单分散聚硅氧烷微球的制备表征及作为光散射剂的应用

以乳液聚合法制备粒径分布均匀、球形度良好的聚硅氧烷微球。采用扫描电镜(SEM)、动态光散射(DLS)、红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TGA)和接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。将平均粒径为1.5μm的聚硅氧烷微球作为光散射剂添加到光学级聚甲基丙烯酸甲酯(PMMA)树脂中,可制备出性能优良的光散射材料。当聚硅氧烷微球添加质量分数约0.6%时,光散射材料的透光率是86.1%,雾度是91.25%,拉伸强度达到最大值77.2 MPa,弯曲强度是87.2 MPa,简支梁缺口冲击强度是2.16 kJ/m2,悬臂梁缺口冲击强度是2.71 kJ/m2,综合性能良好。     

异相聚合物对PET光扩散膜性能的影响研究

通过共混法在PET(聚对苯二甲酸乙二酯)中添加其它聚合物制备PET光扩散膜,采用其他聚合物作为内添加剂进行分析、研究,并通过实验对理论结果进行验证。研究光扩散材料的折射率、光扩散剂粒径、光扩散剂用量、光扩散膜拉伸倍率影响光扩散膜透光率、雾度性能结果。并探讨区别于传统的表面涂布的方法,运用一步法共混挤出工艺方法制备出透光率高、雾度大的光扩散膜材料。     

硅橡胶微球光扩散剂的制备表征及应用EI北大核心CSCD

通过在硅橡胶加成聚合体系中引入稀释剂,利用悬浮聚合一步法制备硅橡胶微球。利用红外光谱、接触角、热重分析、扫描电子显微镜、雾度/透光率测试对硅橡胶微球及其聚甲基丙烯酸甲酯(PMMA)复合材料的结构及性能进行研究和表征。结果表明,硅橡胶微球具有与硅橡胶一样的耐热性,其粒径主要分布在1~4μm之间,且硅橡胶微球表面具有粗糙结构。将硅橡胶微球加入到PMMA中,实验结果表明,硅橡胶微球用量为1%时,PMMA雾度从2.54%提升至92.34%,而透光率仅从90.40%降至84.47%。     

单分散热稳定有机/无机杂化修饰苯乙烯微球的制备及形成机理

采用乳液聚合法,通过乙烯基三乙氧基硅烷(KH151)共聚修饰,制备系列有机/无机杂化聚苯乙烯复合微球。使用激光散射和TEM分别对微球的粒径分布和形貌进行表征,并研究了合成工艺条件对有机/无机杂化修饰微球的颗粒分散性及形貌的影响。结果表明,通过控制乙烯基三乙氧基硅烷(KH151)共聚修饰剂的加入过程,可制得粒径分散均一、表面光滑的杂化修饰微球。使用FT-IR、NRM、TGA和DSC对微球的结构和性能进行表征,显示微球表面富含羟基功能基团,热稳定性较好,并分析了有机/无机杂化修饰苯乙烯微球的形成和热稳定性增强的机理。     

细乳液法合成单核核壳结构氧化硅/聚苯乙烯复合微球

采用细乳液聚合法,以3-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)表面改性的直径50nm的氧化硅粒子为核,在乳化剂、助乳化剂、引发剂存在的情况下制备了小粒径、单核核壳结构氧化硅/聚苯乙烯纳米复合微球.研究表明,苯乙烯的浓度、超声细乳化时间,是制备这种小粒径、单分散、单核核壳结构的氧化硅/聚苯乙烯纳米复合微球的关键因素.透射电镜(TEM)的观察显示,在优化的实验条件下,可以制得平均粒径95nm,壳厚20nm,粒径均一、球形规整度较好、单核核壳结构的氧化硅/聚苯乙烯纳米复合微球.其平均粒径远低于用其它聚合方法制备的复合微球.     

分散聚合法制备SiO2/PAM核壳复合微球

采用分散聚合法制备出以SiO2为核、PAM为壳的核壳复合微球。根据Stber法制备了单分散SiO2微球,粒径随着TEOS、氨水浓度的增加而增大。采用硅烷偶联剂对SiO2微球进行表面处理,TEM显示处理后的微球继续保持单分散性,粒径有所增加。以SiO2微球或处理后的SiO2微球为核,采用分散聚合法在其上包覆AM,借助TEM、IR对其进行表征;研究发现,以处理后的Si O2微球为核能得到核壳结构,这种SiO2/PAM核壳微球的粒径大约为163 nm,包覆层30 nm左右。     

核壳结构喷墨微滴珠液开发研究

用微乳液界面反应制备了含油溶性颜料、酚醛树脂的纳米核壳微球彩色乳液,TEM和激光散射粒度仪测定了微球形态粒径为80～120 nm球形.通过IR和DSC测定了壁材的结构,表明微球外壳为聚脲壳,芯为酚醛树脂.SEM观察了微球喷涂到电解氧化的铝版基上成膜前后的形态,成膜前为球形;成膜后为团聚片状.把制成的纳米核壳微球彩色乳液经计算机直接喷墨成像,在电解氧化形成砂目的铝版上制成喷墨CTP版,并在胶印机上进行了印刷,耐印率超过2万印以上.分辨率取决于喷墨打印机.     

二氧化钛空心微球的制备及表征

采用模板法制备了可控制球壳厚度的亚微米二氧化钛空心微球.首先利用钛酸四丁酯乙醇溶液和聚苯乙烯粒子制备了二氧化钛/聚苯乙烯复合粒子,在空气中经500℃煅烧除去苯乙烯模板后得到锐钛矿二氧化钛空心微球.透射电镜和扫描电镜观察表明,二氧化钛/聚苯乙烯复合粒子煅烧后体积发生了急剧的收缩,形成具有空心结构二氧化钛微球.电子衍射和X射线衍射分析可知空心微球的二氧化钛球壳为锐钛矿.实验发现当钛酸四丁酯与乙醇的体积比从120提高到110时,二氧化钛空心微球的球壳厚度从20～25 nm增加到45～50nm;以不同粒径的聚苯乙烯粒子作模板,可以得到不同内孔直径的二氧化钛空心微球,其内孔直径比聚苯乙烯模板直径小15%～20%.     

PC/SAN共混体系微观结构与光学性能的关系及性能优化

以双酚A型聚碳酸酯(PC)为基体、苯乙烯-丙烯腈共聚物(SAN)为散射体,通过熔融共混法制备出聚碳酸酯基光散射材料,研究了SAN含量及密炼转速对共混物微观结构及光学性能的影响。结果表明,SAN含量的增加使散射体平均粒径呈增大趋势,且当SAN的质量分数小于25%时大部分粒子粒径小于1μm,在25%~35%之间时粒径变化较小,再增加则形成双连续相结构。透光率与雾度则随着粒径的变化呈先增大后保持平衡再下降的变化规律。而密炼转速的增大使小于1μm的散射粒子数目增多,透光率随之下降,雾度则几乎不变。通过Mie散射理论分析可以很好地解释上述变化规律。因此SAN的质量分数在25%~35%之间并以较低的转速进行加工可以得到最佳光散射性能的PC/SAN共混物。     

核-壳式聚苯乙烯/二氧化硅复合微球及空腔硅球的制备

利用层层自组装的方法制备了粒径和组成可裁剪、具有核-壳式结构的单分散聚苯乙烯(PS)/二氧化硅(SiO₂)复合微球.对复合微球进行热处理除去有机物中心,制备出壁厚可剪裁的空腔硅球.透射电镜(TEM)照片显示二氧化硅纳米颗粒在中心外生成均匀壳层,而煅烧后则可得到轮廓分明的球形空腔;热重分析(TG)说明复合球体的硅含量随着所组装的纳米二氧化硅的粒径的增加而增加;比较PS、SiO₂、复合球体及热处理后的粉体的红外光谱,可分别验证二氧化硅的成功组装和热处理过程中作为中心的PS的完全去除.在吸附相同层的前提下,随着所选用的二氧化硅纳米粒子(10um,20um,40um)的粒径的增大,复合微球的粒径增大,空腔球体的壁厚增加.     

Preparation of PS/TiO2 core-shell microspheres and TiO2 hollow shells

PS/TiO₂ core-shell microspheres were prepared by a hydro-thermal method at 105°C. Different-sized PS/TiO₂ core-shell microspheres were obtained with various PS cores, which were prepared by emulsion polymerization and seeds polymerization. Furthermore, intact hollow TiO₂ shells with different shell thickness were obtained by calcining PS/TiO₂ core-shell microspheres at 600°C. Light scattering of core-shell microspheres and hollow shells was tested.     

The sol-gel preparation of ZnO/silica core-shell composites and hollow silica structure

Three kinds of different ZnO colloid particles (flowerlike particles, nanoribbons and microspheres) and one kind of ZnO film have been coated with silica via a simple sol-gel method in the Stöber system and ZnO/silica core-shell microparticles or films have been obtained. The thickness of silica shell can be controlled by adjusting the concentration of TEOS added into the system. If the ZnO core is etched off by HCl, corresponding, hollow silica particles or film will be generated.     

Comparative Study on Optical Properties and Scratch Resistance of Nanocomposite Coatings Incorporated with Flame Spray Pyrolyzed Silica Modified via in-situ Route and ex-situ Route

A new type of transparent scratch resistant coatings including in-situ modified SiO_2(g-SiO_2) in flame spray pyrolysis(FSP) process was prepared. The maximum content of g-SiO_2 in the coating was 15 wt%, which is higher than that of SiO_2 modified by traditional wet chemical route(l-SiO_2, only 10 wt%). The results of transmission electron microscopy have demonstrated that in-situ surface modified g-SiO_2 particles dispersed well with smaller agglomerates in the final coating, which was much better than the particles modified via wet chemical route. Visible light transmittance and haze tests were introduced to characterize the optical quality of the films. All coatings were highly transparent with the visible light transmittance of above 80%, especially for coatings containing g-SiO_2, which exhibited slightly higher visible light transmittance than l-SiO_2 embedded one. The haze value of coatings incorporated with 15wt% g-SiO_2 was 1.85%, even lower than the coating with 5 wt% l-SiO_2(haze value of 2.09%), indicating much better clarity of g-SiO_2. The excellent optical property of g-SiO_2 filled coatings was attributed to the good dispersion and distribution of particles. Nano-indention and nano-scratch tests were conducted to investigate the scratch resistance of coatings on nano-scale. The surface hardness of the coatings rose by 18% and 14%, and the average friction coefficient decreased by 15% and 11%, respectively, compared to the neat coat due to the addition of 10 wt% g-SiO_2 and l-SiO_2. The pencil hardness of the coating with 15 wt% g-SiO_2 increased from 2B for the neat coating to 2H. However, the pencil hardness of coating with 10 wt% l-SiO_2 was only H. The results showed that the g-SiO_2 embedded coatings exhibited higher scratch resistance and better optical properties.     

两步沉淀聚合法制备表面具有羧基的核-壳微球

以高交联的聚二乙烯基苯-55(poly(DVB-55))为核,甲苯/乙腈(体积比1∶3)混合溶剂,采用两步沉淀聚合法,在核的表面接枝了具有羧基官能团的较低交联度的壳,得到了单分散或窄分散微米尺度的poly(DVB55)/poly(DVB55-co-methacrylic acid)核-壳微球。结果表明,以甲苯/乙腈混合物替代纯乙腈作为反应介质可以获得比表面积、孔容、接枝量和粒径相对较大的核-壳微球;随着poly(DVB-55)核的用量的增加或反应时间的缩短或单体和交联剂投料浓度的减小,所得的核-壳微球的粒径减小、接枝量降低、粘连程度减小,微球的均匀性则升高。     

动态光散射测量核壳双层纳米颗粒的研究

用动态光散射方法研究了以聚丙烯酸丁脂（PBA）为核、聚甲基丙烯酸甲脂（PMMA）为壳的核壳双层纳米颗粒的粒径和粒径分布。得出的结论为：由于同一粒径的单层介质颗粒和核壳双层纳米颗粒的散射光不同,在测量中若将核壳双层颗粒当作单层介质颗粒处理时,必将影响测量结果的表征。     

Synthesis and characterization of polyimide-based hybrid thin films from a novel colloidal core-shell nanocomposite particles

In this study, poly(4,4-(hexafluoroisopropylidenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA) and a novel core-shell nanoparticle consisting of a core (SnO2/TiO2) and a shell (ZrO2/Sb2O3) with the composition (SnO2:TiO2:ZrO2:Sb2O3 = 18:5:3:4) were used to prepare polyimide/nanoparticles hybrid thin films. The resultant hybrid thin films were investigated by FTIR, TGA, DSC, TEM, SEM, AFM, alpha-step, UV-Vis, and n&k analyses. The results show that the prepared hybrid thin films had a good thermal stability. The size of nanoparticles was effectively controlled in the range of 8-10 nm in the hybrid thin films. These nanoparticles were evenly distributed across the hybrid thin films and no phase separation occurred. In terms of the optical properties, the prepared hybrid thin films had good transparency in the range of visible light. The cutoff wavelength had a blue shift as the content of the nanoparticles increased. The refractive index of prepared hybrid thin films increased with corresponding increases in nanoparticle content. Moreover, the prepared polyimide/core-shell nanoparticle hybrid thin films displayed excellent film formability and planarity.     

SiO2／Ag核壳复合粒子的制备与表征

首次引入活性SiO2微球作为核基，采用自组装液相还原技术，定向的在核基上沉积纳米银颗粒得到SiO2／Ag核壳复合粒子；并用红外、x射线衍射、场发射扫描电镜、能谱等分析表征该核壳复合粒子的形貌与结构。结果表明：利用活性SiO2作为核基，pH值为12．4，有表面活性剂参与的条件下，通过改变银前驱体浓度，可实现表面包覆致密、银壳厚度可控的核壳复合粒子化学制备技术。     

纳米尺度PS/Ag核壳结构复合球的制备与表征

采用分步法制备了聚苯乙烯/银(PS/Ag)核壳结构复合纳米球。首先采用无皂乳液聚合法并利用丙烯酸(AA)的羧基对制备的PS球进行改性,使其表面带负电荷;然后通过静电吸附作用在改性PS球的表面沉积[Ag(NH3)2]+,水浴(80℃)环境中利用十二烷基磺酸钠(SDS)作为还原剂将PS球表面的[Ag(NH3)2]+还原,制备出PS/Ag核壳结构复合球。通过动态激光粒度分析仪和透射电子显微镜对PS/Ag核壳纳米球的粒度分布、形貌和结构进行了表征,研究了AA的用量对复合球粒径及包覆的Ag壳厚度的影响。结果表明,随着AA用量的增大,所包覆的银层更加致密,厚度增大,当AA用量为15%时可得到Ag完全包覆的PS/Ag复合纳米球。