聚丙烯/层状硅酸盐纳米复合材料的制备、结构和性能

聚丙烯／层状硅酸盐纳米复合材料可通过丙烯单体插层聚合、聚丙烯溶液插层和聚丙烯熔融插层等方法制备，得到插层型或剥离型纳米复合材料，形成了与传统填充型聚合物复合材料不同的微观结构，其机械性能，热性能，阻隔性能和流变性能等明显提高，由于聚丙烯的非极性及层状硅酸盐纳米复合材料制备方法的特殊性，该研究具有一定的理论价值。     

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     

悬浮缩聚法制备酚醛树脂/蒙脱土纳米复合材料

采用悬浮缩聚方法在酸性催化剂作用下制备了酚醛树脂/蒙脱土纳米复合材料。以三种不同的蒙脱土：天然土、带有脂肪链季铵盐修饰蒙脱土和带有苯环基团的插层剂修饰的蒙脱土为原料制备了纳米复合材料,并考察了不同插层剂对纳米复合材料形貌的影响,发现带有苯环的插层剂修饰的蒙脱土与酚醛树脂的相容性能更好;研究了固化过程对纳米复合材料形貌的影响,XRD和TEM的结构表明固化过程可以促进带有脂肪链季铵盐修饰的蒙脱土进一步剥离,对其他两类的影响不大;此外还用TGA研究了纳米复合材料的热性能。     

有机季鏻盐插层改性黏土诱发聚丙烯γ晶

选用有机季鏻盐作为插层剂对黏土进行有机化插层改性,制备出有机黏土,通过熔融插层法制备聚丙烯/有机黏土纳米复合材料.XRD表明有机季鏻盐改性的黏土与聚丙烯形成结构为剥离型与插层型并存的纳米复合材料.利用DSC研究了纳米复合材料的熔融过程,结果显示有机黏土对聚丙烯的结晶度影响不明显.XRD和DSC的研究均表明,有机黏土可以诱发聚丙烯产生不常见的γ晶型.当黏土含量为5 wt%时,γ晶型占整个结晶部分的12%左右.     

丙烯酸树脂／蒙脱土纳米复合材料的制备研究

采用离子交换法,用十六烷基三甲基溴化铵对钠基蒙脱土(Na-MMT)进行改性制备了有机蒙脱土(OMMT).用丙烯酸(AA)、硫酸化蓖麻油、乳化剂OP-10、过硫酸钾为原料进行水溶液聚合制得丙烯酸树脂.将丙烯酸树脂与改性蒙脱土通过聚合插层制备了丙烯酸树脂/ 蒙脱土纳米复合材料.通过傅立叶变换红外(FTIR)和X-射线衍射 (XRD)等手段对复合材料的结构进行了表征,结果表明:丙烯酸树脂插层进入有机蒙脱土内可形成插层型或剥离型的纳米复合材料.蒙脱土含量及蒙脱土与丙烯酸树脂的反应温度、反应时间均对复合材料的剥离行为产生影响,在蒙脱土含量为树脂固含量的7%、温度为70℃、反应4h的条件下可得到完全剥离的纳米复合材料.     

有机季鏻盐插层改性黏土诱发聚丙烯γ晶

选用有机季鏻盐作为插层剂对黏土进行有机化插层改性,制备出有机黏土,通过熔融插层法制备聚丙烯/有机黏土纳米复合材料.XRD表明有机季鏻盐改性的黏土与聚丙烯形成结构为剥离型与插层型并存的纳米复合材料.利用DSC研究了纳米复合材料的熔融过程,结果显示有机黏土对聚丙烯的结晶度影响不明显.XRD和DSC的研究均表明,有机黏土可以诱发聚丙烯产生不常见的γ晶型.当黏土含量为5 wt%时,γ晶型占整个结晶部分的12%左右.     

羧甲基壳聚糖/有机累托石纳米复合材料及其药物缓释性能研究

利用简单的溶液插层法制备了羧甲基壳聚糖/有机累托石纳米复合材料,其中累托石(REC)用十六烷基三甲基溴化铵进行改性.用X-射线衍射(XRD)、红外光谱(FTIR)和扫描电镜(SEM)表征了该纳米复合材料的微观结构和形态,实验表明羧甲基壳聚糖插层进入了累托石层间,增大了累托石的层间距,并且累托石均匀地分布在羧甲基壳聚糖基体中.以牛血清蛋白(BSA)为药物模型,研究了纳米复合材料与海藻酸钠形成的微球的药物缓释性能.结果显示,该微球对药物的包封率及缓释性能与纯羧甲基壳聚糖微球相比都有较大改善,包封率从56%提高到86%,药物缓释时间从24 h上升到72 h.并且纳米复合材料/海藻酸钠微球的释药具有pH响应性,在pH为1.2的条件下释药慢,而在pH为7.4时释药快,可用于小肠或结肠定位缓释系统.因此,羧甲基壳聚糖/有机累托石纳米复合材料很有潜力作为药物载体.     

木质纤维素-蒙脱土纳米复合材料的制备

采用插层复合方法在碱性水溶液中制备了木质纤维素-蒙脱土纳米复合材料,并分析了反应温度、反应时间、木质纤维素与蒙脱土的质量比等因素对纳米复合材料有机化程度的影响,用FT-IR、XRD、TEM、SEM等方法对纳米复合材料的结构进行了表征。结果表明:蒙脱土片层结构在反应过程中被撑开,木质纤维素分散在其中,形成插层-剥离型纳米复合材料,其热稳定性较木质纤维素有了较大提高。     

尼龙6/石墨纳米导电复合材料的制备与性能

通过原位插层聚合制备了尼龙 6 /石墨纳米导电复合材料 ,其室温导电渗滤阈值为 =0 75vol% ,远远低于常规导电粒子填充的聚合物复合材料 .当石墨体积分数为 2 0vol%时 ,室温电导率可达 10 -4 S/cm .透射电镜研究表明 :由于石墨经高温膨胀后其片层被剥离导致了片状石墨粒子具有巨大的径厚比 ,经原位插层聚合其片层厚度进一步被剥离为几十个纳米 ,同时原位插层聚合使得石墨粒子能够均匀分散在尼龙 6基体中 ,因而导致了该导电复合材料的低渗滤阈值和高导电性能 .     

基于氟碳表面活性剂插层水滑石的聚酰亚胺纳米复合材料的制备与性能

以氟碳表面活性剂全氟辛基磺酸钾为插层剂, 通过离子交换制备插层水滑石, 并以其为填料, 通过原位插层聚合方法, 制备了水滑石/氟碳表面活性剂/聚酰亚胺纳米复合材料. 用X射线衍射、 红外光谱和热失重等方法分析插层水滑石结构. 结果表明, 全氟辛基磺酸钾插层水滑石后, 水滑石的层间距由0.76 nm增加到2.52 nm, 在水滑石层间构建了氟碳链的微环境. 这种氟化水滑石可剥离分散于聚酰亚胺基体中, 改善了纳米复合材料的气体阻隔性能、 介电性能和机械性能. 这种影响不仅体现无机纳米片层的杂化效果, 而且展示出氟碳链的特点.     

The influence of intercalation rate and degree of substitution on the electrorheological activity of a novel ternary intercalated nanocomposite

Kaolinite/dimethylsulfoxide (DMSO)/carboxymethyl starch (CMS) ternary nanocomposites were prepared according to the combination of intercalation and solution reaction. The results show that the intercalation rate (IR) of kaolinite in the ternary composite is adjusted by changing the mass rate, and the basal spacing of kaolinite was swelled from 0.715 to 1.120 nm. At the suitable component ratio of ternary nanocomposite, the optimum electrorheological (ER) effect can be attained. It is apparent that the notable ER effect of ternary ER fluid was attributed to the prominent dielectric property of the ternary nanocomposite electrorheological fluids (ERF), which is closely associated with the IR. With the increase of degree of substitution, the ER effect of ternary composite ERF is enhanced.     

Core/shell nanocomposite based on the local polarization and its electrorheological behavior

Aimed at the increase of electrorheological effect, a novel core/shell material was prepared by the combination of mechanochemical activity and sol-gel technique. The structure analyses X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and energy-dispersive spectrometry showed that a modified kaolinite/titanium oxide nanocomposite consisted of the mechanochemically activated kaolinite/NaCl complex coated by titanium oxide. A distinct enhancement of the electrorheological activity was found by using such particles dispersed in silicone oil than those of kaolinite or titanium oxide alone under a direct current electric field. Modified kaolinite/titanium oxide electrorheological fluid has a larger dielectric constant enhancement deltaepsilon', and a strong interfacial polarization occurs with a clear dielectric loss peak around 2 kHz. Doping NaCl into the core (kaolinite) by the mechanochemical activation and limiting the transferring of the ions by the shell (titanium oxide) may increase the interfacial polarizability of particles and induce a high electrorheological effect.     

聚氧化乙烯/高岭石聚合物电解质的制备与表征

通过尿素对高岭石的插层及随后的超声脱除处理,制备了一种片层剥离的高岭石粉体,并将这种剥离高岭石与聚氧化乙烯/高氯酸锂(PEO/LiClO_4)体系复合,制备出PEO/高岭石复合物.采用X射线衍射仪、红外光谱仪、扫描电子显微镜、透射电子显微镜、扫描量热仪、电化学工作站和万能材料试验机进行结构表征和性能测试.结果表明,尿素在高岭石层间的插层和脱除引起了高岭石片层的剥离,片层厚度小于50 nm.剥离高岭石在PEO/LiClO_4体系中与PEO形成了强烈的氢键作用,促进了PEO结晶度的降低,进而提高复合物的离子电导率.含有20 wt%剥离高岭石填料的PEO/高岭石复合物的离子电导率达到6.0×10~(-5) S/cm,与未复合的PEO/LiClO_4相比,提高了一个数量级.复合物制备过程中的烘干温度对PEO的结晶度会产生一定的影响,95°C下的烘干处理能得到结晶度较低,离子电导率较高的复合物.此外,剥离高岭石的添加显著提高了聚合物的杨氏模量和拉伸强度,与未复合的PEO/LiClO_4相比,杨氏模量和拉伸强度最大提高了256%和121%.     

Crystallization, morphology, and dynamic mechanical properties of poly(trimethylene terephthalate)/clay nanocomposites

The poly(trimethylene terephthalate) (PTT)/clay nanocomposite has been successfully prepared via melt intercalation using a co-rotating twin screw extruder. The nanocomposite was characterized by wide angle X-ray diffraction (WAXD), transmission electron microscope (TEM), differential scanning calorimetry (DSC), polarized light microscope (PLM) and dynamic mechanical analysis (DMA). The nanocomposite forms an exfoliated structure, which can be observed by WAXD and TEM. The effect of clay layers on the crystallization behaviors of PTT was studied through isothermal and non-isothermal crystallization methods. The results suggest that the introduction of nanosize clay layers accelerates the crystallization rate of PTT and the clay layers act as nucleation agents. The morphology of spherulites was investigated with PLM and the result is well in agreement with crystallization kinetics. DMA shows that glass transition temperature (T_g) and storage modulus (E^′) of the PTT matrix of the nanocomposite are higher than those of pure PTT.     

高岭土对不饱和聚酯树脂的热稳定性、阻燃及力学性能的影响

不饱和聚酯树脂;高岭土;纳米复合材料;原位聚合;阻燃;成炭     

PEG在微波诱导下对高岭石插层及剥片的研究

利用微波能量，快速制备了高岭石/DMSO插层复合物，并以其为前驱体，在熔融状态，微波诱导聚乙二醇(PEG)置换出高岭石层间的DMSO，微波继续协同PEG作用，可以实现其对高岭石的剥片。同时提出了微波作用机理和微波条件下插层物对高岭石的剥片机理。采用X-射线衍射、FTIR光谱、TG-DTA、TEM等技术对插层复合物进行了表征。     

Synthesis and electrorheological properties of polyaniline-Na+-montmorillonite suspensions

We synthesized polyaniline-Na⁺-montmorillonite nanocomposite particles using an emulsion intercalation method and prepared electrorheological (ER) fluids by dispersing the synthesized nanocomposite particles in an electrically insulating silicone oil. The conducting polymer (polyaniline) was inserted into the layers of clay, and this insertion of polyaniline was confirmed by X-ray diffraction. For the first time, ER properties were determined via a rotational rheometer equipped with a high voltage generator.     

One-step exfoliation of kaolinites and their transformation into nanoscrolls

Kaolinite nanoscrolls, rolled kaolinite sheets with a tubular form, were prepared by a one-step route in which intercalation of guest species and swelling with solvent proceed at the same time. A methoxy-modified kaolinite was exfoliated by the intercalation of hexadecyltrimethylammonium chloride. The formation of nanoscrolls by the one-step route proceeded only by several alkyltrimethylammonium salts and 1-hexadecyl-3-methylimidazolium chloride. Intercalation of primary amines caused the formation of nanoscrolls by a two-step route in which the intercalation and swelling proceed separately. The successful one-step route is ascribed to the relatively weak interactions between the head groups of guest species and the interlayer surface of methoxy-modified kaolinite, and the interaction is thought to allow the formation of a flexible array of interlayer guest species for swelling. The tubular structure was mostly retained after the heat treatment at 600 °C to form hierarchically porous aluminosilicates with amorphous frameworks. The nanoscrolls intercalated organic guests species, which are not directly intercalated into methoxy-modified kaolinite, between the scrolled layers. The formation route to nanoscrolls is quite dependent not only on the surface modification of kaolinite but also on the structure of guest species.     

A new approach of enhancing the shear stress of electrorheological fluids of montmorillonite nanocomposite by emulsion intercalation of poly-N-methaniline

Poly-N-methaniline/montmorillonite (PNMA-MMT) nanocomposite particles with high dielectric constant as well as suitable conductivity were synthesized by an emulsion intercalation method and characterized by FT-IR, XRD, and TEM spectrometry, respectively. The electrorheological (ER) properties of the suspensions of PNMA-MMT particles in silicone oil (20 wt%) were investigated under DC electric fields. It was found that the shear stress of poly-N-methaniline/montmorillonite electrorheological fluid (ERF) is 6.0 kPa in 3 kV/mm (74.5 s(-1)), which is 3.6 times that of electrorheological fluid at zero field, and also much higher than that of pure poly-N-methaniline (PNMA) and montmorillonite (MMT). In the range of 10-90 degrees C, the shear stress changes slightly with the temperature. The sedimentation ratio of PNMA-MMT ERF was about 97% after 60 days. Furthermore, the dielectric constant of PNMA-MMT nanocomposite was increased 3.74 times that of PNMA and 1.99 times that of MMT at 1000 Hz, the dielectric loss tangent also increased about 1.58 times that of PNMA. It is apparent that the notable ER effect of PNMA-MMT ER fluid was attributed to the prominent dielectric property of the poly-N-methaniline/montmorillonite nanocomposite particles.     

原位聚合法制备聚丙烯酸甲酯/ZnAl层状双氢氧化物插层纳米复合材料及其形貌特征

近 2 0年来 ,聚合物 /层状无机物纳米复合材料引起了广泛关注 ,与聚合物材料相比 ,该类纳米复合材料在力学、热稳定性、阻燃、气体阻隔等性能方面都有显著增强 .但所报道的绝大部分无机物均采用蒙脱土为代表的层状硅酸盐[1～ 3] ,而以层状双氢氧化物 (Layered double hydroxide,LDH)为基础制备的聚合物 /层状无机物纳米复合材料的报道极少 .LDH是由水镁石结构中的二价阳离子 (M2 + )被三价阳离子 (M3+ )取代而形成的 ,层上产生的剩余正电荷被吸附在层间的阴离子平衡 .与层状硅酸盐相比 ,L DH层间电荷密度高 ,层与层之间相互作用强 ,导…