Correlation between mesh size and equilibrium degree of swelling of polymeric networks

1989 ◽  
Vol 23 (10) ◽  
pp. 1183-1193 ◽  
Author(s):  
Tiziana Canal ◽  
Nikolaos A. Peppas
Keyword(s):  
Mesh Size ◽  
Equilibrium Degree ◽  
Polymeric Networks ◽  
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 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%.

scholarly journals Semi-interpenetrating networks based on POLY(N-isopropyl acrilamide) and POLY(N-vinylpyrrolidone)

2007 ◽  
Vol 61 (6) ◽  
pp. 350-356 ◽  
Author(s):  
Dragana Zugic ◽  
Pavle Spasojevic ◽  
Jasna Djonlagic
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Molar Ratio ◽  
Dynamic Shear Modulus ◽  
Interpenetrating Networks ◽  
Elongation At Break ◽  
Equilibrium Degree ◽  
Degree Of Swelling

Three series of semi-interpenetrating polymer networks based on cross-linked poly(N-isopropylacrylamide), PNIPA, and 1, 2 and 3 wt% of linear poly(N-vinylpyrrolidone), PVP, were synthesized in order to improve the mechanical properties of PNIPA gels. The effect of the incorporation of the linear PVP polymer into the temperature responsive networks on the phase transition temperature, swelling behavior and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with various molar ratios (25/1 to 100/1) of the monomer (N-isopropylacrylamide) to the cross linker (N,N'-methylene-bisacrylamide). The hydrogels were characterized by determination of the equilibrium degree of swelling at 25 ?C, the dynamic shear modulus and the effective crosslinking density, as well as the ultimate hydrogel properties, such as the tensile strength and elongation at break. Furthermore, the deswelling kinetics of the hydrogels was also studied by measuring their water retention capacity. The inclusion of the linear hydrophilic PVP in the PNIPA networks increased the equilibrium degree of swelling, the highest values of which were obtained for samples with 2 and 3 wt% of PVP and the NIPA/MBA molar ratio of 75/1 and 100/1. The highest reinforcement effect, evaluated from the ratio of G'red(semi-IPN) to G'red(PNIPA), was obtained by incorporation of 2 wt% PVP. The tensile strength of the semi-IPNs reinforced with linear PVP was higher than that of the PNIPA networks. The elongation at break of these semi-IPNs varied between 22 and 55%, which are 22^11% larger than those for single PNIPA networks. The tensile measurements confirmed that the presence of 2 wt% of the linear polymer significantly reinforced the PNIPA network.

A Field Theory for Polymeric Networks with Excluded Volume

1995 ◽  
Vol 5 (10) ◽  
pp. 1241-1246 ◽  
Author(s):  
Thomas A. Vilgis ◽  
Michael P. Solf
Keyword(s):  
Field Theory ◽  
Excluded Volume ◽  
Polymeric Networks

Some Approaches to Viscometric Study of Chitosan in Acetic Acid Solution

2016 ◽  
Vol 10 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Valentina Chernova ◽  
◽  
Angela Shurshina ◽  
Elena Kulish ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Intrinsic Viscosity ◽  
Acetic Acid Solution ◽  
Conformational State ◽  
Macromolecular Coil ◽  
Degree Of Swelling ◽  
Current Value ◽  
Viscometric Study

Some ways of estimating the values of the intrinsic viscosity of chitosan were analyzed. It was shown that the method of Irzhak and Baranov for estimating the current value of the intrinsic viscosity allows to adequately estimates the conformational state of the macromolecular coil and its degree of swelling.

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