Crosslinking poly(ethylene oxide) in dilute solutions by gamma rays

Brederode, R. A. Van; Rodriguez, Ferdinand; Cocks, George G.

doi:10.1002/app.1968.070120912

Cited by 18 publications

(5 citation statements)

References 9 publications

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“…16 Van Brederode has found that the maximum modulus of poly(ethy1ene oxide) gels formed by gamma irradiation varies with concentration to the 2.25 power. 18 As the lower critical concentration is approached, the maximum modulus drops off rapidly as shown by the dotted lines in Figure 2.…”

Section: (4)mentioning

confidence: 93%

Crosslinking aqueous poly(vinyl pyrrolidone) solutions by persulfate

Anderson

Rodriguez

Thurston

1979

J. Appl. Polym. Sci.

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SynopsisAqueous solutions with 1.5 to 6.5 wt-% poly(viny1 pyrrolidone), PVP, are converted to stable gels by reaction with potassium persulfate. Large quantities of persulfate are needed for high-modulus gels, 50% to 150% of the weight of PVP being required typically. The shear modulus G' can be measured during reaction by making the gel the restoring element in a simple torsion pendulum. The increase in modulus to a maximum plateau value of GLm can be expressed as a first-order process:where t is elapsed time of reaction and K increases with the square root of polymer concentration. G-varies with the second power of the polymer concentration. It also increases rapidly with increasing temperature of reaction and with persulfateIPVP ratio.

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Section: (4)mentioning

confidence: 93%

Crosslinking aqueous poly(vinyl pyrrolidone) solutions by persulfate

Anderson

Rodriguez

Thurston

1979

J. Appl. Polym. Sci.

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“…Slightly stiffer gels were formed at higher dose. The increase of the storage modulus G ′ and crosslink density with the irradiation dose has been observed for different radiation crosslinked gels, like PEO [ 58 ] and PVP hydrogels [ 59 ]. All nanocomposite gels had higher storage moduli, yield points and flow points compared to pure PEO gels at a certain dose.…”

Section: Resultsmentioning

confidence: 99%

Rheological, Microstructural and Thermal Properties of Magnetic Poly(Ethylene Oxide)/Iron Oxide Nanocomposite Hydrogels Synthesized Using a One-Step Gamma-Irradiation Method

et al. 2020

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Magnetic polymer gels are a new promising class of nanocomposite gels. In this work, magnetic PEO/iron oxide nanocomposite hydrogels were synthesized using the one-step -irradiation method starting from poly(ethylene oxide) (PEO) and iron(III) precursor alkaline aqueous suspensions followed by simultaneous crosslinking of PEO chains and reduction of Fe(III) precursor. -irradiation dose and concentrations of Fe3+, 2-propanol and PEO in the initial suspensions were varied and optimized. With 2-propanol and at high doses magnetic gels with embedded magnetite nanoparticles were obtained, as confirmed by XRD, SEM and Mössbauer spectrometry. The quantitative determination of -irradiation generated Fe2+ was performed using the 1,10-phenanthroline method. The maximal Fe2+ molar fraction of 0.55 was achieved at 300 kGy, pH = 12 and initial 5% of Fe3+. The DSC and rheological measurements confirmed the formation of a well-structured network. The thermal and rheological properties of gels depended on the dose, PEO concentration and initial Fe3+ content (amount of nanoparticles synthesized inside gels). More amorphous and stronger gels were formed at higher dose and higher nanoparticle content. The properties of synthesized gels were determined by the presence of magnetic iron oxide nanoparticles, which acted as reinforcing agents and additional crosslinkers of PEO chains thus facilitating the one-step gel formation.

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“…In the absence of oxygen, however, poly(ethy1ene oxide) will gel when irradiated at the dosage of 4.5-7.5 X lo4 rad. 24 The scission of polymer chains will be more pronounced in the amorphous regions than in the crystalline regions. This might be due to the so-called "cage effect.…”

Section: Discussionmentioning

confidence: 99%

Effects of enzymes and gamma irradiation on the tensile strength and morphology of poly(p‐dioxanone) fibers

Williams

Chu

Dwyer

1984

J of Applied Polymer Sci

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SynopsisThe objective of this study was to examine how and to what extent a new degradable polymeric fiber, poly(p-dioxanone), used as a surgical suture material, degrades in the presence of enzymes and after y-irradiation. The degradation of the fiber was studied mechanically using an Instron and morphologically by SEM. Both esterase and trypsin enzymes and their corresponding buffer controls were used. The fibers were y-irradiated at the dosages ranging from 0 to 20 Mrad, immersed in the solution for up to 70 days, and then removed for tensile strength and morphological examinations. It was found that y-irradiation alone lowered the tensile strength of PDS fibers and made them more susceptible to hydrolysis. Esterase and trypsin did not accelerate the hydrolytic degradation of this fiber to any significant level. Both y-irradiation and enzymes influenced the gross morphological characteristic of PDS fibers when they were subjected to hydrolysis. The most important morphological observations were the formation of surface cracks and chips on the fibers and the subsequent peeling of the chips. Enzyme-treated PDS fibers exhibited similar morphological findings but the size of the chips was smaller. The morphological observations of PDS fibers were consistent with the tensile strength data.

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Crosslinking poly(ethylene oxide) in dilute solutions by gamma rays

Cited by 18 publications

References 9 publications

Crosslinking aqueous poly(vinyl pyrrolidone) solutions by persulfate

Crosslinking aqueous poly(vinyl pyrrolidone) solutions by persulfate

Rheological, Microstructural and Thermal Properties of Magnetic Poly(Ethylene Oxide)/Iron Oxide Nanocomposite Hydrogels Synthesized Using a One-Step Gamma-Irradiation Method

Effects of enzymes and gamma irradiation on the tensile strength and morphology of poly(p‐dioxanone) fibers

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