高固含量丙烯酸酯无皂乳液的研制

以甲基丙烯酸甲酯(MMA)为硬单体、丙烯酸丁酯(BA)为软单体、丙烯酸(AA)为功能单体和过硫酸铵为引发剂,采用不同的反应性乳化剂合成了固含量为50%～60%的丙烯酸酯无皂乳液。讨论了反应性乳化剂的种类及用量对无皂乳液性能及粒径等影响。结果表明:当反应温度为80～85℃、反应性乳化剂为烯丙氧基壬基酚聚氧乙烯硫酸铵(DNS-86)且w(DNS-86)=4%～5%时,无皂乳液的固含量高达60%左右、凝胶率几乎为零且粒径相对较小。     

纳米级PU-PMMA LIPN的制备与结构研究

以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMG)、聚醚多元醇(PPG3010)、二羟甲基丙酸(DMPA)等为主要原料,甲基丙烯酸甲酯(MMA)为降粘剂合成了聚氨酯(PU)-MMA乳液;采用无皂原位乳液聚合的方法,MMA在PU-MMA乳液内部聚合,制备了纳米级的PU-聚甲基丙烯酸甲酯(PMMA)乳液互穿聚合物网络(LIPN)。对PU-PMMA复合乳液的结构、乳胶粒子粒径、成膜后PU和PMMA两相的相容性进行了讨论。结果表明,PU-PMMA复合结构已经形成;乳胶粒子的粒径分布多在20 nm,由于比表面积较大,部分小粒径粒子发生了团聚;复合体系只有一个Tg且介于PU和PMMA的Tg之间;成膜后PU和PMMA的相畴小于50 nm。     

多级结构PHB基电纺纤维膜的制备及性能研究

以聚β-羟基丁酸酯(PHB)为基体,左旋聚乳酸(PLLA)和聚氧乙烯(PEO)为第二组分,采用多层静电纺丝法制备了三层复合的PHB/PLLA/PHB,PHB/PEO/PHB,PHB/PLLA/PEO多级结构PHB基纤维膜,研究了多级结构PHB基纤维膜的形貌、结晶行为、热性能和亲水性能。结果表明:多级结构纤维膜中PHB组分的平均直径为770~790 nm,PEO的平均直径为280~290 nm,PLLA的平均直径为400~410 nm;PHB,PLLA组分在多级结构纤维膜中的晶型均为α晶型,PEO组分为单斜晶型,多级结构PHB基纤维膜中各组分的热性能没有受到影响;多级结构纤维膜的亲水性由强到弱的顺序依次为PHB/PEO/PHB纤维膜、PHB/PEO/PLLA纤维膜、PHB/PLLA/PHB纤维膜、PHB纤维膜,多级结构可改善PHB电纺纤维膜的亲水性。     

高固含量无皂乳液聚合技术研究进展

综述了国内外采用水溶性单体共聚、用反应性表面活性剂或大分子乳化剂代替常规小分子乳化剂制备稳定高固含量无皂乳液的有效方法。     

纳米二氧化硅改性硅丙无皂乳液稳定性影响因素研究

采用无皂乳液聚合技术和溶胶凝胶技术,合成了纳米二氧化硅改性硅丙无皂乳液。考察了反应温度、引发剂用量、反应性乳化剂用量、丙烯酸用量和正硅酸乙酯(TEOS)用量对乳液稳定性的影响。研究结果表明:当过硫酸钾(KPS)的质量分数为1%,反应性乳化剂的质量分数为3.5%,丙烯酸的质量分数为3%,反应温度为80℃时,乳液的聚合稳定性好,单体转化率高;当TEOS的质量分数小于4%,乳液具有较好的机械稳定性。     

亲水性PEO/PSF复合膜的制备与性能研究

以聚砜(PSF)作为膜材料,再以聚乙烯吡咯烷酮(PVP)为致孔剂,聚氧化乙烯(PEO)为添加剂,N,N-二甲基乙酰胺(DMAc)为溶剂,通过浸没沉淀相转化法制备了一系列的PEO共混改性的PSF复合超滤膜。通过杯式超滤器,接触角测量仪,扫描电镜(SEM),红外光谱仪(FTIR)等表征手段探究了PEO的加入对复合膜性能的影响。结果表明,PEO的加入显著改善了膜的亲水性能和超滤性能。在PEO质量分数为0.8%时,改性的PEO/PSF复合膜性能最佳,纯水通量达到161.12 L/(m^2·h),对BSA溶液的截留率为99.05%。     

PE-g-PEO/PEO共混体系的相容性及结晶行为研究

利用傅里叶红外光谱(FTIR)对聚乙烯(PE)接枝聚氧化乙烯(PEO)共聚物(PE-g-PEO)进行结构表征。采用溶液共混方法制备了PE-g-PEO/PEO共混物,采用偏光显微镜、差动热分析仪(DSC)等对比分析了PE-gPEO/PEO和PE/PEO共混物的相容及结晶性。结果表明,共混物的相容性与其组成有关,在PE-g-PEO与PEO共混质量比为9∶1时相容性最好。PEO质量分数超过70%时室温下能观察到球晶的生长过程。PE-g-PEO/PEO共混体系的相容性比PE/PEO好,PE-g-PEO在共混过程中起到了增容剂的作用。     

高固含量低黏度丙烯酸酯无皂乳液聚合的研究

采用半连续种子乳液聚合方法,利用可聚合的反应性乳化剂和非离子乳化剂复配,以丙烯酸酯为共聚单体,以过硫酸铵为引发剂,制备了高固含量且低黏度的丙烯酸酯无皂乳液。同时,采用正交试验方法,对聚合反应过程中的相关因变量进行了选优分析。     

苯乙烯-甲基丙烯酸甲酯无皂核壳乳液合成及表征

采用溶液聚合法制得苯乙烯(St)与苯乙烯磺酸钠(NaSS)共聚物的种子乳液,将其用于甲基丙烯酸甲酯(MMA)的无皂种子乳液聚合,制得了一系列不同核壳单体配比的核壳乳液.通过对溶液聚合动力学、产物的结构与相对分子质量、种子粒径以及将其用于乳液聚合时所得产物的结构与粒子形态分析,结果表明:以溶液聚合法制得的苯乙烯型种子乳液能成功制备无皂核壳乳液,从而为制备无皂核壳乳液提供了新的途径.     

反应性乳化剂对苯丙乳液合成及性能的影响

在反应性阴离子乳化剂[甲基丙烯酸羟丙磺酸钠(HPMAS)]的作用下,采用甲基丙烯酸甲酯(MMA)、苯乙烯(St)、丙烯酸丁酯(BA)和丙烯腈(AN)为主单体,丙烯酸(AA)为功能性单体,合成了性能优异的无皂苯丙乳液。研究了软硬单体配比、乳化剂、链转移剂和引发剂用量对乳液性能的影响。研究结果表明,合成无皂苯丙乳液的适宜条件(相对于单体总质量而言)是:w(HPMAS)=4%,w(引发剂)=0.8%,w(链转移剂)=2%且前期加入。     

Drag reduction in turbulent pipeline flow of mixed nonionic polymer and cationic surfactant systems

Turbulent drag reduction behaviour of a mixed nonionic polymer/cationic surfactant system was studied in a pipeline flow loop to explore the synergistic effects of polymeric and surfactant drag reducing additives. The nonionic polymer used was polyethylene oxide (PEO) at three different concentrations (500, 1000, and 2000 ppm). The surfactant used was cationic octadecyltrimethylammonium chloride (OTAC) at concentration levels of 1000 and 2500 ppm. Sodium salicylate (NaSal) was used as a counter‐ion for the surfactant at a molar ratio of 2 (MR = Salt/OTAC = 2). Relative viscosity and surface tension were measured for different combinations of PEO and OTAC. While the relative viscosities demonstrated a week interaction between the polymer and the surfactant, the surface tension measurements exhibited negligible interaction. The pipeline results show a considerable synergistic effect, that is, the mixed polymer–surfactant system gives a significantly higher drag reduction (lower friction factors) as compared with pure polymer or pure surfactant. The addition of surfactant to the polymer always enhances drag reduction. However, the synergistic effect in mixed system is stronger at low polymer concentrations and high surfactant concentrations. © 2011 Canadian Society for Chemical Engineering     

Synergistic effect of polymer-surfactant mixtures on the stability of aqueous silica suspensions

The aim of the present work was to investigate the effect of cationic/nonionic surfactant mixtures on the dispersion and flocculation behavior of aqueous silica suspensions. In the study dodecylamine (DDA) was used as the cationic surfactant and polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO–PPO–PEO) triblock copolymers were employed as the nonionic surfactant. The dispersion and flocculation behavior of aqueous silica suspensions were studied mainly by turbidity measurements at low solids loading (0.05 vol.%) to observe the stability of the system for a given time period. Rheological measurements were performed at higher solids loadings to determine the viscosity as a function of shear rate. Adsorption behavior of single and mixed surfactants onto silica surface was studied using a total organic carbon analyzer.Results of the study showed that dispersion and flocculation behavior of aqueous silica suspensions depends on the type and concentration of surfactant, cationic/nonionic surfactant ratio and surfactant addition sequence to the system.     

Poly(ethylene oxide)–polyelectrolyte blends: viscometric and thermal analysis behaviour

The miscibility of binary poly(ethylene oxide) (PEO) and sodium poly(4‐styrene sulphonate) (PSS) or [3,6]‐ionene (ION) systems, was analysed in aqueous solutions and in the solid state by viscometry and thermal analysis, respectively. Both techniques indicate partial miscibility of PEO–PSS and immiscibility of PEO–ION blends. In water solution, the partial miscibility of the PEO–PSS system is probably due to the counterion Na⁺ which can partially provide the driving force association in a similar manner to that observed for PEO–surfactant systems. In blend films, the PEO–polyelectrolyte interaction is also analysed in terms of the effect on the PEO crystallization observed through optical microscopy, and the results indicate compatibility between the components in the PEO–PSS system. © 2000 Society of Chemical Industry     

Kinetics of oil dispersion in the absence and presence of block copolymers

A phenomenological model proposed describes droplet breakup in the turbulently agitated lean oil-in-water dispersions and provides a correlation between the median droplet size in an agitated vessel of standard geometry and the time of dispersion. It was assumed that the droplet breakup takes place in the dispersion-only region and coalescence is negligible. The model described the data from this study and the literature quite satisfactorily under these conditions. The effect of adding triblock PEO/PPO/PEO copolymeric surfactants on the dispersion kinetics of oil was also investigated. Addition of surfactant reduced the median oil droplet size significantly, and the extent of this reduction was a strong function of surfactant concentration. Application of the model on these data demonstrated that the change in the median droplet size could be divided into two distinct regions. The breakage rate was high initially, most probably due to continuous adsorption of surfactant molecules at the oil/water interface. A lower breakage rate was attained at longer times, as the surfactant molecules were depleted from the solution. The time of transition between the two was affected strongly by the concentration of the surfactant added. Furthermore, the time of addition of the surfactant did not affect the final droplet-size distribution in the system.     

Self-Assembly of Polyethylene Glycol Ether Surfactants in Aqueous Solutions: The Effect of Linker between Alkyl and Ethoxylate

The aqueous self-assembly behavior of two homologous series of poly(ethylene oxide) (PEO)-containing nonionic surfactants based on a C₁₀-Guerbet hydrophobe is reported. The two families of surfactants, alkyl ethoxylates and alkyl alkoxylates, are commercially available from BASF under the trade name Lutensol® XP-series and XL-series, respectively. The latter incorporate propylene oxide (PO) units in the surfactant chain. Dye solubilization was used to determine the critical micellization concentration (CMC) of each surfactant at 22 and 50 °C. The PO-containing alkyl alkoxylates displayed lower CMC values, which were also more sensitive to temperature. The Gibbs free energy, enthalpy, and entropy of micellization were computed from the CMC data and used to identify the contribution of each surfactant moiety (alkyl chain, PO unit, and PEO block) in controlling the CMC. The micellization properties are compared with compositionally similar surfactants with linear alkyl chains, yielding information about the effects of the Guerbet alkyl chain on micellization. Isothermal titration calorimetry was also used to characterize the CMC and enthalpy of micellization which generally compare well with the dye solubilization results. Cloud point data reveal nonmonotonic relationships for the Lutensol® surfactants with respect to composition, unlike linear alkyl chain surfactants. Finally, dilute solution viscosity measurements performed on some Lutensol® surfactants show a change in the slope, suggesting a structural change that tends to be more pronounced for surfactants with longer PEO blocks. The data presented herein enhance the understanding of surfactant structure–property relationships required for industrial formulation.     

Melt spinning of silane–water cross-linked polyethylene–octene through a reactive extrusion process

The aim of this study is to produce silane–water cross-linked polyethylene–octene (PEO) fibers through a reactive extrusion process. First, PEO is silane-grafted during an extrusion process followed by a spinning step. Then, grafted PEO monofilaments are introduced in water-based solution to perform cross-linking. The influence of process parameters on bulk PEO cross-linking degree was first investigated through a mixture design methodology which revealed that the most influent parameters are extrusion temperature and time. Using these results and the response surface methodology, silane–water cross-linked PEO monofilaments could be produced with desired gel contents after proceeding to some adjustments of processing parameters. The influence of cross-linking degree and draw ratio on macroscopic properties of PEO monofilaments was investigated. In particular, the cross-linked PEO fibers thermomechanical stability increases with cross-linking degree up to 170 °C for cross-linking degrees higher than 55%. Moreover, cross-linked PEO fibers exhibit higher elastic properties than neat PEO fibers.     

Synthesis,structural, and electrochemical performance of V<Subscript>2</Subscript>O<Subscript>5</Subscript> nanotubes as cathode material for lithium battery

Various vanadium oxide nanostructures are currently drawn interest for the potential applications of Li batteries, super capacitors, and electrochromic display devices. In this article, the synthesis of V₂O₅ nanotubes by hydrothermal method using 1-hexadecylamine (HDA) and PEO as a template and surface reactant were reported, respectively. The structural properties and electrochemical performances of these nanostructures were investigated for the application of Li batteries. Structure and morphology of the samples were investigated by XRD, FTIR, SEM, and TEM analysis. The battery with V₂O₅ nanotubes electrode showed initial specific capacity of 185 mAhg⁻¹, whereas the PEO surfactant V₂O₅ nanotubes exhibited 142 mAhg⁻¹. It was found that PEO surfactant V₂O₅ nanotubes material showed less specific capacity at initial stages but better stability was exhibited at higher cycle numbers when compared to that of V₂O₅ nanotubes. The cyclic performance of the PEO surfactant material seems to be improved with the role of polymeric component due to its surface reaction with V₂O₅ nanotubes during the hydrothermal process.     

Study of interfacial tension in poly(ethylene oxide)/polystyrene/diblock copolymer system by electric deformation method

We investigated the interfacial tension γ between poly(ethylene oxide) (PEO) and polystyrene (PS) focusing our attention on the dependence of γ on the molecular weight (M) of PEO and the surfactant effect of poly(ethylene oxide-b-styrene) diblock copolymer [P(EO-b-S)]. Measurements of γ were carried out by observing electric deformation of droplets of PEO suspended in bulk PS or in a concentrated solution of PS in dioctylphthalate (DOP). The results indicate that γ between PEO and PS is almost independent of M of PEO in the high molecular weight region, but exhibits a minimum around M = 500. Addition of 1 wt% of P(EO-b-S) to the PEO/PS system causes a decrease of γ due to the surfactant effect of the copolymer, but γ is almost independent of further addition of the copolymer. The decrement of the interfacial tension Δγ increases with increasing molecular weight of P(EO-b-S).     

Composite natural rubber based latex particles: a novel approach

The oil resistance of natural rubber (NR) film could be effectively improved by using the heterocoagulation of large NR particle with small polychloroprene (CR) particles. In the preparation of NR/CR composite particle with a core-shell structure, a nonionic surfactant whose molecule bears poly(ethylene oxide) (PEO) was adsorbed on CR particles and allowed to form complexes between PEO and indigenous surfactant (protein-lipid) on the NR particle surface. Composite latex particle obtained was characterised by particle size, zeta potential and glass transition temperature measurements and the data indicated the presence of CR on the outer layer of composite particle. Better oil resistance of film casted from heterocoagulated latex when compared to that of NR film confirmed the NR/CR core-shell structure. The epoxidised natural rubber (ENR), crosslinked ENR and/or skim latex particles were investigated in order to replace the use of CR in the heterocoagulation process.     

Influence of Nonionic Surfactant on Hydrolysis of Vinyl Sulfone Reactive Dye

Nonionic surfactants are widely used in reactive dyeing processes, and the interaction between surfactants and reactive dyes affect the hydrolytic property of reactive dyes. In this study, reactive brilliant blue KN‐R (C.I. reactive blue 19) was employed as a model dye, and fatty alcohol polyoxyethylene ether (AEO‐9) was selected as a model nonionic surfactant. The interaction was first investigated in aqueous solutions by a UV‐spectrophotometry method, then the effect of surfactant concentration on the hydrolytic behavior of KN‐R was studied using high performance liquid chromatography method. Below the critical micelle concentration, the surfactant served as dispersant; the hydrolysis of reactive dye was accelerated. However, when the concentration of surfactant was above its critical micelle concentration, the dye was solubilized into the micellar phase, which was revealed from the changes in absorbance intensity and wavelength of the maximum absorbance. This led to slowed hydrolysis of reactive dye. These findings are useful in understanding the effect of concentration of nonionic surfactant on the hydrolysis of vinyl sulfone reactive dyes.