Nano fibrillated cellulose-based foam by Pickering emulsion: Preparation,characterizations, and application as dye adsorbent

An ecofriendly and biodegradable porous structure was prepared from drying aqueous foams based on nano fibrillated cellulose (NFC), extracted from softwood pulp by subcritical water/CO₂ treatment (SC-NFC). The primary aim of this work was to use the modified SC-NFC as stabilizer for a water-based Pickering emulsion which upon drying, yielded porous cellulosic materials, a good dye adsorbent. In order to exploit the carboxymethylated SC-NFC (CMSC-NFC, with a degree of substitution of 0.35 and a charge density of 649 μeqv/g) as a stabilizer for water-based Pickering emulsion in subsequent step, an optimized quantity of octyl amine (30 mg/g of SC-NFC) was added to make them partially hydrophobic. A series of dry foam structures were prepared by varying the concentrations of treated CMSC-NFCs and 4 wt% was found to be the optimum concentration to yield foam with high porosity (99%) and low density (0.038 g/cc) along with high compression strength (0.24 MPa), superior to the conventionally extracted NFC. The foams were applied to capture as high as 98% of methylene blue dyes, making them a potential green candidate for treating industrial effluent. In addition, the dye adsorption kinetics and isotherms were found to be well suited with second order kinetics and Langmuir isotherm models.     

Interfacial Crystallization of Diacylglycerols Rich in Medium‐ and Long‐Chain Fatty Acids in Water‐in‐Oil Emulsions

The effects of diacylglycerols rich in medium‐ and long‐chain fatty acids (MLCD) on the crystallization of hydrogenated palm oil (HPO) and formation of 10% water‐in‐oil (W/O) emulsion are studied, and compared with the common surfactants monostearoylglycerol (MSG) and polyglycerol polyricinoleate (PGPR). Polarized light microscopy reveals that emulsions made with MLCD form crystals around dispersed water droplets and promotes HPO crystallization at the oil‐water interface. Similar behavior is also observed in MSG‐stabilized emulsions, but is absent from emulsions made with PGPR. The large deformation yield value of the test W/O emulsion is increased four‐fold versus those stabilized via PGPR due to interfacial crystallization of HPO. However, there are no large differences in droplet size, solid fat content (SFC), thermal behavior or polymorphism to account for these substantial changes, implying that the spatial distribution of the HPO crystals within the crystal network is the driving factor responsible for the observed textural differences. MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals to enhance the rigidity of emulsion. This study provides new insights regarding the use of MLCD in W/O emulsions as template for interfacial crystallization and the possibility of tailoring their large deformation behavior. Practical Applications: MLCD is applied in preparing W/O emulsion. It is found that MLCD forms unique interfacial Pickering crystals around water droplets, which promote the surface‐inactive HPO nucleation at the oil‐water interface. Thus MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals, which can greatly enhance the rigidity of emulsion. This observation would provide a theoretical reference and practical basis for the application of the MLCD with appreciable nutritional properties in lipid‐rich products such as whipped cream, shortenings margarine, butter and ice cream, so as to substitute hydrogenated oil. MLCD‐stabilized emulsions can also be explored for the development of novel confectionery products, lipsticks, or controlled release matrices.     

低空间频率银盐明胶全息图的浮雕特性研究及其应用

通过实验研究表明，对低空间频率的振幅型银盐全息图形表面已形成浮雕，经漂白，浮雕深度成倍加深；浮雕深度随空间频率而变化，并且可用不同曝光量进行调制。选择适当条件，可降低零级光强，提高全息图的一级衍射效率。     

乳胶厚度对卤化银反射全息图衍射特性的影响

实验研究了自制的超细颗粒卤化银乳剂SDUF－1分别在AAC显影、改进的R－10漂白处理及改进的GP－8溶解物理显影处理条件下，其乳胶厚度对反射全息图衍射特性的影响。实验结果表明，在这两种不同处理条件下衍射效率与胶厚的关系有相当大的差别，合适的乳胶厚度分别为12μm和6μm左右。     

Characterization of the flow behaviour of sausage emulsions with a simple tube viscometer

A specially designed tube viscometer was used to measure apparent viscosity during flow of Bologna type sausage emulsions moving through a pipe. Emulsions varied in fat content (from 21.8 to 44.3%) and in moisture/protein ratio (from 3.7 to 5.6), and the effects of added sodium chloride, sodium diphosphate, starch and blood plasma were investigated in a 36% fat, 3.7 moisture/protein emulsion.
The shear stresses determined as a function of shear rate were fitted by a power law. Yield stress of the emulsions was negligible relative to the applied stress. However, inspection of the flow profiles indicated that considerable slip of the sausage emulsion occurred at the pipe wall. Both emulsion flow and slip contribute to overall flow behaviour, so a kind of effective viscosity is determined. Intrinsic rheological properties and wall slip will both be affected by the composition of the sausage emulsion.     

氧化石墨烯/石蜡复合相变乳液的制备及对流传热特性

为提高石蜡相变乳液的传热性能，通过添加氧化石墨烯(GO)，制备了GO/石蜡复合相变乳液并对其相关性能进行了表征。搭建了流动阻力、对流换热试验台，对比研究了石蜡相变乳液及GO/石蜡复合相变乳液的流动阻力特性和对流换热特性，试验结果表明，由于GO的亲水性，复合相变乳液都表现出较好的稳定性。当GO的质量分数为0.01％、0.02％、0.03％时，复合相变乳液的热导率分别增加了20.01％、30.50％、35.18％。添加GO使乳液的流动阻力略有增加，直管段最大增加了6.70%，90°弯管处最大增加了13.20%；对流传热系数随着GO浓度的增加而增大，当GO浓度为0.03％时，对流传热系数最大提高了43.90％。     

Rheological properties of bitumen in water emulsions with added solids

Experimental work was carried out to investigate the rheological properties of bitumen in water emulsions containing solids of different shape and size. The bitumen volumetric concentration was varied up to 60%, solids free basis, and the solids volume fraction (total volume basis) was varied up to 0.2. Irregular-shaped silica sand (average diameter: 9 and 33 μm) and smooth spherical glass beads (average diameter: 27 and 44 μm) were used as the added solids. In the low shear stress range, shear thinning behavior was observed for bitumen in water emulsions. At high shear stress, the viscosity of the emulsions became fairly independent of the shear stress. The addition of solids to the bitumen emulsions increased the mixture viscosity. The addition of irregular-shaped silica sand gave a higher viscosity than a similar addition of the spherical glass beads. The viscosity of the emulsion/solids mixtures was influenced by the solids size as well; the smaller size particles gave a higher viscosity. The addition of solids to the bitumen emulsions also induced shear thickening (dilatancy) behavior at high solids volume fraction. The degree of the shear thickening increased with the oil concentration.     

Controlled coagulation of emulsion polymers

Coagulation of latex particles is most often carried out in the diffusion limited aggregation (DLA) regime where the time for coagulation to take place is on the millisecond timescale. This process produces aggregates of low density, irregular shape, and a broad particle size distributions. When the coagulation is carried out in the reaction limited aggregation (RLA) regime, a coagulation time of about 1–120 sec, the system can be controlled by mixing to yield dense, spheroidal aggregates with a very narrow particle size distribution. The important variables in the RLA process for butyl acrylate/methyl methacrylate (BA/MMA) latexes were found to be mixing intensity, latex copolymer composition, and coagulation temperature. Dried aggregates formed in the RLA process were found to have excellent powder flow properties and low dustiness.     

Rheology of oil in water emulsions with added solids

The effect of added solids on the rheology of oil in water emulsions was investigated. The range of the oil concentration, solids free basis, was (0-70%) and the solids volume fraction was (0-0.16). The solids mean diameter was 45 μm and it was about four times larger than the oil droplets. In the absence of added solids, non-Newtonian behaviour was observed for oil concentrations above 40%. The added solids increased the emulsion viscosity in a manner similar to the addition of solids to a homogeneous fluid. The rheological data of all the emulsion-solids mixtures investigated were correlated as relative viscosity versus solids volume fraction, where the relative viscosity is defined as the ratio of the emulsion-solids mixture viscosity to the solids-free emulsion viscosity. In the case of non-Newtonian systems, the emulsion-solids mixture viscosity and the solids-free emulsion viscosity were calculated at the same shear stress. The Barnea and Mizrahi viscosity correlation was found to fit the data well.     

油水乳液分离吸附材料的分离原理、构建方法和分离性能

采用吸附材料进行油水分离是经济且非常有效的方法。吸附材料主要有无机材料、合成高分子材料和天然有机纤维材料等。相比较而言，天然有机纤维材料为可再生生物质资源，来源广泛、生物降解性好，可有效防止二次污染，具有良好的发展潜力，备受关注。本文首先简要介绍了油水乳液稳定性的影响因素，然后综述了油水分离材料的分离原理、构建方法和分离性能等研究进展，并总结了油水乳液分离材料的表征及其分离性能的评价指标。特别地，重点总结了天然有机纤维基吸附材料分离油水乳液的研究进展。最后指出研究智能响应型天然有机纤维基油水乳液分离吸附材料是重要的发展方向。