scholarly journals Competition between Osmotic Squeezing versus Friction-Driven Swelling of Gels

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Miyu Seii ◽  
Tomoki Harano ◽  
Masao Doi ◽  
Yoshimi Tanaka
Keyword(s):  
Polyethylene Glycol ◽  
Theoretical Analysis ◽  
Ethylene Glycol ◽  
Osmotic Pressure ◽  
Viscous Liquid ◽  
Equilibrium Volume ◽  
Equilibrium Swelling ◽  
Outer Water ◽  
Swelling Volume ◽  
Gel Network

Some types of hydro-gels have almost the same equilibrium swelling volume in water and in ethylene glycol (EG), a highly viscous liquid completely miscible with water. Experiments showed that when a gel fully swollen with EG is immersed into a large amount of water, it temporarily swells up and then relaxes to the equilibrium volume in water. The temporary swelling is explained by the friction force exerted on the gel network from the outward EG flux In this paper, we experimentally show that the temporary swelling is suppressed by adding linear PEG (polyethylene glycol) in the outer water. Although the suppression seems to be explained by the osmotic pressure (i.e., by the same mechanism as the conventional osmotic squeezing), our theoretical analysis reveals that the effect of PEG is much stronger than that expected from the equilibrium osmotic pressure, implying that the PEG chains are condensed on the gel surface.

Effect and Detection of Loose Chain Ends in Crosslinked Polyurethane Elastomers

1971 ◽  
Vol 44 (1) ◽  
pp. 152-165 ◽  
Author(s):  
A. E. Oberth
Keyword(s):  
Crosslink Density ◽  
Volume Fraction ◽  
Present Theory ◽  
Swelling Ratio ◽  
Polyurethane Elastomers ◽  
Equilibrium Volume ◽  
Equilibrium Swelling ◽  
Volume Swelling

Abstract The effect of loose chain ends on tensile properties and equilibrium swelling of crosslinked polyurethane rubbers is studied. As in plasticized elastomers, tensile strength and elastic modulus are reduced approximately by a factor (1−νE,P)2, where νE,P is the volume fraction of loose chain ends, plasticizer, or both. This effect is much larger than predicted by present theory. Also the equilibrium volume swelling ratio, V0/V, of rubbers having terminal chains or an equal volume of plasticizer is the same, provided they do not differ in crosslink density. However, the volume fraction of “network rubber” in the equilibrium swollen specimen, ν2, differs owing to the non-extractability of terminal chains. On this basis a method is proposed which allows experimental determination of the volume fraction of loose ends. Elastomers abounding in loose chain ends show markedly less long term stress relaxation. This effect is not clearly understood but is useful to detect the presence of non load-bearing network.

scholarly journals Study of the properties of Ce3+-doped fluoride nanophosphors: phase composition, morphology, luminescence

2021 ◽  
Vol 2056 (1) ◽  
pp. 012048
Author(s):  
A M Dorokhina ◽  
V V Bakhmetyev ◽  
H Kominami ◽  
A Toru ◽  
M Hisashi
Keyword(s):  
Particle Size ◽  
Photodynamic Therapy ◽  
Phase Composition ◽  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Solvothermal Synthesis ◽  
Luminescent Properties ◽  
Optimal Duration ◽  
Oncological Diseases ◽  
Synthesis Medium

Abstract To date, nanophosphors have found application in various fields, one of which is medicine. These phosphors were developed with the aim to become one of the components of a drug for photodynamic therapy of oncological diseases. The aim of this work was to study the effect of the duration, environment, and stabilizers of solvothermal synthesis on the microstructure and luminescent properties of the YF3:Ce nanophosphor. The solvothermal synthesis technique was carried out in three different media: water, ethanol, and ethylene glycol. The optimal duration of the synthesis was also determined (the synthesis was carried out at a temperature of 200°C for 4…20 hours). The dependence of the YF3 luminescence on the phase composition and the solvothermal synthesis medium was studied. Using SEM, the morphology and particle size of YF3:Ce phosphors were studied depending on different stabilizers (polyethylene glycol, polyethyleneimine, polyvinylpyrrolidone). The luminescence intensity of YF3:Ce and Na(Y1,5Na0,5)F6:Ce samples was compared.

scholarly journals Fabrication of Beltlike Fibers by Electrospinning

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1087 ◽  
Author(s):  
Yan-Qing Liu ◽  
Chun-Hui He ◽  
Xiao-Xia Li ◽  
Ji-Huan He
Keyword(s):  
Surface Tension ◽  
Polyethylene Glycol ◽  
Theoretical Analysis ◽  
Minimal Surface ◽  
Crystallite Size ◽  
Zro2 Nanoparticles ◽  
One Dimensional ◽  
Theoretical Predictions ◽  
Spinning Process ◽  
Moving Jet

Electrospinning is always used to fabricate one-dimensional nanofibers. Cylindrical fibers are formed during the spinning process due to the minimal-surface principle. However, when the moving jet has high rigidity, which can counteract the surface tension for a minimal surface, beltlike fibers can be obtained. Using the Hall–Petch effect, the rigidity of the moving jet can be greatly enhanced by adding nanoparticles. Polyethylene glycol with a nanometric crystallite size of 4 nm and ZrO2 nanoparticles are used as additives in the experiment, a theoretical analysis is carried out, and the theoretical predictions are verified experimentally.

Preparation of amphiphilic block copolymers (polyethylene adipate-block-polyethylene glycol) and its application in rotogravure ink formulations

2018 ◽  
Vol 47 (5) ◽  
pp. 415-423 ◽  
Author(s):  
Yasser Assem ◽  
Heba A. Mohamed ◽  
Rana Said ◽  
Ahmed El-Masry
Keyword(s):  
Optical Properties ◽  
Polyethylene Glycol ◽  
Block Copolymers ◽  
Ethylene Glycol ◽  
Adipic Acid ◽  
Amphiphilic Block Copolymers ◽  
Synthesis Process ◽  
Gravimetric Analysis ◽  
Content Type ◽  
Molecular Weights

Purpose The purpose of this paper is to prepare amphiphilic block copolymers polyethylene adipate-block-polyethylene glycol (PEA-b-PEG)s and study their performance as plasticizers in rotogravure ink formulations. Design/methodology/approach Series of amphiphilic block copolymers (PEA-b-PEG1), (PEA-b-PEG2), (PEA-b-PEG3), (PEA-b-PEG4) and (PEA-b-PEG5) were prepared by the reaction of adipic acid, ethylene glycol and polyethylene glycol of different molecular weights (300, 1,000, 2,000, 10,000 and 20,000 g/mol), respectively. Full characterization of the prepared copolymers was achieved using Fourier Transfer Infrared Spectroscopy (FTIR), 1H NMR, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The performance of the prepared copolymers as plasticizers for neat nitrocellulose resin were studied in different formulations, namely, R1, R2, R3, R4 and R5 containing copolymers (PEA-b-PEG1), (PEA-b-PEG2), (PEA-b-PEG3), (PEA-b-PEG4) and (PEA-b-PEG5), respectively. In addition to formula R0 that contains acetyl tributyl citrate (ATBC) as a commercial plasticizer. The mechanical properties, thermal analysis (DSC, TGA) and optical properties of the prepared formulations films were investigated. Theses amphiphilic block copolymers were then applied as plasticizers in different rotogravure ink formulations (F1, F2, F3, F4 and F5) and compared with commercial rotogravure ink formula (F0). The color measurements and optical properties of all formulations were achieved. Findings It was found that the performance of the prepared copolymers as plasticizers in different formulations based on nitro cellulose resin gives better gloss, adhesion for R1 compared with the other samples and color strength for F1 compared with F0. Finally, all the samples gave excellent plasticizing effect. Research limitations/implications The authors believe that type of these materials open the way for a new class of plasticizers that upon application or even degradation gives small ecofriendly molecules (adipic acid and or ethylene glycol moieties) taking into consideration the simplicity of the rout of the synthesis process. Practical implications The prepared ecofriendly (PEA-b-PEG)s could be successfully used as plasticizers instead of commercial plasticizer ATBC. Originality/value The research provides that the prepared (PEA-b-PEG)s with different molecular weights can act as plasticizers in rotogravure ink formulations, and their performance was acceptable and available.

Comparison of two different methods for the vitrification of hatched blastocysts from the dromedary camel (Camelus dromedarius)

2005 ◽  
Vol 17 (5) ◽  
pp. 523 ◽  
Author(s):  
J. A. Skidmore ◽  
M. Billah ◽  
N. M. Loskutoff
Keyword(s):  
Polyethylene Glycol ◽  
Survival Rate ◽  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Survival Rates ◽  
Camelus Dromedarius ◽  
Dromedary Camel ◽  
Vitrification Solution

The uteri of 32 donor camels were flushed non-surgically on Day 6, 7 or 8 after ovulation and a total of 184 embryos was recovered. Sixty Day 6 embryos and 61 Day 7 embryos were vitrified or frozen ultrarapidly using open pulled straws and a modified version of the Vajta protocol. These embryos were subjected to concentrations of either 10% and 20% or 20% and 40% ethanediol as the cryoprotectant before being loaded into open pulled straws (OPS) and plunged into liquid nitrogen. All embryos were subsequently thawed and rehydrated either directly into holding media or into holding media containing 0.2 m sucrose and were incubated for 5 or 10 min before being transferred to holding media before transfer to recipients. Although the survival rate of the embryos immediately after thawing was high (OPS 20%/40% ethanediol resulted in 97% and 100% survival for Day 6 and Day 7 embryos, respectively; OPS 10%/20% ethanediol resulted in 90% and 70% survival for Day 6 and Day 7 embryos, respectively), after 2 h in culture, survival rates had decreased to 46% and 53% for Day 6 and Day 7 embryos, respectively, using OPS 10%/20% and 53% and 63% for Day 6 and Day 7 embryos, respectively, using OPS 20%/40%; however, none of the embryos transferred resulted in a viable fetus. A further 63 embryos (Day 6: n = 31; Day 7: n = 16; Day 8: n = 16) were subsequently exposed to vitrification solution (20% glycerol + 20% ethylene glycol + 0.3 m sucrose + 0.375 m glucose + 3% polyethylene glycol) in three steps and after loading into 0.25 mL straws were plunged into liquid nitrogen. However, a much greater percentage of the Day 7 and Day 8 embryos (43.8% and 81.2% respectively) were fractured or torn after warming and none of the 12 intact embryos transferred resulted in a pregnancy. Better survival rates immediately after thawing and rehydration were obtained with the smaller Day 6 embryos (94%), which resulted in a total of eight fetuses from the 21 embryos transferred.

Modification of Soy Protein Isolate-Polyethylene Glycol Composite Packaging Films with Ethylene Glycol

2015 ◽  
Vol 731 ◽  
pp. 565-568
Author(s):  
Pei Wang ◽  
Zhen Huang ◽  
Wei Zheng ◽  
Ma Dong Si
Keyword(s):  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Soy Protein ◽  
Soy Protein Isolate ◽  
Protein Isolate ◽  
Raw Material ◽  
Casting Method ◽  
Elongation At Break ◽  
E Coli ◽  
Solution Casting Method

With soy protein isolate (SPI) as the main raw material, and ethylene glycol (EG) and polyethylene glycol (PEG) as two additives, a number of SPI-based films were prepared through the solution casting method. Results show that the film flexibility is obviously improved after adding EG and the film tensile strength and elongation at break could reach more than 10.5 MPa and 140%, respectively. The antimicrobial results exhibit EG has higher antibacterial effect against both bacteria ofE. coliandS. aureusthan PEG-400.

Development of Environmentally Friendly Binder in Extrusion Molding

2014 ◽  
Vol 941-944 ◽  
pp. 1735-1739
Author(s):  
Xiao Wei Meng
Keyword(s):  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Ethyl Cellulose ◽  
Environmentally Friendly ◽  
High Strength ◽  
Cemented Carbide ◽  
Homogeneous Microstructure ◽  
Polyoxyethylene Ether ◽  
Thermodynamic Conditions ◽  
Stable Performance

A new kind of binder was developed in extrusion molding. It included four ingredients: ethylene glycol acetate (60%~85% (mass/mass, as follows)), ethyl cellulose (10%~30%), ethylene glycol polyoxyethylene ether (5%~10%), polyethylene glycol stearate (0.8%~3%). The components of binder were compatible with thermodynamic conditions, so the binder was well-distributed in molecule level. The new binder is actual nontoxic, secure and environmentally friendly. The forming property of the binder is so excellent that it can load 54% ~ 56% (vol. /vol.) cemented carbide powders. The rods produced by this new binder provide high strength, stable performance, homogeneous microstructure.

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