粒子表面处理对纳米Ag/PMMA复合粒子的影响

纳米银/聚甲基丙烯酸甲酯(Ag/PMMA)复合粒子是一种新型的功能粒子,可以有效利用昂贵金属纳米粒子组元的独特性能,是高表面能金属纳米粒子稳定化的有效途径。在Ag/PMMA复合粒子的制备过程中,纳米Ag粒子表面处理时所用表面活性剂的种类及用量直接影响Ag/PMMA复合粒子的粒径及分布。纳米Ag粒子在超声波场作用下经十二烷基硫酸钠(SDS)处理后,可在纳米Ag粒子表面形成单体和引发剂的富集区,在适当条件下引发以纳米Ag粒子为核心的原位分散聚合反应。本文通过对各影响因素的研究,采用阴离子表面活性剂SDS对纳米Ag粒子进行表面处理,且用量控制在Ag粒子质量的10%～15%范围内,可实现Ag粒子的PMMA有机包覆。     

苯乙烯/丙烯酸共聚高分子微球的制备与研究

以苯乙烯为主单体,丙烯酸为亲水性功能单体,采用无皂乳液聚合方法制备了苯乙烯/丙烯酸共聚微球,并在微球表面沉积金属Ag纳米粒子。讨论了引发剂用量、功能单体丙烯酸的加入方式以及用量对微球粒径和形态的影响,并研究了金属Ag纳米粒子的沉积过程。通过透射电镜观察发现,微球形态规整,粒径分布均匀。金属Ag纳米粒子较均匀的沉积在微球表面。     

反应体系组成对纳米SiO_2/PS复合粒子粒径及分布的影响

研究了在纳米SiO2粒子表面的苯乙烯原位聚合反应中,反应体系的组成(单体、引发剂、稳定剂及纳米SiO2粒子用量)对纳米SiO2/PS复合粒子的形态、粒径大小及分布的影响。结果表明,当纳米SiO2粒子与单体质量比为5%,苯乙烯质量分数为25%,引发剂及稳定剂用量分别为单体用量(质量比)的0.15%和1.5%时,制备出的纳米SiO2/PS复合粒子呈球形,表面光滑无明显缺陷,颗粒之间分散性很好,粒径为0.923μm,分散系数为0.108。     

聚甲基丙烯酸甲酯／纳米SiO2复合粒子的制备与表征

采用甲基丙烯酸-3-甲氧基硅丙酯（MPs）对分散于甲基丙烯酸甲酯（MMA）中的纳米SiO2粒子进行偶联改性，得到了表面改性的纳米SiO2单体分散液，用原位悬浮聚合方法制备了不同SiO2含量的PMMA／纳米SiO2复合粒子。通过红外光谱、透射电镜、差示扫描量热分析和热重分析等方法对制备的纳米复合粒子进行了表征，结果表明，纳米SiO2粒子在PMMA中分散良好；MMA可通过与MPS的共聚而有效地接枝到SiO2粒子表面，当SiO2含量为6．6％（质量分数，下同）、MPS用量为0．06g／gSiO2时，其接枝率可达73．8％；同时，纳米SiO2的引入可提高PMMA的耐热性能，当Si02含量为14.7％时，其玻璃化转变温度和最大热分解速率时的温度分别提高了11．8℃和18．8℃。     

草莓型PVAc／SiO2有机-无机复合微球的合成

用无皂乳液聚合法制备了草莓型的聚醋酸乙烯酯／二氧化硅（PVAc／SiO2）纳米复合微球,探讨了纳米SiO2溶胶的pH值和用量对复合微球粒径与形态的影响。研究表明纳米SiO2粒子被吸附在有机相表面,形成草莓型结构,其粒子表面的羟基与PVAc分子链中羟基之间的氢键作用是制备这种单分散草莓型PVAc／SiO2纳米复合微球的关键。     

Ag-PVA和Ag-PVA／TiO2复合超薄膜的制备及性能研究

用3种方法制备了银纳米粒子-聚乙烯醇复合体系，其中用加热还原法所得体系中Ag纳米粒子的尺寸较大（15nm），其表面等离子体共振吸收峰较宽，最大吸收波长位于420nm；用室温硼氢化钠还原法得到的复合体系的吸收峰蓝移至409nm，且峰形较窄，Ag纳米粒子的平均粒径为8．7nm；低温NaBH4还原法所得体系吸收峰进一步蓝移至397nm，此时Ag纳米粒子粒径最小（3．5nm）．将室温还原法所得Ag-PVA复合体系旋涂成膜，所得薄膜光滑、透明、均匀性好，该法适用于制备多层薄膜，以调控薄膜的厚度和光谱性质．将Ag-PVA复合体系与钛酸四丁酯（Ti（OnBu）4）的乙醇溶液交替旋涂得到Ag-PVA/TiO2有机／无机复合薄膜，紫外-可见吸收光谱研究表明，随着Ag-PVA层数的增加，薄膜的表面等离子体共振吸收强度呈线性增加，但是TiO2层数的增加对吸收光谱没有明显影响．Ag-PVA／TriO2有机／无机复合薄膜将金属纳米粒子、有机高分子与无机半导体材料结合在一起，这种多层纳米结构在光电、催化功能薄膜等方面具有潜在的应用前景．     

表面处理方式对纳米SiO_2/PS复合粒子粒径及分布的影响

纳米SiO2粒子进行表面处理时所用表面活性剂的种类及用量直接影响二氧化硅/聚苯乙烯(SiO2/PS)复合粒子的粒径及分布。纳米SiO2粒子在超声波场作用下经十六烷基三甲基溴化胺(CTAB)处理后,可在纳米SiO2粒子表面形成单体和引发剂的富集区,在适当条件下引发以纳米SiO2粒子为核心的原位分散聚合反应。当纳米SiO2粒子对CTAB的吸附与初级粒子对聚乙烯吡咯烷酮(PVP)K-30的吸附达到动态平衡时,制备出的SiO2/PS复合粒子表面光滑,分散性好,仅有少量的游离纳米SiO2粒子存在,大部分纳米SiO2粒子被PS包裹。     

有机无机双金属杂化粒子PS/Ag-SiO2-Au的制备

有机无机杂化粒子PS/SiO₂-Au通过有机粒子（聚苯乙烯二聚体,PsD）与无机粒子（SiO₂-Au）反应得到,其中雪人形态的PsD粒子和SiO₂-Au粒子分别通过种子乳液聚合和溶胶-凝胶方法制得。在PS/SiO₂-Au基础上,负载Ag纳米粒子得到双金属杂化粒子PS/Ag-SiO₂-Au。期间,分别考察了单体与种子的配比、氨水加入量等对有机和无机粒子形貌的影响;采用红外光谱（FT-IR）、扫描电镜（SEM）、能谱分析（EDS）、透射电镜（TEM）、激光粒度测试仪（DLS）对所得粒子的结构、形貌、成分、尺寸进行了表征。PS/Ag-SiO₂-Au杂化粒子在催化领域有潜在的应用。     

超声波场下相分离法制备Ag/PA-6复合粒子

在尼龙-6（PA-6）的甲酸溶液中加入表面处理的Ag粒子,然后采用滴加非溶剂法和冷却降温法相结合的相分离法促使PA-6粒子的成型,同时在相分离及分散过程中引入超声波场,制备出Ag/PA-6复合粒子。通过对Ag/PA-6复合粒子的结构表征,发现Ag/PA-6复合粒子形状不规整,表面存在一定的缺陷,但结构非常致密,复合粒子周围及表面无游离的纳米Ag粒子存在,包覆率较高。在相同无机粒子添加量（质量分数20%）的条件下,采用相分离法制备的复合粒子的无机粒子包覆率（81%）高于原位分散聚合法（47%）。     

SiO2／聚丙烯酸酯复合乳液的制备和表征

通过半连续种子乳液聚合法．在Si02溶胶存在情况下,利用有机硅单体乙烯基三乙氧基硅烷（A-151）的桥接作用,制备得到Si02／丙烯酸酯共聚物杂化乳液。对有机硅单体和二氧化硅用景对复合乳液稳定性能的影响进行了研究,采用投射电镜（TEM）和热重分析（TGA）对制备得到的复合乳液的形貌和耐热性进行测试表征。结果表明：在有机硅单体乙烯基三乙氧基硅烷用量为总单体4．0wt％,SiO2溶胶用鲢为单体15wt％以内,可制备出稳定的SiO2／丙烯酸酯共聚物杂化乳液。由于有机硅单体的桥接作用,部分SiO2粒子形成与乳胶粒上,形成草莓状的复合结构,且复合乳液其有较高的耐热性。     

Composite magnetic particles: 1. Deposition of magnetite by heterocoagulation method

In this paper we report synthesis and characterization of composite polymeric particles bearing magnetite inclusions and reactive β-diketone groups on the surface. Composites were prepared by two-step method in which first step requires preparation of the functionalized polystyrene core and during second step magnetite was deposited onto core particle surface. This procedure gives a possibility to obtain composite particles with core-shell morphology and both the core size and magnetite shell thickness can be varied. Highly monodisperse PS/AAEM microspheres were synthesized by surfactant-free emulsion polymerization. Change of monomer fleet-ratio gives a possibility to change effectively the final particle size of dispersions without strong changes in particle size distribution. PS/AAEM particles were characterized by light scattering techniques (DLS, SLS) and electron microscopy (SEM) with respect to their particle size and morphology of the surface layer. Magnetite was deposited in form of nano-crystals onto PS-AAEM particle surface by heterocoagulation process. It has been established that more uniform magnetite coating was obtained at lower base amounts used for synthesis of magnetite. Amount of the magnetite on the polymeric particle surface can be effectively controlled by changing the initial FeCl₂ and FeCl₃ concentrations and/or variation of the PS/AAEM core dimensions. It has been confirmed by separation centrifugation technique, that stepwise increase of the magnetite content on the particle surface decrease gradually the stability of colloidal system. Magnetization curves for composite particles indicate that deposited magnetite content is high enough to achieve considerable magnetic response to external magnetic field.     

Production of NiO,NiO/Ag,NiO/Au,and NiO/Pt hollow spheres by using block copolymer stabilized microspheres as a template

Hollow spheres of nickel oxide (NiO) and silver, gold, and platinum nanoparticle loaded NiO composites were successfully produced by using polystyrene (PS) latexes as hard template. Due to the presence of tertiary amine based diblock copolymer stabilizer on the surface of PS, the tertiary amine functional groups provided homogene deposition of nickel hydroxide, and then the precursor NiO salt production on the surface of PS latexes with a controlled precipitation technique. Then, NiO and NiO/metal NP hollow spheres were produced by calcination at 600 °C. Thermogravimetric analysis indicated that the amounts of NiO and NiO-composite after calcination were in the range of 21.1–29.7 wt%. The diameters of metal oxide spheres were in the range of 2.0–2.7 μm and the shell thickness were in the range of 250–350 nm. These structures had very low densities due to their porous and hollow structures and had outer layers with highly rough surfaces due to formation of nanosheets, which may offer important advantages for catalysis studies.     

聚苯乙烯和聚丙烯酸丁酯无皂核壳乳液聚合反应的研究

聚苯乙烯 (PS)和聚丙烯酸丁酯 (PBA)复合乳液是无皂乳液聚合反应生成的 ,采用丙烯酸丁酯加到聚苯乙烯种子微粒中反应得到的。PS/PBA复合微粒的结构通过红外光谱图明显的吸收峰特征而得到证实。纯PS微粒和低BA含量的PS/PBA微粒几乎是球形和规则的 ,而随着BA单体含量的增加 ,PS/PBA复合微粒的粒子尺寸变大和呈现类似高尔夫球形状。同时 ,本文进一步研究了PS/PBA复合微粒的表面形态学     

超细CaCO3的聚合物胶囊化研究

先通过乳液聚合制备了粒径约为100nm带正电荷的聚苯乙烯PS纳球,再利用异相凝集,使正电性的PS吸附在带负电荷的超细碳酸钙（CaCO3）表面,后在高于PS玻璃化温度（Tg)下,进行热处理,形成胶囊化复合粒子,用Zeta电势,扫描电镜和粒径分布对复合前后的粒子进行了表征。     

Ag/PMMA复合粒子的制备及表征

纳米银/聚甲基丙烯酸甲酯(Ag/PMMA)复合粒子是一种新型的功能粒子,可以有效利用昂贵金属纳米粒子组元的独特性能,是高表面能金属纳米粒子稳定化的有效途径.本文首先在超声波场中用表面活性剂SDS对纳米Ag粒子进行亲油化处理,然后在N<,2>保护下利用超声波的分散、粉碎、活化、引发等多重作用,在实现纳米Ag粒子在反应介质...     

Ag–Sr doped mesoporous bioactive glass nanoparticles loaded chitosan/gelatin coating for orthopedic implants

In this study, we investigated surface and biological properties of Ag–Sr-doped mesoporous bioactive glass nanoparticle (Ag–Sr MBGN) loaded chitosan/gelatin coatings deposited by electrophoretic deposition (EPD) on 316L stainless steel. The EPD parameters, that is, deposition time, applied voltage, and distance between the electrodes was optimized by the Taguchi design of experiment (DoE) approach. Scanning electron microscopy (SEM) images illustrated the spherical morphology of the synthesized Ag–Sr MBGNs with the mean particle size of 160 ± 20 nm. Energy-dispersive X-ray (EDX) spectroscopy results confirmed the presence of Ag and Sr in the synthesized MBGNs. Optimum EPD parameters determined by DoE approach were 5 g/L of Ag–Sr MBGNs, deposition time of 5 min, and applied voltage of 30 V. SEM images confirmed that the coatings were fairly homogenous. Fourier-transform infrared spectroscopy and EDX results confirmed the presence of chitosan, gelatin, and Ag–Sr MBGNs in the coatings. Chitosan/gelatin/Ag–Sr MBGN composite coatings exhibited suitable wettability for the protein attachment and proliferation of osteoblast cells. The composite coatings exhibited suitable adhesion strength with the substrate. The coatings developed HA crystals upon immersion in simulated body fluid. The results of the turbidity test confirmed that the coatings are antibacterial to the Escherichia coli cells.     

A convenient approach to synthesize stable silver nanoparticles and silver/polystyrene nanocomposite particles

In this study, silver nanoparticles were prepared by the reduction of silver nitrate in SDS+ isopentanol/styrene/H₂O reverse microemulsion system using sodium citrate as reducing agent. The Ag/PS nanocomposite particles were prepared by in situ emulsion polymerization of the styrene system containing silver nanoparticles that did not separate from the reaction solution. The polymerization dynamic characteristic was studied, at the same time, silver nanparticles and the encapsulation of composite particles were characterized by Fourier‐transform‐infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X‐ray diffraction (XRD) measurement, UV–vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The results of TEM and UV–vis absorption spectra showed that well‐dispersed silver nanoparticles have a narrow size distribution. XRD showed that Ag and Ag/PS nanocomposite particles were less than 10 and 20 nm in size, which is similar to those observed by TEM. The results of XPS spectra revealed that the microemulsion system can stabilize the silver nanoparticles from aggregation and provided supporting evidence for the polystyrene encapsulated silver nanoparticle structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

Fabrication of hybrids based on graphene and metal nanoparticles by in situ and self-assembled methods

In this work, we developed two novel strategies to attach metal nanoparticles (Au and Ag) to the surface of graphene nanosheets, in which graphene oxide was first modified by the linking molecule (3-mercaptopropyl)triethoxysilane and then subjected to different treatments including in situ and self-assembled techniques. The synthesis processes and the resulting hybrids were investigated by ultraviolet-visible measurements, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that both approaches could effectively immobilize metal nanoparticles onto a graphene surface, and that better distribution and size control of metal nanoparticles were obtained by the self-assembled method. Moreover, we prepared poly(vinylidene fluoride)/graphene-Ag nanocomposites by a solution blending method. The AC conductivity of the resulting nanocomposites could be increased significantly when the loading amount of graphene-Ag was only 2 wt%. We expect that such graphene-metal nanoparticle hybrids may be potentially useful in composite reinforcement, sensors, and electronic devices.     

Preparation and dielectric properties of nano-silver/epoxy composites

以硝酸银为原料,用聚乙烯吡咯烷酮（PVP）作保护剂,在N,N-二甲基甲酰胺（DMF）溶液中,通过光化学反应法分别合成了平均粒径为80 nm、100 nm、120 nm的银胶,并用扫描电子显微镜及激光粒度仪测试了其分散程度和粒径正态分布;采用溶液-超声法制备了纳米Ag/环氧树脂复合材料;采用XRD、FTIR表征了纳米Ag对环氧树脂的改性结果,并详细讨论了纳米Ag粒径及含量对复合材料介电性能的影响。结果表明：一定尺寸和分布的纳米金属粒子能够提高聚合物的击穿强度,纳米Ag的粒径越小,击穿强度的提升越明显;并且在固定粒径时,聚合物的击穿强度随着Ag的含量提高出现先增加又降低的趋势,介电常数和介电损耗却出现了先降低后增加的趋势,这种特殊的现象可以用库伦阻塞效应限制电荷运动的理论来解释。