微乳液的研究进展及应用

综述了微乳液的形成机理、聚合机理、聚合方法、影响因素及其应用。详细介绍了单体浓度、引发剂、乳化剂、油相、反应温度等因素对乳胶粒子粒径、粒径分布、聚合物平均相对分子质量等的影响;从聚合机理和形成机理两个方面,比较了微乳液聚合与乳液聚合的差异;对正相微乳液聚合、反相微乳液聚合以及双连续相微乳液聚合的研究作了简要的介绍,指出了目前微乳液研究中存在的一些问题,对今后的研究发展方向进行了展望。     

微乳液聚合在钻井液中的研究进展

概述了微乳液的结构,形成机理以及微乳液聚合的基本原理。简单介绍了正相微乳液聚合、反相微乳液聚合以及双连续相微乳液聚合的研究,综述了微乳液聚合产品在钻井液中的应用。探讨了微乳液聚合存在的一些问题,并对今后的发展前景进行了展望。     

微乳液聚合研究进展

概述了微乳液的性质,并对国内外正相微乳液聚合、反相微乳液聚合、双连续微乳液聚合的研究进行了简要综述。     

助乳化剂对双连续微乳液聚合稳定性的影响

采用电导法确定单相微乳液的相区发现，水相分率＜18wt%为反相微乳液，水相分率在18－80wt%的区域是双连续相，水相分率大于80wt%则为正相微乳液区。利用高效的KMnO4-H2C2O4氧化还原引发体系引发双连续微乳液聚合，通过改变体系中助乳化剂的含量，考察了微乳液聚合的稳定性，得到了透明多孔的聚合物材料，并对双连续微乳液初始组成对聚合产物孔结构的影响进行了初步探讨。     

CO2和苯乙烯非平衡态等离子体连续引发聚合反应

利用自制等离子体引发聚合装置进行了ＣＯ２和苯乙烯（Ｓｔ）的等离子体连续引发聚合反应，并采用红外光谱、Ｘ射线光电子能谱和核磁共振谱对聚合产物的结构进行了表征。对比ＣＯ２／Ｓｔ等离子体引发聚合产物和常规方法聚合得到的聚苯乙烯的红外光谱图可以发现，前者在１...     

PHMS为反应性助稳定剂的苯乙烯细乳液聚合

以含氢聚硅氧烷(PHMS)为反应性助稳定剂,研究苯乙烯(St)细乳液聚合。表征了细乳液聚合产物的结构,探讨了PHMS与St接枝共聚反应机理,考察了不同体系聚合产物接枝量、接枝产物中PHMS的含量以及不同乳液聚合反应稳定性和乳胶耐盐稳定性。通过红外和核磁分析结果表明,除St均聚反应外,PHMS通过游离基加成反应与St生成了接枝共聚物。细乳液体系中,PHMS用量由5%质量分率增加到20%,聚合产物接枝量和接枝产物中PHMS质量百分比先增大后降低。当PHMS质量分率为10%时,聚合产物接枝量和接枝产物中PHMS质量百分比出现峰值,分别为73.35%和8.46%。与普通乳液聚合反应相比,细乳液聚合过程中凝胶量减少,细乳液聚合产物接枝量和接枝产物中PHMS质量分率的增加,乳胶耐盐稳定性增强。     

细乳液聚合法制备共聚物的研究

阐述了细乳液的反应机理、细乳液与传统乳液聚合的不同以及细乳液的应用、传统乳液的聚合机理,为以后进一步研究传统乳液聚合和细乳液聚合的相似与不同之处做好准备。该聚合方法在以后的研究和工业中可能会得到很大的应用。[摘要]阐述了细乳液的反应机理、细乳液与传统乳液聚合的不同以及细乳液的应用、传统乳液的聚合机理,为以后进一步研究传统乳液聚合和细乳液聚合的相似与不同之处做好准备。该聚合方法在以后的研究和工业中可能会得到很大的应用。     

超声辐照在乳液聚合中的应用

介绍了超声辐照乳液聚合与常规乳液聚合的差别、产生条件、聚合机理及聚合影响因素。     

碱溶性MAA／VAc共聚乳液的合成与研究

采用无种子全连续法和核／壳聚合工艺制备碱溶性MAA／VAc共聚乳液，讨论了聚合工艺、MAA的含量及反应时间对乳液聚合过程和性能的影响，并用IR表征了共聚物的结构。     

核壳结构乳液研究进展

综述了核壳乳液聚合的发展、聚合工艺及影响因素，并对比了核壳结构与其他结构乳液在性能方面的优缺点，而且阐述了核壳结构的不足以及发展前景。     

含离子液体的复配表面活性剂微乳液的电导性质

研究了CTAB和TritionX-100复配表面活性剂在氯仿作为溶剂时,增溶离子液体bmimBF(IL)时所形成非水微乳液的电导性质,并且与含水体系的微乳液作了比较,发现两者存在较大的差别.在非水微乳液中,随着离子液体质量分数的增加,体系经历了IL/O型微乳液、双连续相、O/IL微乳液三种状态,并且采用循环伏安法对此结论进行了验证.两种表面活性剂复配后,在IL/O型微乳液阶段电导率随着CTAB的摩尔分数(α)增大而增大,在双连续相和O/IL微乳液阶段,体系的电导率随着α增大而减小.在含水微乳液中,只出现O/W型微乳液,而且随着增溶水质量分数的增加电导率下降.增溶水量一定的情况下,电导率随着α值增大而增大.     

A new cationic surfactant N,N′-dimethyl-N-acryloyloxyundecyl piperazinium bromide and its pH-sensitive gels by microemulsion polymerisation

A piperazine-based cationic surfactant, N,N′-dimethyl-N-acryloyloxyundecyl piperazinium bromide (DAOUPB) was synthesised by a two-step procedure. The monomer was polymerised in two new microemulsion systems: (i) DAOUPB/water/methyl methacrylate (MMA):hydroxyethylmethacrylate (HEMA) and (ii) DAOUPB/water/acrylonitrile with ethyleneglycol dimethacrylate (EGDMA) as the crosslinking agent. Transparent solid polymeric materials were obtained by photo-initiated polymerisation of some of these microemulsion compositions. Most of the bicontinuous microemulsions investigated gelled within 10 min resulting in transparent solid polymers. The electron micrographs of the polymers obtained from microemulsion compositions containing MMA:HEMA did not show any micropores, while those obtained using acrylonitrile revealed the existence of open-cell type micropores and also of the bicontinuous nature of the system. The width of the bicontinuous structure (micropores) was about 33 nm in the dry state, with long and winding channels of random distribution. The swelling of the gels was highly sensitive to pH.     

New Interfacial Rheology Characteristics Measured Using a Spinning Drop Rheometer at the Optimum Formulation. Part 2. Surfactant–Oil–Water Systems with a High Volume of Middle-Phase Microemulsion

This article is a continuation of our first study on dilational interfacial rheology properties at optimum formulation for surfactant-oil–water systems at low surfactant concentration just above the cμc. Here, we have investigated a high content of middle-phase microemulsion with an optimum WIII phase behavior for a system containing sodium dodecyl sulfate, n-pentanol, and kerosene. A new oscillating spinning drop interfacial rheometer was used to measure the interfacial properties. The very low dilational elasticity moduli and phase angle found at or near hydrophilic–lipophilic deviation (HLD) = 0 are related to the presence of the bicontinuous phase microemulsion and to the fast surfactant exchanges between the bulk and the interface, regardless of the phases involved in the measurement using the spinning drop apparatus, i.e., the two-phase excess oil and excess water (O-W) or the bicontinuous microemulsion and excess water (M-W). We show that at or near optimum formulation, the interfacial tension and the dilational modulus for the M-W case almost instantly reach equilibrium, because of the high surfactant content in the microemulsion and the fast exchanges between the bulk and the interface. In contrast, when both excess phases (O-W) are measured, the changes in these properties are slower, due to the scarce presence of surfactants in both phases. The possibility of having almost all the surfactants trapped in the middle-phase bicontinuous microemulsion could explain the emulsion instability in all the WIII range. This is behaving as if there were no surfactant available in the oil and water phases to stabilize the oil or water droplets thus formed.     

Phase behavior of a sodium dodecanol allyl sulfosuccinic diester/n‐pentanol/methyl acrylate/butyl acrylate/water microemulsion system and preparation of acrylate latexes by microemulsion polymerization

Pseudoternary phase diagrams of quaternary microemulsion systems composed of the reactive surfactant sodium dodecanol allyl sulfosuccinic diester, n‐pentanol, methyl acrylate/butyl acrylate, and water were made. The influence of the mass ratio of sodium dodecanol allyl sulfosuccinic diester to the cosurfactant (n‐pentanol) in the system and the influence of electrolyte sodium chloride on the microemulsion area were examined. The microstructure of the microemulsion was determined with a conductance technique. The results suggested that there were three structures in the microemulsion system: water in oil, oil in water, and a bicontinuous phase. Microemulsion polymerizations were carried with some point in the microemulsion region being chosen as the formulation. The structure and configuration of the polymer latexes were determined and analyzed with Fourier transform infrared, differential scanning calorimetry, and scanning electron microscopy. The results suggested that the reactive surfactant could participate in the polymerization with the monomers to some extent; the glass‐transition temperature of the latex was ?31.4°C. The polymer latex was transformed gradually from an open porous structure to a closed porous structure when its pregnant microemulsion was varied from a bicontinuous structure to an oil‐in‐water structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Formation of microporous polymeric materials by microemulsion polymerization of methyl methacrylate and 2-hydroxyethyl methacrylate

The investigated microemulsion system consisted of methyl methacrylate, 2-hydroxyethyl methacrylate and water using sodium dodecyl sulphate as surfactant. Ethylene glycol dimethacrylate acting as a cross-linker was also incorporated to enhance the mechanical strengths of the microporous polymeric materials. The polymerization was carried out at room temperature using a reactive redox initiator comprising ammonium persulphate and N,N,N′,N′-tetramethylethylene diamine. The conductivities of the microemulsion samples were monitored during the course of polymerization. The conductivities for a bicontinuous microemulsion before and after polymerization were found to be very similar. In addition, the transformation of microstructures was also examined using a transmission as well as a field emission scanning electron microscope. It is evidenced from the micrographs that microporous polymeric materials prepared from bicontinuous microemulsion polymerization are attributed to numerous coagulations of spherical particles. A possible mechanism for the microstructural transformation is discussed based on the information of conductivity measurements and electron micrographs. © 1996 John Wiley & Sons, Inc.     

吐温-80/正丁醇/环己烷/水系微乳液性能及对木材的渗透能力

考察了吐温-80/正丁醇/环己烷/水系微乳液各组分及其质量比对其形成的影响,通过电导率、表面张力和动态光散射(DLS)表征体系的物化性质。结果表明,以吐温-80为表面活性剂,正丁醇为助表面活性剂,环己烷为油相形成的微乳区较大。微乳体系的电导率随含水量的增加呈现规律性变化,可以判断微乳液的3种类型(油包水型、双连续型和水包油型);不同类型的微乳液均具有较低的表面张力(约24.6 mN/m)和粒径(小于100nm),且粒径随体系含水量的增加而增大。此外,采用液体吸收法考察了微乳液对木材的渗透能力,与普通溶剂相比,微乳液具有很强的渗透能力,特别是对于双连续型微乳液,10 min时,对马尾松和桉木的渗透能力分别达70%和50%。     

添加剂对烷基糖苷微乳液相图的影响

通过实验绘制了烷基糖苷(APG)微乳液的拟三元相图,发现少量的离子型表面活性剂能够使APG形成的单相微乳液区域变大。氯霉素、硼酸 /硼酸钠的缓冲溶液、NaCl以及洁而灭对微乳液区域影响非常小;透明质酸钠使微乳液相图区域减小,双连续的微乳液区域消失,这可能是因为透明质酸钠在油水中分配得不均匀,油包水型向双连续型微乳液过渡时,水含量增加,同时透明质酸钠的含量增加,油核里很难包结这种大分子,因此,微乳液被破坏。硼酸 /硼酸钠缓冲溶液的加入有助于提高氯霉素的稳定性。     

Effect of the molecular weight of the homopolymers on the morphology in ternary blends of polystyrene, polyisoprene, polystyrene-block-polyisoprene copolymer

Three nearly symmetrical ternary systems made of ternary blends of polystyrene, polyisoprene, polystyrene—block—polyisoprene copolymer have been investigated by small angle X-ray scattering (SAXS). The molecular weights of the homopolymers were varied, keeping the diblock length constant, to obtain ratios of homopolymer to diblock length, α, of 0.19, 0.38 and 0.74. For all experimental phase diagrams determined, a phase transition from lamellar to bicontinuous microemulsion, and then macroscopic phase separation have been observed with increasing homopolymer content. In addition, for α=0.38 and 0.74, a region of coexistence of bicontinuous microemulsions and lamellae, between the periodically ordered phase (lamellar) and the channel of microemulsion is reported at low temperature, which transform into a pure bicontinuous microemulsions at a higher one. For α=0.74, the concentration at which the macroscopic phase separation occurs is lower than the one obtained with α=0.19 and 0.34, suggesting that, as the molecular weight of the two homopolymers is increased, the microemulsion morphology becomes less stable. The thermal fluctuations begin to destroy the microemulsion morphology in favour of macroscopic phase separated system. This observation is further confirmed by the study of the variation of the d-spacing for the lamellar phase, where no wetting of the diblock monolayers was noticed for α=0.74 as compared to α=0.19 and 0.38.