聚α-氰基丙烯酸丁酯纳米微囊的制备研究

通过界面聚合方法合成了聚α－氰基丙烯酸丁酯纳米微囊，研究了搅拌速率、乙醇浓度等聚合条件对粒径的影响，获得了平均粒径为100nm，壁厚为15nm的纳米微囊。     

SiO2/聚合物核壳型杂化粒子及其空心结构的制备

SiO2/聚合物核壳型杂化粒子及其空心结构以其独特的形貌在药物控制释放、催化剂载体、生物医药等领域应用前景广阔,引起了人们的广泛关注。本文着重从乳液聚合法、仿生矿化法等制备方法角度阐述了SiO2/聚合物核壳型杂化粒子及其空心结构的研究进展。乳液聚合制备SiO2/聚合物核壳型杂化粒子简单易行,一般需要预先合成SiO2纳米粒子,其合成过程通常需要一些非理想的条件,如高温高压、极端pH、昂贵或有毒的有机试剂等,而且预先合成的SiO2粒子无法与聚合物实现100%匹配,即总有纯的聚合物粒子存在。相比之下,原位仿生矿化法制备SiO2杂化粒子不仅在环境条件下可进行,而且能够精确控制其纳米尺度的形态及分级有序结构。目前对材料科学家来讲,要使人工合成SiO2/聚合物杂化粒子实现像自然生物硅那样优异的性能,仍然是很大的挑战。     

Preparation of Bowl-Like Polymer Particles via Multi-Step Emulsion Polymerization and Alkali Post-Treatment

Summary : Monodisperse P(BA-MMA-MAA-EGDMA)/P(St-MAA-DVB) core/shell latex particles were first synthesized by a four-step emulsion polymerization, and a new kind of latex particles with “bowl-like” morphology were obtained by post-treating the resultant core/shell particles under alkali condition. Results indicated that the feeding rates of the monomer mixture and initiator aqueous solution were the key parameters to obtain monodisperse core/shell latex particles in the emulsion polymerization process, and the latex particles with “bowl-like” morphology could be generated only when the treatment temperature was equal or higher than 70 °C.     

核壳乳液聚合法制备含氟硅丙烯酸酯乳液

以氟醇RfCH2CH2OH和乙烯基硅氧烷VTES为原料合成的氟硅单体,与甲基丙烯酸甲酯、丙烯酸丁酯在复合乳化体系中通过核壳乳液聚合制备了稳定的氟硅共聚乳液。对氟硅单体和氟硅丙烯酸酯共聚物的结构用红外光谱进行了表征,结果表明,得到了目标单体和共聚物。共聚物的TEM形态观察发现,乳胶粒子具有明显的核壳结构,平均粒径在125 nm左右。与丙烯酸酯共聚物相比,氟硅丙烯酸酯共聚物乳胶膜的吸水率降低至8.32%,热分解温度提高了23℃,耐溶剂性与氟硅单体的含量关系不大。     

核壳结构PAM-ZnS纳米杂化微球的制备研究

随着高新科技的发展,人们对材料的要求越来越高,纳米材料的研究和材料的杂化已成为材料发展的重点之一.近年来,有彬无机杂化材料因其具有可调的光、电、磁等特性而备受关注．有彬无机杂化材料的杂化尺度通常为纳米级,甚至小到分子水平,因而可实现不同组分性质结合于一体,并产生协同效应．纳米ZnS材料因具有热红外透明、荧光、磷光等特性已引起人们极大的兴趣,例如ZnS纳米颗粒量子点及其掺杂具有独特的光电性质,主要用于传感器和高分辨显示器．     

Fluorescent Polyurethane Nanocapsules Prepared via Inverse Miniemulsion: Surface Functionalization for Use as Biocarriers

The functionalization of well‐defined PU nanocapsules with an aqueous core prepared by performing a polyaddition at the interface of inverse (water‐in‐oil) miniemulsion droplets is demonstrated. The miniemulsion technique involving the nanoreactor concept allows one to obtain an encapsulation efficiency as high as 90% within the nanocapsules. A pH independent fluorescent dye is used as a model system for the aqueous core. By varying the molar ratio of the diol to the diisocyanate at a fixed surfactant concentration, the shell thickness of the nanocapsules can be finely tuned. The carboxy‐ and amino‐functionalized surface of the nanocapsules can be tailored by an in‐situ carboxymethylation reaction and by physical adsorption of a cationic polyelectrolyte, i.e. PAEMA or PEI. The increased uptake of amino‐functionalized fluorescent nanocapsules by HeLa cells clearly demonstrates the potential of the functionalized nanocapsules to be successfully exploited as biocarriers.

     

乳化剂在双重乳液合成含胰岛素纳米胶囊中的作用

Insulin entrapped nanocapsules to use polylactide （PLA） as the encapsulating material were prepared through a modified water-in-oil-in-water （W/O/W） emulsification and solvent evaporation method, The average particle size of PLA nanocapsules obtained was decreased to （181.5 ± 8.4） nm, and capably adjusted from 180 to 370 nm by using different types and content of nonionic emulsifiers. The influence of emulsifiers on property of nanocapsules was discussed in detail. The effects of spans and tweens to modify the size of the nanocapsules were different, which can be due to the distribution of the surfactants on the inner interface between the inner water and oil of the double emulsion. The encapsulation efficiency and drug release of nanocapsules were affected obviously by the content and type of emulsifiers.     

二氧化硅-聚丙烯腈核-壳结构复合纳米粒子的制备与表征

以甲基丙烯酸-3-(三甲氧基硅基)丙酯改性的SiO2纳米粒子为种子,采用乳液聚合法制备了粒径分布较窄的SiO2-聚丙烯腈(SiO2-PAN)核-壳结构复合纳米粒子。采用动态光散射、傅里叶红外光谱、透射电镜和扫描电镜表征了复合纳米粒子的粒径及分布、组成、形态和结构,并研究了表面活性剂的加入方式、反应温度及交联剂的引入对制备SiO2-PAN复合纳米粒子的影响。结果表明:SiO2-PAN复合纳米粒子为核-壳结构。采用半连续加入表面活性剂的方法,可以成功抑制乳液聚合中次级粒子的生成。通过增加表面活性剂的初始加入量、加快表面活性剂的补加速率,或降低反应温度,可使SiO2-PAN复合纳米粒子的粒径变小。反应温度的降低以及交联剂的引入使SiO2-PAN复合纳米粒子的表面变得平滑。     

Preparation and Optical Properties of Silica-Poly(ethylene oxide) Hybrid Materials

Structural evolution and optical properties of the silica-poly(ethylene oxide) hybrid films prepared from -glycidoxypropyltrimethoxysilane (GPTS) and 1-methylimidazol (MI) are studied. Polymerization of the epoxy groups is achieved by using 1-methylimidazol as a thermal curing agent. In liquid state ¹H &¹³ C NMR spectroscopy, it is found that silica condensation mainly occurs without epoxy ring opening. The epoxide polymerization is confirmed by using FT-IR, solid state CP-MAS ¹³C-NMR, and differential scanning calorimetry (DSC). The hybrid material is densified due to the epoxide polymerization as well as silica condensation with thermal curing. As a result, the thermal curing increases refractive index and extinction coefficient and shifts UV optical absorption edge to longer wavelength.     

Preparation of temperature-sensitive polymer particles having different lower critical solution temperatures

Preparation of temperature-sensitive core-shell composite polymer particles was carried out by seeded emulsion copolymerization of dimethylaminoethyl methacrylate and ethylene glycol dimethacrylate with submicron-sized polystyrene seed particles as core. The lower critical solution temperature (LCST) of the core-shell composite was about 35°C, while the LCST could be controlled toward higher or lower temperatures by copolymerizing the shell layer with hydrophilic/hydrophobic vinyl comonomer.     

萘基相互连接的多孔碳纳米囊的制备及超电容性能

以萘为碳源, 采用MgO模板诱导耦合KOH裁剪技术制备了相互连接的多孔碳纳米囊(ICNC). 结果表明所制备的ICNC₂具有大的比表面积(1811 m²/g)、 高的压实密度(1.38 g/cm³)和微孔孔容含量(58.93%). 在对称的超级电容器(SC)中, ICNC₂电极的体积比容在不同电流密度下分别高达420.8 F/cm³(0.069 A/cm³)和315 F/cm³(27.6 A/cm³), 容量保持率为74.82%. 在38 W/L功率密度下, ICNC₂基SC的体积能量密度为14.6 W?h/L. 经过20000次循环后, 其体积比容仅衰减1.4%, 库伦效率为99.1%, 为从萘基小分子制备储能用功能碳材料提供了一种可行的方法.     

聚甲基丙烯酸甲酯-氯化银复合纳米微球的制备及其摩擦学性能

采用原位种子乳液聚合法合成了聚甲基丙烯酸甲酯 氯化银(PMMA AgCl)核壳结构复合纳米微球,通过透射电镜(TEM),红外光谱(IR),热分析(TG DTA)和X射线粉末衍射(XRD)等测试手段对其结构及性能进行了表征.在四球试验机上对其摩擦学行为进行了考察,研究结果表明,PMMA AgCl核壳结构复合纳米微球用作润滑油添加剂具有良好的抗磨性能,能显著提高基础油的失效负荷.     

Antiseptic Nanocapsule Formation via Controlling Polymer Deposition onto Water-in-Oil Miniemulsion Droplets

The stable nanodroplet was prepared by inverse miniemulsion with an aqueous antiseptic solution dispersed in an organic medium of solvent/nonsolvent mixture containing an oil-soluble surfactant and the polymer for shell formation. The change in gradient of the solvent/nonsolvent mixture, obtained by heating at 50 °C, led to the precipitation of the polymer in the organic phase and deposition onto the large interphase of the aqueous miniemulsion droplets. The monodisperse polymer nanocapsule, with the size range of 80–240 nm, dispersed in cyclohexane phase was achieved as a function of surfactant concentration. By variation of polymer content, molecular weight and type, an encapsulation efficiency of 20–100% was obtained as detected by proton-nuclear magnetic resonance spectroscopy measurement. The nanocapsule could be easily transferred into water as continuous phase resulting in aqueous dispersion with nanocapsule containing the antiseptic agent as an aqueous core. The encapsulated amount of the antiseptic agent was evaluated to indicate the durability of the nanocapsule's wall. Additionally, the different types of polymer having glass transition temperature ranging from −60 to 100°C have been successfully used. Currently, the research work on the incorporation of nanocapsules onto natural rubber (NR) latex in order to prepare NR latex glove containing the antiseptic agent nanocapsules is carried out. By using the simple and versatile layer-by-layer (LbL) technique based mainly on an electrostatic interaction between oppositely charged species, the deposition of nanocapsules onto NR latex film has successfully been fulfilled.     

新型光敏聚酰亚胺/SiO2杂化材料的制备与性能研究

通过溶胶－凝胶法制备了一种新型的光敏聚酰亚胺／二氧化硅杂化材料。研究表明当ＳｉＯ２的含量≤１０ｗｔ％时杂化材料除了保持光敏聚酰亚胺原有的感光性能外其热稳定性能、力学性能以及与基底的粘附性能均有明显地提高,同时材料的热膨胀系数也显著地降低。     

Preparation of Ag‐Embedded Polystyrene Nanospheres and Nanocapsules by Miniemulsion Polymerization

An isopropyl myristate (IPM) biocompatible oil and an IPM solution of dodecanethiol‐capped Ag nanoparticles (NPs, 4.5 nm) were used as hydrophobes to suppress the Ostwald ripening of monomer/hydrophobe miniemulsified droplets in a surfactant‐stabilized water phase. The formation of non‐IPM‐encapsulated nanospheres (48 nm) and IPM‐encapsulated nanocapsules (90 nm) were precisely controlled by using a water‐soluble and an oil‐soluble initiator, respectively, in the presence of a pure IPM as a hydrophobe in miniemulsion polymerization. Well‐defined PS nanospheres, on which surfaces were coated with Ag NPs (Ag/PS nanospheres, 65 nm), and nanocapsules encapsulating both NPs and IPM liquid phase (Ag‐IPM/PS nanocapsules, 115 nm) were made by replacing the hydrophobe from pure IPM with Ag/IPM solution. These nanostructures were characterized by transmission and scanning electron microscopes.

     

聚硅氧烷/甲基丙烯酸甲酯核壳结构复合粒子的制备

聚硅氧烷/甲基丙烯酸甲酯核壳结构复合粒子的制备;种子乳液聚合;核壳结构     

Semicontinuous Emulsion Copolymerization of Vinyl Acetate and Butyl Acrylate Using Different Initiators and Different Chain Length Emulsifiers

The semicontinuous emulsion copolymerization of vinyl acetate and butyl acrylate (VAc/BuA) (85:15) initiated by thermal initiators ammonium persulfate (APS) and potassium persulfate (PPS) at 70°C in the presence of nonylphenol ethoxylates of varying chain lengths (NP-n) and acrylamide partially polymerized (Amol) was investigated. VAc-BuA copolymer latexes were synthesized as two different series in the glass reactor, in the first serie was initiated by APS and PPS was used as initiator in the second serie. The influence of the counterions or initiators and chain lenghts of non-ionic emulsifier on the properties of VAc-BuA copolymer latexes were determined by measuring Brookfield viscosities, weight average molecular weights (M̄_w), number average molecular weights (M̄_w), molecular weight distribution and surface tension of latexes to air. The results of copolymer latexes indicated that their physicochemical properties increased with the increasing chain length of nonionic emulsifier for two initiators.     

乳液聚合制备纳米银/聚苯乙烯核壳复合粒子

采用乳液聚合方法制备出纳米银／聚苯乙烯核壳复合粒子，并借助TEM、XPS、FTIR分析了其微观结构。研究了纳米银粒子存在下苯乙烯聚合反应转化率-时间关系，分析了纳米银／聚苯乙烯核壳复合粒子的形成机理。     

Preparation of Silica-Based Inorganic-Organic Hybrid Membrane via the Sol-Gel Route

Silica-based inorganic-organic hybrid membranes have been prepared on porous -Al₂O₃ substrate (pore size, 2 m) using tetraethoxysilane (TEOS) and phenyltrimethoxysilane (PTMOS) as precursors. The effects of sol synthesis conditions on the processing and performance of deposited hybrid layers were observed. The thickness of the hybrid layers after three deposition cycles is about 2 m, estimated from their cross-section SEM micrographs. The gas permselectivity of the hybrid membrane was characterized by O₂/N₂, CO₂/N₂, and CO₂/O₂ mixing gases, which was mainly governed by the surface diffusion at lower pressures and Knudson diffusion at higher pressures. The introduction of phenyl groups can not only improve the selectivity of O₂/N₂ and CO₂/N₂, but also densify the membrane network.