有机改性与乳液插层法相结合制备的丁苯橡胶/黏纳米复合材料的结构与性能(英文)

针对现有的乳液插层法所制备的橡胶/黏土纳米复合材料中填料与橡胶之间界面结合较弱的缺点,在乳液插层法中对无机黏土进行有机改性,制备出力学性能优异的纳米复合材料。X射线衍射和透射电子显微镜技术分析表明,有机改性后的复合材料中黏土被部分地有机改性,且在基体中以纳米尺寸分散。     

固相法插层改性黏土在PP中的应用

采用固相法对黏土进行有机化插层改性制备有机黏土,再通过熔融插层法制备聚丙烯(PP)/有机黏土纳米复合材料。有机黏土在PP中的层间距由原来的4.07 nm扩大到5.84 nm,PP分子链成功插入到固相法改性的黏土中,形成纳米复合材料。PP/有机黏土纳米复合材料的结晶温度由112.9℃提高119.6℃,熔融过程、熔点及结晶度没有明显变化。PP/有机黏土纳米复合材料的力学性能优于PP/钠基黏土复合材料,有机黏土的质量分数在3%-5%时,纳米复合材料的力学性能最佳。     

固相法制备有机黏土改性聚丙烯

采用固相法对黏土进行有机化插层改性,制备出有机黏土;通过熔融插层法制备聚丙烯/有机黏土纳米复合材料。X射线衍射分析表明,固相法改性黏土可以与聚丙烯形成纳米复合材料。利用DSC研究了纳米复合材料的结晶和熔融过程,结果表明:聚丙烯/有机黏土纳米复合材料的结晶温度提高,熔融过程、熔点及结晶度没有明显变化。力学性能测试结果表明:有机黏土含量在3%～5%范围内,纳米复合材料的力学性能最佳。     

聚丙烯/黏土纳米复合材料结构及流变性能研究

采用固相法对黏土进行插层改性,制备有机黏土,再与聚丙烯熔融共混,成功制备聚丙烯/有机黏土纳米复合材料。XRD和TEM测试均表明:固相法改性黏土可以与聚丙烯形成结构为插层型和剥离型共存的纳米复合材料。利用动态流变仪研究纳米复合材料的加工流变性能,结果显示,有机黏土的加入有效地改善了聚丙烯的加工流变性能。     

聚合物/纳米黏土复合材料的研究进展

简述了纳米黏土的结构特点,常见的有机化改性方法,介绍了可插层黏土的有机单体和聚合物类型。综述了聚合物/纳米黏土复合材料的制备方法,介绍了单体溶液插层、聚合物水溶液插层、乳液插层等溶液插层方法和单体熔融插层、聚合物熔融插层、熔融挤出插层等熔融插层方法。总结了聚合物/纳米黏土复合材料的国内外研究进展与应用现状,主要在汽车工业、包装材料、环境友好材料、新型工程材料等领域得到了广泛应用。     

硫化方法对橡胶/黏土纳米复合材料黏土片层分散状态的影响

通过熔体插层法以及常压硫化法制备了橡胶/黏土纳米复合材料,并与模压硫化法制备的复合材料进行了对比,研究了硫化方法对橡胶/黏土纳米复合材料微观分散状态的影响。结果表明:采用熔体插层法制备的橡胶/黏土混合物,其受限状态的橡胶大分子链在高温、高压条件下,在黏土片层之间处于一种热力学不稳定状态;模压处理会对橡胶/黏土混合物的分散状态产生不利影响。透射电子显微镜和X光衍射分析表明,采用模压硫化、常压硫化得到的丁基橡胶或丁苯橡胶/黏土纳米复合材料中黏土片层的微观分散状态不同;排除压力的影响,常压硫化有利于提高橡胶/黏土纳米复合材料中黏土片层的分散程度。     

用橡胶乳液-黏土水悬浮液共凝法制备的橡胶/黏土纳米复合材料的结构及其复合机理

研究了利用橡胶乳液-黏土水悬浮液共凝法制备的橡胶／黏土纳米复合材料的结构和复合机理。结果表明,在加入絮凝剂使橡胶乳液-黏土水悬浮液共凝聚的过程中,由于存在胶乳粒子对黏土片层的隔离作用与在混合液中分散的黏土单片层的重新聚集作用的竞争,因此,在絮凝物中,橡胶大分子将黏土片层隔离成纳米分散单元（包括单片层和多片层的聚集体）,在多片层的黏土聚集体层间没有橡胶大分子插入。采用该共凝法制备的橡胶／黏土纳米复合材料具有“隔离型”结构。     

季鏻盐改性黏土及其对尼龙6性能的影响

首先采用季鏻盐作为插层剂对钠基黏土进行插层改性,制备有机黏土,再与尼龙6熔融共混,成功制备尼龙6/有机黏土纳米复合材料。XRD测试结果表明:季鏻盐改性黏土可以与尼龙6形成纳米复合材料。转矩流变仪的测试结果显示:有机黏土能够略微改善尼龙6树脂的加工性能。力学性能的测试结果显示:有机黏土的含量在3%~5%范围内其,纳米复合材料的力学性能最佳。     

CTAB/CPL复配改性黏土制备NBRCNs的结构与性能研究

采用CTAB/CPL(比例为3.0g∶1.0g)复配改性有机黏土制备NBRCNs,考察了复配改性有机黏土制备的NBRCNs的微观结构、力学性能和分散相态。实验结果表明,无机黏土经CTAB/CPL复配改性后,黏土晶层间距由起始1.25nm扩大至1.82nm,NBRCNs中黏土晶层间距进一步扩大为4.67nm,即橡胶大分子链进一步插层进入黏土片层中,制备得到插层型纳米复合材料。有机黏土用量为10份时,复配改性有机黏土制备的NBRCNs的各项力学性能最优,拉伸强度为5.16 MPa,撕裂强度为20.97kN/m,较纯NBR硫化胶的1.53MPa和8.77kN/m分别提高了237%和139%,且明显优于采用单一阳离子CTAB改性有机黏土制备的NBRCNs,充分显示了复配有机改性黏土的可行性和优越性。复配有机改性黏土制备的NBRCNs的微观分散相态优于单一阳离子改性有机黏土制备的NBRCNs。     

剥离型黏土/丁吡橡胶/丁腈橡胶纳米复合材料的制备及表征(英文)

采用溶液法将剥离型黏土/丁吡橡胶纳米复合材料与丁腈橡胶复合,制备了黏土/丁吡橡胶/丁腈橡胶纳米复合材料。热重分析表明黏土在复合材料中的含量提高,大部分丁吡橡胶被去除。通过与乳液絮凝法制备的黏土/丁腈橡胶纳米复合材料的X射线衍射及透射电子显微镜分析结果比较表明,厚为1 nm数量级的黏土片层均匀地分散在橡胶基质中,制得的黏土/丁吡橡胶/丁腈橡胶复合材料属于剥离型纳米复合材料。     

Characterization of latex-based isotactic polypropylene/clay nanocomposites

Polypropylene/clay nanocomposite (PCN) containing 1 wt% organo-modified clay was prepared by latex technology, previously successfully applied for preparation of carbon nanotubes (CNTs)/polymer composites. The level of dispersion of organoclay and the microstructure of the resulting PCNs were characterized by means of X-ray diffraction analysis, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The obtained results have demonstrated that the latex technique represents a promising method for preparation of PP/clay nanocomposites with good dispersion of exfoliated nanoclay particles. The influence of clay nanoparticles on nonisothermal crystallization of PCN was investigated by DSC. The crystallization onset temperature of the matrix rises for about 5 °C when crystallizing from the quiescent melt. Improved thermal stability of PP/nanoclay was observed as evaluated by TGA. The dynamic mechanical analysis reveals an increase in storage modulus of PP matrix in the nanocomposites for 30% over a temperature range, indicating an increase in the stiffness of the material with the addition of organically modified clay.     

Synthesis of exfoliated acrylonitrile-butadiene-styrene copolymer (ABS) clay nanocomposites: role of clay as a colloidal stabilizer

Acrylonitrile-butadiene-styrene copolymer (ABS) clay nanocomposites were synthesized using two clays (sodium montmorillonite, laponite). Both colloidal stability and mechanical properties of the nanocomposites were dependant on aspect ratios of clays. Laponite, a low aspect ratio clay, reduced particle sizes of ABS clay nanocomposite latexes, enhanced colloidal stabilities, and increased viscosity of the latexes. The colloidal stability of ABS clay latexes may result from four factors. Firstly, the electrostatic repulsion forces originated from surface charges of clays and anionic surfactant contribute to colloidal stability. Secondly, laponite layers separate sodium montmorillonite layers and polybudadiene latex particles preventing the coagulation. Thirdly, the laponite layers adsorbed on latexes act like steric barriers against coagulation. Fourthly, increased viscosity reduces latex mobility, lowering collision possibility among latex particles. Resultant ABS clay nanocomposites showed exfoliated structures, and their mechanical properties related to the relative weight ratio of sodium montmorillonite to laponite: as portions of sodium montmorillonite increased, dynamic moduli of the nanocomposites increased, because sodium montmorillonite has higher aspect (length/thickness) ratio than laponite.     

Synthesis and characterization of styrene butadiene rubber—Bentonite clay nanocomposites

In the present study, naturally occurring unfractionated bentonite clay was used to prepare styrene butadiene rubber/bentonite clay nanocomposite by latex stage blending. The bentonite clay was organo‐modified by in situ resol formation by the reaction of resorcinol and formaldehyde. The latex clay mixture was co‐coagulated with acid. The resulting clay masterbatch was compounded and evaluated by Fourier Transform Infrared spectroscopy, X‐ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X‐ray spectroscopy (EDS), Scanning Electron Microscopy, Thermogravimetric analysis, and Differential Scanning Calorimetry. XRD showed that the interplanar distance of the in situ resol‐modified bentonite clay increased from 1.23 to 1.41 nm for the unmodified bentonite. TEM analysis indicated partial exfoliation and/or intercalation. EDS (Si and Al mapping) of the clay revealed the nature of the dispersion in the nanocomposites vis‐à‐vis the conventional styrene‐butadiene rubber (SBR)/bentonite clay composite. Thermogravimetric analysis was used to compare the decomposition trends of the SBR/clay nanocomposites with the SBR/clay composite. The glass transition temperature of SBR/clay nanocomposites increased as compared with that of neat SBR. Substantial improvement in most of the other mechanical properties was also observed in case of the nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Facile preparation of nylon 6 nanocomposites based on clay reinforcement and core‐shell latex toughening: Morphology,properties, and impact fracture behavior

This work is focused on a facile route to prepare a new type of nylon 6‐based nanocomposites with both high fracture toughness and high strength. A series of nylon 6‐matrix blends were prepared via melting extrusion by compounding with poly (methyl methacrylate‐co‐butadiene‐co‐styrene) (MBS) or poly(methyl methacrylate‐co‐methylphenyl siloxane‐co‐styrene) (MSIS) latices as impact modifier and diglycidyl ether of bisphenol‐A (DGEBA) as compatibilizer. Layered organic clay was also incorporated into above nylon 6 blends for the reinforcement of materials. Morphology study suggests that the MBS or MSIS latex particles could achieve a mono‐dispersion in nylon 6 matrix with the aid of DGEBA, which improves the compatibilization and an interfacial adhesion between the matrix and the shell of MBS or MSIS. High impact toughness was also obtained but with a corresponding reduction in tensile strength and stiffness. A moderate amount of organic clay as reinforcing agent could gain a desirable balance between the strength, stiffness and toughness of the materials, and tensile strength and stiffness could achieve an improvement. This suggests that the combination of organic clay and core‐shell latex particles is a useful strategy to optimize and enhance the properties of nylon 6. Morphology observation indicates that the layered organic clay was completely exfoliated within nylon 6 matrix. It is found that the core‐shell latex particles and the clay platelets were dispersed individually in nylon 6 matrix, and no clay platelets were present in MBS or MSIS latex particles. So the presence of the clay in nylon 6 matrix does not disturb the latex particles to promote high fracture toughness via particle cavitation and subsequent matrix shear yielding, and therefore, provides maximum reinforcement to the polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Morphology and mechanical properties of clay/styrene‐butadiene rubber nanocomposites

Based on the character of a clay that could be separated into many 1‐nm thickness monolayers, clay styrene‐butadiene rubber (SBR) nanocomposites were acquired by mixing the SBR latex with a clay/water dispersion and coagulating the mixture. The structure of the dispersion of clay in the SBR was studied through TEM. The mechanical properties of clay/SBR nanocomposites with different filling amounts of clay were studied. The results showed that the main structure of the dispersion of clay in the SBR was a layer bundle whose thickness was 4–10 nm and its aggregation formed by several or many layer bundles. Compared with the other filler, some mechanical properties of clay/SBR nanocomposites exceeded those of carbon black/SBR composites and they were higher than those of clay/SBR composites produced by directly mixing clay with SBR through regular rubber processing means. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1873–1878, 2000     

Structure and properties of strain‐induced crystallization rubber–clay nanocomposites by co‐coagulating the rubber latex and clay aqueous suspension

Natural rubber (NR)–clay (clay is montmorillonite) and chloroprene rubber (CR)–clay nanocomposites were prepared by co‐coagulating the rubber latex and clay aqueous suspension. Transmission electron microscopy showed that the layers of clay were dispersed in the NR matrix at a nano level, and the aspect ratio (width/thickness) of the platelet inclusions was reduced and clay layers aligned more orderly during the compounding operation on an open mill. However, X‐ray diffraction indicated that there were some nonexfoliated clay layers in the NR matrix. Stress–strain curves showed that the moduli of NR were significantly improved with the increase of the amount of clay. At the same time, the clay layers inhibited the crystallization of NR on stretch, especially clay content of more than 10 phr. Compared with the carbon‐black‐filled NR composites, NR–clay nanocomposites exhibited high hardness, high modulus, high tear strength, and excellent antiaging and gas barrier properties. Similar to NR–clay nanocomposites, CR–clay nanocomposites also exhibited high hardness, high modulus, and high tear strength. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 318–323, 2005     

黏土/天然橡胶纳米复合材料的制备及性能

利用乳液插层法制备了黏土／天然橡胶纳米复合材料,研究了该复合材料的力学性能、应力应变行为、耐磨性、气体阻隔性和耐老化性能。结果表明,黏土／天然橡胶纳米复合材料与高耐磨炭黑(N330)、白炭黑增强橡胶相比,邵尔A型硬度、定伸应力和撕裂强度较高,拉伸强度相当。黏土、N330以及白炭黑对天然橡胶的拉伸结晶有影响,填料用量对材料拉伸强度的影响存在最佳值。黏土／天然橡胶纳米复合材料具有良好的耐磨性、气体阻隔性和耐老化性能。     

SBR粘土纳米复合材料的气密性

对乳液法制备的SBR粘土纳米复合材料的气密性进行了研究,结果表明：SBR粘土纳米复合材料的气密性优于传统填料填充的硫化胶,且随温度的变化较小;填料的用量、形状以及与橡胶的结合性是影响气密性的主要因素;填充20份粘土的纳米复合材料气密性优于NR／SBR内胎,比IIR内胎差。     

Montmorillonite clay nanocomposites based on vinyl pyridine‐styrene‐butadiene terpolymer (VPR)/acrylonitrile‐butadiene rubber (NBR) blend

This study describes a novel route to synthesize vinyl pyridine‐styrene‐butadiene terpolymer rubber (VP rubber) montmorillonite clay nanocomposites by latex blending technique. The pyridine moiety of the VP rubber was modified with methyl iodide to form the pyridinium ion during latex blending. Cation exchange reaction of the pyridinium ion of the VP rubber latex with sodium montmorillonite occurred during latex stage mixing which helped to form VP rubber‐montmorillonite clay nanocomposites. Coagulation of the latex‐clay slurry produced nanocomposites master batch. The master batch was compounded with acrylonitrile butadiene rubber (NBR). Fourier Transform Infrared Spectroscopy (FTIR) confirmed the modification of the pyridine moiety of VP rubber. Wide angle X‐ray diffraction (WAXD), scanning electron microscopy‐energy dispersive X‐ray spectrophotometry (SEM‐EDS) and transmission electron microscopy (TEM) provided the evidences of formation of nanocomposite. Remarkable improvements in the mechanical properties were found by addition of small amount of modified clay. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers