有机蒙脱土改性环氧树脂的研究

利用离子交换反应制备了有机蒙脱土，用插层聚合法制得了有机蒙脱土／改性环氧树脂纳米复合材料。利用傅立叶红外光谱（FTIR）、X射线衍射（XRD）、元素分析对有机蒙脱土进行了表征，探讨了长链烷基季铵盐类表面活性剂与蒙脱土片层的界面作用对复合材料性能的影响。     

Gemini插层蒙脱土抑杀铜绿微囊藻的研究

本文采用离子交换法制备了Gemini季铵盐插层蒙脱土,并使用XRD、IR、DSC-TGA对其进行表征,研究了Gemini季铵盐插层蒙脱土去除铜绿微囊藻的效果.结果表明:Gemini季铵盐可以插入蒙脱土层间,在实验条件下,其插入量为17.4wt％.当铜绿微囊藻初始浓度为2.67×lo8 cell/L,Gemini季铵盐插层蒙脱土加入量为0.09 g/L,作用12 h后,叶绿素a去除率达到了88％左右.插层物Gemini季铵盐可以缓慢释放,可以长期抑制藻细胞絮体中藻活性来防止藻絮体的重新悬浮.     

有机化蒙脱土改性PET研究

用长链季铵盐和聚乙二醇(PEG)对蒙脱土进行交换反应,使季铵盐嵌入到蒙脱土的晶层间,使蒙脱土由亲水性变为亲油性;有机化改性后的蒙脱土与聚对苯二甲酸乙二醇酯(PET)熔融插层后可以较大地提高原树脂的耐热性和阻隔性能.     

三聚阳离子表面活性剂改性蒙脱土的制备与表征

合成了一种含六氢三嗪的新型三聚季铵盐阳离子表面活性剂T16,以13C NMR和ESI-MS表征其结构,并作为有机插层剂应用于蒙脱土的改性。红外光谱(FTIR)、热重分析(TGA)表明,T16已插层到蒙脱土片层间。X射线粉末衍射(XRD)表明,T16改性后蒙脱土层间距从原来的1.486 nm增加到3.324 nm。沉降实验表明,改性后蒙脱土在苯乙烯和甲苯中形成凝胶体系,表现出很好的相容性和分散性,有利于聚合物或其单体进入蒙脱土层间形成纳米复合材料。     

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。     

季铵盐改性蒙脱土的抗菌活性及抗菌机理

采用离子交换法将不同季钱盐插层到钠基蒙脱土中制备了改性蒙脱土.改性蒙脱土对革兰氏阳性菌(S.aereus)和革兰氏阴性菌(E coli)均有很强的抗菌作用,并且随着季铵盐在蒙脱土中的质量分数增加其抗菌活性增强.不同季铵盐改性蒙脱土的抗菌活性不同,其中双季铵盐改性蒙脱土的抗菌活性最好,对S.aereus和E coli的最小抑菌浓度分别为6.25 mg/L和12.5 mg/L.用扫描电镜对与细菌接触不同时间后的改性蒙脱土进行观察,结果表明:细菌先吸附到改性蒙脱土的表面,然后慢慢的变形死亡.同时,对在0.9%的生理盐水中浸泡不同时间后的改性蒙脱土进行X射线衍射和热重分析.结果表明:随着浸泡时间的增加,蒙脱土中的有机物质量分数及层间距均逐渐减少,说明季铵盐能从蒙脱土的层间解吸出来,并进入溶液中直接杀死细菌.因而,改性蒙脱土的抗菌活性是吸附与释放到溶液中的季铵盐离子协同作用的结果.     

一种含氮磷蒙脱土阻燃剂的合成及表征

采用二氯化磷酸苯酯,2-溴乙胺氢溴酸盐,十二烷基二甲基叔胺等为原料合成含有氮磷元素的双长链烷烃季铵盐,并用其对蒙脱土进行有机化插层改性,并通过红外光谱（FT-IR）、X射线衍射（XRD）、热重分析（TGA）以及沉降实验等表征手段对含氮磷蒙脱土阻燃剂进行研究,最后将改性后的有机蒙脱土（OMMT）与聚碳酸亚丙酯（PPC）复合,研究其热性能与应用前景.     

新型聚合物季铵盐改性蒙脱土的研究进展

聚合物改性蒙脱土具有比小分子改性更好的热稳定性,更多的结构变化性,聚合物改性蒙脱土可以赋予蒙脱土更多的表面性能和物理机械性能.综述了近年来此领域的最新研究进展,详细介绍了不同聚合物季铵盐、共聚物季铵盐和层间聚合的季铵盐作为改性剂的情况和效果.重点介绍了聚合物有机改性剂的组成、结构、性质及改性后纳米复合材料的性能和应用,并对未来的研究趋势进行展望.     

有机蒙脱土的制备及表征

用长链季铵盐对蒙脱土进行离子交换反应,季铵盐嵌入到蒙脱土的层间。研究了季铵盐的种类、结构对插层效果的影响。用FT-IR、XRD和TGA等测试手段对改性蒙脱土进行了表征与测试。结果表明:插层剂脂肪烷基链越长,链越柔顺,插层效果越好,且苯环取代基的引入有利于增大蒙脱土层间距,提高插层效果。     

表面活性剂和硅烷偶联剂有机复合改性蒙脱土的制备及性能表征

为增加蒙脱土与有机物的相容性,采用十六烷基三甲基溴化铵(CTAB)与硅烷偶联剂(KH-560)对蒙脱土进行了有机复合改性。X-射线衍射和红外光谱的结果表明,CTAB已插入蒙脱土片层,平均层间距离从1.54 nm增大到3.98 nm和2.08 nm,而KH-560未插入蒙脱土片层,只是覆盖在蒙脱土表面,未改变蒙脱土的插层结构;分散性实验表明,表面活性剂和硅烷偶联剂有机复合改性的蒙脱土在苯乙烯、液体石蜡中的分散性好于其他改性蒙脱土;有机复合改性不仅增大了蒙脱土层间距,且改善了蒙脱土与聚氯乙烯的界面效果,提高了蒙脱土在聚氯乙烯基体中的分散均匀性,从而使聚氯乙烯/蒙脱土复合材料玻璃化转变温度的提高和力学性能的改善更明显。     

功能化聚乙烯蜡／有机蒙脱土插层复合母粒的研制

用两种不同改性剂与蒙脱土进行离子交换制得了两种有机蒙脱土，用功能化聚乙烯与有机蒙脱土进行熔融插层复合制备了功能化聚乙烯蜡/有机蒙脱土插层复合母粒，用X-射线衍射，傅立叶红外光谱，热重分析，差示扫描量热和抽提实验等对所得有机蒙脱土和功能化聚乙烯蜡/有机蒙脱土插层复合母粒的结构与性能进行表征。结果表明，有机蒙脱土层间距的增大和功能化聚乙烯蜡的极性活性官能团使得功能化聚乙烯蜡可以被插入到有机蒙脱土的夹层之间，甚至与层间的有机改性剂形成共价键而不被有机溶剂抽提出来。     

Modification of montmorillonite with cationic surfactants. Thermal and chemical analysis including CEC determination

The thermal stability of synthesized and commercial organically modified montmorillonites has been investigated using thermogravimetric analysis (TGA). Four organo-montmorillonites have been prepared by replacing the inorganic cations of a commercial montmorillonite with aliphatic and aromatic ammonium bromide or chloride salts. The modification has been carried out by cation exchange to obtain a high level of intercalation in the montmorillonite. Conformations of the intercalated surfactants have been characterized using Fourier transform infrared spectroscopy (FTIR). Besides fixed organic surfactant, some surfactant in excess still remained in the montmorillonite after repeated washing with water or ethanol/water. The use of a suitable eluent for the surfactants in the washing step was the key issue as shown by the changes of the first degradation peak of Cloisite-Na⁺-hexadecyl benzyl dimethylammonium (CLO-BDHA), Cloisite-Na⁺-benzyl triethylammonium (CLO-BTA) and Cloisite-Na⁺-hexadecyl trimethylammonium (CLO-HTA). Hexadecyl trimethylammonium (HTA) was more sensitive to water and ethanol/water as eluents. Sonication and the use of a polar activator during the modification of montmorillonite increased the amount of surfactant adsorbed by cation exchange. Ammonium acetate method has been revealed as an adequate chemical method to measure the cation exchange capacity (CEC) of inorganic and organic montmorillonites. This method has the advantage with respect to TGA that it does not measure the unfixed surfactant.     

Modification of montmorillonites with thermally stable phosphonium cations and comparison with alkylammonium montmorillonites

Alkylammonium montmorillonites have onset temperature of degradation in the same temperature range used for compounding of thermoplastics, thus, requiring more thermally stable organic cations. In the current study, phosphonium, imidazolium and pyridinium ions differing in their chemical architecture (length of alkyl chains, number of phenyl groups etc.) were exchanged on the surface of montmorillonites. The montmorillonites with two different cation exchange capacities (CECs) were used. The thermal behavior of the modified montmorillonites was analyzed by thermogravimetric analysis. To achieve quantitative insights into the onset of degradation, temperatures to reach 5% and 10% mass loss and peak degradation temperatures were compared. Time to reach 1% mass loss was also calculated in the dynamic TGA. The surfactants used in the study were more thermally stable than the conventional alkylammonium cations due to their delayed onset as well as peak degradation temperatures. The time required to attain certain extent of degradation was also much higher in the case of phosphonium montmorillonites, thus, confirming their better thermal resistance. Though the degradation temperatures as well as profiles of the modified montmorillonites with different CECs were similar, the dynamic TGA revealed better thermal behavior of the higher CEC montmorillonite. The X-ray diffraction studies also concluded that optimal modification of the montmorillonite surface could be attained, thus, confirming the high potential of phosphonium montmorillonites for nanocomposites.     

Thermally stable phosphonium-montmorillonite organoclays

Sodium montmorillonite (MMT) was modified with several organic phosphonium salts. Organoclays with water soluble surfactants were prepared by the traditional cation exchange reaction. An alternative procedure was used to prepare organoclays with water insoluble salts. The effect of chemical composition and molecular weight of the salts on the thermal stability and basal spacing were evaluated. The phosphonium montmorillonites exhibit higher thermal stability than conventional ammonium organoclays. The basal spacing is generally larger for the phosphonium montmorillonites. These properties provide a good potential for the use of phosphonium organoclays for the synthesis of polymer/clay nanocomposites by melt processing.     

不同蒙脱石的有机插层及聚合剥离

以成因、类型、性质不同的6种蒙脱石为原料,制备了有机插层和聚酰胺6／蒙脱石纳米复合材料。研究了蒙脱石矿物类型、成分及阳离子交换容量对其有机插层及聚合剥离的影响。结果表明：有机插层蒙脱石层间距随插层剂用量及阳离子交换容量的增加而增加,低阳离子交换容量及高钠含量蒙脱石更有利于插层剥离。钠化对蒙脱石有机插层影响不明显。     

Reaction of acid activated montmorillonites with hexadecyl trimethylammonium bromide solution

Acid-activated montmorillonites (AMt) prepared at different acid montmorillonite ratios were reacted with hexadecyl trimethylammonium (C16TMA) bromide solution. The acid treated Mt incorporated smaller amounts of the surfactants than the parent Mt, due to the reduction of the cation exchange capacity after acid-treatment. The powder X-ray diffraction patterns exhibited a similar basal spacing of 3.80 nm but with less ordered structure at higher acid montmorillonite ratios. A certain degree of conformational heterogeneity was observed by ¹³C CP NMR spectroscopy due to the different local environment of C16TMA⁺ ions in the interlayer space. The in-situ PXRD patterns showed an increase of the basal spacing of organo acid-activated montmorillonites when heated at intermediate temperatures (100–200 °C), while the basal spacing was almost constant in this range of temperature for the organomontmorillonite. Generally, the stability of the surfactant decreased when intercalated into the montmorillonites compared to the pure C16TMABr. This fact implies that the interlayer space influences the decomposition steps.     

铁硅改性膨润土对废水有机污染物的吸附性能研究

以钠基膨润土为原料，制备了铁硅交联土、铁硅有机复合土，以CODCr的去除率为指标，对原土、铁硅交联土、铁硅有机复合土进行了筛选，结果表明：铁硅有机复合土对CODCr的去除率明显好于铁硅交联土和原土；将铁硅有机复合土应用于造纸废水，探讨了其用量、废水PH值、搅拌时间等对CODCr去除率的影响，通过正交实验确定了最佳条件，并在此条件下考察了其对废水CODCr、色度、浊度的去除率，结果表明：以上指标分别可达到87．69％、98．00％、98．18％；最后对铁硅改性膨润土对废水有机污染物的吸附机理进行了探讨。     

Effect of POSS on morphology and mechanical properties of polyamide 12/montmorillonite nanocomposites

Sodium-montmorillonite (MMT) was modified with two types of AP-POSS and OA-POSS and dual-surfactants (POSS with a ditallow-based second surfactant: 04AP-POSS/08DTDMA and 04OA-POSS/08DTDMA), respectively, via ion-exchange reaction. The interlayer space, interlamellar structure, thermal and surface properties of these organo-montmorillonites were investigated by X-ray diffraction, thermogravimetric analysis, and contact angle measurement. The interlayer space of POSS modified clay was strongly dependent on the arrangement of POSS surfactants, but less on the POSS concentration. The POSS modified montmorillonites have partially exchanged silicate surfaces and good thermal stabilities due to steric hindering and thermal stability of the POSS molecules. Dual-surfactant modified montmorillonites showed higher exchange ratio and possessed better compatibility with PA12 due to the lower interfacial free energy. Polyamide 12-montmorillonite nanocomposites were prepared by conventional melt compounding with the four POSS based organo-montmorillonites. The best dispersion of modified montmorillonite was observed for 3 mass% 04AP-POSS/08DTDMA/MMT filled PA12 nanocomposites, which resulted in the best mechanical performance with an increase of 60% in tensile modulus and 10% in yield strength, respectively, compared to that of pure PA12. Compatibility between montmorillonites and polymer was not the only key factor affecting dispersion, thermal stability and interlayer space were also crucial for good dispersion of montmorillonites in polymer matrix.     

Synthesis of organic montmorillonite contained polyhedral oligomeric silsesquioxane and its nanocomposites with poly(l‐lactide)

Three kinds of novel organic montmorillonites (OMMTs) were prepared by reacting the amino polyhedral oligomeric silsesquioxanes (POSSs) with the OMMTs that had already been modified by cationic surfactants. The layer spacing of OMMT increased from 1.68 to 3.81 nm after being intercalated by POSS. Poly(l ‐lactide) (PLLA) based nanocomposites with montmorillonites were produced by melt compounding. The PLLA nanocomposites with POSS modified OMMT were comprised of a random dispersion of intercalated/exfoliated aggregates of layered silicates throughout the PLLA matrix. The incorporation of POSS modified OMMT resulted in a significant increase in both crystallization temperature and decomposition temperature for 5% weight loss in comparison with the virgin PLLA. Gas Permeation Analysis showed that the increase of the montmorillonite concentration in the polymer matrix led to an expected decrease in permeation values. Gas barrier properties of the nanocomposites were compared with those predicted by phenomenological models such as the Nielsen model and Cussler model. POLYM. ENG. SCI., 54:2489–2496, 2014. © 2013 Society of Plastics Engineers     

改性蒙脱土的研究进展

改性蒙脱土是近年来受国内外学者广泛关注的矿物材料之一,由于其层间的特殊结构而被广泛应用于吸附、催化等领域。概括介绍了蒙脱土的结构和基本性质,重点讨论了蒙脱土改性方法和机理。对无机改性、有机改性和有机一无机复合改性分别作了论述,并展望了其应用前景。