聚丙烯/蒙脱土纳米复合材料Ⅰ.制备、表征及动态力学性能

用原位接枝插层法成功地制备了聚丙烯 /蒙脱土纳米复合材料 (PPMNC) .采用X射线衍射研究复合材料中蒙脱土硅酸盐片层间距 ,发现硅酸盐片层间距从 1 94nm升至 4nm左右 .同时研究了PPMNC的动态力学性能 ,结果表明 :PPMNC的动态储能模量明显高于聚丙烯 (PP) ,尤其在T >Tg 高温段 ,甚至可以达到PP基体的 2倍     

双单体原位接枝插层法制备聚丙烯纳米复合材料的研究Ⅰ.制备、表征及力学性能的研究

用有机插层剂处理蒙脱土原土 ,制得有机蒙脱土 (O MMT) .采用双单体 (马来酸酐和苯乙烯 )原位接枝插层法 ,制备了聚丙烯 蒙脱土纳米复合材料母料 .将母料与聚丙烯基体在双螺杆上共混挤出 ,制得聚丙烯 蒙脱土纳米复合材料 (PP Montmorillonetenanocomposites,PMNC) .这是制备聚合物纳米复合材料的一种新方法 .通过X 射线衍射测试 (XRD)表明 ,有机蒙脱土片层 0 0 1面间距从原土的 1 4 9nm扩大到 2 96nm ,复合材料中蒙脱土片层 0 0 1面间距由有机蒙脱土的 2 96nm扩大到 4 0nm .力学性能测试表明 ,复合材料的力学性能明显优于PP基体 ,在提高材料拉伸强度的同时 ,缺口冲击强度也得到很大的提高 .用扫描电镜 (SEM)对材料的冲击断面形貌进行了研究 ,并从理论上分析了断裂机理 .随着蒙脱土含量的增加 ,冲击断裂形式逐渐从脆性断裂变成韧性断裂     

β-羟基丁酸与β-羟基戊酸共聚物 (PHBV)/蒙脱土纳米复合材料的结构与性能

用溶液复合法成功地制备了插层型PHBV／蒙脱土纳米复合材料。采用X射线衍射（XRD）和透射电子显微镜（TEM）研究了复合材料的结构，硅酸盐片层间距从1.8nm升至2.4nm左右。同时研究了复合材料的结晶，熔融，动态力学行为和力学性能，发现有机蒙脱土的加入，可以加快PHBV的结晶,降低熔融温度，使基体的玻璃化转变温度升高，提高了材料的力学性能，有机蒙脱土含量在3％时，其综合性能最佳。     

聚苯乙烯/蒙脱土纳米复合材料中的剪切诱导有序结构(Ⅰ)——广角X射线衍射与透射电镜研究

聚合物/层状硅酸盐(PLS)纳米复合材料是近10余年来迅速发展起来的的交叉学科.由于其具有常规复合材料所没有的结构、形态以及较常规聚合物基复合材料更优异的性能等而引起人们的广泛关注[1].以往文献主要报道PLS纳米复合材料的制备与性能表征,如尼龙-6/蒙脱土[2]、PET/蒙脱土[3]和硅橡胶/蒙脱土[4]等.对于熔融加工过程中粘土片层及高分子的取向和结构研究很少.Kojima等[5]发现并研究了尼龙-6/蒙脱土纳米复合材料中的熔融剪切诱导取向结构,其X射线衍射与透射电镜(TEM)结果均表明,粘土片层沿熔体流动方向平行取向,但片层间距不等,因此为一平行取向但无序的结构.对于PLS纳米复合材料中的剪切诱导有序结构尚未见报道.     

甲苯-2,4-二异氰酸酯修饰蒙脱土及聚苯乙烯蒙脱土纳米复合材料的制备与表征

用FTIR和WAXD法研究了甲苯-2,4-二异氰酸酯(TDI)的邻位和对位异氰酸酯基团与蒙脱土表面羟基的修饰反应,在此基础上提出了结构模型;用TDI修饰后的蒙脱土成功制备了插层型聚苯乙烯/蒙脱土纳米复合材料,并用WAXD和TEM进行了表征.实验结果表明,修饰后TDI与蒙脱土表面形成化学键,使蒙脱土的片层间距显著增大,十六烷基三甲基溴化铵(CTAB)在蒙脱土层间由双层平行排列转变为双层脂肪链倾斜方式排列.在苯乙烯插层聚合过程中,蒙脱土层间距进一步扩大,其初级粒子在聚苯乙烯基体中的厚度约20～50nm.     

4,4'-二氨基二苯醚二苯酮固化环氧树脂/粘土纳米复合材料的研究

采用离子交换法, 用十六烷基三甲基溴化铵处理钙基蒙脱土(MMT), 使蒙脱土的层间距由1.49 nm扩大到2.21 nm, 制备了环氧树脂/ BADK/MMT纳米复合材料, 并用XRD等手段研究了有机蒙脱土在环氧树脂中的插层及剥离行为. 研究结果表明, 蒙脱土含量及环氧树脂与有机土的混合温度和时间均对固化后复合材料的剥离产生影响, 只有在特定条件下才能得到剥离型纳米复合材料.     

高抗冲聚苯乙烯/蒙脱土复合材料的阻燃性研究

用经十六烷基三甲基溴化铵有机化改性的蒙脱土 (OMMT)与高抗冲聚苯乙烯 (HIPS)通过熔融插层法制备了HIPS OMMT复合材料 ,用X ray衍射技术对材料结构进行了表征 ,发现钠基蒙脱土 (Na+ MMT)和有机蒙脱土的层间距分别为 1 5 1nm和 2 18nm ,HIPS OMMT(5phr)复合材料中蒙脱土的层间距因聚合物大分子的插入扩大为 3 4 4nm ;而HIPS与Na+ MMT形成的复合材料的层间距与Na+ MMT的层间距相比却没有变化 ,表明未有机化处理土没有形成插层结构 .锥形量热仪的研究结果表明HIPS OMMT复合材料的热释放速率、质量损失速率以及生烟速率等燃烧特性参数均显著降低 ,具有较明显的阻燃性和抑烟性 ,而HIPS Na+ MMT非插层型复合材料只有在Na+ MMT很高填充量下 (>2 0phr)才有一定阻燃效果 .比较了铵盐对HIPS阻燃性的影响 ,结果表明铵盐自身的阻燃作用很小 ,主要是插层复合结构起阻燃作用 .     

三聚苯撑乙烯/蒙脱土发光光谱的时间依赖性

用原位插层法制备了插层型的三聚苯撑乙烯/蒙脱土(TPV/MMT)纳米复合材料. 研究了新制备及在室温储存180天后的TPV/MMT纳米复合材料的荧光光谱及蒙脱土层间距的变化情况. 荧光光谱分析表明, 储存180天后, TPV/MMT纳米复合材料的最大发射峰由494 nm蓝移到438 nm, 半峰宽由77 nm增加到104 nm. X射线衍射结果表明, 与新制备的复合材料相比, 蒙脱土的层间距由1.52 nm减小到1.22 nm. 红外光谱分析表明, 室温储存180天后的三聚苯撑乙烯苯环的某些特征峰由1598 和1554 cm-1分别红移到1506和1462 cm-1. 依据相关实验和理论数据探讨了储存180 天前后TPV在蒙脱土中聚集态结构的变化方式.     

聚N-甲基苯胺/蒙脱土纳米复合材料的合成及其协同电流变效应

用插层聚合法制备了聚N 甲基苯胺 蒙脱土纳米复合材料微粒 ,通过IR、XRD及TEM对其结构进行了表征 .观察发现聚N 甲基苯胺插入蒙脱土层间后 ,蒙脱土片层间距由 0 96nm扩大至 1 34nm .将其分散在甲基硅油中 (2 0wt% )配制成无水电流变液 ,该复合材料表现出显著的协同效应 ,具有较好的电流变行为 .实验表明在电场作用下聚N 甲基苯胺 蒙脱土纳米复合材料的电流变效应比聚苯胺、蒙脱土都有显著提高 ,在 3kV mm(DC ,74 5s- 1 )时 ,剪切强度达 6 0kPa ;同时抗沉降性极好 ,静置 6 0天沉淀率小于 3% .介电性能测试表明聚N 甲基苯胺 蒙脱土纳米颗粒的介电常数和介电损耗较蒙脱土和聚N 甲基苯胺明显提高 ,电导率也达到了最佳范围 .     

聚氨酯弹性体/蒙脱土纳米复合材料的合成、结构与性能

采用插层聚合法合成了综合力学性能优异的聚氨酯 蒙脱土纳米复合材料 .X 射线衍射结果表明 ,蒙脱土以平均层间距不小于 4 5nm的宽分布分散在聚氨酯基体中 .加入 7 5wt%左右的蒙脱土 ,复合材料的拉伸强度高于纯PU基体的 2倍 ,断裂伸长率则高于纯PU基体的 4倍以上 .TGA分析表明 ,聚氨酯 蒙脱土纳米复合材料的热稳定性略有提高     

插层聚合制备聚丙烯/蒙脱土纳米复合材料及其结构性能表征

将插层聚合的概念引入烯烃聚合,制备了聚丙烯／蒙脱土（PP／MMT）纳米复合材料。X射线衍射和TEM分析结果表明,蒙脱土在聚丙烯基体中达到了纳米级的分散,动态力学性能研究结果表明,在高于Tg的温度区域内PP／MMT纳米复合材料的储能模量（E′）成倍增加,加入8％的蒙脱土（MMT）,PP／MMT的E′提高近3倍。PP／MMT的玻璃化转变温度Tg有一定程度的提高,随蒙脱土含量的增加,PP／MMT的热分解温度和热变形温度（HDT）都有大幅度提高。     

Isotactic Poly(propylene)/Monoalkylimidazolium‐Modified Montmorillonite Nanocomposites: Preparation by Intercalative Polymerization and Thermal Stability Study

Summary: Poly(propylene)/monoalkylimidazolium‐modified montmorillonite (PP/IMMT) nanocomposites were prepared by in situ intercalative polymerization of propylene with TiCl₄/MgCl₂/MMT catalyst. The PP synthesized possessed high isotacticity and molecular weight. Both wide‐angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM) examinations evidenced the nanocomposite formation with exfoliated MMT homogeneously distributed in the PP matrix. A thermal stability study revealed that the nanocomposites possess good thermal stability.

X‐ray diffraction patterns of PP/IMMT (MMT = 2.2 wt.‐%) nanocomposite before and after processing.     

Synthesis of Novolac/Layered Silicate Nanocomposites by Reaction Exfoliation Using Acid‐Modified Montmorillonite

Novolac/layered silicate nanocomposites were synthesized by condensation polymerization of phenol and formaldehyde catalyzed by H‐montmorillonite (H‐MMT). Exfoliation of the clay was investigated by X‐ray diffraction and transmission electron microscopy (TEM). It turned out that the intra‐gallery condensation of phenol and formaldehyde played a predominant role in the exfoliation of MMT. Exfoliated clay plates with interlayer spacings of 10–30 nm were dispersed in the matrix uniformly as shown by the TEM micrograph.     

混合条件对环氧有机土纳米复合材料插层剥离行为及性能的影响

采用X 射线衍射仪、透射电镜 (TEM )研究了混合条件 ,即混合温度和时间 ,对环氧 /16 烷基胺有机蒙脱土体系在固化前的混合物以及加入固化剂、促进剂固化后有机土的插层与剥离行为的影响 .同时采用拉伸试验机、冲击试验机和热机械分析仪测定了插层与剥离型纳米复合材料的物理力学性能 .从X 射线衍射看出 ,有机土很容易在混合过程被环氧所插层 .混合物经固化后可以形成插层型或剥离型纳米复合材料 .存在一个混合温度 时间 插层剥离转变的 3 T图 .只有在一定的混合条件的区域内才能形成剥离型纳米复合材料 .剥离型比插层型纳米复合材料具有较高的力学性能     

原位插层聚合制备聚丁二烯/蒙脱土纳米复合材料的结构与性能研究

聚合物 /粘土纳米复合材料由于具有常规复合材料所没有的结构、形态及更优异的力学、热学、阻燃、阻隔等性能 ,自 1 987由日本丰田公司首次报道了制备尼龙 6 粘土纳米复合材料以来 ,立刻引起人们的普遍关注[1～ 17] .目前报道的聚合物 /粘土纳米复合材料主要集中在以树脂为基体 ,例如 ,聚酰胺[1～ 4] 、聚苯乙烯[5～ 8] 、聚甲基丙烯酸甲酯[9,10 ] 、聚丙烯[11,12 ] 等 .制备以橡胶为基体的橡胶/粘土纳米复合材料研究较少 ,采用的方法多为通过橡胶大分子插层 ,如熔融插层法[1 3] 、溶液插层法[14 ] 、乳液法[15,16] 等 ,这些方法均存在插层…     

Influence of Fe‐MMT on crosslinking and thermal degradation in silicone rubber/clay nanocomposites

In this article, silicone rubber (SR)/clay nanocomposites were synthesized by a melt‐intercalation process using synthetic Fe‐montmorillonite (Fe‐MMT) and natural Na‐MMT which were modified by cetyltrimethyl ammonium bromide (CTAB). This study has been designed to determine if the presence of structural iron in the matrix can result in radical trapping and then enhance thermal stability, affect the crosslinking degree and elongation. The SR/clay nanocomposites were characterized by X‐ray diffraction (XRD) patterns and transmission electron microscopy (TEM). Exfoliated and intercalated nanocomposites were obtained. Thermo gravimetric analysis (TGA) and mechanical performance were applied to test the properties of the SR/clay nanocomposites. The presence of iron significantly increased the onset temperature of thermal degradation in SR/Fe‐MMT nanocomposites. The thermal stability, gel fraction and mechanical property of SR/Fe‐MMT were different from the SR/Na‐MMT nanocomposites. So the iron not only in thermal degradation but in the vulcanization process acted as an antioxidant and radicals trap. Copyright © 2006 John Wiley & Sons, Ltd.     

The influence of a quaternary ammonium salt and MMT on the in situ intercalative polymerization of PMMA

Poly(methylmetacrylate)/montmorillonite (PMMA)/(MMT) nanocomposites were prepared by a one-step in situ intercalative solution polymerization involving the simultaneous modification of the MMT with a quaternary ammonium salt (cetyl-trimethylammonium bromide (CTMAB)), polymerization and polymer intercalation. Using benzoyl peroxide as an initiator, intercalated nanocomposites were formed and characterized by NMR, DSC, TGA, XRD, TEM and SEC. It was observed that it was not the MMT, but rather the CTMAB, that influences the polymerization reaction, especially the reaction yield, the molar mass averages and the molar mass distribution of the PMMA. The thermal stability of the PMMA was improved by the addition of both the MMT and/or the CTMAB.     

In situ intercalative polymerization of conducting polypyrrole/montmorillonite nanocomposites

Conducting polypyrrole (PPy)‐montmorillonite (MMT) clay nanocomposites have been synthesized by the in situ intercalative polymerization method. The PPy‐MMT nanocomposites are characterized by field‐emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), ultraviolet–visible (UV–vis) spectroscopy, thermogravimetric analysis (TGA), and Fourier‐transform infrared (FTIR) spectroscopy. XRD patterns show that after polymerization by the in situ intercalative method with ammonium persulfate and 1 M HCl, an increase in the basal spacing from 1.2 to 1.9 nm was observed, signifying that PPy is synthesized between the interlayer spaces of MMT. TEM and SEM micrographs suggest that the coexistence of intercalated MMT layers with the PPy macromolecules. FTIR reveals that there might be possible interfacial interactions present between the MMT clay and PPy matrix. The study also shows that the introduction of MMT clay results in thermal stability improvement of the PPy. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2279–2285, 2008     

新型茂钛催化剂原位本体聚合法制备间规聚苯乙烯/蒙脱土纳米复合材料

采用多碳氨基酸对蒙脱土进行改性 ,得到改性蒙脱土 (MTN) ,并使其层间距扩大 ,在一定条件下用茂金属催化剂Cp Ti(O C6 H4 F) 3 进行苯乙烯原位聚合发现 ,在氨基酸改性的蒙脱土存在下 ,茂金属催化剂活性有所提高 ,能制得间规聚苯乙烯 (sPS) 蒙脱土纳米复合材料 ,考察了蒙脱土用量对配位聚合的影响及该复合材料的形态结构、热稳定性和结晶性能     

Effect of surface modification of montmorillonite on the properties of aromatic polyamide/clay nanocomposites

The surface modification of montmorillonite clay was carried out through ion‐ exchange reaction using p‐phenylenediamine as a modifier. This modified clay was employed to prepare aromatic polyamide/organoclay nanocomposite materials. The dispersion behavior of clay was examined in the polyamide matrix. Polyamide chains were synthesized from 4‐aminophenyl sulfone and isophthaloyl chloride (IPC) in dimethylacetamide. These amide chains were suitably end‐capped with carbonyl chloride end groups to interact chemically with modified montmorillonite clay. The resulting nanocomposite films containing 2–20 wt% of organoclay were characterized by TEM, X‐ray diffraction (XRD), thin‐film tensile testing; thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and water absorption measurements. Mechanical testing revealed that modulus and strength improved up to 6 wt% organoclay loading while elongation and toughness of nanocomposites decreased with the addition of clay content in the matrix. Thermal decomposition temperatures of the nanocomposites were in the range 225–450 °C. These nanocomposites expressed increase in the glass‐transition temperature values relative to pure polyamide describing interfacial interactions among the phases. The percent water uptake of these composites reduced upon the addition of modified layered silicate depicting improved barrier properties. Copyright © 2008 John Wiley & Sons, Ltd.