生物表面活性剂对堆肥中含烃有机质降解过程的影响

进行了将生物表面活性剂引入堆肥过程的实验研究。采用好氧堆肥法,模拟堆肥中石油烃污染,加入不同的生物表面活性剂发酵液对堆肥过程中的石油烃进行降解,将实验组与空白样进行对照,结果发现,生物表面活性剂的加入不仅可改善堆肥环境,提高堆肥效率,还对堆肥过程中石油烃的降解有促进作用。实验证明,鼠李糖脂发酵液的效果比莎梵婷发酵液的效果好。     

扩链改性对聚(3-羟基丁酸酯-co-4-羟基丁酸酯)性能的影响

以多苯基多亚甲基多异氰酸酯(PAPI)为扩链剂,采用熔融共混法扩链改性聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)]。使用凝胶渗透色谱、热失重分析仪、电子拉力机、毛细管流变仪、旋转流变仪等研究了PAPI添加量对P(3HB-co-4HB)的相对分子质量、热稳定性、力学性能以及流变性能的影响。结果表明,PAPI的使用能够提高P(3HB-co-4HB)的相对分子质量和熔体黏度,并能有效改善P(3HB-co-4HB)的热稳定性和力学性能,成功实现了对P(3HB-co-4HB)的扩链改性。PAPI的添加量为2.0phr时,体系综合性能最佳,其起始分解温度和最大分解温度分别比纯P(3HB-co-4HB)提高了16.7℃和11.4℃,其拉伸强度和断裂伸长率分别比纯P(3HB-co-4HB)提高了21%和218%。     

扩链改性对聚(3-羟基丁酸酯-co-4-羟基丁酸酯)性能的影响EI北大核心CSCD

以多苯基多亚甲基多异氰酸酯(PAPI)为扩链剂,采用熔融共混法扩链改性聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)]。使用凝胶渗透色谱、热失重分析仪、电子拉力机、毛细管流变仪、旋转流变仪等研究了PAPI添加量对P(3HB-co-4HB)的相对分子质量、热稳定性、力学性能以及流变性能的影响。结果表明,PAPI的使用能够提高P(3HB-co-4HB)的相对分子质量和熔体黏度,并能有效改善P(3HB-co-4HB)的热稳定性和力学性能,成功实现了对P(3HB-co-4HB)的扩链改性。PAPI的添加量为2.0phr时,体系综合性能最佳,其起始分解温度和最大分解温度分别比纯P(3HB-co-4HB)提高了16.7℃和11.4℃,其拉伸强度和断裂伸长率分别比纯P(3HB-co-4HB)提高了21%和218%。     

接枝层厚度对聚(N-异丙基丙烯酰胺)改性表面与蛋白质相互作用的影响

采用表面引发原子转移自由基聚合(ATRP)的方法制备了聚(N-异丙基丙烯酰胺)(PNIPAAm)改性表面,通过改变聚合时间进而调控表面接枝层厚度.水接触角和蛋白质吸附测试发现PNIPAAm改性表面的浸润性和对蛋白质吸附都具有一定的温度响应性,且随着PNIPAAm接枝层厚度的增加,该温度响应性有一定程度的增强.同时,纤维蛋白原和溶菌酶的吸附测试表明PNIPAAm改性表面对尺寸不同的蛋白质具有不同的温度响应性.     

Effects of surfactants on spinning carbon nanotube fibers by an electrophoretic method

Abstract

Thin fibers were spun from a colloidal solution of single-walled carbon nanotubes (SWNTs) using an electrophoretic method. Sodium dodecylbenzenesulfonate (NaDDBS) was chosen as a surfactant and showed good performance owing to its special chemical structure. The highest spinning velocity reached 0.5 mm s^?1. The resulting SWNT fibers had a tensile strength of 400 MPa and a conductivity of 355 S cm^?1. Their mechanical and electrical properties were markedly improved after adding NaDDBS as the dispersant in water.     

Effects of surfactants on spinning carbon nanotube fibers by an electrophoretic method

Thin fibers were spun from a colloidal solution of single-walled carbon nanotubes (SWNTs) using an electrophoretic method. Sodium dodecylbenzenesulfonate (NaDDBS) was chosen as a surfactant and showed good performance owing to its special chemical structure. The highest spinning velocity reached 0.5 mm s⁻¹. The resulting SWNT fibers had a tensile strength of 400 MPa and a conductivity of 355 S cm⁻¹. Their mechanical and electrical properties were markedly improved after adding NaDDBS as the dispersant in water.     

Effects of surfactants on size and structure of amylose nanoparticles prepared by precipitation

The present work investigated the influence of surfactants on size and structure of amylose nanoparticles (ANPs) prepared through precipitation. ANPs were fabricated using absolute ethanol containing surfactants (Tween80, Span80 and mixtures of Tween80 and Span80 with ratios of 25/75, 50/50 and 75/25, respectively) as non-solvents. The obtained ANPs were characterized using dynamic light scattering (DLS), scanning electron microscopy and X-ray diffraction. The results showed that surfactant type, concentration and hydrophilic–lipophilic balance (HLB) value had great impact on size of precipitated ANPs. The smallest ANPs with mean size of 155 nm determined by DLS were obtained by using 0.5% (in proportion of the amylose solution volume) of Tween80/Span80 mixture (HLB = 12.33). The precipitated ANPs possessed the V-type crystalline structure no matter whether using the surfactants or not.     

表面活性剂对TiO_2纳米晶体生长动力学的影响

采用水热法,分别以丙二酸、正丁醇、乙二胺为表面活性剂,研究3种体系下TiO2纳米晶体的生长过程。XRD结果显示3种体系下主要产物为锐钛矿TiO2;TEM和HRTEM结果表明在不同的生长阶段,纳米晶体的生长结构特点明显不同。分别采用定向生长理论(Orientation attachment,OA)、弗兰克尔收缩理论(Frenkel shrinking,SH)、奥斯特瓦尔德熟化理论(Ostwald ripening,OR)对3种体系下的晶体生长进行理论模拟,结果发现在丙二酸、乙二胺体系下晶体生长分为3个阶段:定向聚集生长、颗粒收缩、奥斯特瓦尔德熟化,且乙二胺体系下颗粒明显增大;但是在正丁醇体系下晶体生长仅显示明显的OR特征,不存在OA生长。理论和实验分析说明不同体系下晶体生长方式不同的主要原因是由于3种表面活性剂以及溶液pH值的不同作用。     

Effects of surfactants on the microstructure of porous ceramic scaffolds fabricated by foaming for bone tissue engineering

A porous scaffold comprising a β-tricalcium phosphate matrix and bioactive glass powders was fabricated by foaming method and the effects of surfactants as foaming agent on microstructure of scaffolds were investigated. Foaming capacity and foam stability of different surfactants in water firstly were carried out to evaluate their foam properties. The porous structure and pore size distribution of the scaffolds were systematically characterized by scanning electron microscopy (SEM) and an optical microscopy connected to an image analyzer. The results showed that the foam stability of surfactant has more remarkable influence on their microstructure such as pore shape, size and interconnectivity than the foaming ability of one. Porous scaffolds fabricated using nonionic surfactant Tween 80 with large foam stability exhibited higher open and total porosities, and fully interconnected porous structure with a pore size of 750-850 μm.     

Effects of surfactants on the particle morphology and self-organization of Co nanocrystals

A synthesis method based in the principles of the so-called polyol process has been developed to prepare Co nanocrystals of 5, 8 and 20 nm average diameter. The influence of stabilizers, as oleic and lauric acids, on the morphology and the self-assembled aggregates of the final Co nanocrystals has been analysed, as well as on their magnetic properties. Rather spherical Co nanoparticles were obtained using oleic and lauric acid, respectively, with 8 and 5 nm in diameter and narrow particle size distribution. The lauric acid, having a shorter chain length, seems to be more effective in coating the particles.     

Effects of mixed surfactants on the volatilization of naphthalene from aqueous solutions

The effects of mixed anionic-nonionic surfactants, Tween40-SDS (sodium dodecyl sulfate), Tween40-SDBS (sodium dodecylbenzene sulfonate), Tween20-SDS and Tween20-SDBS, on the solubility and volatilization of naphthalene from static aqueous solutions were investigated. The experiment results indicated that mixed anionic-nonionic surfactants can solubilize naphthalene synergistically, which was resulted from the reduction in critical micelle concentration (CMC) of the mixed surfactant and the increase in micellar partition coefficient (K(mc)) of naphthalene between micelles and aqueous phase. The synergistic effects of mixed surfactants resulted in further reduction in volatilization of naphthalene than that induced by single surfactant. A positive linear correlation was found between the synergistic solubilization ratio (DeltaS) and the synergistic inhibitory capacity on naphthalene volatilization (DeltaC) in the presence of mixed surfactants. Results from this study imply that mixed surfactants can be employed in environmental remediation to formulate the needed solubility and volatilization of volatile and semivolatile compounds in aqueous solutions.     

Reduction of hydrodynamic resistance by surfactants

Experimental results are given on reducing the hydrodynamic resistance in a flowing liquid by adding surfactants; the effects are ascribed to micelles.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 27, No. 4, pp. 682–686, October, 1974.     

表面活性剂对超滤膜表面改性的研究

采用三类表面活性剂对聚砜超滤膜进行表面改性．实验结果表明，非离子表面活性剂Ｔｗｅｅｎ２０效果最明显，改善了膜表面的亲水性，提高了通量．     

Effects of ionic surfactants on methane hydrate formation kinetics in a static system

This paper reports an experimental study of the kinetics of methane hydrate formation in the presence of ionic surfactants with equal carbon chain length, such as sodium dodecyl sulfate (SDS), dodecylamine hydrochloride (DAH), dodecyltrimethylammonium chloride (DTAC) and N-dodecylpropane-1,3-diamine hydrochloride (DN₂Cl). Methane hydrates were formed at 274 K with incipient gas pressure of 15 MPa in an unstirred isochoric/isothermal reactor containing aqueous solutions at different initial surfactant loadings. It was found that addition of DTAC had little effect on methane hydrate formation whereas SDS, DAH, and DN₂Cl had pronounced promoting effects. This result coincides with the fact that the Krafft point of DTAC is below 273 K and those of SDS, DAH, and DN₂Cl are near room temperature. At a given initial surfactant loading, the effectiveness of the surfactants for reducing the induction time of methane hydrate formation followed the order of SDS > DAH > DN₂Cl. SDS also gave higher hydrate growth rates than DAH and DN₂Cl. At 1000 and 2000 ppm, however, DN₂Cl gave slightly higher final methane uptake than SDS. It was also found that during the nucleation or induction period, addition of SDS, DAH and DN₂Cl instead of DTAC, considerably reduced methane mole fraction in the liquid phase. Possible promotion mechanisms of surfactants during the hydrate nucleation period were discussed.