原位插层法制备SMA/MMT纳米复合材料

采用原位聚合的方法制备了苯乙烯马来酸酐无规共聚物（SMA）/蒙脱土（MMT）纳米复合材料,研究了MMT的用量对插层效果的影响.研究表明,采用原位聚合的方法可制得SMA/MMT纳米复合材料,随着MMT用量的增加,SMA/MMT纳米复合材料逐渐由插层型过渡到部分剥离.并且将原位聚合所得SMA/MMT纳米复合材料再次进行熔融插层后,可得到剥离效果更为明显的纳米复合材料.制得的SMA/MMT纳米复合材料具有较好的加工性能.     

苯乙烯-马来酸酐共聚物／蒙脱土纳米复合材料的制备

通过季铵盐与内层Na^＋的交换修饰蒙脱土，单体在季铵盐阳离子和有机物亲和力作用下插入蒙脱土片层中，使用非水分散共聚合法制备了苯乙烯-马来酸酐（SMA）共聚物／蒙脱土纳米复合材料并进行了表征。结果表明，苯乙烯和马来酸酐的共聚反应能够使蒙脱土层剥离，形成片层均匀分散在SMA聚合物基体中，获得了耐热性较高、透明性好的SMA／O-MMT纳米复合材料。     

改性剂和增容剂在EPDM/蒙脱土纳米复合材料中的作用

采用熔融插层和不同链长的改性荆改性蒙脱土的方法制备了三元乙丙橡胶(EPDM)／蒙脱土(MMT)纳米复合材料。X-射线衍射(XRD)和透射电镜(TEM)的测试结果表明：采用分子中亚甲基的数量小于16的改性剂改性MMT获得的有机蒙脱土与EPDM复合所得到的复合材料为传统型复合材料。而采用分子中亚甲基的数量大于16的改性剂改性MMT获得的有机蒙脱土与EPDM复合所得到的纳米复合材料为插层型。同时，笔者还探讨了EPDM接枝马来酸酐增容剂时复合材料形态的影响以及获得剥离型纳米复合材料的增容剂中马来酸酐的临界接枝率和增容剂最佳含量。此外，时该纳米复合材料的物理机械性能进行了评价。     

聚甲基丙烯酸/蒙脱土纳米复合材料的制备及性能

用甲基丙烯酸(methacrylic acid,MAA)在钠基蒙脱土(montmorillonite,MMT)层间直接原位插层聚合制备了聚甲基丙烯酸/蒙脱土(polymethacrylic acid/montmorillonite,PMAA/MMT)纳米复合材料.以蒙脱土的层间距、插层进入蒙脱土层间的聚合物含量及应用于皮革鞣制的实验结果为考察指标,对制备过程中的引发剂用量及蒙脱土用量进行了单因素实验研究.结果表明:所制备的PMAA/MMT纳米复合材料属于剥离型纳米复合材料,应用于皮革鞣制所得坯革的增厚率及湿热稳定性均有较大提高.     

有机插层剂对聚酰胺6／MMT纳米复合材料制备的影响研究

以烷基胺、季铵盐和氨基酸作为有机插层剂与蒙脱土片层进行阳离子交换，制备出层间距不同的有机蒙脱土。采用熔融插层法和原位聚合法分别制备聚酰胺（R％）／蒙脱土（MMT）纳米复合材料，并利用XRD、FT-IR、TEM对有机蒙脱土及纳米复合材料进行结构表征。研究结果表明：用烷基胺、季铵盐和氨基酸有机插层剂改性的蒙脱土层间距由原来的1．25nm分别增大到3．21nm、3．99nm和1．82m；季铵盐有机插层剂更适用于熔融插层法制备PA6／MMT纳米复合材料，而氨基酸有机插层剂更适用于原位聚合法制备PA6／MMT纳米复合材料。     

原位插层聚合制备PVC/蒙脱土纳米复合材料

采用氯乙烯单体直接插层到蒙脱土中进行原位插层聚合，制备纳米复合材料，并用小角X射线衍射（XRD）、扫描电子显微镜（SEM）和电子探针技术对复合材料进行了结构表征。实验结果表明：采用原位插层聚合法制得的PVC／蒙脱土（MMT）复合材料为剥离型纳米复合材料。     

高密度聚乙烯／蒙脱土纳米复合材料的制备与性能研究

采用马来酸酐接枝乙烯醋酸乙烯酯（EVA-g-MAH）和马来酸酐接枝低密度聚乙烯（PE-LD-g-MAH）为相容剂，制备了高密度聚乙烯傣脱土（PE-HD／MMT）纳米复合材料。用X射线衍射和扫描电镜对有机蒙脱土和PE-HD／MMT复合材料的结构进行了表征，研究了蒙脱土和相容剂含量对制备的纳米复合材料力学性能及热性能的影响。结果表明，相容剂的加入有利于插层。MMT在复合材料中呈纳米级分散。其层间距可由2．10nm增大至3．85nm。MMT含量为3％（质量分数，下同）、EVA-g-MAH含量为15％时，复合材料的综合力学性能最好，冲击强度和拉伸强度分别较PE-HD提高43．7％和5.8％。     

原位有机改性法EPDM/Na-MMT纳米复合材料的结构和性能

直接将EPDM、未改性蒙脱土（Na-MMT）和插层剂共混，制备原位有机改性法EPDM／Na—MMT纳米复合材料，研究插层剂对复合材料结构和物理性能的影响。结果表明，添加Na-MMT和插层剂对EPDM的硫化反应有延迟效应，并可降低EPDM硫化胶的交联密度；原位有机改性法EPDM／Na-MMT纳米复合材料物理性能较未改性复合材料有较大幅度的提高，可达到剥离型EPDM／有机蒙脱土纳米复合材料的水平；Na—MMT以完全剥离、插层和未插层3种微观形态共存于EPDM基体中，未插层Na—MMT的存在基本上不影响完全剥离Na-MMT片层对EPDM的补强效果。     

剥离型(苯乙烯/马来酸酐)共聚物/蒙脱土纳米复合材料的制备

研究了制备剥离型(苯乙烯/马来酸酐)共聚物(SMAH)蒙/脱土(MMT)纳米复合材料的方法。研究表明,通过原位插层及熔融插层只能制备出插层型的SMAH/MMT纳米复合材料。为了制备剥离型的SMAH/MMT纳米复合材料,先将尼龙6(PA6)与MMT熔融插层制备出PA6/MMT纳米复合材料,再用抽提的方法将PA6/MMT复合材料中的部分PA6除去,得到含有少量PA6的剥离型MMT,然后将剥离型MMT与SMAH共混,从而制备出剥离型的SMAH/MMT纳米复合材料。该复合材料的粘度低于SMAH,且具有较好的加工性能。     

聚苯胺/蒙脱土纳米材料的制备及改性环氧应用

将苯胺直接插层到有机蒙脱土(MMT)片层间,以过硫酸铵为氧化剂,原位聚合制备了聚苯胺(PANI)/蒙脱土纳米复合材料。傅里叶变换红外分析、X射线衍射分析和透射电镜观察表明,当MMT的用量为苯胺质量的10%以下时,可制得纳米级复合材料。考察PANI/MMT纳米复合粉末对环氧树脂力学性能、热性能的影响表明:蒙脱土以1nm厚的剥离片层形式分散在环氧树脂中时,材料的力学性能和热性能都有明显改善,这与所制备的有机无机纳米结构有直接的关系。     

Properties and morphology of nanocomposites based on styrenic polymers, Part II: Effects of maleic anhydride units

Based on enhancement in exfoliation for polyolefin-g-maleic anhydride composites with the addition of as little as 1 wt% maleic anhydride (MA), the effect of MA in styrene–maleic anhydride copolymer (SMA)-based nanocomposites was studied. SMA nanocomposites were mixed using a DSM melt compounder followed by injection molding in a pneumatic bench top molder. These materials produced the same modulus enhancement and TEM-based areal particle densities on a weight percent basis as SAN-based nanocomposites from a previous study, but the areal TEM-based particle densities remained lower overall than literature values for polyolefin-g-MA mixtures. This behavior is explained by repulsive interactions between styrene and the alkyl tail of the surfactant, suggesting that polar surfactant tails could lead to improved exfoliation in styrene copolymer-based/montmorillonite nanocomposites. The role of increased melt viscosity and shearing on particle dispersion as MA is added to the copolymer is discussed.     

Joint Effect of Compatibilizer and Organo-Montmorillonite on Compatibilization of Polyamide-6/Poly(phenylene oxide) Blend: Morphology and Properties

Compatibilizer (styrene–maleic anhydride copolymer, SMA) and organo-montmorillonite (OMMT) were introduced into immiscible polyamide-6 (PA6)/ poly(phenylene oxide) (PPO) blend to obtain quaternary nanocomposites simply by melt extrusion. OMMT tactoids formed in PA6/PPO/OMMT ternary blend would become smaller or disappear with the addition of SMA. Besides, viscosity of SMA compatibilized PA6/PPO blend decreased a lot with the addition of OMMT. Based on these results, a mechanism for joint effect of SMA and OMMT in compatibilizing PA6 and PPO was proposed. We further studied water absorption and tensile properties of the nanocomposites, which were in consistent with the proposed mechanism.     

二釜串联连续本体法制备SMA

用二釜串联连续本体工艺制备苯乙烯-顺丁烯二酸酐无规共聚物,分别研究并获得了首釜和第二釜的启动操作策略和稳态工艺条件。     

Effect of Layered Silicates on the Crystallinity and Mechanical Properties of HDPE/MMT Nanocomposite Blown Films

Summary The highdensitypolyethylene (HDPE)/montmorillonite (MMT) nanocomposites were prepared by melt blending using twin screw extruder with two step process. The master batches were manufactured by melt compounding with maleic anhydride grafted HDPE (HDPE-g-MAH) and MMT. The HPDE/MMT master batches were subsequently mixed with HDPE. The blown nanocomposite films were obtained by a single screw extruder attached film blowing and take-off unit. The MMT dispersion in the nanocomposite films was characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The influence of MMT on the crystallinity, thermal properties and mechanical properties as a function of compatibilizer was investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and universal testing machine, respectively. X-ray and TEM images showed the partially exfoliated nanocomposites which have the 5:1 – 20:1 ratios of HPDE-g-MAH and MMT. The thermal and mechanical properties of nanocomposites were enhanced by increasing the contents of MMT and in the presence of compatibilizer.     

Functional copolymer/organo‐montmorillonite nanoarchitectures. IX. Synthesis and nanostructure–morphology–thermal behaviour relationships of poly[(maleic anhydride)‐alt‐(acrylic acid)]/organo‐ montmorillonite nanocomposites

Functional copolymer/clay hybrids were synthesized by radical‐initiated interlamellar copolymerization of maleic anhydride/maleic acid and acrylic acid with 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride as a water‐soluble ionizable radical initiator in the presence of reactive (octadecylamine‐montmorillonite (ODA‐MMT)) and non‐reactive (dimethyldodecylammonium‐montmorillonite) organoclays at 60 °C in aqueous medium under nitrogen atmosphere. The monomers were dissolved in aqueous medium, and the two types of clay particles used were easily dissolved and dispersed partially swollen, respectively, in deionized water. Structure, thermal behaviour and morphology of the synthesized nanocomposites were investigated using Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning and transmission electron microscopy. It is demonstrated that intercalative copolymerization proceeds via ion exchange between organoclays and carboxylic groups of monomers/polymers, which essentially improves interfacial interactions of polymer matrix and clay layers through strong hydrogen bonding. In the case of intercalative copolymerization in the presence of ODA‐MMT clay, a similar improvement is provided by in situ hydrogen bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine groups of ODA‐MMT. The nanocomposites exhibit higher degree of intercalation/exfoliation of copolymer chains, improved thermal properties and fine dispersed morphology. Copyright © 2011 Society of Chemical Industry     

Fracture behavior of thermoplastic polyolefin/clay nanocomposites

A thermoplastic polyolefin (TPO) containing 70 wt % styrene–ethylene–butadiene‐styrene‐g‐maleic anhydride and 30 wt % polypropylene and its nanocomposites reinforced with 0.3–1.5 wt % organoclay were prepared by melt mixing followed by injection molding. The mechanical and fracture behaviors of the TPO/clay nanocomposites were investigated. The essential work of fracture (EWF) approach was used to evaluate the tensile fracture behavior of the nanocomposites toughened with elastomer. Tensile tests showed that the stiffness and tensile strength of TPO was enhanced by the addition of low loading levels of organically modified montmorillonite. EWF measurements revealed that the fracture toughness of the TPO/clay nanocomposites increased with increasing clay content. The organoclay toughened the TPO matrix of the nanocomposites effectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of polypropylene-g-(maleic anhydride/styrene) compatibilizer on mechanical and rheological properties of polypropylene/clay nanocomposites

To enhance the dispersibility of clay in polypropylene (PP) matrix, PP-g-(maleic anhydride/styrene) (MA/ST) was prepared as a compatibilizer by graft copolymerization of maleic anhydride (MA) and styrene (ST) with PP. The addition of ST was known to be effective in improving the graft degree. PP/clay nanocomposites with the compatibilizer were prepared by melt intercalation. The X-ray diffraction (XRD) peaks of (0 0 1) plane of the organo-modified montmorillonite (O-MMT) were shifted to lower angles by an addition of PP-g-(MA/ST), indicating the intercalation capability of PP-g-(MA/ST) in the silicate layers. Transmission electron microscopy (TEM) photographs showed that the O-MMT in the presence of PP-g-(MA/ST) was intercalated and partly exfoliated during melt mixing. The addition of O-MMT and PP-g-(MA/ST) improved the thermal stability, tensile and rheological properties of the nanocomposites.     

Preparation and UV weathering of polyethylene nanocomposites

Polyethylene / montmorillonite (PE/MMT) nanocomposites films were prepared by blending in the molten state: Low-density polyethylene (LDPE), montmorillonite clay, and polyethylene grafted maleic anhydride (LDPE-g-MA) or zinc neutralized carboxylate ionomer (Surlyn B) as compatibilizers. A chemically modified clay Cloisite 20A has been used. Nanocomposites were prepared by melt blending in a twin-screw extruder by using two-step mixing. Characterization of the nanocomposites was performed by mechanical properties, X-ray diffraction, light transmittance, infrared spectroscopy (FTIR) and transmission electronic microscope (TEM) techniques. Changes in UV irradiated nanocomposites film samples were characterized by FTIR. The results were analyzed in terms of the effect of the compatibilizing agent in the clay dispersion, and UV degradation of the nanocomposite.