两步法制备聚丙烯/蒙脱土纳米复合材料及其性能研究

采用两步法制备聚丙烯/蒙脱土纳米复合材料PP/MMT,考察了工艺配方和制备条件对材料力学性能的影响。结果表明,两步法制备工艺对PP/MMT的力学性能有明显提高,最佳工艺配方:蒙脱土含量为2%,相容剂含量为15%,最佳制备条件:加工温度200℃,螺杆转速50 r/min。在此条件下制备的PP/MMT复合材料中蒙脱土达到纳米级分散。     

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.     

不饱和聚酯/蒙脱土纳米复合材料制备及性能研究

通过原位聚合法制备了不饱和聚酯(UP)/蒙脱土(MMT)纳米复合材料,且研究了蒙脱土的用量对UP性能的影响.研究结果表明,采用原位聚合法可制备剥离型UP/MMT纳米复合材料,当蒙脱土的质量分数为3%时,复合体系的力学性能较UP有大幅提高.通过密度法测量复合体系的体积收缩率发现,少量蒙脱土的加入就可大幅降低UP的体积收缩率;通过DSC研究UP/MMT复合体系的固化性能发现,蒙脱土的加入可降低体系的固化温度.     

乳液插层法制备丁苯橡胶/天然橡胶/蒙脱土纳米复合材料的研究

采用乳液插层法制备了丁苯橡胶/天然橡胶/蒙脱土（SBR/NR/MMT）纳米复合材料。采用透射电子显微镜研究了复合材料的亚微观形态,并对复合材料的性能进行了研究。透射电镜结果显示,制备出了插层型的SBR/NR/MMT复合材料。当蒙脱土含量较低时,SBR/NR/MMT纳米复合材料的力学性能随蒙脱土用量的增加而增大。SBR/NR/MMT复合材料的耐油性能随蒙脱土含量的增加而提高。蒙脱土的加入对纳米复合材料的耐磨性能没有太大影响。     

含氮相容剂对聚丙烯/蒙脱土复合材料阻燃性能的影响

以N-羟甲基丙烯酰胺接枝聚丙烯(PP-g-NHA)为相容剂,采用熔融插层法,制备聚丙烯(PP)/蒙脱土(MMT)纳米复合材料;采用X射线衍射仪(XRD)、偏光显微镜(POM)、差式扫描量热仪(DSC)和氧指数仪(LOI)等对复合材料的微观结构和性能进行了研究。结果表明PP-g-NHA能有效地改善PP与MMT的相容性,当蒙脱土用量为5%、PP-g-NHA用量为15%时,PP/PP-g-NHA/MMT纳米复合材料的极限氧指数(LOI)由PP的18提高到23。X射线衍射(XRD)测试表明,PP已经插层进入到蒙脱土片层中,当蒙脱土用量为5%、PP-g-NHA用量为5%时插层效果最好,DSC分析结果表明,复合材料的熔融温度和分解温度都有所上升。     

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。     

聚合物／蒙脱土纳米复合材料的研究进展

综述了蒙脱土(MMT)的结构特征、蒙脱土的有机化改性、聚合物/蒙脱土纳米复合材料(PMN)的制备方法以及聚合物/蒙脱土纳米复合材料的结构特性及性能特点。     

NBR／PP／蒙脱土纳米复合体系的制备和性能研究

以丙烯酸接枝聚丙烯为增容剂,采用熔融复合方法制备出NBR/PP/蒙脱土纳米复合体系。对丙烯酸熔触接枝PP的增容体系进行了深入得研究,其次还对未处理的MMT和处理过的纳米MMT对共混物结构和性能得影响进行了讨论。研究表明,在使用丙烯酸接枝PP对NBR/PP体系得增容性较好,通过熔融共混得方法制备了NBR/PP/蒙脱土纳米复合材料。对复合材料的介电性能,力学性能和相容性进行了研究,用红外光谱和扫描电镜表征该复合材料的结构。结果表明:丙烯酸接枝聚丙烯能够很好的改善PP和NBR、MMT的相容性,当十六烷基三甲基溴化铵(CTAB)改性的蒙脱土用量为5Wt%、PP-g-AA用量为10Wt%时,NBR/PP/蒙脱土纳米复合材料的断裂伸长率提高20%,拉伸强度提高10%,撕裂强度提高80%。     

聚乙烯/纳米蒙脱土复合材料的非等温结晶行为

原位聚合法制备了不同蒙脱土含量的聚乙烯(PE)/纳米蒙脱土(MMT)复合材料.用透射电镜分析了MMT在PE基体中的分散情况,结果表明:随着MMT含量的增加,复合材料的结构从剥离型转变为剥离型和插层型混合结构.用DSC分析了PE/纳米MMT复合材料的非等温结晶行为,结果表明:复合材料的非等温结晶行为符合Avramin方程,随着MMT含量的增加,Avramin方程指数(n)减小,结晶时间(t1/2)增加.     

纳米蒙脱土增强聚氨酯-异氰脲酸酯材料研究

采用原位插层聚合法制备了纳米蒙脱土(nano-MMT)增强聚氨酯-异氰脲酸酯(PUI)材料,考察了PUI聚合物基础配方及其nano-MMT用量对材料性能的影响。结果表明:使用碳化二亚胺改性的MDI和相对分子质量为2000的聚醚二醇为原料、催化剂DMP-30的质量分数为2.5%、n(NCO)/n(OH)为10∶1、nano-MMT质量分数为3%时,nano-MMT/PUI材料的力学性能和热稳定性都得到显著提高,综合性能最优。     

PUI/nano-CaCO3弹性体的合成及性能研究

采用原位聚合方法合成了聚氨酯-异氰脲酸酯(PUI)/nano-CaCO3弹性体材料,并对其组成及性能进行了研究。结果表明,当PUI配方中NCO/OH摩尔比为10∶1、催化剂DMP-30质量分数为2%时,利用超声辐照技术将nano-CaCO3均匀分散于碳化二亚胺改性的液化MDI中原位聚合而成的PUI/nano-CaCO3弹性体,其力学性能和热稳定性得到明显提高,且随nano-CaCO3含量的增加而增加,当nano-CaCO3质量分数为8%时,弹性体综合性能最优。     

丙烯酸酯类聚合物/蒙脱土纳米复合材料的研究

用烷基胺盐对钠基蒙脱土(MMT)进行有机处理,采用插层聚合法制备了聚甲基丙烯酸甲酯(PMMA)／MMT及聚(甲基丙烯酸甲酯／丙烯酸丁酯)[P(MMA／BA)]／MMT纳米复合材料,探讨了MMT含量、MMA／BA配比对复合材料性能的影响。结果表明,MMT可提高复合材料的冲击强度和耐热性,MMT含量为2％时复合材料的综合性能最佳,BA可明显提高复合材料的冲击强度,MMA／BA配比为10／1时复合材料的综合性能较好。     

Synthesis and Characterization of Temperature-Sensitive Poly(N-isopropylacryamide-co-acrylamide)/Montmorillonite Nanocomposite Hydrogels

This paper reports a temperature-sensitive poly(N-isopropylacryamide-co-acrylamide)/montmorillonite (P(NIPAAm-co-Am)/MMT) nanocomposite hydrogel with enhanced mechanical properties and thermodynamic stability based on chitosan and nanoparticle MMT. With biodegradable N-maleyl chitosan crosslinker, the temperature-sensitive nanocomposite hydrogel was prepared by free radical polymerization in aqueous solution, using N-isopropylacryamide (NIPAAm), acrylamide (Am), and montmorillonite (MMT) as materials. The clay content varied from 0 to 7 wt% (based on the monomer). The temperature-sensitive behavior, mechanical property, thermodynamic stability, and enzymatic degradation of the nanocomposite hydrogels were investigated in detail.     

A New Type of Dispersant [Sodium Salt of Styrene–Methacrylic Acid Copolymer (SSMA)/Montmorillonite (MMT) Nanocomposite] for Pesticide Water Dispersible Granules

A new type of dispersant [sodium salt of styrene–methacrylic acid copolymer (SSMA)/montmorillonite (MMT) nanocomposite] with different content of the MMT was synthesized through in situ solution free radical copolymerization. X‐ray diffraction measurements and electron microscopy observations prove that SSMA molecules can enter the interlayer space of MMT and form an intercalated structure. There are both fully intercalated and partly intercalated structures in the nanocomposites, which are related to the loading content of MMT. Transmission and scanning electron microscopy images indicate that the exfoliation degree of MMT in the nanocomposites decrease with increasing MMT content. Infrared spectroscopy (FTIR) analysis shows that there are hydrogen‐bonding interactions between carboxyl groups of SSMA and hydroxyl groups of MMT. Atrazine water dispersible granules were prepared by using SSMA/MMT nanocomposite as dispersant and their suspensibility in aqueous solution was determined to evaluate the dispersion properties of the nanocomposite. The results show that the addition of MMT can not only increase the steric effect of the SSMA to improve its dispersion properties, but also reduce the production cost of SSMA. The optimum loading content of MMT is 10 wt%.     

High‐temperature‐resistant polyimide/montmorillonite nanocomposite foams by solid blending

A series of high‐temperature‐resistant polyimide/montmorillonite (PI/MMT) nanocomposite foams were prepared by solid blending method. The dispersion of MMT and effects of MMT content on the properties of the PI/MMT nanocomposite foams were investigated. Results indicated that MMT could be exfoliated effectively and dispersed uniformly in the PI matrix by the solid blending method. The introduction of MMT could considerably increase the reduced compressive strength, thermal resistance, and decrease the dielectric constant of the PI/MMT nanocomposite foams. The reduced compressive strength of nanocomposite foams showed a maximum value at the MMT content of 5 wt%, which was 197% higher than that of pure PI foams. It was worth noting that a significant increase in glass‐transition temperature (T _g) could be achieved with the increase of MMT content, and the maximum T _g was as high as 436°C at the MMT content of 7 wt%. This study may provide a useful method to prepare PI/MMT nanocomposite foams with improved properties for targeted high‐temperature applications. POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers     

Effect of the incorporation of montmorillonite-layered double hydroxide nanoclays on the corrosion protection of epoxy coatings

A series of layered double hydroxide (LDH)/montmorillonite (MMT) nanocomposite coating, LDH nanocomposite coating, and MMT nanocomposite coating were successfully prepared. The nanocomposite materials were characterized by X-ray diffraction and scanning electron microscopy (SEM). To understand the effect of MMT and LDH on the corrosion inhibition performance of epoxy resin coatings immersed in 3.5 wt% saline solution at 90°C, electrochemical impedance spectroscopy and an autoclave test were performed on epoxy resin; epoxy resin blended with LDH, MMT, and LDH + MMT (LM) coatings painted on Q345 steel. The metal/coating interfaces were observed by SEM and energy-dispersive spectroscopy. Results showed that addition of LDH and MMT improved the protection properties of the epoxy resin coatings. The corrosion protection of the LM nanocomposite coating was superior to that of the other coatings. This finding can be attributed to the ionic selectivity and barrier effect of MMT and LDH nanoclay platelets dispersed within the composite coatings.     

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.     

阻隔性尼龙611／有机蒙脱土纳米复合材料的研究

以11-氨基十一酸对蒙脱土(MMT)进行有机化改性,采用原位聚合法制备了尼龙611/有机蒙脱土(OM-MT)纳米复合材料.通过傅立叶变换红外光谱仪研究了OMMT及尼龙611/OMMT纳米复合材料的化学结构,使用扫描电子显微镜观察了纳米复合材料的形貌.详细考察了OMMT含量对尼龙611/OMMT纳米复合材料阻隔性能和力学性能的影响,探讨了OMMT的阻隔机理.结果表明,MMT经有机化改性后,其片层在尼龙基体中分散均匀,并与尼龙基体发生键合作用,使尼龙611分子的内聚力增强,分子链堆积程度提高,极大地提高了阻隔性能;OMMT质量分数为3%时,材料的拉伸强度达到最大值,但在常温、低温下冲击强度略有下降.     

Influence of clay content on the melting behavior and crystal structure of nonisothermal crystallized poly(L‐lactic acid)/nanocomposites

To study the effect of organophilic clay concentration on nonisothermal crystallization, poly(L ‐lactic acid) (PLLA)/montmorillonite (MMT) nanocomposites were prepared by mixing various amounts of commercial MMT (Cloisite^® 30B) and PLLA. The effect of MMT content on melting behavior and crystal structure of nonisothermal crystallized PLLA/MMT nanocomposites was investigated by differential scanning calorimetry (DSC), small‐angle X‐ray scattering, and wide‐angle X‐ray diffraction (XRD) analyses. The study was focused on the effect of the filler concentration on thermal and structural properties of the nonisothermally crystallized nanocomposite PLLA/MMT. The results obtained have shown that at filler loadings higher than 3 wt %, intercalation of the clay is observed. At lower clay concentrations (1–3 wt %), exfoliation predominates. DSC and XRD analysis data show that the crystallinity of PLLA/MMT composites increases drastically at high clay loadings (5–9 wt %). In these nanocomposites, PLLA crystallizes nonisothermally in an orthorhombic crystal structure, assigned to the α form of PLLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012