Physicochemical Properties and Phase Behavior of Didecyldimethylammonium Chloride/Alkyl Polyglycoside Surfactant Mixtures

Mixed surfactant systems, used in many formulations, have aroused great attention and interest from researchers and industry due to the possibility of synergism. Alkyl polyglycoside (APG) and didecyldimethylammonium chloride (DDAC) mixtures combine the excellent properties of pure surfactants and play an important role in the development of multi‐functional washing products. To study the synergism between APG and DDAC, the physicochemical properties of different mixed systems have been investigated. The critical micelle concentration (CMC) is about 180 mg·L^?1 and the surface tension at the CMC is about 26.0 mN·m^?1 at a mass fraction of 40 % DDAC (ω_DDAC40 %). The values are significantly lower than pure surfactants. The foaming property shows the best performance at ω_DDAC20 %. When the mass fraction of DDAC is 80 %, the mixture exhibits better wetting and emulsifying properties. Synergism was observed in surface tension, foaming and emulsifying properties, while the wetting ability and detergency exhibited no such effects. Phase behavior of the APG/DDAC/water ternary system has also been carried out by polarized optical microscope. The phase diagram is characterized by a micellar phase, a region where lamellar and micellar phases coexist and a lamellar phase.     

Zinc Corrosion in Acidic Solutions Containing Single and Mixed Surfactants

The influence of surfactant synergism on Zn corrosion inhibition in 0.1-M HCl aqueous solutions has been determined at room temperature. Solutions of single and mixed surfactants consisting of sodium dodecylsulfate (SDS) and N,N-dimethyldodecan-1-amine oxide (DDAO) in water and in 0.1-M HCl were also prepared at room temperature. Critical micelle concentration (CMC) data were obtained through surface tension measurements as a function of mixing composition. A regular solution model was considered to analyze CMC values. The interaction parameter (β), the composition of mixed micelles (x) and the activity coefficients (f) were estimated by a regular solution model for all amphoteric–anionic mixed systems. β Vvalues showed synergism for the binary mixtures of these solutions in the absence and presence of 0.1-M HCl at all investigated compositions. Zinc corrosion in single and binary SDS/DDAO mixed solutions at 5-mM total surfactant concentrations in the presence of 0.1-M HCl was also investigated at static and dynamic conditions. The weight loss data revealed corrosion inhibition activity obeyed the following order: binary (0.75 DDAO + 0.25 SDS) > binary (0.50 DDAO + 0.50 SDS) > single DDAO > single SDS, suggesting an enhancement in the corrosion inhibition activity of DDAO in the presence of a proper amount of SDS. Conductivity time measurements show a similar trend as that obtained by a weight loss method at (0.50 DDAO + 0.50 SDS). The results were illustrated on the basis of synergistic interaction between the mixed surfactants.     

二烷基二硫代氨基甲酸铁抗氧光敏剂配合体系及其应用研究

本文研究了二烷基二硫代氨基甲酸铁（ＦｅＤＲＣ），芳香酮和抗氧剂配合体系的组成，各组分的协同关系及其光降解聚乙烯的作用机理。结果表明，以ＦｅＤＲＣ配合体系为添加剂的聚乙烯地膜使用性能和光降解可控性良好，完全适全制造可控光降解聚乙烯的地膜。     

酸洗缓蚀协同机理研究与进展

概述了酸洗缓蚀协同的重要性。综述了国内外酸洗协同缓蚀剂的研究现状及协同作用的分类,根据研究应用的不同情况,列举了无机物与无机物之间、无机物与有机物之间、有机物与有机物之间的协同作用。并阐述了协同缓蚀机理及其发展趋势。     

Montmorillonite/graphene oxide nanocomposite as superior adsorbent for the adsorption of Rhodamine B and Nickel ion in binary system

A series of montmorillonite reduced graphene oxide (MrGO) composites were synthesized using different ratios (5, 10, 15 and 20) of montmorillonite (MMt) to GO. The synthesized composites were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface area analyzer (BET), and Fourier transform- infrared spectroscopy. The adsorption capacity and efficiency of the synthesised composites were examined towards removal of Rhodamine B (RhB) and Nickel ion (Ni²⁺). The results were compared with that of GO and commercial MMt clay. The kinetic sorption models were evaluated, and it was observed that sorption follows the pseudo-second-order kinetics. Adsorption isotherm was best fit into the Langmuir model (R²?=?0.996 for RhB & 0.957 for Ni²⁺). Among all the synthesized composites, MrGO-2, a composite of GO and montmorillonite with (1:10) ratio, showed maximum activity towards the adsorption of Rhodamine B and Ni²⁺ calculated to be 625?mg/g and 178?mg/g respectively at neutral pH condition. From the calculated ΔG⁰ (?3.99 & ?0.71?kJ?mol^?1), ΔH (28.6 & 4.61?kJ?mol^?1) and ΔS (?107.5 & ?17.8?J?mol^?1 K) values for RhB & Ni²⁺ respectively, it can be unambiguously inferred that the adsorption process was feasible, endothermic and exhibiting least randomness, respectively. The prepared MrGO composites showed good adsorption capacity towards efficient removal of RhB and Ni²⁺ in single as well as binary system.     

有关聚乙二醇抑制机理的不同看法——读郭东荣等同志的“聚乙二醇抑制机理研究”一文之后

郭东荣等同志提出聚乙二醇抑制机理之一是聚乙二醇与K~ 形成复合物而起作用,而本文认为是协同作用的结果,就是K~ 能使粘土表面的水化膜变薄,有利于聚乙二醇的吸附包被作用,从而有利于抑制泥页岩的分散。     

Cavitation Erosion Corrosion Behaviour of Manganese-nickel-aluminum Bronze in Comparison with Manganese-brass

The cavitation erosion corrosion behaviour of ZQMn12-8-3-2 manganese-nickel-aluminum bronze and ZHMn55-3-1 manganese-brass was investigated by mass loss, electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) and the cavitation damaged surfaces were observed by scanning electron microscopy (SEM). The results showed that ZQMn12-8-3-2 had better cavitation erosion resistance than ZHMn55-3-1. After the cavitation erosion for 6 h, the cumulative mass loss of ZQMn12-8-3-2 w...     

猪油中复合型抗氧化剂的研究

研究了几种没食子酸酯对猪油氧化的抑制作用，以及与其它物质的协同增效作用，考查了一定配比组成的复合型抗氧化中增效剂的配比，发现没食子酸辛酯与柠檬酸及蛋氨酸按一定配比组成的复合抗氧化剂，对猪油有良好的抗氧化活性，并有高效、低毒的特点。     

Bioethanol production from renewable polymer lichenan using lichenase from an alkalothermophilic Thermomonospora sp. and thermotolerant yeast

Biomass feedstocks available decentrally will be more commodious for localized biorefinery approach than the exhaustive large scale and centralized plants driven by cost intensive technology. Lichen is present in a wide range of habitats in a distributed manner. A maximum hydrolysis of 73%-76% for lichenan from Cetraria islandica, Usnea barbata and Parmelia sp. were obtained in 24 h using lichenase from an alkalothermophilic Thermomonospora sp. wherein the hydrolysis was 100% with commercial enzyme Accellerase™1000. The synergistic role of β-glucosidase in lichenan hydrolysis was demonstrated by the exogenous addition of β-glucosidase to Thermomonospora lichenase which resulted in complete hydrolysis. The hydrolysates of lichenan obtained using Accellerase or a cocktail of Thermomonospora lichenase and β-glucosidase when fermented with free cells of Saccharomyces at 40 °C produced an ethanol yield of 0.45 g/g-0.48 g/g with theoretical conversion efficiencies of 93%-96%. The Ca-alginate immobilized yeast cells were reused eight times at 40 °C with 100% fermentation efficiency.     

Response of phosphine-resistant mixed-age cultures of lesser grain borer,Rhyzopertha dominica (F.) to different phosphine-carbon dioxide mixtures

Mixed-age cultures of a phosphine-resistant strain of lesser grain borer, Rhyzopertha dominica (F.) were exposed to various concentrations of phosphine and phosphine plus 10, 20 and 30% carbon dioxide combinations (CO₂) for different time intervals at 25 °C to evaluate the comparative efficacy of admixtures of phosphine-CO₂. The mortality data of the mixed age cultures were recorded taking the adult count at weekly intervals for 8 weeks. Lethal concentrations were determined by probit analysis. Phosphine with carbon dioxide exerted significant synergistic effect on the mortality of mixed-age cultures at 4, 6 and 7 days of exposure, while individually phosphine or carbon dioxide did not show a raised increase in their response. The addition of 30% carbon dioxide to lower concentrations of phosphine over shorter exposures of 4 days showed better synergistic effect among the treatments. The present study revealed that CO₂ augmented the effect of phosphine thereby reducing the concentration and exposure time required to bring about significant mortality in the mixed-age cultures of R. dominica.