聚苯乙烯/蒙脱土熔融插层复合的研究

用熔融法制备了聚苯乙烯／蒙脱土插层复合材料，用Ｘ 射线衍射、ＤＳＣ等手段研究了复合材料的结构与性能．聚苯乙烯熔体不能插层于钠基蒙脱土中，但能插层于经有机化合物处理过的蒙脱土中．     

聚丙烯酰胺/蒙脱土纳米复合物-聚乙烯醇共混膜的制备及其渗透汽化性能

用原位聚合法制备聚丙烯酰胺/蒙脱土(PAM/MMT)纳米复合材料, 通过透射电镜研究了蒙脱土在聚丙烯酰胺基体中的形貌和分布. 结果表明, 蒙脱土以片层结构分布在聚合物基体中. 用超声波分散聚乙烯醇和聚丙烯酰胺-蒙脱土共混铸膜液制得共混膜, 用红外吸收光谱和扫描电镜研究了两者的相互作用和形貌. 考察了共混膜在异丙醇-水混合溶液中的溶胀吸附性能及共混比和蒙脱土含量对膜分离性能的影响, 结果显示, 聚乙烯醇膜中添加适量的蒙脱土纳米粒子可以大大改善膜的分离选择性.     

熔体插层制备尼龙6/蒙脱土纳米复合材料的性能表征

通过熔体插层成功地制备了尼龙６／蒙脱土纳米复合材料，测试了力学性能、耐热性能和耐溶剂性．通过ＴＥＭ、ＷＡＸＤ、ＤＳＣ等手段，研究了结构与结晶行为，并与插层聚合的尼龙６／蒙脱土纳米复合材料进行了对比．实验表明通过熔体插层可使尼龙６基体插层于蒙脱土中，所得到的复合物的性能较尼龙６有很大提高，且与插层聚合的尼龙６／蒙脱土纳米复合材料的性能相当．     

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？…

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因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     

酸化粘土负载ZnCl2催化剂的制备及其对苯苄基化反应的催化性能

 以酸化粘土矿物蒙脱土为载体，采用浸渍蒸发法制备了蒙脱土负载的ZnCl2固体酸催化剂，并以苯与苄基氯的苄基化反应评价了其催化性能．考察了催化剂制备条件、苄基化反应条件和催化剂的再生性能，比较了负载前后催化剂的活性．利用XRD，TG－DTA和FT－IR等技术对催化剂的结构和表面酸性进行了表征．结果表明，较适宜的催化剂制备条件为：原矿土经30％硫酸酸化处理4h，ZnCl2负载量为2．0mmol／g，催化剂于250～350℃焙烧活化．过量的苯和较高的反应温度有利于提高苄基氯的转化率，催化剂与苄基氯的用量比为1．5g／mol．产物二苯甲烷的收率最高可达83．5％．表征分析表明，蒙脱土酸化处理后层状结构遭到破坏，比表面积增大，负载和活化处理使ZnCl2与蒙脱土载体的羟基之间发生了化学键合，提高了蒙脱土表面的总酸量，从而提高了催化剂的催化活性．     

碳酸钙与碳化硅对室温硫化硅橡胶的补强作用

在有关硅橡胶补强的研究中,人们已经对ＳｉＯ２ 等补强性填料对硅橡胶的补强作用进行了深入的研究,但对非补强填料对室温硫化硅橡胶的补强作用则相对涉及较少．作者研究了ＣａＣＯ３ 和ＳｉＣ 两类非补强性填料以及填料的粒径与分布对室温硫化硅橡胶拉伸强度、断裂伸长率和耐温性能等的影响,发现合适粒径的非补强性填料对室温硫化硅橡胶有较好的补强效果,且在填料粒径及分布匹配时有最好的补强效果,选用ＳｉＣ时还可以有效提高室温硫化硅橡胶的热稳定性．     

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。     

蒙脱土修饰电极上某些神经递质的电化学行为

采用不同电化学方法对神经递质多巴胺（ＤＡ）在蒙脱土修饰电极上的行为进行了研究，结果发现，蒙脱土修饰膜地ＤＡ有明显的富集作用。在ＰＨ７．４时，ＤＡ强烈地富集在蒙脱土膜内，并显示完成的伏安响应而抗坏血酸（ＡＡ）和ＤＡＲ的代谢产物３，４－二羟基苯乙酸（ＤＯＰＡＣ）则无任何响应。采用计时库仑法测定了ＤＡ在蒙脱土膜内的表观扩散系数为２．３×１０＾－９ｃｍ＾２／ｓ，并计算了异相速率常数为２．７×１０＾－６ｃｍ     

丁二烯/苯乙烯/4-乙烯基吡啶共聚物-蒙脱土嵌入混杂材料的研究

用聚合物乳液与蒙脱土的水分散体共混 共凝的方法制备混杂材料 .在混合过程中乳胶粒与蒙脱土晶层相互穿插 ,用盐酸絮凝 ,带正电的共聚物能够嵌入带负电的蒙脱土层间 .萃取实验发现在混杂材料中蒙脱土吸附了大量的共聚物 ,说明蒙脱土晶层与共聚物之间存在静电吸附作用 .XRD实验发现在混杂材料中蒙脱土的晶层结构发生了膨胀 ,并且变得混乱 ,而在共混物中蒙脱土晶层结构几乎不变 .用TEM观察在混杂材料中蒙脱土晶层均匀分散于共聚物基体中 ,蒙脱土的层间距大于 6nm .共聚物嵌入蒙脱土的层间 ,受到蒙脱土晶层的限制作用 ,共聚物的Tg 发生了变化 .交联以后的混杂材料的性能比共聚物有了较大的提高 ,蒙脱土晶层在共聚物基体中起到很好的补强作用 .     

双功能催化体系制备聚丙烯/蒙脱土复合材料

为了制备聚丙烯/蒙脱土纳米复合材料,将Brookhart型的乙烯齐聚催化剂负载于有机蒙脱土片层间,进一步与丙烯聚合茂金属催化剂进行复配得到双功能催化体系。采用这种双功能催化剂体系通过催化乙烯齐聚得到α-烯烃/蒙脱土的齐聚产物,进一步将丙烯与这种齐聚产物共聚,合成了一系列结构不同的聚丙烯/蒙脱土纳米复合材料。通过气相色谱、X射线衍射(XRD)分析得出蒙脱土负载的铁系催化剂催化乙烯齐聚产物是以C_4~C_(16)为主的α-烯烃,蒙脱土以片层形式分散于齐聚产物的甲苯溶液中。研究了蒙脱土负载的铁系催化剂与共聚催化剂复配催化乙烯齐聚以及丙烯与齐聚产物共聚合的情况。通过XRD、透射电镜、差示量热分析、凝胶渗透色谱分析表征可知,蒙脱土以纳米片层剥离的形式均匀分散于聚丙烯基体中,聚丙烯/复合材料的结晶温度比纯聚丙烯有所下降,所得聚丙烯基体分子量在8.1×10~4~17.1×10~4g/mo L。     

剥离型硅橡胶/黏土纳米复合材料研究

利用层状硅酸盐制备有机 无机纳米复合材料是当前人们研究的热点[1,2 ] ,这类材料具有较常规聚合物 无机填料复合材料无法比拟的优点 ,可以明显改善高分子材料的物理机械性能、热稳定性、气体阻隔性、阻燃性、导电性、光学性等 .一般来说 ,聚合物 层状硅酸盐 (Ｐｏｌｙｍｅｒｌａｙｅｒｅｄｓｉｌｉｃａｔｅ ,ＰＬＳ)纳米复合材料可分为插层型和剥离型两种类型 .插层型纳米复合材料即聚合物插入到硅酸盐层中 ,硅酸盐在近程仍保持原有的有序晶体结构 ,在远程则是无序的 .对弹性体而言 ,硅酸盐含量在插层型杂化材料中的含量比较高 ,力学性能…     

酸处理Silicalite—I沸石填充硅橡胶渗透蒸发分离膜

研究酸处理Ｓｉｌｉｃａｌｉｔｅ—Ｉ沸石对有机溶剂、水的吸附、脱附性质，酸处理Ｓｉｌｉｃａｌｉｔｅ—Ｉ填充硅橡胶膜对低浓度有机溶剂水溶液的渗透蒸发分离性能以及填充膜的力学性能。实验结果表明，在硅橡胶膜中填充酸处理Ｓｉｌｉｃａｌｉｔｅ—Ｉ沸石能改善膜对有机溶剂－水混合物的分离性能，且分离性能的改善与沸石在膜中的填充量以及硅橡胶的品种有关。另外，沸石的填充也有利于改善膜的力学性能。     

PREPARATION OF HIGH-TEMPERATURE VULCANIZED SILICONE RUBBER OF EXCELLENT MECHANICAL AND OPTICAL PROPERTIES USING HYDROPHOBIC NANO SILICA SOL AS REINFORCEMENT

Hydrophobic nano silica sol(HNSS)was incorporated into polyvinylmethylsiloxane to prepare reinforced high- temperature vulcanized(HTV)silicone rubber.HTV silicone rubber filled with 40 phr HNSS showed excellent mechanical and optical properties:the tensile strength reached 11.7 MPa and the optical transmittance was higher than 90%.Possible reasons for reinforcement and transparency were discussed on the basis of the bound rubber percentage,total crosslink density,and SEM analysis.Our work suggests that H...     

填充粒子对复合型导电硅橡胶电阻温度特性的影响

研究了炭黑填充复合型导电硅橡胶的电阻温度特性,分析了升温过程中导电硅橡胶电阻特性的详细变化过程。研究了导电粒子和白炭黑含量对导电硅橡胶电阻温度特性的影响,测量了在不同热处理温度下电阻率的变化及加力时电阻的驰豫时间。分析了热处理对电阻特性影响的机理。     

Barrier property of clay/Acrylonitrile‐butadiene copolymer nanocomposite

The resistance to air permeation was investigated for ­an intercalated clay/acrylonitrile‐butadiene copolymer ­nanocomposite. The nanocomposite is prepared by melt mixing the organo‐treated montmorillonite into a rubber matrix, together with peroxide curative, and crosslinked by conventional compression molding for typical rubbers. In the case of intercalated nanocomposite, the air permeability decreases considerably with increasing clay content, and the decreasing trend agrees reasonably with the Neilson's tortuous model. No considerable improvement is found when the pure montmorillonite is added. Copyright © 2002 John Wiley & Sons, Ltd.     

硅橡胶/氟橡胶并用胶的制备及力学性能

硅橡胶和氟橡胶作为国防、航天等重要领域的耐热材料一直被人们青睐,但其有着各自地优缺点且价格昂贵,本文尝试将这两种橡胶制成并用胶以解决氟橡胶不耐低温和加工性差的问题,以期增大其使用温度范围。采用机械共混法制备硅橡胶/氟橡胶并用胶,研究了硅橡胶和氟橡胶的混炼工艺、并用比、共硫化体系和硫化条件对并用胶力学性能的影响。结果表明,当硅橡胶/氟橡胶的质量比为10∶90,共硫化体系为3~#硫化剂/过氧化二异丙苯(DCP),一段硫化温度为170℃、硫化压力为10MPa、硫化时间为30min,二段硫化温度为200℃、硫化时间为6h时,并用胶的力学性能达到最好。     

Antimicrobial properties of Ag loaded zeolite polyester polyurethane and silicone rubber and long-term properties after exposure to in-vitro ageing

In biomedical applications, tubes (e.g. catheters etc.) are commonly produced from polyurethane (PU) and silicone rubber which are known to be biocompatible materials. Several studies have shown that tubes, which are connected to the body (invasive) (especially urinary, tracheotomy and central venous catheters) are associated with infections. The present study reports the development of a new method aiming at obtaining antibacterial properties for PU and silicone rubber by mixing respective material with a natural antibacterial agent (Ag+ loaded zeolite) in different weight fractions. The influence of the zeolite content on the antimicrobial properties were analysed by exposure to bacteria (ISO 22196) and mixtures of fungi (ISO 846). The materials were also subject to artificial body fluids (Artificial Lysosomal Fluid (ALF) and Gamble’s solution) for periods up to three months and the subsequent changes in the chemical properties after in-vitro exposure were determined by Matrix Assisted Laser Deposition/Ionization Time Of Flight Mass Spectrometry (MALDI-TOF MS) and Attenuated Total Reflection Fourier Transform Infra Red spectroscopy (ATR-FTIR). It was established that the antimicrobial effect of the materials increased with the increase of the zeolite content. The wettability of the materials was found to decrease significantly during the in-vitro exposure, but this could not be correlated to the zeolite content. In the PU samples, the formation of free carbonyl and -OH groups was observed, which corresponds to oxidative degradation. In case of the silicone rubber the ratio of cyclic PDMS to linear PDMS (H, CH3 and dimethyl terminated) decreased, which indicates a change in the concentration of the compounds. The formation and increase of the O-H bond during the exposure was also confirmed by the infrared spectra of the material which corresponds to hydrolysis of the silicone rubber.     

Structure and dynamics of polymer chains in hydrophilic nanocomposites

Poly(hexa(ethylene glycol) methacrylate)/sodium montmorillonite, (PHEGMA/Na⁺-MMT) nanocomposites with varying composition were synthesized utilizing melt intercalation and solution mixing. Intercalated hybrids were obtained but, for the solution prepared hybrids, the equilibrium structure could only be reached following thermal annealing. At equilibrium, all nanocomposites showed the same interlayer distance independent of the hybrid composition. For low polymer content nanocomposites, where all polymer chains reside within the inorganic galleries, the glass transition temperature of PHEGMA was completely suppressed. Quasielastic neutron scattering was utilized to investigate the effect of severe confinement on the dynamics of the intercalated polymer chains. Both elastic and quasielastic measurements were performed and showed that the confined system exhibits a much weaker temperature and wavevector dependence of the elastic intensity and of the respective relaxation times. The segmental mean square displacement in confinement begins to increase at temperatures well below the bulk polymer glass transition, indicating enhanced mobility compared with the pure polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1658–1667, 2010     

A novel phase-change composites based on silicone rubber containing energy-storage microcapsules

A novel phase-change composites based on silicone rubber (MVQ) containing n-octadecane/poly (styrene-methyl methacrylate) microcapsules were successfully obtained by mixing energy-storage microcapsules into MVQ matrix using three preparation methods. The effect of microcapsules content on thermal property of the composites was investigated by thermogravimetric analysis. The mechanical properties of the composites prepared by three methods were also investigated. The morphology and thermal properties of the composites were characterized by scanning electron microscopy (SEM), differential scanning calorimetry, and thermal response. Thermal and mechanical properties of the composites were excellent when the microcapsules were added into room temperature vulcanized silicone rubber with 2 phr (per hundred rubber) content and cured at room temperature. The composites were proved to have good energy-storage performance with 67.6 J g^?1 enthalpy value.     

Properties of rubber filled with montmorillonite with various surface modifications

Layered silicate/natural rubber composites were prepared by direct polymer melt intercalation. Na‐montmorillonite Kunipia‐F and its organic derivates (organo‐clays) prepared by ion exchange were used as clay fillers. Silica (SiO₂) Ultrasil VN3, a filler commonly used in the rubber industry, was used in combination with clay fillers. The effect of clay or organo‐clay loading from 1 up to 10 phr without (0 phr) or with silica (15 phr) showed significant improvement of the tensile properties (stress at break, strain at break and modulus M100). Modification of montmorillonite by three alkylammonium cations with the same length of alkylammonium chain (18 carbons) and different structure resulted in altered reinforcing and plasticizing effects of the filler in composites with rubber matrix. Copyright © 2011 John Wiley & Sons, Ltd.