An ESCA Study on the X-ray Induced Changes in Polymeric Materials

Chaney, Robert; Barth, G

doi:10.1007/978-1-4684-1291-8_12

Cited by 2 publications

(5 citation statements)

References 4 publications

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“…The loss of fluorine content between 90°(I) and 90°(redo) is significant in all the SMM-containing samples. This phenomenon appears to be particularly related to the fluorine component of the SMM and not to the whole SMM itself, since previous studies have reported on the degradation of fluoropolymers, 30 while degradation of polyurethanes using XPS analysis has not been previously observed by the authors. 23 A significant increase in fluorine is observed for all modified surfaces when compared to TDI/PCL/ED.…”

Section: Xps Analysismentioning

confidence: 75%

Use of surface-modifying macromolecules to enhance the biostability of segmented polyurethanes

Tang

Santerre

Labow

et al. 1997

J. Biomed. Mater. Res.

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Polyurethanes are widely used as biomaterials for medical implants because of their excellent mechanical properties and moderate biocompatibility. However, the demand for more bioresistant and biocompatible polyurethanes to meet the needs of long-term implant devices still remains an important issue. Since most biological interactions with materials occur at the interface, a significant number of studies for improving the biocompatibility of polyurethanes have concentrated on surface modification. It is well known that additives used in polymeric materials as processing aids, mold releasing agents, antioxidants, etc., migrate to the surface and change the surface properties of the material. Under certain conditions polymeric additives may also migrate toward surfaces. This study describes two fluorine-containing, surface-modifying macromolecules (SMMs) that have been evaluated for their ability to inhibit polyurethane degradation. These materials actively migrate to the upper surface of a material film when they are mixed with a base polymeric materia. Contact angle measurements for the mixture of SMM with base polyurethane indicate that the surface becomes more hydrophobic after adding the SMMs, while X-ray photoelectron spectroscopy analysis shows an enrichment of fluorine on the polymer surfaces. Differential scanning calorimetry thermograms indicate that the micro-structure, as defined by the thermal transitions of the base polymer, are not altered by the addition of SMMs. Enzyme-induced biodegradation tests exhibit a significant reduction of polyurethane degradation in the presence of these surface-resident materials. The results indicate that the SMMs have the potential to resist hydrolytic degradation mediated by lysosomal enzymes while generating a surface chemistry on the native elastomer which is similar in nature to that of a fluoropolymer, e.g., Teflon.

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Section: Xps Analysismentioning

confidence: 75%

Use of surface-modifying macromolecules to enhance the biostability of segmented polyurethanes

Tang

Santerre

Labow

et al. 1997

J. Biomed. Mater. Res.

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“…33 Experiments with poly(methyl methacrylate) showed that despite a reduction in the molecular weight (as inferred from solubility tests), X-ray irradiation of ca. 7 h produced no detectable changes in the XPS results.…”

Section: Methodsmentioning

confidence: 99%

“…In general, however, it is claimed that other polymers are fairly stable under X-ray irradiation. ,− For example, non- fluorine-containing polymers were found to undergo considerable less beam damage at prolonged exposure times: 33 poly(methymethacrylate) (PMMA), polyacrylonitrile (PAN), poly(vinyl chloride) (PVC), and poly(ethyleneterephthalate) (PET) showed a much lower rate of elemental compositional change with X-ray exposure (changes 10 to 100 times lower than those observed in the case of fluorinated polymers) …”

Section: Methodsmentioning

confidence: 99%

“…2 It has been found, however, that the damage is mainly caused by X-rays rather than by electron bombardment. Some investigators have found that poly(tetrafluorethylene) (or Teflon) suffered damage when exposed to monochromatic 33 and nonmonochromatic 34 X-rays in an XPS spectrometer. This damage was essentially observed as a depletion of fluorine in the near-surface region after long exposure times (typically 5-24 h).…”

Section: Methodsmentioning

confidence: 99%

“…35 In general, however, it is claimed that other polymers are fairly stable under X-ray irradiation. 34,[36][37][38] For example, non- fluorine-containing polymers were found to undergo considerable less beam damage at prolonged exposure times: 33 poly-(methymethacrylate) (PMMA), polyacrylonitrile (PAN), poly(vinyl chloride) (PVC), and poly(ethyleneterephthalate) (PET) showed a much lower rate of elemental compositional change with X-ray exposure (changes 10 to 100 times lower than those observed in the case of fluorinated polymers). 33 Experiments with poly(methyl methacrylate) showed that despite a reduction in the molecular weight (as inferred from solubility tests), X-ray irradiation of ca.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

X-ray Photoelectron Spectroscopy in the Study of Polyelectrolyte Adsorption on Mica and Cellulose

et al. 2000

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X-ray photoelectron spectroscopy was used to estimate the absolute amount of cationic polyelectrolytes that adsorbs on mica and cellulose surfaces in aqueous media. The calculation takes advantage of the knowledge of the mica crystal composition at the basal plane and its ion-exchange properties in aqueous solution. The XPS was operated under monochromatic and unmonochromatic mode and good agreement was observed in the resulting adsorbed amount. The evaluation of the amount of cationic polyelectrolyte adsorbed on cellulose was achieved using calibration curves obtained from adsorption data for the same polyelectrolytes on bare mica surfaces. The adsorption isotherm for polyelectrolytes of low charge density adsorbed on cellulose reveals that their affinity toward cellulose is weaker compared to that observed for highly charged surfaces such as mica. The effect of the polyelectrolyte charge density on the adsorbed amount and the number density of charged segments adsorbed on cellulose were also investigated. From these results it can be concluded that nonelectrostatic interactions are the main contributors to the adsorption of polyelectrolytes on cellulose, but it cannot be ruled out that electrostatic effects also take part in the adsorption mechanism. Finally, it is demonstrated that it is not correct to use the adsorbed amount of polyelectrolytes to determine the surface charge on cellulose surfaces.

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An ESCA Study on the X-ray Induced Changes in Polymeric Materials

Cited by 2 publications

References 4 publications

Use of surface-modifying macromolecules to enhance the biostability of segmented polyurethanes

Use of surface-modifying macromolecules to enhance the biostability of segmented polyurethanes

X-ray Photoelectron Spectroscopy in the Study of Polyelectrolyte Adsorption on Mica and Cellulose

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