, derived from the polarization, showed a usual increasing trend on decreasing the measurement frequency (inverse of the time) of driving electric voltage. The measured electrical polarization in the samples was found to be highly correlated to their electrical conductivity and the results are helpful to understand the role of electrical conductivity on exhibiting the apparently ferroelectric properties in high conductive and low polarizable dielectric oxides.     

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.     

Influence of amorphous Al(OH)3 on the hydration of tricalcium aluminate

The influence of amorphous Al(OH)₃ on the hydration of tricalcium aluminate was investigated in pastes and in suspensions. In suspensions it was found that amorphous Al(OH)₃ started to dissolve almost immediately, and a stage was passed in which most of the anions present in the aqueous phase were polymeric aluminate units. Paste hydration results could be understood by assuming that highly soluble amorphous Al(OH)₃ dissolved and, by so doing, adjusted the concentrations in the aqueous phase so as to cause precipitation of some less soluble form of Al(OH)₃, thereby retarding hydration.     

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     

原位反应增容无机非卤阻燃ABS微观结构研究

利用扫描电镜对原位反应增容技术制各的无机非卤阻燃ABS母粒及材料的界面形态进行了系统研究，考察了无机非卤阻燃剂与ABS树脂间的相容性。结果表明：采用该法制得的无机非卤阻燃ABS材料阻燃剂粒子被基体树脂包覆后均匀地分散在ABS树脂中，很难看出阻燃剂与ABS之问明显的界面，断裂截面显示出韧性断裂的基本特征，无机非卤阻燃剂与ABS良好的相容性是母粒法加工技术和原位反应增容技术共同作用的结果。     

Effect of fillers and additives on the properties of SBR vulcanizates

Methacrylic acid (MAA) and methyl methacrylate (MMA) were used as additives for peroxide‐cured styrene–butadiene rubber (SBR) filled with three inorganic fillers with different particle sizes and surface activity, for example, MgO, Mg(OH)₂, and BaSO₄. The experimental results show that the introduction of MAA can improve the mechanical properties of SBR vulcanizates filled with MgO, Mg(OH)₂, or BaSO₄. A small amount of MAA leads to significant increases in the modulus, tensile strength, and tear strength. MMA has little effect on the mechanical properties of the SBR vulcanizates. The SEM micrographs show that MAA can improve the interfacial bonding between SBR and the three kinds of fillers. The SBR–filler interaction was studied by Kraus plots. The relationship between the SBR–filler interaction and the mechanical properties was explored. m, a characteristic constant of a filler–SBR matrix, represents the interfacial bonding between fillers and SBR and the accumulated structure of the fillers. At a given ?, a high value of m means a strong interaction between SBR and the filler and, therefore, strong mechanical properties. The Payne effect of the SBR vulcanizates was observed, and the vulcanizates have low storage moduli at high strains and high storage moduli at low strains, and the moduli are nonlinear and increase the nonlinearity as the filler content increases. The loss moduli and loss factor reach their maximums at moderate and high strain amplitudes, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 775–782, 2003     

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