悬浮聚合法制备纳米蒙脱土/聚合物(苯乙烯-共聚-二乙烯基苯)复合材料及性能

采用悬浮聚合法制备了纳米蒙脱土/聚合物(苯乙烯-共聚-二乙烯基苯)复合材料。钠基蒙脱土(SMMT)经十六烷基三甲基溴化铵(CTAB)离子交换后获得有机蒙脱土(OMMT)。采用XRD和FTIR分析表征了有机蒙脱土的结构与性能。通过XRD、TEM、SEM、和FTIR对复合材料微观结构进行了表征;通过热重分析仪(TG)对复合材料的热稳定性能进行了研究。讨论了蒙脱土含量和交联剂用量对复合材料热稳定性能的影响。结果表明,钠基蒙脱土的层间距为1.48 nm,经有机改性蒙脱土的层间距为2.85 nm,纳米蒙脱土/聚合物复合材料的层间距约为4 nm;纯聚苯乙烯最大质量损失温度为399℃,当蒙脱土含量为5%、交联剂用量为10%时,纳米蒙脱土/聚合物最大质量损失温度提高到437℃。在实验条件下,纳米蒙脱土/聚合物复合材料具有更好的热稳定性能。     

水性聚苯胺/蒙脱土/丙烯酸乳液复合防腐蚀涂层研究

采用原位化学氧化聚合方法制备了聚苯胺/蒙脱土复合材料,并以丙烯酸乳液为成膜物,制备了水性聚苯胺/蒙脱土/丙烯酸乳液复合防腐蚀涂层材料。研究了蒙脱土与苯胺的配合比、聚苯胺/蒙脱土复合材料用量、磷酸浓度等对复合涂层防腐性能的影响。实验结果表明,苯胺/蒙脱土复合材料具有片层结构,聚苯胺/蒙脱土/丙烯酸乳液复合涂层对马口铁具有较好的防护效果,当蒙脱土与苯胺质量配合比为2∶10,聚苯胺/蒙脱土复合材料用量为0.10%(wt,质量分数),磷酸浓度为0.10mol/L时,制得的水性聚苯胺/蒙脱土/丙烯酸乳液复合防腐涂层,腐蚀电流为2.187×10~(-6) A/cm~2,极化电阻为14455.9Ω,复合涂层具有最佳的防腐性能。     

DMDAAC在蒙脱土中插层环化聚合及其应用的研究

首先采用单因素试验优化了聚二烯丙基二甲基氯化铵(PDM DAAC)的合成工艺;选用二烯丙基二甲基氯化铵(DM DAAC)在不同用量的蒙脱土中插层环化聚合,制备了系列纳米复合材料(PDM DAAC/MM T);对纳米复合材料进行了X射线衍射(XRD)测试;通过单体转化率和聚合物的特性黏度考察不同用量的蒙脱土对单体环化聚合的影响;将纳米复合材料用于皮革预鞣,再进行2%标准铬粉鞣制的试验初试。XRD、单体转化率和聚合物的特性黏度测定结果表明:蒙脱土的用量为5%时,蒙脱土的层间距、单体转化率、聚合物的特性黏度均达到最大值。纳米复合材料预鞣结果表明,蒙脱土用量为4%时,纳米复合材料对坯革的增强效果最明显。     

聚苯胺/蒙脱土电流变液的稳定性

采用乳液共混插层法制备了高介电常数的聚苯胺／蒙脱土纳米复合材料微粒。聚苯胺／蒙脱土电流变液在外电场下的剪切强度达8.26kPa(3KV/mm DC,5s^-1)，并具有较好的温度稳定性，其剪切应力在10－100℃内随温度变化仅为6．5％（1.5kV/mm,DC,1.61s^-1)，静置60天沉降率仅为1％，IR及XRD分析表明，聚苯胺插入到蒙脱土层间，形成纳米复合颗粒，TEM标示颗粒的粒径约为100nm，在1000Hz，20℃时，聚苯胺／蒙脱土颗粒的介电常数比纯蒙脱土提高2．7倍，比纯聚苯胺提高5．5倍，电导率增加8．5倍。     

掺杂不同金属离子聚苯胺/蒙脱土的制备及其电导率研究

在聚合温度为25℃、n(过硫酸铵):n(苯胺)=1:1、掺杂剂磺基水杨酸c(SSA)=0.03mol/L、蒙脱土量为1%的实验条件下,采用插层聚合法制备出聚苯胺/蒙脱土复合纳米材料.在该复合材料中掺杂不同的金属离子,测其导电率的变化情况,并且与未掺杂复合材料的导电率进行比较.TGA分析表明.有机物进入到蒙脱土片层间;FT-IR分析表明,蒙脱土进入到聚苯胺中;XRD分析表明,制备的复合材料中蒙脱土被完全剥离;电导率实验表明,聚苯胺/蒙脱土掺杂氧化铁的氯盐溶液电导率最高.     

PMAA／MMT纳米复合材料的制备

采用原位插层聚合法制备聚甲基丙烯酸/蒙脱土(PMAA/MMT)纳米复合材料,探讨了引发剂用量对复合材料结构的影响。通过X射线衍射、红外光谱、固体核磁共振表征了改性蒙脱土及复合材料的结构。研究结果表明,甲基丙烯酸钠与蒙脱土具有一定的相互作用,甲基丙烯酸或甲基丙烯酸钠在蒙脱土层间聚合形成的PMAA/MMT纳米复合材料属于插层型纳米复合材料,引发剂用量对蒙脱土的层间距影响较小。     

微波辅助原位熔融缩聚法制备聚乳酸/有机蒙脱土纳米复合材料

以微波为热源替代传统加热方式,采用原位熔融缩聚法制备出聚乳酸/有机蒙脱土纳米复合材料。有机蒙脱土的加入有利于聚乳酸分子链进入蒙脱土片层,当蒙脱土用量为1.5%时,微波辐射60 min所制得的聚乳酸/有机蒙脱土纳米复合材料与纯聚乳酸相比,拉伸强度提高近2倍,热失重中心温度提高7.3℃,对紫外线的屏蔽波段扩展了50nm以上。透射电镜(TEM)结果表明,有机蒙脱土以剥离态均匀分散于聚乳酸基体中。     

阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的性能

采用原位插层复合法,制备了包含十溴二苯醚和蒙脱土的阻燃剂/不饱和聚酯/蒙脱土纳米复合材料。通过XRD、SEM和TEM等手段表征阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的微观结构。通过拉伸、冲击和氧指数实验对阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的力学性能、阻燃性能进行研究。结果表明,当蒙脱土的含量为0.6%时,阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的氧指数与阻燃剂/不饱和聚酯复合材料相比从24.1上升到25.4,冲击强度和拉伸强度分别提高82.66%和31.05%。燃烧残余物数码照片和扫描电镜照片显示蒙脱土促进了炭层形成。     

原位插层聚合尼龙6/超分散有机蒙脱土剥离型纳米复合材料的结构和性能

采用原位插层聚合法制备了尼龙6/蒙脱土剥离型纳米复合材料,讨论了超分散有机蒙脱土的用量对复合材料性能的影响,用动态力学分析(DMA)、X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等手段研究了纳米复合材料的结构和性能。结果表明,有机蒙脱土加入量为3%(质量分数,下同)时,复合材料综合性能最佳;有机蒙脱土的加入大大提高了尼龙6的综合性能,并提高了尼龙6的储能模量和玻璃化温度。有机蒙脱土在尼龙6基体中有良好的分散性和相容性,蒙脱土片层被完全剥离,在尼龙6基体中实现了纳米级分散。     

蒙脱土对聚丙烯酸基纳米复合材料性能的影响

对聚丙烯酣蒙脱土纳米复合材料的制备方法及其吸水、何水性能进行了研究。利用高温快速反应法成功制备了聚丙烯酣蒙脱土高吸水性纳米复合材料，考察了蒙脱土质量分数对复合材料吸水倍率的影响规律，当蒙脱土用量为5％时，可获得较好的结果，所得纳米复合材料吸水倍率为511ml／g对纳米复合材料的保水性能研究的结果表明，聚丙烯酸，蒙脱土高吸水性纳米复合材料在高温条件下具有优异的保水性能。     

污水厂脱水污泥制吸附剂及脱除H2S效能研究

采用热解炭化法制备了一系列污泥吸附剂,优化制备工艺,利用扫描电镜(SEM)、比表面积和孔径分析等技术对污泥吸附剂的结构进行了表征,并研究了脱除H2S效能。结果表明,活化温度、活化时间和固液比等因素均对污泥吸附剂的碘吸附值产生影响。当活化温度为550℃、活化时间为2.0h、固液比为1∶2时所制备材料(SA)的碘吸附值最高,为493.12mg/g;制备的SA具有较好的脱除H2S效能,能满足精脱硫的要求,当空速为4600h-1时,SA的除臭时间可达48min;此外SA中含有的多种金属元素,平均孔径为3.4nm,这些性质均有利于H2S的吸附脱除。     

一步模板炭化法制备新型沥青基中孔炭材料

以乙酸镁和柠檬酸镁为模板(MgO)镁源,沥青为碳前驱体,在氮气氛中950℃一步炭化制得高表面积中孔炭材料.采用1 mol/L的HCl去模,并将炭材料洗涤至中性.采用低温N2吸附测得炭材料的比表面积和孔径分布,透射电镜观察炭材料的内部结构特征.结果表明:尽管未经活化,所得炭材料中的孔大多为中孔,BET比表而积达到1295 m2/g,当以柠檬酸镁为MgO前驱体时,所得炭材料的收率可高达50%.     

聚甲基丙烯酸甲酯/膨胀石墨纳米导电复合材料的制备与表征

通过原位插层聚合制备了聚甲基丙烯酸甲酯/膨胀石墨纳米导电复合材料,其室温导电渗滤阈值约为3%(质量分数),当膨胀石墨的质量分数为8%时,室温电导率可高达60 S/cm。通过TEM、SEM观察了复合材料的形貌,用DSC测定其热力学性能并探讨了不同外加电压对PMM A/膨胀石墨纳米导电复合材料体积电导率的影响,同时研究了复合材料的拉伸强度。     

不饱和聚酯/海泡石纳米复合材料的制备及表征

以独特的松解方法对海泡石原矿进行分散,然后采用季胺盐对其进行有机改性处理,最后将有机海泡石纤维均匀分散到不饱和聚酯中,加入引发剂、促进剂和交联剂,使不饱和聚酯交联制得纳米复合材料。用SEM,FT-IR对复合体系的分散效果进行了分析和表征,并用差热分析方法对其热稳定性能进行了研究。结果表明,海泡石纤维以纳米级水平均匀分散在不饱和聚酯中,纳米复合材料的热分解温度也有所提高。     

多尺度功能性填料PVDF基纳米复合材料的制备和性能

先以两种直径(50 nm,100 nm)的羟基化钛酸钡(BT)和两种长度(10~20 nm,20~40 nm)的酸化多壁碳纳米管(MWCNTs)为功能填料,进行液相反应制备四种BT/MWCNTs杂化纳米填料(分别记为BT-A/MWCNTs-B,其中A=5,10;B=1,2),再用熔融共混-压板成型技术分别将其与PVDF复合制备出BT-A/MWCNTs-B/PVDF纳米复合材料。使用X射线衍射(XRD)、红外光谱(FTIR)、差示扫描量热分析(DSC)、扫描电子显微镜(SEM)、拉伸性能测试和介电性能测试系统研究了多尺度功能性填料BT-A/MWCNTs-B对这种纳米复合材料的组织结构和结晶性能、介电性能和力学性能的影响。结果表明,与BT/PVDF和MWCNTs/PVDF体系相比,BT-A/MWCNTs-B/PVDF纳米复合材料具有更高的结晶度和热性能,BT-10的含量(质量分数,下同)为16%、MWCNTs-2的含量为5%的BT-10/MWCNTs-2/PVDF纳米复合材料其熔融温度可达173.8℃,比纯PVDF(159.6℃)提高了14.2℃,其结晶度可达43.1%。三相BT-A/MWCNTs-B/PVDF纳米复合材料比两相纳米复合材料具有更优异的介电性能,BT-10/MWCNTs-2/PVDF纳米复合材料100Hz下的介电常数为119,为纯PVDF的14倍,其介电损耗只有0.051。BT-10/MWCNTs-2/PVDF纳米复合材料的拉伸强度和弹性模量分别达到57.7 MPa和1226 MPa。     

Preparation,solubility, and electrorheological properties of carbon nanotubes/poly(methyl methacrylate) nanocomposites by in situ functionalization

Poly(methyl methacrylate) (PMMA) nanobeads-decorated multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) nanocomposites were prepared using two processing steps. Initially, spherical PMMA nanoparticles were synthesized using an emulsion polymerization method. Afterward, the PMMA nanobeads were decorated to MWNTs and SWNTs using benzoyl peroxide as an initiator in water during a high temperature refluxing process. The results confirmed the linkage of the nanotubes to the surrounding PMMA nanobeads via a covalent bond. The resultant nanocomposites showed high solubility in chloroform without flocculation after 24 h. In addition, the nanotubes/PMMA nanocomposites were characterized by electrical resistance measurements to analyze their electrical conductivity and examined as electrorheological (ER) materials when dispersed in silicone oil.     

Photocatalytic oxidation of nitric oxide with immobilized titanium dioxide films synthesized by hydrothermal method

Gas-phase photocatalytic oxidation (PCO) of nitric oxide (NO) with immobilized TiO2 films was studied in this paper. The immobilized TiO2 films were synthesized by hydrothermal method. The characterization for the physicochemical properties of catalysts prepared under different hydrothermal conditions were carried out by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller measurements (BET) and scanning electron micrograph (SEM). It was found that the PCO efficiency of the catalyst was mainly depended on the hydrothermal conditions. The optimal values of hydrothermal temperature and hydrothermal time were 200 degrees C and 24 h, respectively. Furthermore, it was also known that the photocatalytic efficiency would decrease remarkably when the calcination temperature was over than 450 degrees C. Under the optimal conditions (hydrothermal condition: 200 degrees C for 24 h; calcination temperature: 450 degrees C), the photocatalytic efficiency of catalyst could reach 60% higher than that of Degussa P25.     

Modified treatment for carbonized cellulose nanofiber application in composites

In the present study, carbon nanofibers (CNF) from carbonized cellulose nanofibers (CCNF) were prepared by carbonizing freeze-dried cellulose nanofibers first, then preparing acrylonitrile-butadienestyrene (ABS)/CCNF nanocomposites by extruder. To increase the dispersibility and operability of the CCNF, the ultrasound-assisted master batch method was adopted to make an ABS/CCNF master batch. Dicumyl peroxide and maleic anhydride were added to increase the interface compatibility between the CCNF and the ABS by reactive extrusion. The surface morphology, chemical structure, and mechanical properties of the ABS/CCNF nanocomposites were characterized by SEM, FTIR, and DMA/tensile tests, respectively. The tensile strength of ABS/CCNF was improved 36% compared to that of ABS. The improved properties demonstrated that the approach used in this study has the potential to solve the bottleneck issues of mass producing and applying CNF in a green way.     

A new strategy to prepare polyethylene nanocomposites by using a late-transition-metal catalyst supported on AlEt3-activated organoclay

A new strategy for in situ polymerization was developed to prepare the polyethylene nanocomposites, in which a nickel α-diimine late-transition-metal catalyst supported on the AlEt₃-activated organoclay was adopted to initiate the ethylene polymerization and to provide the reinforcement materials after the polymerization. It was found that the polymerization conditions such as reaction time, Al/Ni molar ratio, and reaction temperature affected the polymerization activity and the clay loading. The nanoscale dispersion of the clay layers in the polyethylene matrix was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). From the thermogravimetric analyses (TGA), it was found that the decomposition temperature of the nanocomposite with the organoclay of 11.91 wt% could be 46.8 °C higher than that of pure polyethylene when 30% weight loss was selected as a measuring point, showing enhanced thermal oxidation stability of this kind of polyolefin nanocomposites.     

窄分子量分布端羟基聚四氢呋喃的合成与表征

以高氯酸为催化剂,乙酸酐为促进剂及分子量调节剂,通过四氢呋喃阳离子开环聚合合成了分子量可控且分子量分布较窄(Mw/Mn1.2)的聚四氢呋喃,聚合产物端部含有乙酸酯基,经醇解后得到端羟基聚四氢呋喃(PTMEG)。探讨了聚合时间、高氯酸用量、乙酸酐用量、溶剂对聚四氢呋喃分子量(Mn)及分子量分布(Mw/Mn)的影响。研究表明,延长聚合时间、增加高氯酸及乙酸酐的用量均会造成Mn先升后降,但只有聚合时间对Mw/Mn会造成显著的影响,聚合时间为4h时Mw/Mn最小;加入CH2Cl2溶剂会降低聚四氢呋喃的Mn及Mw/Mn。采用凝胶渗透色谱-多角度激光散射联用仪(SEC-MALLS)对聚合产物的Mn及Mw/Mn进行了准确地测定,应用FT-IR、1 H-NMR表征了端羟基聚四氢呋喃大分子结构,利用DSC及TG研究了其热性能,结果表明,端羟基聚四氢呋喃的熔点及分解温度随着Mn的增加略有升高。