An improved correlation to predict molecular weight between crosslinks based on equilibrium degree of swelling of hydrogel networks

2017 ◽  
Vol 106 (3) ◽  
pp. 1339-1348 ◽  
Author(s):  
Andrea C. Jimenez‐Vergara ◽  
John Lewis ◽  
Mariah S. Hahn ◽  
Dany J. Munoz‐Pinto
Keyword(s):  
Molecular Weight ◽  
Equilibrium Degree ◽  
Degree Of Swelling

Estimation, from Swelling, of the Structural Contribution of Chemical Reactions to the Vulcanization of Natural Rubber. Part II. Estimation of Equilibrium Degree of Swelling

1964 ◽  
Vol 37 (2) ◽  
pp. 571-575 ◽  
Author(s):  
Bryan Ellis ◽  
G. N. Welding
Keyword(s):  
Natural Rubber ◽  
Chemical Reactions ◽  
Volume Fraction ◽  
Equilibrium Degree ◽  
Degree Of Swelling ◽  
Rubber Part ◽  
Structural Contribution

Abstract An investigation has been made of the measurement of degree of swelling of vulcanizates and the estimation of υτ, the volume fraction of polymer in a vulcanizate swollen to equilibrium. Methods have been established for dealing with a volatile swelling liquid, allowing for small percentages of nonpolymer in the vulcanizates, testing for diffusion equilibrium and correcting for swelling increment. The resulting values of υτ are suitable for use as described in the preceding Part I.

scholarly journals An investigation of the effects of a silicalite type zeolite on PDMS-composites

2000 ◽  
Vol 65 (3) ◽  
pp. 173-179
Author(s):  
Borivoj Adnadjevic ◽  
Jelena Jovanovic
Keyword(s):  
Thermal Stability ◽  
Polymer Network ◽  
Equilibrium Degree ◽  
Degree Of Swelling ◽  
Type Zeolite ◽  
Time Required ◽  
Reinforcing Filler

The aim of this paper was to investigate the effect of a silicalite type zeolite on PDMS-zeolite composites. The obtained results show that the introduction of a silicalite type zeolite into polysiloxane matrices results in a change of the equilibrium degree of swelling of the composites in toluene, their hardness and their thermal stability. With increasing amount of zeolite, the time required to achieve the equilibrium degree of swelling (DSe) is reduced, the DSe decreases and the hardness increases. Two ranges of the effect of the zeolite concentration on the composite characteristics were noted. At zeolite concentrations up to about 12% there are significant changes of the DSe and the hardness with zeolite concentration, while these effects are considerably less pronounced at higher concentrations. The results obtained show that the silicalite type zeolite acts as a reinforcing filler. We believe that with increasing zeolite concentration in the composite the total number of established polymer-zeolite interactions increases, as does the spatial irregularity of the polymer network, but that the density of the interactions decreases. This could be the most probably explanation for the changes in the characteristics of the composite with changing zeolite concentration.

Synthesis and Application of Electro-Thermally Sensitive Gels

2008 ◽  
Vol 61 ◽  
pp. 147-156 ◽  
Author(s):  
Karl Friedrich Arndt ◽  
Andreas Richter ◽  
Stephan Klatt ◽  
Georgi Paschew
Keyword(s):  
Phase Transition ◽  
Ph Value ◽  
Sensor Arrays ◽  
Molecular Transport ◽  
Ion Concentration ◽  
Volume Phase Transition ◽  
Equilibrium Degree ◽  
Volume Phase ◽  
Swelling Agent ◽  
Degree Of Swelling

Stimuli-sensitive change their volume (equilibrium degree of swelling), mechanical properties (elasticity, stiffness) and molecular transport properties in response to a small change in the properties of the swelling agent, like temperature, solvent composition, pH value, ion concentration, etc. Widespread used smart gels take advantages of the volume phase transition induced by a change of temperature. The temperature of volume phase transition depends on the interaction between gel and solvent. For a gel with defined chemical structure it can be changed by the composition of the swelling agent, e.g. content of salt or organic components. For application, e.g. in MEMS, an easy and controlled stimulation of volume phase transition is required. The degree of swelling (Q) and therefore the dimension of gel structures are determined by temperature. It is possible to regulate Q to a predetermined value by heating/cooling. Thermal energy inside a gel-based device can be easily generated and regulated by incorporated heating resistors and temperature sensors. Different structures (micro-spheres, pads, patterned layers) of smart hydrogels are applied. The switching between two different states of swelling is induced by changes of temperature or by changing the environment. Using the example of gel-based microvalves, sensors, sensor arrays, pumps, and chemostats (concentration control of chemical substances) the sensor-actuator properties and advantages of this group of polymers are discussed.

scholarly journals PREPARATION OF CHITOSAN GRAFT COPOLYMERS AND STUDY OF THEIR WATER-SWELLING PROPERTIES

2021 ◽  
pp. 83-90
Author(s):  
A. D. Moroz ◽  
S. S. Dryabina ◽  
M. A. Vaniev ◽  
Zh. N. Malysheva ◽  
I. A. Novakov
Keyword(s):  
Molecular Weight ◽  
Aprotic Solvent ◽  
Graft Copolymers ◽  
Controlled Radical Polymerization ◽  
Methyl Sulfate ◽  
Swelling Properties ◽  
Degree Of Swelling ◽  
Water Swelling ◽  
Kinetics Of ◽  
Kinetics Of Swelling

In this work, graft copolymers of chitosan with trimethylmethacryloxyethylammonium methyl sulfate were synthesized by the method of controlled radical polymerization, and it was found that replacing the dimethylformamide aprotic solvent with water increases the degree of grafting. With the aim of the possible use of chitosan copolymers as a functional component for regulating the water-swelling properties of elastomers, the kinetics of swelling of the samples was investigated. An increase in the degree of swelling of the copolymers in comparison with the initial chitosan was revealed, and the influence of the molecular weight and the conditions of their synthesis was established.

Influence of Temperature, Time and Crosslinking Agent on Structure and Properties of Polyurethane Gel

2020 ◽  
Vol 856 ◽  
pp. 253-260
Author(s):  
Pornlada Pongmuksuwan ◽  
Wanlop Harnnarongchai ◽  
Soratorn Katabunyanont
Keyword(s):  
Molecular Weight ◽  
Crosslink Density ◽  
Average Molecular Weight ◽  
Crosslinking Agent ◽  
Curing Temperature ◽  
Curing Time ◽  
Gel Content ◽  
Methylene Diphenyl Diisocyanate ◽  
Degree Of Swelling ◽  
Temperature Time

Polyurethane (PU) gel was synthesized based on methylene diphenyl diisocyanate (MDI) and polyols corporation with 1,1,1-Tris(hydroxymethyl)propane (TMP) as a crosslinking agent. The chemical structure of synthesized polyurethane gel was investigated using Fourier-transform infrared spectroscopy (FTIR). The effects of curing temperature, curing time, and crosslinking concentration on the degree of swelling, gel content and hardness of polyurethane gel are investigated. In addition, the crosslink density and average molecular weight between crosslinking points were determined using the Flory-Rehner equation. The results revealed that the curing temperature had more pronounced effect on degree of swelling and gel content than curing time. As the curing temperature increased the degree of swelling and gel content in polyurethane gel increased. Curing time seem to have a complicated effect on crosslink density and average molecular weight between crosslinking points. The hardness of polyurethane gel tends to increase with increasing crosslinking concentration and curing time.

scholarly journals Superabsorbent hydrogels made from bio-sourced butyrolactone monomer in aqueous solution

2017 ◽  
Vol 8 (39) ◽  
pp. 6039-6049 ◽  
Author(s):  
Sharmaine B. Luk ◽  
Jozef Kollár ◽  
Anna Chovancová ◽  
Miroslav Mrlík ◽  
Igor Lacík ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Radical Polymerization ◽  
Polymerization Kinetics ◽  
Equilibrium Degree ◽  
Degree Of Swelling ◽  
Kinetics Of ◽  
Superabsorbent Hydrogels

A study of the radical polymerization kinetics of sodium 4-hydroxy-4-methyl-2-methylene butanoate with acrylamide in aqueous solution provides insights to the performance of superabsorbent hydrogels synthesized with equilibrium degree of swelling in the range of 6700–59 000%.

Effect of Oxidation of Rubber on the Kinetics of Its Swelling

1956 ◽  
Vol 29 (1) ◽  
pp. 135-144 ◽  
Author(s):  
V. E. Gul ◽  
I. V. Khodzhaeva ◽  
B. A. Dogadkin
Keyword(s):  
Molecular Weight ◽  
Structural Properties ◽  
Polar Solvent ◽  
Kinetic Curve ◽  
Linear Segment ◽  
Oxidation Processes ◽  
Degree Of Dispersion ◽  
Degree Of Swelling ◽  
Kinetics Of ◽  
Oxidation Effect

Abstract 1. Swelling of rubber during reaction with oxygen is described by a kinetic curve. After a sharply rising segment, corresponding to the diffusion of the solvent, the curve has a practically linear segment, reflecting a slow change of the degree of swelling due to the oxidation processes which accompany swelling. 2. The swelling maximum of rubber in a polar solvent when the oxidation effect is disregarded, corresponds to the molecular weight, degree of dispersion, and other structural properties of the rubber. The slope of the linear segment of the kinetic curve of swelling can serve as a characteristic of the resistance of the rubber to oxidation.

Sign in / Sign up

Export Citation Format

Share Document