Fluoropolymer Research Articles

Metachronous Malingnancy, 27 Years After Teflon Cordal Injection

We report a rare case of a patient known for a long-time history of iatrogenic VC paralysis, with unusual PET-CT findings. Due to a bilateral paragangliomas (PGLs), 27 years before the patient underwent a left jugulo-petrosectomy. After admission for contralateral sudden hearing loss, MRI and PET-CT scans were acquired. We tried to critically analyze the clinical relevance of multimodal imaging in an unusual condition of comorbities. Moreover, we suggested a physiopathological interpretation of collecting imagings and clinical otorhinolaryngological aspects. We could determine that high SUV in paralyzed left VC was related to a foreign-body reaction after laryngeal injection by polytetrafluoroethylene fluoropolymer resin (Teflon) performed 27 years before. Moreover, an asymptomatic pT1c mixed lung adenocarcinoma was serendipitously detected in the left lung. The SUVs of these two lesions were both compatible with neoplasms. A further possible lesion in the right lung highlighted by MRI was not confirmed by PET-CT imaging (MRI artifact). Although Teflon is no longer in use for laryngeal injection, clinicians should be aware of the potential misinterpretation laryngeal findings in patients with such a clinical history, even long time after the procedure.

Multimedia fate and transport simulation of perfluorooctanoic acid/ perfluorooctanoate in an urbanizing area

Strong global demand leads to significant production of fluoropolymers (FP) in China which potentially release large quantities of perfluorooctanoic acid/perfluorooctanoate (collectively called PFOA/PFO) to the environment. Modelling the fate and transport of PFOA/PFO provides an important input for human health risk assessment. Considering the effects of urbanization and existing forms of PFOA/PFO, this study used the modified multispecies Berkeley-Trent-Urban-Rural model to simulate the transfer behavior of PFOA/PFO in the Bohai Rim, China. Spatial distributions of PFOA/PFO emissions during the year 2012 for the study area were illustrated. About two thirds of the total amount of PFOA/PFO was estimated to be released into fresh water, and the total releases to rural areas were 160-fold higher than those to urban areas due to the location of fluorochemical industrial parks. The simulations predicted that hydrosphere was the fate of PFOA/PFO, followed by soil and vegetation, which was consistent with field data. The highest PFOA/PFO concentration was modeled in the Xiaoqing River basin with a value of 32.57 μg/L. The PFOA/PFO concentrations in urban soils were generally higher than those in rural soils except for grids 1, 3 and 46. In addition, it was estimated that the total flux of PFOA/PFO entering into the Bohai Sea was 24.57 ton/year, 100-fold higher than that of perfluorooctane sulfonates (PFOS).

DuPont sets new plant for fluoropolymer

DuPont plans to spend $45 million to build a facility in Newark, Del., for its Kalrez-brand perfluoroelastomer. The firm says the facility will be twice the size of an existing Kalrez plant in Newa...

Electrowetting on dielectric: experimental and model study of oil conductivity on rupture voltage

Electrowetting on dielectric devices uses a conducting (water) and insulating (oil) liquid phase in conjunction on a dielectric layer. In these devices, the wetting properties of the liquid phases can be manipulated by applying an electric field. The electric field can rupture the initially flat oil film and promotes further dewetting of the oil. Here, we investigate a problem in the operation of electrowetting on dielectric caused by a finite conductivity of the oil. In particular, we find that the voltage at which the oil film ruptures is sensitive to the application of relatively low DC voltages prior to switching. Here, we systematically investigate this dependence using controlled driving schemes. The mechanism behind these history effects point to charge transport processes in the dielectric and the oil, which can be modeled and characterized by a decay time. To quantify the effects the typical response timescales have been measured with a high-speed video camera. The results have been reproduced in simulations. In addition, a simplified yet accurate equivalent circuit model is developed to analyze larger data sets more conveniently. The experimental data support the hypothesis that each pixel can be characterized by a single decay time. We studied an ensemble of pixels and found that they showed a rather broad distribution of decay times with an average value of about 440 ms. This decay time can be interpreted as a discharge timescale of the oil, not to be confused with discharge of the entire system which is generally much faster (<1 ms). Through the equivalent circuit model, we also found that variations in the fluoropolymer (FP) conductivity cannot explain the distribution of decay times, while variations in oil conductivity can.

Influence of fluoropolymer surface wettability on electrowetting display performance

Amorphous fluoropolymer (FP), as a material for both insulating and hydrophobic coating, plays an essential role in electrowetting displays (EWD). In this work, three FPs based on Teflon AF1600, Hyflon AD60 and Cytop 809A were studied according to their influence on the EWD performance. Both water/air and oil/water contact angles were utilized to compare the surface wettability of these three FPs. Reversible and fast optical switch could be achieved in the EWD devices fabricated using all three FPs; however, the less hydrophobicity of the Cytop 809A surface would lead to a slower Off-switching speed or even incomplete close of the micro-pixels. The “reflow” temperature for restoring the hydrophobicity of fluoropolymer surface should be high enough to achieve a sufficient surface recovery, and at the same time avoid inducing failures like film dislocation and breakdown. The optimal “reflow” temperature has been investigated and evaluated based on the EWD performance. This work would help us deeply understand the surface wettability effect on fluidic behavior in micro-pixels driven by electrowetting, and related optical phenomena in EWDs as well.

Imparting superhydrophobic and biocidal functionalities to a polymeric substrate by the sonochemical method

Multifunctional substrates with superhydrophobic and biocidal properties are gaining interest for a wide range of applications; however, the production of such surfaces remains challenging. Here, the sonochemical method is utilized to impart superhydrophobicity and antimicrobial properties to a polyethylene (PE) sheet. This is achieved by sonochemically depositing nanoparticles (NPs) of a hydrophobic fluoro-polymer (FP) on the PE sheets. The polymer is a flexible, transparent fluoroplastic composed of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride in the form of a powder. The NPs of polymers are generated and deposited on the surface of the PE using ultrasound irradiation. Optimizing the process results in a homogeneous distribution of 110–200 nm of NPs on the PE surface. The coated surface displays a water-contact angle of 160°, indicating excellent superhydrophobicity. This superhydrophobic surface shows high stability under outdoor conditions for two months, which is essential for various applications. In addition, metal-oxide nanoparticles (CuO or ZnO NPs) were integrated into the polymer coating to achieve antibacterial properties and increase the surface roughness. The metal oxides were also deposited sonochemically. The antibacterial activity of the FP@ZnO and FP@CuO PE composites was tested against the bacterium Staphylococcus aureus, and the results show that the FP@CuO PE can effectively eradicate the bacteria. This study highlights the feasibility of using the sonochemical method to deposit two separate functions, opening up new possibilities for producing “smart” novel surfaces.

High performance of fluoro polymer modified by hexa-titanium boride nanocomposites

In the present research polyvinylidene fluoride was modified by loading the ceramic titanium boride (TiB2) through sonication route. The structure, morphology, thermal, dielectric and softness properties were disclosed as a function of TiB2 weight fraction composition. The decreased interplanar distance d (A) and increased crystallinity D (A) confirmed by X-ray diffraction technique. The C=C stretching band is shifted due to loading (wt%) of TiB2 confirmed by Fourier transform infrared spectroscopy. Electronic structure (π–π* transition at λ = 271 nm) demonstrated the decrease in direct band gap (Eg) of nanocomposites has been confirmed by Ultraviolet–Visible spectroscopy. Optical polarizing microscopy confirms the dispersion of TiB2 in host polymer system. The TiB2 aggregated morphology was observed by the scanning electron microscopy (SEM). Subatomic nanoscale topography confirm the textured pattern of fillers by atomic force microscopy. The energy dispersive X-ray spectroscopy (EDXS) reveals the presence of titanium (Ti) and boron (B) elemental composition. The increased glass transition temperature (Tg), melting temperature (Tm) and thermal degradation (Td) is due to TiB2 weight fraction loading by thermogravimetric analysis. Dielectric constant (er) increased due to loading of TiB2 (wt%) and measured as a function of frequency and obeys the Maxwell–Wagner–Sillars interfacial polarization model. The composition of TiB2 demonstrated the influence on decreased dissipation factor (tan δ) ultimately to control the dielectric loss relatively. The decrease in softness due to crystalline phase of nanocomposites examined by shore A durometer test. The prospectus and scope of this investigation may have headway to high charge storing multilayer capacitors and electronic applications.

Retraction of “Environmentally Compliant Fluoro-Containing MMA/nBA Colloidal Dispersions; Synthesis, Molecular Modeling, and Coalescence”

While aqueous phase colloidal synthesis of F-containing dispersions is often restricted by low solubility and surface tension of monomers, the use of bioactive dispersing agents, such as phospholipids, may alleviate these problems. Using 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), we copolymerized heptafluorobutyl methacrylate (FBMA), heptafluorobutyl acrylate (FBA), heptadecafluorodecyl methacrylate (FMA), heptadecafluorodecyl acrylate (FA) with methyl methacrylate (MMA) and n-butyl acrylate (nBA) monomers which resulted in the formation of stable nonspherical colloidal dispersions that contain up to 15% (w/w) of the fluoropolymer (FP) phase. These studies report for the first time an aqueous phase FP colloidal dispersion synthesis without the use of fluoro-dispersing agents. Experimentally determined by transmission electron microscopy (TEM) particle phase-separated morphologies consist of the FP phase that polymerize on the surface of p-MMA/nBA core particles. Thermodynamic molecular modeling sim...

Fluoropolymer-Based Flexible Neural Prosthetic Electrodes for Reliable Neural Interfacing.

We covalently bound fluoropolymer (FP) films by plasma treatment followed by thermal pressing at temperatures below their melting point and fabricated an adhesion-metal-free flexible gold electrode array entirely encapsulated by the FP film, excepting the active electrode openings. The fabricated device was chemically resistant and was modified to have a lower impedance and efficient charge injection capability. The fabricated device was evaluated in vivo in rats and was confirmed to record the epidural epileptiform activity induced by chemical administration. The chemically inert nature of FPs and the gold electrode is expected to facilitate reliable neural interfacing without abiotic issues. Plasma treatment-induced covalent binding of FP films can also be utilized in a variety of applications requiring durability, such as implantable biosensors and sensor platforms operating under chemically harsh environments, including humid conditions.

Volatile organic compound and semivolatile organic compound outgassing rates for ethylene propylene diene monomer and fluoropolymer seals

High-power laser facilities, such as Laser MegaJoule, are currently being operated for inertial confinement fusion experiments. Emission of volatile organic compounds (VOC) and moreover semivolatile organic compounds (SVOCs) from seals in laser environment is of tremendous importance for the optics lifetime and laser performance. That is why all the seals were screening in the same conditions: 48 h at 30°C and three successive cycle of 1.5 h at 50°C. This paper focuses on the qualification test performed on three seals: two ethylene propylene diene monomer (EPDM) and one fluoropolymer (FPM). It is shown that the molded and the extruded EPDM do not outgas the same amount neither the same molecules whereas EPDM and FPM outgas nearly the same level of phthalates.

Highly luminescent and free-standing, PVDF/doped ZnS nanocomposite films for flexible device applications

Zinc Sulphide doped with manganese (ZnS:Mn) and copper (ZnS:Cu) is well studied, due to its promising luminescence characteristics. Though there are numerous publications related to manganese and copper doped zinc sulphide, there are no reports on the growth of free standing and stable nanocomposite films of ZnS:Mn or ZnS:Cu with a polymer. The search for freestanding, flexible, mechanically and thermally stable films endowed with the excellent luminescent properties of doped zinc sulphide is the motivation behind the present studies. Poly(vinylidene flouride) (PVDF) is a fluoro polymer with impressive piezoelectric, ferroelectric and pyroelectric properties and at the same time highly flexible and processable. When PVDF/ doped ZnS nanocomposite film is placed in UV light, bright yellow orange luminescence is observed for the manganese doped film and blue luminescence, for the copper doped film. These nanocomposite films offer high prospects of wide range of applications in field emission displays, plasma displays and electroluminescent devices. By combining the yellow orange emission of ZnS:Mn and the blue emission of ZnS:Cu in the required optimised ratio, it is possible to develop white light emitting, freestanding, stable and flexible nanocomposite films of PVDF/doped ZnS.

Toxicity from fluoropolymer-containing grout, tile and stone floor sealants reported to the UK National Poisons Information Service 2009–2015

Context: Grout, tile and floor stone sealants contain a solvent, a water-repelling agent and in the case of aerosols a propellant. The water-repelling agent used is typically a fluoropolymer resin, a silicon-based resin, or a combination of both.Objective: To report the clinical course in patients exposed to fluoropolymer-containing sealants referred to the United Kingdom National Poisons Information Service.Methods: A retrospective analysis was performed of telephone enquiries received between 2009 and 2015.Results: 101 enquiries involving 96 exposures were received. The majority of the exposures (n = 88) occurred when the sealant was delivered from an aerosol. Twelve patients were exposed occupationally and the remainder were exposed while using the product at home. Eighty-nine exposures were as a result of inhalation alone, two followed ingestion, three skin contact and one eye contact; one involved inhalation and eye contact. All 90 patients exposed by inhalation developed clinical features: 31 had a World Health Organisation/International Programme on Chemical Safety/European Commission/European Association of Poison Centres and Clinical Toxicologists Poisoning Severity Score of 1 (minor toxicity), 51 patients had features of moderate toxicity (PSS 2) and eight were graded PSS 3 (severe poisoning). The most common features were dyspnea (n = 52; 57.8%; 95% CI = 47.0–68.5), chest pain/tightness (n = 34; 37.8%; 95% CI = 27.2–48.4), coughing (n = 27; 30.0%; 95% CI = 20.0–40.0) and sinus tachycardia (n = 11; 12.2%; 95% CI = 4.1–18.2); hypoxemia was present in 20 (22.2%; 95% CI = 13.1–31.4). At the time of the enquiry a chest X-ray had been performed on 15 patients: in eight patients (all of whom were PSS 3) the X-ray was reported as being abnormal and showed bilateral shadowing.Conclusions: This study demonstrates that if fluoropolymer-containing sealants are inhaled then clinical features may occur and in a small proportion (9%) these features may be severe.

Blue green fluorescence from freestanding films of PVDF/ZnS:Cu Nanocomposites

The growth of a novel nanocomposite consisting of Poly Vinylidene Di Fluoride (PVDF) and copper doped zinc sulphide (ZnS:Cu), its realization as flexible freestanding films and its application prospects as a bluish green phosphor form the essence of the work presented in this paper. PVDF is a semicrystalline fluoro polymer with the repeat unit of CH2-CF2.The photoluminescence emission characteristics were investigated in detail for various concentrations of ZnS:Cu in the nanocomposite films. The highlight of the present work is the observation that these luminescent films can be easily peeled off to yield free standing films which are quite stable and flexible.

Fluorinated zirconia-based sol-gel hybrid coatings on polycarbonate with high durability and improved scratch resistance

Hard, scratch-resistant and transparent fluoropolymer-based hybrid coatings are successfully prepared through the sol-gel chemistry and investigated, in the attempt to correlate the chemical, physical and surface properties of these materials with the mechanical properties (i.e. hardness and elastic modulus) measured at the nanoscale by atomic force microscopy (AFM). The organic component of these coatings consists in a hydroxyl-functional fluoropolymer resin, which belongs to the class of chlorotrifluoroethylene-vinylether copolymers and exhibits remarkable properties such as easy handling, great weather resistance, good adhesion and flexibility of coatings. A functionalization of this copolymer is also performed using an isocyanate-functionalized silane in order to assure a covalent cross-linking of organic fluorinated resin with inorganic phases. The combination of the silanized chlorotrifluoroethylene-vinylether copolymer with different sols composed of silica and zirconia is used to obtain high scratch resistance and high durability coatings on polycarbonate. A series of three hybrid coatings with different zirconia/silica molar ratios (0.09/0.48) are developed and analyzed by differential scanning calorimetry (DSC), water contact angle measurements, pencil hardness and adhesion tests. AFM scratch hardness, coating wettability and surface composition measured by Fourier transform infrared spectroscopy (FTIR) are regularly monitored over long-term UV–vis light exposure, to assess the durability of the hybrid coatings. Interestingly, the hybrid fluorinated coatings exhibit an improved scratch resistance and a superior long-term stability when exposed to an accelerated weathering, compared to pristine PC substrates. The mixed silica/zirconia hybrid coatings with a low and intermediate zirconia-to-silica ratio also show excellent mechanical strength, high level of hardness and superior integrity after long-term light exposure.

Behavioral Assay on Asian Citrus Psyllid Attraction to Orange Jasmine

The Asian citrus psyllid (ACP) is an important pest because it transmits a bacterium putatively responsible for huanglongbing, a devastating citrus disease. Research on ACP chemical ecology is of interest with respect to identifying attractants and repellents for managing the psyllid. We report on an assay for investigating ACP attraction to the foliar odor of one of its host plants, orange jasmine (Murraya exotica L.). Flush shoots from this plant were placed into 25 dram vials covered with a paper wrapper, a lid with a small entrance hole was snapped onto each vial, the vials were placed into a small cage, adult ACP were released into the cage, and the location of the adults was determined 24 h later. A positive response required an adult to find and enter a vial. When single males or females were released, they were attracted into vials with flush 64 % of the time. At release rates of 25, 50 or 100 adults with 30 repetitions for each rate, relatively large mean percentages of adults (ca. 83 %) positively responded to flush shoots. ACP can escape from the assay vial and will do so if flush is not present. Working with ACP in empty vials, fluoropolymer resin applied to the inside of vials reduced escapes but did not eliminate them. An entrapment funnel for reducing escapes was tested, but it reduced ACP response rates. A good method of preventing escapes remains to be developed. When two vials of flush were placed in the assay cage and one was treated with a candidate repellent, only 8 % of adults settled in the vial with the repellent.

Global fluoropolymer coating additives market worth $1703.02 million by 2018

Global fluoropolymer coating additives market worth $1703.02 million by 2018

Magnetic, durable, and superhydrophobic polyurethane@Fe3O4@SiO2@fluoropolymer sponges for selective oil absorption and oil/water separation.

Magnetic, durable, and superhydrophobic polyurethane (PU) sponges were fabricated by chemical vapor deposition (CVD) of tetraethoxysilane (TEOS) to bind the Fe3O4 nanoparticles tightly on the sponge and then dip-coating in a fluoropolymer (FP) aqueous solution. The sponges were characterized using scanning electron microscopy and other analytical techniques. The effects of CVD time of TEOS and FP concentration on wettability, mechanical properties, oil absorbency, and oil/water selectivity of the sponges were also investigated. The sponges exhibit fast magnetic responsivity and excellent superhydrophobicity/superoleophilicity (CAwater = 157° and CAoil ≈ 0°). The sponges also show very high efficiency in oil/water separation and could, driven by a magnet, quickly absorb floating oils on the water surface and heavy oils under water. Moreover, the PU@Fe3O4@SiO2@FP sponges could be used as membranes for oil/water separation and for continuous separation of large amounts of oil pollutants from the water surface with the help of a pump. The in turn binding of Fe3O4 nanoparticles, SiO2, and FP can also improve mechanical properties of the PU sponge. The sponges maintain the superhydrophobicity even when they are stretched with 200% strain or compressed with 50% strain. The sponges also show excellent mechanical stability, oil stability, and reusability in terms of superhydrophobicity and oil absorbency. The magnetic, durable, and superhydrophobic PU sponges are very promising materials for practical oil absorption and oil/water separation.

Assessment of the performance of three ultrafiltration membranes for fractionation of ovine second cheese whey

Second cheese whey (SCW) is a whey by-product resulting from the production of ovine whey cheeses, by thermal aggregation of proteins. It constitutes a natural source of valuable compounds, such as proteins, small peptides, oligosaccharides, lactose and minerals. In this work, ultrafiltration was used for fractionation of second cheese whey. Three commercial membranes with similar cut-off (10 kDa), made from different hydrophilic materials: RC70PP (cellulose regenerated acetate), ETNA10PP (composite fluoro polymer) and UFX10pHt (polysulphone permanently hydrophilic) were tested. The performance of the three membranes was studied in terms of permeate fluxes, reversible and irreversible fouling resistances, water recovery fluxes and rejection factors. Membrane RC70PP showed better performance, because it had the highest permeate fluxes, the lowest irreversible fouling, with good selectivity (compared with that of membrane ETNA10PP) and water recovery fluxes of about 100%. The higher hydrophilicity of membrane RC70PP seems to justify these results.

Ultrafiltration of black tea using diafiltration to recover valuable components

Ultrafiltration of black tea liquor in a constant volume diafiltration regime has been carried out to remove the haze characteristically associated with this product. Commercial polymeric membranes with a range of molecular weight cut-offs (25, 50, and 100 kDa) fabricated from both polysulphone (PS) and fluoropolymer (FP) were used to assess the total solids throughput of the system. A shortfall in the amount of polyphenols transmission over the amount of residual tea solids transmission is the main driver for operating in this regime. The result of this shortfall means membrane permeates are impaired in terms of colour, flavour and health-giving properties. From an initial tea concentration of 1.0 wt.%, diafiltration was carried out, with rejection coefficients for total solids and total solids being assessed continuously. An acceptable (but not ideal) permeate product was the result, which showed excellent clarity (<2.0 nephelometric turbidity units (NTU) in the majority of cases) although the associated transmission in polyphenols meant the tea has lost some of the deep red colour associated with a higher-quality tea infusion. This shortfall in polyphenols transmission gave rise to higher concentrations of polyphenols in the retained side of the process than for original raw tea. In addition, membranes were pre-treated using ethanol, which had a significant effect on both their water permeability and zeta potential. When used in a filtration environment, fluxes increased for all membranes following treatment, with the 100 kDa PS membrane recording a 41% increase in terminal filtration flux. With the exception of the 25 kDa PS membrane, alcohol treatment resulted in all membranes showing increases in the total solids throughput, with the proportion of polyphenols transmitting through the membrane increased to a greater degree over all other components. The disproportionate increase in polyphenols transmission was attributed to reduced charge interactions following ethanol treatment. The results show that as fouling builds up, the separation of polyphenols from all other tea solids increases, meaning that small batches (relative to membrane area) and short-term operation are favoured, in order to maximise polyphenol content in the product stream. In summary, the operation of UF in a diafiltration regime is shown to be an effective industrial processing option for the clarification of black tea liquors.

Facile preparation of super durable superhydrophobic materials

The low stability, complicated and expensive fabrication procedures seriously hinder practical applications of superhydrophobic materials. Here we report an extremely simple method for preparing super durable superhydrophobic materials, e.g., textiles and sponges, by dip coating in fluoropolymers (FPs). The morphology, surface chemical composition, mechanical, chemical and environmental stabilities of the superhydrophobic textiles were investigated. The results show how simple the preparation of super durable superhydrophobic textiles can be! The superhydrophobic textiles outperform their natural counterparts and most of the state-of-the-art synthetic superhydrophobic materials in stability. The intensive mechanical abrasion, long time immersion in various liquids and repeated washing have no obvious influence on the superhydrophobicity. Water drops are spherical in shape on the samples and could easily roll off after these harsh stability tests. In addition, this simple dip coating approach is applicable to various synthetic and natural textiles and can be easily scaled up. Furthermore, the results prove that a two-tier roughness is helpful but not essential with regard to the creation of super durable superhydrophobic textiles. The combination of microscale roughness of textiles and materials with very low surface tension is enough to form super durable superhydrophobic textiles. According to the same procedure, superhydrophobic polyurethane sponges can be prepared, which show high oil absorbency, oil/water separation efficiency and stability.