Health & Environmental Research Online (HERO)


PFPeS (2706-91-4)


156 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

ADSORPTION AND CONFIGURATION OF LUBRICANT MOLECULES ON OVERCOAT MATERIALS

Author: Yanagisawa, M (1993) HERO ID: 3860677

[Less] Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel . . . [More] Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel SiO2 has been applied as a protective overcoat for plated magnetic disks. Adsorption of PFPEs on a surface of the protective overcoat is an important issue to evaluate lubrication characteristics, such as coefficient of friction, wear resistance, volatility and spin-off, for magnetic disks. Molecular configuration and magnitude of adsorption between lubricants and protective overcoats were measured using various analytical methods: diffuse reflectance IR spectroscopy, polarization reflection IR spectroscopy, refractive index analysis, flow microcalorimetry etc. Functional groups in PFPE molecules adsorb to silanol groups on the sol-gel SiO2 surface. The main chain of the PFPE molecule orients parallel to the sol-gel SiO2 surface. The thickness of adsorbed PFPE agrees well with the diameter of the PFPE main chain. The heat of adsorption increases with increasing hydrophilic affinity of functional groups. The heat of adsorption decreases with increasing baking temperature of sol-gel SiO2, which corresponds to the decrease in silanol group density.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

AN ADSORPTION OF PERFLUOROPOLYETHERS ON SIO2 SURFACES FOR THIN-FILM MAGNETIC DISK OVERCOATS

Author: Yanagisawa, M (1993) HERO ID: 3860678

[Less] Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel . . . [More] Perfluoropolyethers (PFPEs) have been widely used as an excellent lubricant on magnetic disks. Sol-gel SiO2 has been applied as a protective overcoat for plated magnetic disks. Adsorption of PFPEs on the surface of a protective overcoat is an important issue in evaluating lubrication characteristics, such as coefficient of friction, wear resistance, volatility, spin-off, etc. for magnetic disks. Molecular configuration and magnitude of adsorption between lubricants and protective overcoats were measured, using various analytical methods, i.e., diffuse reflectance IR spectroscopy, polarization reflection IR spectroscopy, refractive index analysis, flow micro-calorimetry, etc. Functional groups in PFPE molecules adsorb to silanol groups on the sol-gel SiO2 surface. The main chain of PFPE molecule orients parallel to the sol-gel SiO2 surface. The thickness of adsorbed PFPE agrees well with the diameter of the PFPE main chain. The heat of adsorption increases with increasing hydrophilic affinity of functional groups. The heat of adsorption decreases with increasing baking temperature of sol-gel SiO2, which corresponds to the decrease in silanol group density.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

CHARACTERIZATION OF PERFLUOROPOLYETHERS BY DESORPTION CHEMICAL IONIZATION AND TANDEM MASS-SPECTROMETRY

Authors: Guarini, A; Guglielmetti, G; Vincenti, M; Guarda, P; Marchionni, G (1993) HERO ID: 3860686

[Less] Desorption chemical ionization mass spectrometry (DCI-MS) was investigated as a technique for obtaining . . . [More] Desorption chemical ionization mass spectrometry (DCI-MS) was investigated as a technique for obtaining the structural characterization of perfluorinated polyethers (PFPE). Negative-ion DCI mass spectra were dominated by sequences of oligomeric alkoxy fragment ions, each retaining one of the terminal groups of the polymeric chain. Ion abundances showed Gaussian distributions, which were ascribed to low-energy deposition during desorption. The most Important process in the gas-phase ion chemistry of PFPEs resulted in the cleavage of C-O bonds, associated with charge retention on the oxygen; only low-intensity peaks were due to formation of carbanions. The high selectivity of this process produced extremely simple mass spectra, even for complex copolymers. The type and molar fraction of monomeric units and terminal groups contained in the analyzed PFPEs were easily inferred from their DCI mass spectra. Tandem mass spectrometry of oligomeric alkoxy ions and carbanions produced by DCI showed that the most favored dissociation was the loss of monomeric units. The mechanism of other fragmentation processes was also investigated. An interesting difference was found between metastable and collisionally activated loss of CnF2nO: the former occurs via fluorine rearrangement, whereas the latter involves a direct a cleavage at the charge site.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

LUBRICATION PERFORMANCE OF PERFLUOROPOLYALKYLETHERS UNDER HIGH-VACUUM

Authors: Masuko, M; Fujinami, I; Okabe, H (1992) HERO ID: 3860716

[Less] The tribological properties of three types of commercially available perfluoropolyalkylethers (PFPEs) . . . [More] The tribological properties of three types of commercially available perfluoropolyalkylethers (PFPEs) were measured under vacuum using a vacuum four-ball friction apparatus with 440C stainless steel balls as test specimens. A non-fluorinated polyalkylether was also used as a reference, and it showed high friction and wear at atmospheric pressure due to local seizure, while PFPEs did not. On the contrary, PFPEs showed high wear under vacuum at high load while maintaining low friction coefficients. Derivatives of PFPE, i.e. carboxylic acid, alcohol and phosphate, were also studied. The lubrication mechanism of PFPE can be explained using the analogy of ordinary EP additives, considering their reactivity with the surface.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

SYNTHESIS OF POLYESTERS-PERFLUOROPOLYETHERS BLOCK COPOLYMERS .3. USE OF VARIOUS TELECHELIC PERFLUOROPOLYETHERS

Authors: Pilati, F; Toselli, M; Vallieri, A; Tonelli, C (1992) HERO ID: 3860646

[Less] Multiblock -(A-B)n- copolymers containing polyester segments together with perfluoropolyether (PFPE) . . . [More] Multiblock -(A-B)n- copolymers containing polyester segments together with perfluoropolyether (PFPE) segments have been prepared by polymerizing dimethyl terephthalate (DMT), or an equimolar mixture of DMT and dimethyl isophthalate (DMI), with ethylene glycol (EG) in the presence of different telechelic perfluoropolyethers in various amounts (5-30 wt%), using Ti(OBu)4 as the catalyst. Fomblin ZDEAL (a -COOCH3 terminated PFPE), Fomblin ZDOL (a PFPE having -CH2OH terminal groups), and Fomblin ZDOLTX (a PFPE having -CH2O(CH2CH2O)yH terminal groups) were used as telechelic PFPEs. Fomblin ZDOLTX gave the best results: the highest yield in block copolymer (less sensitive to hydrolysis with respect to block copolymers prepared from the other PFPEs), a longer average length of polyester segments, and a relatively low fraction of PFPE lost by distillation during polymerization.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

QUANTITATIVE TIME-OF-FLIGHT SECONDARY ION MASS-SPECTROMETRY OF A PERFLUORINATED POLYETHER

Authors: Fowler, DE; Johnson, RD; Vanleyen, D; Benninghoven, A (1991) HERO ID: 3860624

[Less] Quantitative determination of the molecular weight and composition of submicrogram quantities of a perfluorinated . . . [More] Quantitative determination of the molecular weight and composition of submicrogram quantities of a perfluorinated polyether (PFPE) supported on Ag and Si substrates was made from empirical relationships derived from the intensities of specific high-mass (greater-than-or-equal-to 800 amu) fragmentation ions from time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements. These relationships are explained in terms of simple concepts regarding the process of volatilization, fragmentation and ionization in TOF-SIMS. The results for both negative and positive ions are nearly independent of the substrate materials used, demonstrating that the high-mass fragmentation ions in TOF-SIMS may be useful generally for in situ quantitative analysis of PFPEs on non-specific substrates. This is an important difference between the TOF-SIMS fragmentation spectrum and the complementary TOF-SIMS cationized molecular ion spectrum, which requires special sample preparation and/or substrates. In order to interpret the quantitative information available in the TOF-SIMS fragment spectrum, it was absolutely necessary to characterize extensively the PFPE samples using NMR and TOF-SIMS Ag+-cationized molecular ion results. This characterization helped to demonstrate the power of TOF-SIMS to do quantitative analysis and led to additional insight concerning the SIMS ion-forming process for PFPE. This study represents one of the first attempts to make quantitative use of the high-mass fragment ion intensities in SIMS studies of polymers, and presents a method for confirming the origin of the mass peaks in the spectra.