聚氨酯乳液的改性及其应用研究

用丙酮法合成了固含量为35%的聚氨酯成膜乳液。主要考查了复合型软段对聚氨酯成膜乳液及其胶膜性能的影响,并考查了乳液在水性印刷油墨中的应用。结果表明,亲水基团-COOH质量分数达到1.5%,能保证乳液的力学稳定性;随着不同聚多元醇复配比例的变化,乳液的稳定性和黏度、聚氨酯胶膜的力学性能以及吸水性均呈规律性变化,所制备的水性聚氨酯油墨对PET薄膜的附着力好。     

聚乙烯用高性能水基喷码油墨的研制

将马来酸酐接枝改性的氯化聚丙烯树脂(CPP-g-MAH)溶于乙酸丁酯中,再加入由Tween-20和Span-80组成的复合乳化剂进行乳化,获得了稳定的CPP-g-MAH乳液。研究了CPP-g-MAH乳液、丙烯酸复配树脂RX、乙二醇以及表面活性剂Surfynol465的用量对喷码油墨体系稳定性和墨层在聚乙烯(PE)表面附着力的影响,确定了较佳的乳化条件为:Tween-20与Span-80质量比3:2,Tween-20与Span-80的总质量为CPP-g-MAH质量的12%。较佳的水基喷码油墨配方(以质量分数表示)为:CPP-g-MAH乳液30%,水溶性丙烯酸树脂RX2%,乙二醇15%,Surfynol4651.5%。在此条件下制取的水基喷码油墨在PE表面的附着力达1.04N/mm2,非常适合于PE制品表面的喷码打印。     

一种非离子表面活性剂的合成及其对涂布纸的脱墨效果

以月桂醇聚氧乙烯醚(AEO)与异佛尔酮二异氰酸酯(IPDI)为原料,合成了一种新型的非离子表面活性剂AEOIPDI-AEO(AIA),并用于分离回收涂布纸。以白度和残余油墨量为指标,考察AIA的较佳合成条件。采用傅里叶红外光谱和核磁共振氢谱对产物的结构进行表征。将AIA与其他表面活性剂进行复配,考察复配脱墨剂的脱墨效果。结果表明,AIA的较佳合成条件为:n(AEO_7)∶n(IPDI)=2∶1,反应温度(60±2)℃,反应时间2 h,脱墨体系的p H=8。结构表征表明合成的产物为目标产物。相比于市售脱墨剂,AIA脱墨剂对涂布纸具有良好的脱墨效果,而对于新闻纸和打字纸,脱墨效果相差不大。将AIA与脂肪醇聚氧乙烯醚硫酸钠按质量比为1∶2进行复配,制得的复配脱墨剂对涂布纸的白度达71.9%,残余油墨量仅为58.5 mm~2/m~2;将AIA与壬基酚聚氧乙烯醚按质量比为1∶2进行复配,制得的复配脱墨剂对涂布纸的白度达71.3%,残余油墨量仅为61.4 mm~2/m~2。     

Solubilisation of water in alkanes using nonionic surfactants

Nonionic surfactants are frequently used as emulsifiers in nonpolar oil + water systems and as solubilisation agents for oil in water, or vice versa. In the latter application the amount of, say, water that can be solubilised in nonpolar oil (to give microemulsion droplets) depends on: (a) the capacity of the micelles to incorporate water; and (b) the fraction of surfactant originally present as micelles. This paper is concerned with the single-phase water-in-oil (W/O) microemulsion regions enclosed by the haze and solubilisation boundaries at the oil-rich end of Shinoda-type phase diagrams. The systems studied contain the nonionic surfactant C₁₂H₂₅(OCH₂CH₂)₅OH (C₁₂E₅), normal alkane (heptane, decane or tetradecane) and water. Critical microemulsion concentrations (cμc) and droplet compositions for w/o microemulsions formed from C₁₂E₅ in alkane have been determined at phase boundaries over a range of temperatures. The results show how the maximum extent of water solubilisation is determined jointly by the cμc and the maximum droplet size for a given temperature. It appears that for larger (microemulsion) droplets, the cμc is determined by temperature rather than by droplet size. However, along part of the haze curves, aggregates form with only small amounts of water (less than four molecules per ethyleneoxy group on the surfactant head groups). For a given temperature, in the small range where either micelles or microemulsion droplets can exist, reverse hydrated micelles have much higher critical micelle concentrations (cmc) than the cμc of the larger microemulsion droplets.     

Study of nonionic surfactants on HVOCs removal from coacervate solutions using cocurrent vacuum stripping in a packed column

ABSTRACT

Cloud point extraction has been shown to be an effective technique to remove hydrophobic volatile organic compounds (HVOCs) from aqueous solution using nonionic surfactant. A cocurrent vacuum stripper is used to recover the surfactant in coacervate phase from extraction for economic viability. The solutions containing two series of aromatic and chlorinated HVOCs. Surfactants studied were alkyl phenol ethoxylates, secondary alcohol ethoxylates (AEs), and branched secondary AEs. From equilibrium measurements, the apparent Henry’s law constant (volatility) of the HVOCs in surfactant solution decreased with increasing HVOCs hydrophobicity due to solubilization of the HVOCs in micelles. The results showed that the mass transfer of HVOC decreases due to the solubilization enhancement of the HVOCs.     

Effect of hydrophilic group on thin film formation using redox-active surfactants with an azobenzene group

Thin films of organic pigments were prepared at higher than pH 1 by the contact plating method using an anionic surfactant (AZNa, first figure of this article (part c) (n = 4)) containing an azobenzene moiety. The effects of hydrophilic group of the surfactants on the rate of following reaction of the reduction product were studied by cyclic voltammetry. The positive shift of the reduction peak potential of AZNa compared to those of cationic and non-ionic surfactants was ascribed to higher rate of following reaction of reduction product due to the presence of the anionic hydrophilic group of the surfactant. The present investigation revealed that the anionic hydrophilic group accelerates the cleavage of the NN bond of the azobenzene group. This phenomenon enabled us to prepare the organic thin film at higher pH condition.     

Desorption of the surfactant from the particle surface during latex film formation

Properties of latex films are very dependent on the distribution of the surfactants in the film. It has been recognized that distribution itself depends on the desorption characteristics of the surfactant from the particle-water interface during film formation. This article deals with this problem of surfactant desorption in the particular situation of latex film formation. First, FTIR spectroscopic evidence is presented for desorption of hexadecyl pyridinium chloride (HPCI) in poly(2-ethyl hexyl methacrylate) (P2EHMA) latex films. Some consequences of desorption or non-desorption of various surfactants on the structure and properties of P2EHMA latex films are then presented. This concerns the crystallization of cationic surfactants, HPCI and hexadecyl trimethylammonium bromide (HTAB), in the films and the mechanical properties of films containing ethoxylated nonyl phenol with 10 ethoxy segments (NP10) or sodium dodecyl sulphate (SDS). In the last part, the determination of the fraction of SDS desorbing from the particle–water interface in a model poly(styrene–butyl acrylate–methacrylic acid) latex coalescing in water is described. Other methods for studying desorption are proposed.     

热熔型纸塑复合预涂膜的研制

以EVA弹性体为主体材料,配以适宜的增粘树脂及其他助剂,制成热熔胶粘剂并涂于BOPP或聚酯膜上,用于纸塑复合。讨论了各种基料对热熔胶软化点、熔融粘度的影响。该预涂膜性能优良,无毒无污染,复合工艺简单,可提高生产效率。     

Synthesis of TiO2 particles by reverse microemulsion method using nonionic surfactants with different hydrophilic and hydrophobic group and their photocatalytic activity

TiO₂ nanoparticles were prepared using hydrolysis of titanium tetraisopropoxide in W/O microemulsions consisting of water, nonionic Brij series surfactants with different hydrophilic and Tween series surfactants with different hydrophobic group, and cyclohexane. The properties of these particles were characterized by TEM, XRD, FT-IR, TGA and DTA. The photocatalytic degradation of p-nitrophenol has been studied in order to compare the photocatalytic activity of prepared nanosized titania. TiO₂ particles calcined at 500 °C have a stable anatase phase which has no organic surfactants and the product completely transforms into the anatase phase above 300 °C and the rutile phase begins to appear at 600 °C regardless of surfactants. The particles are shown to have a spherical shape and have an uniform size distribution but the shape becomes distorted with a decrease of hydrophilic group chain length according to rapid hydrolysis of water and titanium alkoxide. In addition, the crystallite size and crystallinity increase with a decrease of hydrophilic and hydrophobic group chain length and an increase of calcination temperature. The photocatalytic activity increases with an increase of hydrophilic and hydrophobic group length and the titania calcined at 500 °C shows the highest activity on the photocatalytic degradation of p-nitrophenol regardless of surfactants.