溶胶-凝胶法制备硅系有机-无机杂化分离膜

以α-Al₂O₃多孔陶瓷片为载体,用溶胶-凝胶法制备有机-无机杂化分离膜.通过考察前驱物的组成及杂化溶胶的合成条件对制膜工艺过程的影响,得到了制备有机-无机杂化分离膜的各种适宜性参数.红外光谱(FTIR)分析结果表明,杂化溶胶的性能不仅决定分离膜的性能,而且对膜热处理过程中的龟裂有很大影响.膜层的厚度为1～2μm;在膜两侧压差为0.10MPa、n(PTMOS)/n(TEOS)=1.16时,膜对O₂/N₂,CO₂/N₂和CO₂/O₂的分离因子分别为2.30,4.31和1.17,渗透系数为75.81×10^-17,75.28×10^-17和72.78×10^-17m₃(STP)·m/(m₂·s·Pa).     

十七氟癸基修饰的有机-无机杂化二氧化硅膜材料的制备及气体分离性能

以十七氟癸基三乙氧基硅烷(PFDTES)和1,2-双(三乙氧基硅基)乙烷(BTESE)为前驱体, 通过溶胶-凝胶法制备了十七氟癸基修饰的SiO₂溶胶, 采用浸渍提拉法在γ-Al₂O₃/α-Al₂O₃多孔陶瓷支撑体上涂膜, 然后在N₂气氛保护下烧结成完整无缺陷的有机-无机杂化SiO₂膜. 利用扫描电子显微镜对膜材料的形貌进行观察, 通过动态光散射技术对溶胶粒径及分布进行测试, 利用视频光学接触角测量仪、 红外光谱仪和热分析仪表征了十七氟癸基修饰对有机-无机杂化SiO₂膜疏水性的影响. 结果表明, 十七氟癸基已经成功修饰到SiO₂膜材料中, 且随着PFDTES加入量的增大, 溶胶粒径和膜材料对水的接触角不断增大. 当n(PFDTES): n(BTESE)=0.25: 1时, 溶胶粒径分布较窄, 平均粒径为3.69 nm, 膜材料对水的接触角为(112.0±0.4)º. 在修饰后的有机-无机杂化SiO₂膜中H₂的输运遵循微孔扩散机理, 在300℃时, H₂的渗透率达到5.99×10^-7 mol·m^-2·Pa^-1·s^-1, H₂/CO和H₂/CO₂的理想分离系数分别达到9.54和5.20, 均高于Knudsen扩散的理想分离因子, 表明膜材料具有良好的分子筛分效应.     

水性聚氨酯阻燃纳米复合材料的Click反应制备及性能

以4,4'-二羟甲基-1,4-庚二炔功能单体作为扩链剂制备了端炔基功能化聚氨酯, 与叠氮基改性纳米蒙脱土(MMT-N₃)、 纳米氢氧化铝(ATH-N₃)和纳米氢氧化镁(MH-N₃)通过Click反应制备了水性聚氨酯(WPU)阻燃纳米复合材料. 采用红外光谱(FTIR)、 核磁氢谱(¹H NMR)和扫描电子显微镜(SEM)对WPU阻燃纳米复合材料的结构进行了表征, 对比研究了纳米阻燃剂配比和制备方法对WPU阻燃纳米复合材料的氧指数、 动态燃烧行为和热稳定性的影响. 阻燃性能研究结果表明, 当MMT-N₃, MH-N₃和ATH-N₃的质量分数分别为7%, 2%和1%时, 采用Click反应制备的复合材料的氧指数比纯WPU高7%, 点燃时间从10 s延长到29 s, 峰值热释放速率和烟释放速率分别降低了41%和42%. 热失重分析结果表明, 当MMT-N₃质量分数为10%时, 与WPU相比, 采用Click反应制备的MMT/WPU复合材料在热失重50%时的温度提高了21 ℃. 复合材料断面和燃烧后残渣的SEM分析证明在聚合物基体中Click反应是分散纳米材料的一种有效方法.     

具有不对称孔道结构的小介孔二氧化硅粒子的合成及其高分子杂化膜的构建

利用手性阴离子酸表面活性剂, 采用软模板法制备了具有不对称孔道结构的小介孔二氧化硅(SiO₂)粒子. 将小介孔SiO₂粒子引入聚偏四氟乙烯(PVDF)和聚酰亚胺(PI)中构建了两种有机/无机杂化膜. 利用傅里叶变换红外光谱(FTIR)、 透射电子显微镜(TEM)、 扫描电子显微镜(SEM)和比表面积分析等表征了小介孔SiO₂粒子和有机/无机杂化膜的微结构, 并通过超滤实验和气体渗透实验分别考察两种杂化膜的性能. 研究结果表明, 表面含有大量亲水基团的小介孔SiO₂粒子具有规则有序排列的孔道结构, 该孔道结构呈现螺旋扭曲和不对称性. 构建的两种有机/无机杂化膜的极性显著提升, 进而有效增强了PVDF杂化膜的膜通量和抗污染性能及PI杂化膜对CO₂气体的分离性能, 克服了高分子膜的博弈效应(Trade-off效应). 另外, SiO₂的小介孔孔道还可以在PI杂化膜中引入优先通过CO₂分子的限域传质通道, 加速了CO₂气体在杂化膜中扩散. 但过多小介孔SiO₂粒子的加入导致其在高分子基质中团聚, 削弱杂化膜的极性和亲水性, 从而降低了两种杂化膜的分离性能.     

三氟丙基修饰的有机-无机杂化二氧化硅膜制备、氢气分离及水热稳定性能

以三氟丙基三甲氧基硅烷(TFPTMS)和1,2-双(三乙氧基硅基)乙烷(BTESE)为前驱体, 通过溶胶-凝胶法在酸性条件下制备三氟丙基修饰的有机-无机杂化SiO₂膜材料, 并深入研究三氟丙基修饰对溶胶粒径和疏水性能的影响以及膜材料的氢气渗透分离性能和长期水热稳定性. 结果表明三氟丙基已成功修饰到有机-无机杂化SiO₂膜材料中, 且随着TFPTMS修饰量的增加, 溶胶粒径有减小趋势, 膜材料的疏水性能逐渐提高. 当n(TFPTMS)/n(BTESE)＝0.6时, 溶胶平均粒径为2.11 nm, 膜材料对水的接触角达到111.6°±0.7°. H₂在修饰后膜材料中的输运主要遵循微孔扩散机理, 300 ℃时H₂的渗透率为8.86×10^-7 mol·m^-2·s^-1·Pa^-1, H₂/CO₂的理想分离系数达到5.4, 且当进气摩尔比例为1∶1时H₂/CO₂的双组分气体分离系数达到了4.82, 均高于Knudsen扩散分离因子(H₂/CO₂＝4.69), 膜材料呈现出良好的分子筛分性能. 膜材料在250 ℃及水蒸气摩尔含量为5%的水热环境中能稳定工作300 h以上.     

两亲性杂侧链聚合物刷的合成及其乳化功能

报道了一种随机高密度接枝亲水、疏水聚合物侧链的刷形两亲性聚合物.首先,结合可逆加成-断裂链转移(RAFT)聚合和后修饰方法,得到含叠氮侧基的聚甲基丙烯酸缩水甘油酯(PGMA-N3)作为主链;再分别合成端炔基聚苯乙烯(PS)和端炔基聚环氧乙烷(PEO),然后通过铜催化的叠氮-炔环加成反应,将疏水性PS和亲水性PEO同时高效的接到PGMA主链上,制得两亲性杂侧链的聚合物刷.由凝胶渗透色谱(SEC)分析得知,在主链叠氮基团与两侧链总炔基的摩尔投料比为1∶1的条件下,PS和PEO的接枝效率很高,都大于90%.通过调节主链长度和2种侧链的投料比,获得不同组成的聚合物刷.通过等质量的甲苯/水混合体系,考察两亲性聚合物刷的乳化能力,发现主链聚合度为100,PS∶PEO比例为70∶30的聚合物刷表现出最佳的乳化性能.     

溶胶-凝胶法制备聚醚砜-二氧化硅复合材料

以聚醚砜(PES)为基体,通过溶胶-凝胶过程,得到了分散均匀的PES/SiO₂杂化材料,用扫描电镜、透射电镜、傅里叶红外及差示扫描量热法研究不同SiO₂含量的PES/SiO₂杂化材料材料性能.结果表明,当PES/SiO₂杂化材料中SiO₂的质量分数大于10%时可获得有机聚合物链段与无机网络互穿的均匀分散的复合材料.此材料的玻璃化转变温度(Tg)明显提高.     

含膦酰杂菲侧基的4-炔基苯甲酸酯对聚叠氮缩水甘油醚点击接枝反应及其聚集诱导发光增强性能

在CuI催化作用下,实现了含膦酰杂菲侧基的4-炔基苯甲酸酯(MAT4)与聚叠氮缩水甘油醚(GAP)的点击接枝反应,得到新型接枝聚合物G-M4,并由红外谱图确定了等摩尔反应.由于分子内含膦酰杂菲基团侧基之间较强的π-π和极性共同相互作用以及聚醚主链的柔顺性,使G-M4分子链内侧基之间相对空间位置比较固定,分子链构型规整,...     

硫醇-烯/炔点击化学制备有机/无机杂化材料

有机/无机杂化材料因其独特、优异的结构和性能已经成为目前材料领域的研究热点,硫醇-烯/炔点击化学是近年发展起来的一类新型点击化学,以其反应条件温和、速率快、产率高、产物容易分离以及高度选择性等优点受到国内外研究者的广泛关注。本文综述了近年来硫醇-烯/炔点击化学制备有机/无机杂化材料的研究进展,重点介绍了利用硫醇-烯/炔点击化学制备硅类、碳类、金属及金属氧化物类有机/无机杂化材料,并归纳了这些有机/无机杂化材料在生物医用、环境保护、光电材料等方面的应用,最后展望了硫醇-烯/炔点击化学制备有机/无机杂化材料未来的发展方向。     

Cd基化合物纳米晶-有机聚合物杂化太阳能电池研究进展

有机-无机杂化太阳能电池因其结合了有机材料和无机材料各自的优势而引起了人们的广泛关注和研究. Cd基化合物纳米晶因其具有制备方法简单、尺寸及形貌可控、载流子迁移率高和稳定性好等优点而成为最早被研究的一类无机受体. 本文介绍了有机-无机杂化太阳能电池的结构及原理, 分析了影响有机-无机杂化太阳能电池效率的三个主要因素, 分别是开路电压(V_oc)、短路电流(J_sc)和填充因子(FF). 从改善Cd基化合物纳米晶的合成方法, 增加Cd基化合物纳米晶和有机聚合物间的界面接触, 以及优化Cd基化合物纳米晶和有机聚合物所用溶剂和所占比例等方面阐述了近年来Cd基化合物纳米晶-有机聚合物杂化太阳能电池的研究进展. 并展望了Cd基化合物纳米晶-有机聚合物杂化太阳能电池的发展方向.     

水性聚氨酯硬段含量对其氢键相互作用及性能的影响

异佛尔酮二异氰酸酯（IPDI）、二羟甲基丙酸(DMPA)作为硬段,合成了水性聚氨酯。 研究了硬段含量（质量分数）对乳液稳定性、膜耐热和力学性能等的影响。 当硬段质量分数低于26%时,乳液贮存稳定性较差。 随着硬段含量增加,聚氨酯膜拉伸强度迅速增加,断裂伸长率略有降低;红外光谱显示,自由的N-H伸缩振动峰强度减弱,氢键化N-H的振动峰强度增加;同时C=O伸缩振动峰整体向低波数方向移动,C=O伸缩振动峰峰形有明显的变化;DSC测试在50～125 ℃出现明显的氢键解离现象,吸热峰增强,证实了氢键作用力随着硬段含量的增加逐渐增强。 TG测试表明,水性聚氨酯硬段和软段分步解离,随着硬段含量的增加,硬段分解温度降低,水性聚氨酯耐热性能下降。     

丙烯酸酯改性水性聚氨酯/纳米二氧化硅复合材料的制备和性能

利用原位聚合伴随溶胶-凝胶进行的过程,合成了丙烯酸酯改性聚氨酯(PUA)/纳米SiO₂(PUAS)复合乳液。 通过纳米粒度仪、扫描电子显微镜、透射电子显微镜和热重分析仪等技术手段表征了复合乳液及胶膜的结构和性能。 结果表明,纳米SiO₂能够均匀地分散在复合材料中,随着原料中前驱体正硅酸乙酯(TEOS)质量分数的增加,复合乳液粒径有所增大,胶膜力学性能和热稳定性明显提高。 当TEOS质量分数为8%,胶膜拉伸强度达到16.8 MPa,邵氏硬度A达到94,最大分解速率温度提高到416 ℃,且胶膜耐水性明显改善,吸水率降低到2.1%。     

Synthesis and thermal properties of antimony doped tin oxide/waterborne polyurethane nanocomposite films as heat insulating materials

The waterborne polyurethane (WPU) was synthesized from the polycondensation between isophorone diisocyanate (IPDI) and polyoxypropylene glycol (N‐210) and then dispersed into water. Subsequently, the WPU emulsion was modified with antimony doped tin oxide (ATO) nanoparticle by ultrasonic dispersion. The ATO/WPU emulsion was cast onto Teflon molds. After being dried, ATO/WPU films were prepared. TEM indicated that the ATO nanoparticles were homogeneously dispersed in the polymer matrix at the nanometer scale. DSC showed that the ATO/WPU nanocomposites displayed increased glass transition temperatures compared to the control WPU. The mechanical properties of the films were characterized by dynamic‐mechanical analysis (DMA). The higher glass transition temperature and storage modulus indicates the superior mechanical properties of WPU modified by ATO nanoparticles over the conventional unmodified WPU. The thermal behaviors of the films were evaluated by thermogravimetric analysis (TGA). It could be found that the incorporation of ATO into WPU can improve the thermal stability dramatically. The results from UV–visible–near infrared spectra indicated that the ATO/WPU films could decrease the infrared transmission effectively. The heat‐insulation measurements showed that glass coated with ATO/WPU films possessed better heat‐insulating effect than empty glass. Copyright © 2010 John Wiley & Sons, Ltd.     

天然蚕丝丝素蛋白的乳化活性

采用不同油相制备了系列丝素蛋白乳液, 研究了丝素蛋白浓度、 油相体积分数和油相极性对丝素蛋白的乳化活性指数、 丝素蛋白乳液的稳定性和类型及乳液液滴的微观形态、 粒径与zeta电位的影响, 探讨了丝素蛋白的乳化活性和乳液稳定机制. 结果表明, 丝素蛋白具有两亲性和表面活性, 可在油水界面富集并形成稳定的黏弹性保护膜; 丝素蛋白的乳化活性随其浓度的增大而减小, 随油相体积分数的增大而增大; 丝素蛋白浓度和油相体积分数的增加可提高稳定乳液体积分数.     

大分子不饱和单体法合成具有核壳结构的丙烯酸酯/聚氨酯乳液及表征

采用丙烯酸酯（AC）对水性聚氨酯（WPU）进行改性,合成了接枝型丙烯酸酯/聚氨酯(PUA)复合乳液。 随着共聚物中丙烯酸酯质量分数的增加,乳液外观由透明变为不透明,乳液粒径随之增大、分布变宽。 TEM显示,PUA乳胶粒子呈现清晰的核壳结构,且形态规整,粒径分布在60~120 nm之间。 FTIR测试表明,随着丙烯酸酯质量分数的增加,聚氨酯(PU)硬段氢键化作用先增强后减弱,硬段的有序度逐渐降低。 DSC分析表明,当AC的质量分数低于75%时,PU、聚丙烯酸酯(PA)两组分相容性较好,只出现一个玻璃化转变温度,并且随着PA质量分数的增加逐渐升高。 PA质量分数的增加,使胶膜的最大热失重速率从363 ℃提高至412 ℃,吸水率从11.3%降低至5.7%,弹性模量从16.4 MPa提高至47.6 MPa,拉伸强度从9.0 MPa提高至23.7 MPa,断裂伸长率从365%提高至408%,同时乳液的粘度下降,干燥时间变短,胶膜的附着力变好。     

Hybrids of colloidal silica and waterborne polyurethane

Waterborne polyurethane (WPU) was synthesized and followed by adding colloidal silica to prepare WPU-silica hybrids. The silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results revealed that the viscosity of these hybrid solutions increased with increasing silica content and resulted in the aggregation of silica particle in the hybrid films. The latter result was evidenced by SEM examination. The effect of interaction between silica particle and urethane polymer chains is more significant with increasing silica content. The prepared hybrid films show much better thermal stability and mechanical properties than pure WPU. The optical transparence did not linearly decrease with increasing the silica fraction in the hybrid thin film. At below 20% silica content, the film transparence decreased with increasing silica content; the converse is true at above 20% silica content. These results showed that the prepared hybrid films demonstrated tunable transparence with the silica fraction in the films.     

pH和光对复合型乳液拓扑结构的调控

Complex emulsions have attracted much attention because of their relevant application in various fields over the past decade. Though complex emulsions with various topologies can be created by adjusting the fraction of selected components during the homogenization processes, it is still a challenge to control the topology of complex emulsion droplets in situ using stimuli-responsive factors such as light, pH, and temperature. In this work, a three-phase complex emulsion of heptane and perfluorohexane (1:1 volume ratio) in an aqueous solution of a fluorosurfactant, F(CF₂)_x(CH₂CH₂O)_yH (Zonyl FS-300), and a synthesized pH and light dual-responsive surfactant, 1-[2-(4-decylphenylazo-phenoxy)-ethyl]-1-diethylenetriamine (C₁₀AZOC₂N₃) (both serving as emulsifiers), was prepared using the temperature-induced phase separation method. The topology of the heptane-perfluorohexane-water (H/F/W) three-phase complex emulsion was highly dependent on the concentration of C₁₀AZOC₂N₃. Light microscopy images showed that phase inversion from H/F/W to F/H/W type double emulsion via Janus emulsion was achieved by gradually increasing the concentration of C₁₀AZOC₂N₃. It was noticed that interfacial tension between heptane and an aqueous solution containing 0.1% Zonyl FS-300 (mass fraction) decreased from 28.2 to 7.4 mN∙m^-1 when the concentration of C₁₀AZOC₂N₃ was increased to 0.1% (mass fraction). The topology of the complex emulsion droplets is primarily determined by three interfacial tensions at the contact line: the H/W interface (γ_H), F/W interface (γ_F), and H/F interface (γ_HF). The reduction in interfacial tension between heptane and water was the major factor that controlled the topological transition of the complex emulsion. First, it decreases the contact angle between the H/W and H/F interfaces (θ_H). Second, it increases the contact angle between the F/W and H/F interfaces (θ_F) simultaneously. Surfactant C₁₀AZOC₂N₃ is responsive to both pH and light, and therefore, it potentially endows the fabricated complex emulsion with the corresponding stimuli-responses. Experimental results confirmed that the morphologies of complex emulsions can be tuned reversibly between Janus emulsion and F/H/W type double emulsion either by pH variation or UV/blue light irradiation. Interfacial tension measurements between heptane and water show that either protonation variation or trans-cis isomerization of C₁₀AZOC₂N₃ caused a decrease of about 5 mN∙m^-1 in interfacial tension, suggesting that the nature of pH- and light-induced morphological changes of complex emulsion droplets is the same as that induced by the changes in the concentration of C₁₀AZOC₂N₃. Correspondingly, a mechanism for the stimuli-responsive morphological change of complex emulsion was proposed based on the reduction of interfacial tension between heptane and aqueous solution interface by changing the configuration of C₁₀AZOC₂N₃ using pH alteration and light irradiation. This work provides a new approach for controlling the morphologies of complex emulsion droplets with an external double stimulus by simply introducing a dual-responsive surfactant.     

Synthesis,morphology, and properties of waterborne m-TMXDI-based anionic polyurethane and hybrids

In this study, waterborne polyurethane (WPU) hybrid emulsions with a weight ratio of 2/1 were prepared by emulsion polymerization using a mixture of styrene (St) and/or butyl acrylate (BA) monomers with WPU dispersion. WPU dispersion was synthesized with isocyanic acid and m-tetramethylxylene diisocyanate (m-TMXDI)-based anionic poly(urethane-urea) dispersions using the prepolymer mixing process. The structures of WPU and hybrids were characterized by FTIR spectroscopy. The size and morphology of the latex particles were investigated using dynamic light scattering and transmission electron microscopy, respectively. The stability of the emulsions was determined according to their shelf life and particle size using the dispersion analyser LUMiSizer® with STEP?-Technology. The thermal and mechanical properties of these films were examined by thermogravimetric analysis and strain-stress curves.     

Janus纳米金稳定的Pickering乳液界面催化氧化性能

Janus纳米粒子的结构设计和简易合成是Pickering乳液界面催化的关键. 本文通过在Pickering乳液保护法中操纵共轭亚油酸的自组装、 自交联性和弱还原性, 合成了Janus型自交联吸附胶束修饰的纳米Fe₃O₄ (SCA-Fe₃O₄), 并在其表面原位还原金后, 合成了Janus型催化剂Au-SCA-Fe₃O₄, 考察其同时作为乳化剂和催化剂在乳液界面催化苯甲醇氧化生成苯甲醛的性能. 结果表明, 该Janus纳米粒子的金修饰量(质量分数)仅为0.66%, 兼具乳化性、 催化性和磁响应性. Au-SCA-Fe₃O₄可制备外观稳定(100 μm)和热稳定(90 ℃)的苯甲醇/水型Pickering乳液, 可显著提高互不相溶反应物与催化剂间的接触面积, 使其催化活性达到均匀纳米催化剂的2倍和非乳液催化时的3倍, 其在界面的不可转动性使苯甲醛的选择性高于99.9%, 避免了苯甲醛被过度氧化成苯甲酸.     

铌酸银可见光催化降解聚氯乙烯薄膜

采用涂层法在玻璃基底上分别制备了纯聚氯乙烯(PVC)薄膜和添加水热法制备的钙钛矿型铌酸银(AgNbO₃)光催化剂的复合薄膜(PVC-wAgNbO₃, 其中w为AgNbO₃的质量分数), 在500 W氙灯照射120 min条件下进行了薄膜的光催化降解实验. 利用X射线衍射仪(XRD)、 扫描电子显微镜(SEM)和傅里叶变换红外光谱仪(FTIR)等对光照前后薄膜的形貌及光催化降解过程进行了表征. 结果表明, 在光催化降解过程中纯PVC薄膜失重率为4.09%, 而PVC-3%AgNbO₃, PVC-6%AgNbO₃, PVC-9%AgNbO₃和PVC-15%AgNbO₃复合薄膜分别失重20.36%, 23.52%, 27.62%和33.83%. AgNbO₃光催化剂加速了PVC薄膜的降解, 且随着AgNbO₃光催化剂添加量的增加, PVC薄膜的光催化降解速率不断增大.