聚丙烯/蒙脱土复合材料的热氧老化性能

用3种蒙脱土(原土、OMMT1、OMMT2)与聚丙烯分别熔融插层复合.经X射线衍射(XRD)分析表明,3种蒙脱土均与聚丙烯成功插层复合,制备出聚丙烯/蒙脱土纳米复合材料.重点研究聚丙烯/蒙脱土纳米复合材料的热氧老化性能.结果表明,在聚丙烯材料中,添加少量蒙脱土不但可以提高材料的力学性能,而且明显改善材料的抗热氧老化性能.对3种PP/MMT复合材料热氧老化样品进行傅立叶红外(FTIR)分析和表面形貌观察,发现蒙脱土片层在聚丙烯中插层复合越充分(乃至剥离),其抗热氧老化效果就越明显.     

阻燃聚丙烯/蒙脱土纳米复合材料的燃烧性能

采用X射线衍射和透射电镜对所制备的聚丙烯/蒙脱土（PP/MMT）插层纳米复合材料的结构进行表征;通过热分析、锥形量热、氧指数、垂直燃烧测试对其热解和燃烧性能进行了研究.热分析表明蒙脱土片层在热解过程中显示出能量阻隔作用,提高了材料的热稳定性和成炭量;蒙脱土片层与膨胀型阻燃剂之间的协效作用使得纳米复合材料热释放速率、CO与CO2释放量及比消光面积明显降低;将不同阻燃级别的材料制成电视机壳进行全尺寸锥形量热仪实验表明,V-0级别的阻燃聚丙烯材料的火灾危险性最小.     

甲基丙烯酸甲酯/蒙脱土纳米复合材料的研究

用烷基铵盐和甲基丙烯酰氧乙基三甲基氯化铵(DMC)对钠基蒙脱土进行有机化处理,采用二次插层法制备有机蒙脱土.X射线衍射(XRD)表明有机阳离子同钠离子发生离子交换作用,导致层间距扩大.采用本体聚合法制备了聚甲基丙烯酸甲酯(PMMA)/蒙脱土(MMT)纳米复合材料,测试了光学性能、力学性能、热稳定性.通过721分光光度计I、R、AFM、XRD、DMTA等手段研究了结构与性能,并与纯PMMA进行了对比.实验结果表明:PMMA可以插层于蒙脱土片层之中,得到共混物的透光率与纯PMMA相当,玻璃化温度比纯PMMA提高了约十几度.     

乳液聚合法制备聚甲基丙烯酸甲酯/蒙脱土嵌入混杂材料

利用蒙脱土能够均匀分散在水中的特点 ,用乳液聚合的方法制备聚甲基丙烯酸甲酯 (PMMA) /蒙脱土嵌入混杂材料。嵌入混杂材料用热甲苯进行萃取并用XRD、IR、DSC、TG等方法对嵌入混杂材料进行分析。结果表明,PMMA嵌入蒙脱土层间,二者之间存在较强的相互作用,嵌入的PMMA分子不能被萃取出来;嵌入混杂材料的玻璃化转变温度和热分解温度比纯PMMA均有明显提高。     

季鳞盐柱撑蒙脱土的制备及表征

采用离子交换法将不同组份的十烷基三丁基溴化鳞交换到蒙脱土的层间得到柱撑蒙脱土.用热重分析(TGA)、X-射线衍射(XRD)和傅里叶变换红外光谱法(FTIR)等对其结构进行了表征,并测定其抗菌活性.研究发现柱撑蒙脱土中季鳞盐的热分解起始温度大于210℃,具有较好的热稳定性;季鳞盐含量越高,柱撑蒙脱土的层间距越大,抗菌活性越高.     

Preparation of polypropylene/montmorillonite nanocomposites by intercalative polymerization： Effect of in situ polymer matrix functionalization on the stability of the nanocomposite structure

The copolymerization of propylene and 5-hexenyl-9-borabicyclo[3.3.1]nonane (5-hexenyl-9-BBN) has been conducted with an MgCl2/TiCl4 catalyst intercalated in an organically modified montmorillonite (OMMT) with triethylaluminum (AlEt3) cocatalyst and diphenyldimethoxysilane (DDS) external donor. This polymerization process simultaneously results in both the exfoliation of MMT layers to realize the preparation of polypropylene (PP)/MMT nanocomposites and the implantation of reactive borane groups in the formed PP matrix. The polymer-borne borane groups have been able to undergo an effi-cient hydrolysis process under very mild reaction conditions (40℃, 3 h, in THF), introducing hydroxy groups into PP without sacrificing the polymerization-formed nanocomposite structure (the exfoliation of MMT). The resultant hydroxyl-functionalized PP/MMT nanocomposites exhibit enhanced structural stability against processing compared with those based on unfunctionalized PP matrix.     

聚醋酸乙烯/蒙脱土复合乳液的制备及性能

利用半连续乳液聚合方法制备涂料用聚醋酸乙烯/蒙脱土复合乳液,通过FT-IR、XRD对该复合乳液的结构进行表征,研究蒙脱土质量分数对乳液固含量、硬度、耐水性的影响.结果表明,聚醋酸乙烯很好地插层于蒙脱土片层当中,获得插层型聚醋酸乙烯/蒙脱土纳米乳液;当蒙脱土质量分数为7%时,聚醋酸乙烯/蒙脱土纳米乳液涂膜硬度从2 B提高到3 H,固体质量分数达到33.2%,而且涂膜静置于水中100 h不脱落,相对一般聚醋酸乙烯乳液,其耐水性获得极大的提高.     

POLYMER/MONTMORILLONITE COMPLEXES:PREPARATION AND INTERACTIONS WITH ROSIN ACID

Polymer/montmorillonite complexes were prepared via intercalating polymers of low molecular weight into layers of montmorillonite and evaluated for their interactions with rosin acid. Three polymers from various amines modified by epichlorohydrin and an acidified diethylenetriamine were separately intercalated into montmorillonite via direct solution intercalation. X-ray diffraction patterns are performed to obtain information about the intercalation of these agents. The examination revealed that it was feasible for the direct intercalation of polymers, while hard for the unmodified diethylenetriamine. Adsorption isotherm curves were established to assess the efficiency of the various montmorillonites including the intercalated montmorillonites, the simple mixtures of the corresponding intercalation agents and ordinary montmorillonite in removing pitch from water solution. From the adsorption behavior of various samples, it was found that the interaction of the montmorillonite with pitch was not only through van der Waals attraction, but also through electrostatic interactions. Both the organo-philic and the surface electrostatic properties of the montmorillonites are important for successful pitch control.     

New evidence for microstructural evolution model of acid-activated montmorillonite

Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, ²⁹Si and ²⁷Al MAS NMR, to investigate the microstructure of the activated montmorillonites. With the increase of acid concentration and dissolution of cations of montmorillonite, the intensity of d(001) decreased obviously and significant changes of the microstructure of Si and Al occurred. There were two new types of structural units of Si atoms formed: (SiO)₃SiOH units and Q⁴(0Al) units. For Al atoms, in the course of activation, the removal of one of a pair of octahedral aluminium atoms from montmorillonite removed two hydroxyl groups and left the other aluminum of the pair in the four-fold coordination. The ²⁷Al signal at δ 54.0 corresponding to Al^Ⅳ arose from the four- coordinated Al in the octahedral sheet. This study first con-firmed, by ²⁹Si and ²⁷Al MAS NMR spectra, that the model of microstructural evolution for activated montmorillonite postulated by Thomas et al. (1950) is correct.     

SBS/蒙脱土纳米复合材料插层结构影响因素和力学性能

为提高苯乙烯-丁二烯共聚物(SBS)的性能,采用溶液混合方法制备了SBS/有机蒙脱土(OMMT)纳米复合材料(NC).对影响NC插层结构的因素:混合条件、OMMT种类和含量、线型和星型结构SBS等进行了研究.XRD测试结果表明:存在一最佳混合时间和最佳OMMT含量;SBS在不同种类OMMT中插层效果明显不同,星型SBS更容易插层,制备的NC具有插层型结构.力学性能研究表明,添加OMMT对于所有复合材料均产生增强效果,其中以SBS4303/OMMT-DK1B NC最为明显,拉伸强度提高1倍多,并且断裂伸长率显著增加.表明OMMT具有增强和提高SBS弹性的双重作用.应力-应变曲线、300%定伸强度均从不同角度证实了OMMT的增强效果,但SBS/OMMT NC永久变形增大.     

苯乙烯在蒙脱土上的接枝共聚合研究

通过离子交换反应,将甲基丙为惭基在氯化铵嵌入蒙脱土晶层之间。研究发现,在Ｎ,Ｎ－二甲基甲酰胺溶剂中苯乙烯能够与改性蒙脱土进行聚合反应,但聚苯乙烯不是嵌入脱土的层间,而是通过离子吸附接枝在蒙脱土晶层上。     

有机蒙脱土的制备及其结构表征

为增加蒙脱土与有机相的相容性,制备有机蒙脱土,并观察蒙脱土的层状结构在有机化前后的变化.以钠基蒙脱土为原料,用季铵盐、有机胺和复合试剂作为有机插层剂与蒙脱土层间的Na+交换,制备出一系列有机蒙脱土,并对其结构进行表征.FTIR证明有机插层剂已进入蒙脱土的层间.XRD结果表明蒙脱土的层间距由1.2 nm增加到1.7～4.2 nm.TEM观察也表明蒙脱土的层间距增大,粒层厚度约为50 nm左右.研究结果表明选择高交换容量的钠基蒙脱土和合适的插层剂,制备的有机蒙脱土层间距增加明显.     

高温处理对钠化膨润土蒙脱石结构变化的影响

以安徽芜湖(WH)、四川三台(ST)和河南信阳(XY)三个地区的膨润土为原料,以碳酸钠为钠化剂分别对三种原料进行钠化改性处理,获得钠化膨润土样品WH-G、XY-G和ST-G,随后对钠化后样品进行高温热处理.对原样、钠化样品及热处理样品的物相、结构、热学属性及谱学特征进行了表征分析.结果表明,WH-G、XY-G和ST-G三个样品中蒙脱石失去吸附水和层间水的温度随着样品中蒙脱石的层电荷的增加呈上升趋势,但膨润土的热稳定性却与之相反. WH-G和XY-G样品在处理温度900℃时蒙脱石的结构完全被破坏,而ST-G样品在800℃时蒙脱石的结构即完全被破坏.     

Decoration of C60 nanorods with nickel and their magnetic properties

We studied the coating of C60 nanorods with nickel by electroless plating method and investigated their magnetic properties. The morphology and structure of the nickel layer coated on C60 nanorods were characterized by transmission electron microscopy （TEM）, energy-dispersive X-ray spectroscopy （EDX）, X-ray diffraction （XRD） and Raman spectroscopy. The coated nickel is in the form of nano-sized crystals and becomes a continuous layer as reaction time increases. The hysteresis loop shows a super paramagnetic characteristic similar to that of nanometer-sized nickel particle. These results suggest that the average size of nickel particles on C60 rods is below 10 nm. Our study has shown that electroless plating is an efficient and simple method for coating C60 nanorods with nickel.     

有机改性粘土的制备与X-射线衍射和热失重分析

对膨润土及凹凸棒土进行有机改性处理 ,制备出有机改性粘土 ,并通过X -射线衍射和热失重分析比较了膨润土及凹凸棒土有机改性前后的层间距和热失重性能变化 ,结果表明 ,改性后有机阳离子已和粘土发生了离子交换作用 ,同时使层间距变大 ;同等条件下 ,有机化膨润土的热失重百分率比改性前要高。经有机改性的粘土可用作聚合物基层状硅酸盐纳米复合材料的无机填料。     

Preparation and characterization of poly（styrene／maleic anhydride）／kaolin nanocomposites

The direct exfoliation of in situ intercalative copolymerized styrene/maleic anhydride charge-transfer-complex (PSMA) into the inter lamellar spaces of modified kaolin (Kao-DMSO), which was intercalated and surface modified by dimethyl sulfoxide (DMSO), was reported. The nano structure of the composites was investigated by wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). The interaction between kaolin surface and PSMA chain was conformed by FTIR analysis.The XRD results showed that the intercalated polystyrene-maleic anhydride units were arranged in the flattened monolayer arrangements, and the 001 diffraction peak of the original kaolin disappeared. The TEM image showed that thekaolin was exfoliated into nanometer size and dispersed in the polymer matrix. Additionally the thermal stability of the nanocomposites was studied by thermo-gravimetric analysis(TGA), and the resulting thermogram indicated that the thermal stability of the nanocomposites was significantly increased.     

聚碳酸亚丙酯/有机蒙脱土纳米复合材料的制备与性能

通过熔融插层法制备了聚碳酸亚丙酯(PPC)/有机蒙脱土(OMMT)复合材料。XRD分析表明:PPC/OMMT复合材料形成了插层型纳米复合结构。相对于纯PPC材料,纳米复合材料的拉伸性能和抗冲击性能得到了显著提高,但复合材料的断裂伸长率降低。当OMMT含量为6%时,PPC/OMMT纳米复合材料具有最优的力学性能和最高的玻璃化温度。     

精氨酸改性蒙脱石的制备及其吸附性能

用精氨酸对蒙脱石进行改性,对改性后的蒙脱石进行X射线衍射(XRD)、红外光谱(FT-IR)和热重(TGA)等分析表征,找到具有最优配比的精氨酸改性蒙脱石,将其负载5-氟尿嘧啶.结果表明:精氨酸确实插层进入钠基蒙脱石的层间,精氨酸改性蒙脱石的有机化程度最高可达到30.17％,且其对5-氟尿嘧啶的吸附率可达34.98％.     

聚甲基丙烯酸甲酯/蒙脱土纳米复合材料的热分解

采用TG、DTA研究聚甲基丙烯酸甲酯(PMMA)及聚甲基丙烯酸甲酯/蒙脱土纳米复合材料(PMNC)在N2气氛条件下的热降解行为.结果表明,在N2中,PMMA有一个失重阶段,而PMNC为两个失重阶段.利用改进的Coats-Redfern积分法计算PMMA及PMNC的热分解动力学参数,PMMA热分解的平均表观活化能E为160.58kJ/mol,指前因子的对数值lnA为28.07,其热分解的机理函数为三维扩散方程.PMNC第一个阶段的平均表观活化能E为258.731 kJ/mol,lnA为45.623 1,第二个阶段的平均表观活化能E为199.897 kJ/mol,lnA为27.482 4,其热分解的机理函数均为二维扩散方程.