Search results for "Fluoroethyl"
showing 10 items of 50 documents
A Generalized Method for High‐Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta 3 O 7 F and TaO 2 F with High Photocatalytic Act…
2021
A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta3 O7 F and TaO2 F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination. ii) Short reaction times (minutes rather than days) reduce the process time the energy costs by almost three orders of magnitude. iii) The oxyfluorides Ta3 O7 F and TaO2 F are produced in gram amounts of nanoparticles. Their synthesis can be upscaled to the kg range with industrial sintering …
ePTFE functionalization for medical applications
2021
Abstract Polytetrafluoroethylene (PTFE) is a ubiquitous material used in implants and medical devices in general due to its high biocompatibility and inertness; blood vessels, heart, jawbone, nose, eyes, or abdominal wall can benefit from its properties in the case of disease or injury. Its expanded version, ePTFE, is an improved version of PTFE with better mechanical properties, which extend its medical applications. However, ePTFE implants often lack improvement in properties such as antibacterial, antistenosis, or tissue integration properties. Improvements in these properties by several strategies of functionalization for medical purposes are discussed in this review. Covalent and non-c…
Hemostatic agents in endodontic surgery of maxillary molars : a randomized controlled pilot study of polytetrafluoroethylene (PTFE) strips as an adju…
2019
Background Hemostasis is of critical importance in endodontic surgery. Studies on bleeding control in maxillary molars are scarce. The present study compares the efficacy of two hemostatic techniques in controlling bleeding in endodontic surgery. Material and Methods A randomized two-arm pilot study involving 30 patients with peri-radicular lesions in maxillary molars (first and second molars) was carried out including the following hemostatic agents: polytetrafluoroethylene (PTFE) strips as an adjunct to epinephrine impregnated gauze (test group; n = 15) and aluminum chloride (Expasyl™) (control; n = 15). Bleeding control was independently assessed by the surgeon and by two blinded observe…
Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography
2017
[EN] In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch®), or mixtures of H2O2 and H2SO4, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification…
Photografted fluoropolymers as novel chromatographic supports for polymeric monolithic stationary phases
2018
[EN] In this study, porous polymer monoliths were in situ synthesized in fluoropolymers tubing to prepare microbore HPLC columns. To ensure the formation of robust homogeneous polymer monoliths in these housing supports, the inner surface of fluoropolymer tubing was modified in a two-step photografting process. Raman spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the inner poly(ethylene-co-tetrafluoroethylene) (ETFE) wall and the subsequent attachment of a monolith onto the wall. Poly(glycidyl methacrylate-co-divinylbenzene), poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) and poly(styrene-co-divinylbenzene) monoliths were in situ synt…
A Novel Technique Using Polytetrafluoroethylene Tape to Solve Screw Loosening Complication in Implant-Supported Single Crowns
2020
This study aimed to analyze a novel technique to make screws with greater untightening resistance and to solve screw loosening in implant-supported single crowns. Thirty grade IV titanium straight abutments were screwed onto 30 external hex implants using grade IV titanium screws (30 Ncm). They were exposed to cyclic loading (300,000 cycles, 200 N). Samples were divided into 4 groups (15 samples per group): new screws (SCREW group) (control), reused screws (rSCREW group), new screws wrapped with polytetrafluoroethylene (PTFE) tape (PTFE group), and reused screws wrapped with PTFE tape (rPTFE group). Reverse torque values (RTVs) were recorded with a digitally calibrated implant motor. Mean R…
Resource or waste? A perspective of plastics degradation in soil with a focus on end-of-life options.
2018
‘Capable-of-being-shaped’ synthetic compounds are prevailing today over horn, bone, leather, wood, stone, metal, glass, or ceramic in products that were previously left to natural materials. Plastic is, in fact, economical, simple, adaptable, and waterproof. Also, it is durable and resilient to natural degradation (although microbial species capable of degrading plastics do exist). In becoming a waste, plastic accumulation adversely affects ecosystems. The majority of plastic debris pollutes waters, accumulating in oceans. And, the behaviour and the quantity of plastic, which has become waste, are rather well documented in the water, in fact. This review collects existing information on pla…
Some Features of Polymeric Membranes for Water Purification via Membrane Distillation
2011
Polymeric membranes are currently adopted in water purification processes, such as reverse osmosis (RO) and membrane distillation (MD). This latter technique is very promising for separation effectiveness and energy savings. A valuable and effective MD unit must be equipped with polymeric membranes that exhibit specific properties, for example, hydrophobicity, a narrow pore size range, a high water penetration pressure, and a large vapor permeability. In this work, we present and examine the main features of membranes for MD processes, with the aim of experimentally evaluating the related performances. Scanning electron microscopy analysis was carried out for a first estimate of the pore si…
Implantation of Gore-Tex chordae on aortic valve leaflet to treat prolapse using "the chordae technique": surgical aspects and clinical results.
2008
Background Repair of prolapsed aortic valve leaflets has been considered a challenging technique for cardiac surgeons. In this paper we describe our surgical approach, "the chordae technique." It consists of the correction of aortic cusp prolapse by shortening the free margin length and of an adjustment of the leaflets coaptation height by anchoring the prolapsing cusp to the aortic wall at the sinotubular junction level. Methods Between February 2003 and December 2006, 26 patients with one or more prolapsed aortic leaflets underwent surgical repair using the new approach. The mean age of patients was 55 ± 10 years. There were 10 (38.5%) patients with grade II aortic valve regurgitation, 4 …
External reinforcement of varicose veins with PTFE prosthesis in infrainguinal bypass surgery -- clinical results.
2003
OBJECTIVE Segmental varicose degeneration of the autogenous greater saphenous vein may limit its use in infrainguinal bypass surgery. Wrapping a PTFE prosthesis around dilated veins has emerged as an option to create externally reinforced vein bypasses. Results regarding graft patency and limb salvage were analyzed. METHODS Between September 1995 and January 2001, 35 infrainguinal bypass operations in 33 patients were performed with greater saphenous veins exhibiting segmental varicose dilatation. Grafts were followed by duplex scan and retrospective analysis of graft patency and limb salvage was performed. RESULTS One bypass prompted successful revision for early occlusion. Four bypasses r…