Search results for "Perfluoropolyether"

showing 4 items of 4 documents

High performance composites containing perfluoropolyethers-functionalized carbon-based nanoparticles: Rheological behavior and wettability

2016

Abstract Ultra High Molecular Weight Polyethylene (UHMWPE) based composites filled with carbon nanotubes (CNTs) and carbon black (CB) modified by perfluoropolyethers (PFPE) have been formulated. All composites show a segregated morphology with nanofillers selectively localized at the polymer particle–particle interface. The composites rheological properties have been deeply investigated: the PFPE functionalities linked on CNTs facilitate the semi-3D nanofillers network formation in the composites that show a solid-like behaviour even at lower investigated filler contents, reaching the rheological percolation threshold at lower nanofiller content than bare CNTs filled composites. For composi…

B. Rheological propertiePolymer-matrix composites (PMCs)Materials scienceNano-structures Polymer-matrix composites (PMCs) Rheological properties Surface properties Perfluoropolyethers nanofillersB. Surface propertiesNanoparticlechemistry.chemical_elementCeramics and Composite02 engineering and technologyCarbon nanotube010402 general chemistry01 natural sciencesPerfluoropolyethers nanofillersIndustrial and Manufacturing Engineeringlaw.inventionchemistry.chemical_compoundA. Polymer-matrix composites (PMCs)lawA. Nano-structures; A. Polymer-matrix composites (PMCs); B. Rheological properties; B. Surface properties; Perfluoropolyethers nanofillers; Ceramics and Composites; Mechanics of Materials; Mechanical Engineering; Industrial and Manufacturing EngineeringA. Nano-structuresSurface propertiesMechanics of MaterialRheological propertiesComposite materialPerfluoropolyethers nanofillerUltra-high-molecular-weight polyethylenechemistry.chemical_classificationMechanical EngineeringPercolation thresholdCarbon blackPolymer021001 nanoscience & nanotechnologyB. Surface propertie0104 chemical sciencesB. Rheological propertieschemistryNano-structuresMechanics of MaterialsA. Nano-structureCeramics and CompositesWetting0210 nano-technologyCarbon
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Temperature and pressure dependence of the viscosities of perfluoropolyether fluids

1987

The viscosities of two structurally different perfluoropolyether fluids were determined at a series of temperatures and pressures, from 25 to 100°C and from 1 to 1000 bars. Flow activation energies and volumes as well as their temperature and pressure coefficients were derived. An attempt was made to relate measured and derived quantities to the compound structures.

Physics::Fluid DynamicsViscosityTemperature and pressurePolymers and PlasticsChemistryFlow (psychology)Materials ChemistryPerfluoropolyetherThermodynamicsActivation energyPhysical and Theoretical ChemistryCondensed Matter PhysicsJournal of Polymer Science Part B: Polymer Physics
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Surfactant Assisted Polymerization of Tetrafluoroethylene in Supercritical Carbon Dioxide with a Pilot Scale Batch Reactor.

2008

Chain-free radical polymerization of tetrafluoroethylene (TFE) was carried out in supercritical carbon dioxide (scCO2), at 50 °C and 121–133 bar, with tertiary-amyl-per-pivalate as a free radical initiator, using a 5-L pilot scale batch reactor. Experiments were carried out both in the absence and in the presence of perfluoropolyether (PFPE) carboxylate surfactants. Stabilizers were employed under the free acid form and as sodium and calcium salts. An expanded fibrillated poly(TFE) was obtained in all experiments. In the case of surfactant-free polymerizations, the product was mainly constituted by irregular shape macroparticles having size in the range 200–500 μm. Quite interestingly, when…

chemistry.chemical_classificationSupercritical carbon dioxidePolymers and Plasticsperfluoropolyether surfactantOrganic ChemistryRadical polymerizationBatch reactorSolution polymerizationPolymerSettore ING-IND/27 - Chimica Industriale E Tecnologicaradical polymerizationsurfactantschemistry.chemical_compoundpoly(tetrafluoroethylene)chemistryChemical engineeringPolymerizationsupercritical carbon dioxidePolymer chemistryMaterials ChemistryRadical initiatorTetrafluoroethylenemembrane
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Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability

2022

Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites’ electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes dur…

flexible electrode functionalized CNTs hydrogen evolution perfluoropolyethers UHMWPE compositesUHMWPE compositesperfluoropolyethersflexible electrodehydrogen evolutionfunctionalized CNTsSettore ING-IND/22 - Scienza E Tecnologia Dei MaterialiGeneral Materials ScienceUHMWPE composites; functionalized CNTs; perfluoropolyethers; flexible electrode; hydrogen evolutionMaterials; Volume 15; Issue 19; Pages: 6883
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