scholarly journals Controlling the Internal Structures of Polymeric Microspheres via the Introduction of a Water-Soluble Organic Solvent

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 789 ◽  
Author(s):  
Yanping He ◽  
Xin Li ◽  
Tianci Zhu ◽  
Mengxing Shan ◽  
Linhua Zhu ◽  
...  

Polymeric microspheres with different internal structures have been widely used because of their characteristics in the structures. This paper reports a method of controlling the internal structures of polymeric microspheres via the introduction of a water-soluble organic solvent to the continuous phase in the foam phase preparation of porous polymeric microspheres. The introduction of a water-soluble organic solvent enables the control of polymeric microspheres’ internal structures, from porous to hollow. Because a water-soluble organic solvent is introduced, the organic solvent may be diffused toward the interface because of the affinity between the organic solvent and the oil droplets, resulting an accumulation of organic solvent molecules at the interface to form an organic solvent layer. The presence of this layer may decrease the evaporation rate of the internal organic solvent in an oil droplet, which extends the time for the mingling of porogen droplets to form a few large pores or even an extremely large single pore inside. This method is also capable of altering the thickness of hollow microspheres’ shells in a desired way, with improved efficiency, yield and the capacity for continuous use on an industrial scale.

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaodi Wang ◽  
Yongchao Zhang ◽  
Luyao Wang ◽  
Xiaoju Wang ◽  
Qingxi Hou ◽  
...  

AbstractAn efficient separation technology for hydrolysates towards a full valorization of bamboo is still a tough challenge, especially regarding the lignin and lignin-carbohydrate complexes (LCCs). The present study aimed to develop a facile approach using organic solvent extraction for efficiently fractionating the main components of bamboo hydrolysates. The high-purity lignin with only a trace of carbohydrates was first obtained by precipitation of the bamboo hydrolysate. The water-soluble lignin (WSL) fraction was extracted in organic solvent through a three-stage organic solvent extraction process, and the hemicellulosic sugars with increased purity were also collected. Furthermore, a thorough characterization including various NMR techniques (31P, 13C, and 2D-HSQC), GPC, and GC-MS was conducted to the obtained lignin-rich-fractions. It was found that the WSL fraction contained abundant functional groups and tremendous amount of LCC structures. As compared to native LCC of bamboo, the WSL fraction exhibited more typical LCC linkages, i.e. phenyl glycoside linkage, which is the main type of chemical linkage between lignin and carbohydrate in both LCC samples. The results demonstrate that organic phase extraction is a highly efficient protocol for the fractionation of hydrolysate and the isolation of LCC-rich streams possessing great potential applications.


2021 ◽  
Author(s):  
Ruby R. Rafanan

Emulsified microemulsions (EMEs), first described in detail in 2005 by the group of Garti, consist of a thermodynamically stable water-in-oil microemulsion phase (w1/o) further dispersed within an aqueous continuous phase (w2). These internally-structured w1/o/w2 dispersions are promising controlled release vehicles for water-soluble flavouring compounds, drugs and nutraceuticals. With a stable internal droplet structure, storage stability is improved over non-thermodynamically stable structured emulsions and may exhibit unique controlled release behaviour. Use of food-grade components allows for wider and safer applications in food and pharmaceutical products. In this thesis, a food-grade w1/o microemulsion consisting of glycerol monooleate, tricaprylin and water was dispersed in an aqueous (w2) phase by membrane emulsification and stabilized by a caseinate-pectin complex to produce w1/o/w2 EMEs. The resulting EME showed no signs of phase separation for weeks at room temperature. The microemulsion and EME were characterized by differential scanning calorimetry (DSC), cryo-TEM and small angle x-ray scattering (SAXS) to determine whether the microemulsion’s internal structure was maintained after emulsification. It was shown that EME droplets displayed ordering around the periphery consistent with some loss of microemulsion structure, but maintained the characteristic disordered microemulsion structure at the droplet core. Overall, this research demonstrated the feasibility of developing EME for possible applications in food and non-food applications.


2021 ◽  
Author(s):  
Ruby R. Rafanan

Emulsified microemulsions (EMEs), first described in detail in 2005 by the group of Garti, consist of a thermodynamically stable water-in-oil microemulsion phase (w1/o) further dispersed within an aqueous continuous phase (w2). These internally-structured w1/o/w2 dispersions are promising controlled release vehicles for water-soluble flavouring compounds, drugs and nutraceuticals. With a stable internal droplet structure, storage stability is improved over non-thermodynamically stable structured emulsions and may exhibit unique controlled release behaviour. Use of food-grade components allows for wider and safer applications in food and pharmaceutical products. In this thesis, a food-grade w1/o microemulsion consisting of glycerol monooleate, tricaprylin and water was dispersed in an aqueous (w2) phase by membrane emulsification and stabilized by a caseinate-pectin complex to produce w1/o/w2 EMEs. The resulting EME showed no signs of phase separation for weeks at room temperature. The microemulsion and EME were characterized by differential scanning calorimetry (DSC), cryo-TEM and small angle x-ray scattering (SAXS) to determine whether the microemulsion’s internal structure was maintained after emulsification. It was shown that EME droplets displayed ordering around the periphery consistent with some loss of microemulsion structure, but maintained the characteristic disordered microemulsion structure at the droplet core. Overall, this research demonstrated the feasibility of developing EME for possible applications in food and non-food applications.


Author(s):  
Liyan Feng ◽  
Zixin Wang ◽  
Ping Yi ◽  
Weixin Gong ◽  
Jingchen Cui ◽  
...  

The distribution of lubricating oil droplets in cylinder is one of main causes of abnormal combustion of natural gas engines. The evaporation of lubricating oil droplet is one of the key sub-processes controlling its auto-ignition event. The components of lubricating oil with different carbon number (16–50) shows significantly different evaporation and ignition characteristics from gasoline and diesel fuels. Even though there are many evaporation models focusing on the evaporation behaviors of multi-component droplets, most of them are limited to the liquid fuels, which are composed by more volatile hydrocarbons. Therefore, understanding the evaporation characteristics of lubricating oil droplets is very important for investigating the mechanism of abnormal combustion of natural gas engines. In this study, a multi-component evaporation model for lubricating oil was developed, which considers several key characteristics in the droplet evaporation process, including the finite heat conduction and limited mass diffusion in liquid phase, multi-component diffusion in gas phase, real vapor-liquid equilibrium at the droplet interface, as well as the nitrogen quantity dissolved in liquid phase. The simulation results by this model were compared with experimental results, and good agreements have been achieved. Then, this model was used to study the evaporation behaviors of different hydrocarbon droplets, including lubricating oil droplet. The influences of ambient temperatures and pressures, as well as methane concentration on evaporation characteristics (namely the heat up period, average evaporation rate, and droplet lifetime) were investigated. The results show that both heat up period and evaporation rate of lubricating oil droplets increase as the methane concentration increases. Besides, the droplet lifetime monotonically decreases as the ambient pressure decreases. This is different from the diesel and gasoline droplets, for which the effects of pressure on the droplet evaporation behaviors are depended on the ambient temperature.


2019 ◽  
Vol 43 (13) ◽  
pp. 5219-5227 ◽  
Author(s):  
Sharanabasava D. Hiremath ◽  
Ram U. Gawas ◽  
Starlaine C. Mascarenhas ◽  
Anasuya Ganguly ◽  
Mainak Banerjee ◽  
...  

A water-soluble TPE-based AIEgen (TPE-diBuS) was developed for organic-solvent-free detection of Al3+ ions and its wash-free cell imaging. The TPE-diBuS-Al ensemble was used for the detection of F− ions and DNA tracking.


2004 ◽  
Vol 4 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Marcin Fialkowski ◽  
Agnieszka Bitner ◽  
Bartosz A. Grzybowski

2004 ◽  
Vol 847 ◽  
Author(s):  
Giulia Fornasieri ◽  
Stéphane Badaire ◽  
Rénal Vasco Backov ◽  
Philippe Poulin ◽  
Cécile Zakri ◽  
...  

Using reverse emulsion systems, we were able to trigger mineralization confined at an oil-water interface. In this process, the alcoxide silica precursor is dissolved in the oil continuous phase of the emulsion and diffuses through the bulk to the interface where it starts to hydrolyze and condense as soon as a certain concentration threshold is attained. The process takes place only in the presence of a water soluble surfactant inside the droplet. This surfactant leads to the presence of a controlled mesoporosity inside the silica shells. The obtained objects could be used in different encapsulation applications.


1983 ◽  
Vol 14 (7) ◽  
Author(s):  
R. I. GELB ◽  
L. M. SCHWARTZ ◽  
M. RADEOS ◽  
R. B. EDMONDS ◽  
D. A. LAUFER

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