Good Water Repellency Research Articles

Novel polystyrene bearing highly branched hexafluoropropene trimer pendants

A novel styrenic monomer having hexafluoropropene trimer on the benzene ring was prepared. The highly fluorinated monomer was polymerized to yield a white powdery polymer, which was soluble in fluorinated solvents and had resistance to usual organic solvents, good water repellency, and low refractivity. In contrast to common fluoropolymers having linear-fluorinated side-chains, the polymer has a characteristic high glass transition temperature. Thus, the fluorinated polymer and copolymer with styrene are suitable for applications at elevated temperature. The polymers can replace the conventional fluorinated polyacrylates, which are used in large quantity as repellents with potentially generating perfluorooctanoic acid in the environment.

Direct polymer-transfer lithography for high-throughput fabrication of Cu line patterns

A novel direct polymer-transfer lithography (DPTL) technique is proposed for fabricating fine patterns having feature sizes ranging from ten to several tens of micrometers with extremely high throughput. By means of this technique, a homemade fluorine-containing polymer “ ink”, which has good water repellency, was imprinted directly onto a Cu/polyimide sheet by using an elastomeric polydimethylsiloxane (PDMS) stamp; imprinting was followed by wet etching of the Cu layer, with the transferred polymer patterns serving as an etch mask. Under the optimized imprinting conditions, Cu lead patterns with a minimum line width of approximately 10 μm were successfully fabricated with high accuracy and good reproducibility. The DPTL technique will be very useful for manufacturing flexible printed circuit boards (FPCs).

Fabrication and superhydrophobicity of fluorinated titanium dioxide nanocoatings

This study demonstrates the fabrication of a stable superhydrophobic surface with low contact angle hysteresis (CAH) using an arrangement of nanoscale TiO 2 spheres. The control of precursor quantity is selected as the key factor in determining surface roughness that significantly intensifies water contact angle (CA) of TiO 2 films. After surface fluorination treatment, the anatase-type crystalline surfaces exhibit good water repellency (CA ∼166.1°), low CAH (∼6°), and superhydrophobic stability (>60 min). Enhanced water repellency is attributed to the fact that the higher density of TiO 2 spheres results in more tortuous three-phase contact line, leading to the self-cleaning effect. Such a unique textured surface imparts many promising potentials for engineering and the development of optics devices with robust superhydrophobic materials.

Application of the Water and Oil Repellent Finishing Agent EX-910E in Polyester Nonwovens

By the experiment, the optimal technological conditions that the water and oil repellent finishing agent EX-910E is applied in polyester nonwovens were confirmed. The technological conditions include that EX-910E usage is 40g/l, the bridging agent F-2921E usage is 6g/l, the pre-curing condition is 100?× 2/3min, and the curing condition is 160?× 2.5 min. The results of the experiment indicated that the nonwovens finished by the optimal conditions possessed good water and oil repellent effects.

Self-assembly of the polysiloxane modified with cationic and perfluorocarbon groups on the polyester surface and its effect on the color shade of the dyed polyester

The polysiloxane modified with cationic and perfluorocarbon groups could form film on the polyester surface by macromolecular self-assembly process. The thin film on the polyester surface could affect the color shade of dyed materials. The effect of the polysiloxane film on the color shade of the dyed polyester was investigated by reflectance spectra, color yield (K/S) and the color differences (ΔE). The colorimetric data of CIELAB was discussed. The results show that the thin film of the polysiloxane modified with cationic and perfluorocarbon groups on the polyester surface had good water repellency. The effect of the polysiloxane film on the color shade of dyed polyester was noticeable. The K/S of the dyed polyester fabrics with the modified polysiloxane film obviously increased. The reflectance spectra of the dyed fabrics treated without and with the modified polysiloxane had not significant change.

Fluorinated hyperbranched polyester acrylate used as an additive for UV curing coatings

The fluorinated hyperbranched polyester acrylate (FHPA) was synthesized by modifying the hyperbranched polyester Boltorn H20 with fluorinated isocyanate, and characterized with 1H NMR and FTIR spectroscopic analysis. The water and oil wettability of the UV cured film with FHPA as an additive was investigated by measuring the contact angle. The results showed that an extremely low concentration of FHPA, even below 0.1 wt%, resulted in efficient decrement of the surface tension of UV cured film to 10–15 mN/m, and thus makes the film highly hydrophobic and oleophobic. The film with FHPA addition was stable in acidic and neutral solutions, and still had good water repellency after immersion in a pH 1 solution for several days. The X-ray photoelectron spectroscopic analysis confirmed that the film surface was enriched with fluorinated species. Moreover, the molecule with the highest average number of perfluoroalkyl groups had the highest tendency to aggregate at the surface of the UV cured film.

Laboratory and outdoor water repellency and dimensional stability of southern pine sapwood treated with a waterborne water repellent made from resin acids

Abstract A major consumer concern regarding lumber in above-ground exposure such as decking is the poor dimensional stability that leads to warping, splitting, and checking. One method to increase dimensional stability is to treat lumber with a water repellent. A waterborne water repellent made from the resin acid abietic acid or a commercial source of resin acids, tall oil rosin or TOR, was tested using southern pine sapwood. In laboratory water-swelling tests, the waterborne abietic acid provided water repellency that was almost equivalent to that provided by wax, while no water repellency was observed with solventborne resin acid. Wood treated with waterborne TOR also provided good water repellency in laboratory tests and fair water repellency at up to 13 months of outdoor exposure, but the laboratory efficacy was partially reduced by a water leach. The dimensional stability (cupping and checking) and mold growth on TOR-treated lumber in above-ground exterior exposure was better than for untreated boards, but not as good as for wax-treated lumber. Analysis of the wood in southern pine tree trunks of 14 or 29 years of age of various diameters and sampled at the bottom, middle and top showed that the resin acid content in southern pine wood is quite variable. This may explain the wide variation in natural water repellency and decay resistance previously observed with untreated southern pine sapwood.

A novel perfluorooctylated triazine pyridine quaternary ammonium salt: Synthesis and its application on cotton fabrics finishing

AbstractA novel perfluorooctyl‐containing triazine pyridine quaternary ammonium salt was designed and synthesized, which was applied to cotton fabrics by pad‐dry‐cure process. The treated fabrics showed good water and oil repellency, and washing durability. The water and oil repellent ratings were 100 and 6 respectively, and after 10 washing cycles, the water repellent rating was 90 and the oil repellent rating was 5. The modified specimen had the ultra low critical surface energy and showed excellent repellency to selected liquids (water, tea, milk, wine, machine oil, and wooster sauce). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4561–4564, 2006

Preparation and properties of core [poly(styrene‐n‐butyl acrylate)]–shell [poly(styrene–methyl methacrylate–vinyl triethoxide silane)] structured latex particles with self‐crosslinking characteristics

AbstractStructured latex particles with a slightly crosslinked poly(styrene‐n‐butyl acrylate) (PSB) core and a poly(styrene–methacrylate–vinyl triethoxide silane) (PSMV) shell were prepared by seed emulsion polymerization, and the latex particle structures were investigated with Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy, and dynamic light scattering. The films that were formed from the structured core (PSB)–shell (PSMV) particles under ambient conditions had good water repellency and good tensile strength in comparison with films from structured core (PSB)–shell [poly(styrene–methyl methyacrylate)] latex particles; this was attributed to the self‐crosslinking of CH2CHSi(OCH2CH3)3 in the outer shell structure. The relationship between the particle structure and the film properties was also investigated in this work. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1824–1830, 2006

Facile synthesis of polystyrene bearing highly branched perfluorinated groups

A novel styrene monomer with a highly branched perfluoroalkenyl group was readily prepared in good yield from hexafluoropropene trimer and hydroxystyrene. The fluorinated monomer radically polymerized yielded a white powdery polymer which was soluble in fluorinated solvents and had good water repellency. The polymer had a unique high glass transition temperature despite the introduction of perfluorinated groups. The monomer was copolymerized with styrene, and their monomer reactivity ratios were determined.

Synthesis of a novel perfluorooctylated polyacrylate and its application on cotton fabrics

AbstractA perfluorooctylated acrylate monomer (FAC) containing a urethane linkage was synthesized, and fluorinated polymers [perfluorooctylated polyacrylate (PFAC)] were obtained from the copolymerization of FAC with other acrylate monomers by emulsion polymerization. The size of the emulsion particles was about 40–60 nm. PFAC was applied to cotton fabrics by a pad–dry–cure process. The treated fabrics that were dried at 100°C after being washed showed good water and oil repellency: the water repellency rating and the oil repellency rating were 100 and 5, respectively. Those dried at room temperature also showed water and oil repellency: the water repellency rating was 70 and the oil repellency rating was 3. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 222–226, 2005

환경친화형 수분산성 불소 아크릴레이트 공중합체에 의한 섬유 표면개질

Waterborne fluorinated acrylate copolymer (WFAC) for surface modification of textile was synthesized from perfluoroalkyl ethyl acrylate, octadecyl acrylate, glycidyl methacrylate, surfactant and 3,3 methyl-methoxy butanol. The structures of the synthesized WFAC were determinated by FT-IR and <TEX>$^{19}F-NMR$</TEX> analysis. The thermal stability investigated with DSC and TGA was decreased with increasing the content of fluorinated acrylate in the copolymer. However, the particle sizes of WFAC were increased with increasing the content of fluorinated acrylate in the copolymer. The surface energies calculated by contact angles of WFAC were in the range of 29.80<TEX>$\~$</TEX>13.41 dyne/cm. On the observing SEM of the textile surface treated with WFAC, the textile was swollen and compacted with increasing the concentration of water repellency agent. WFAC synthesized in this study showed a good water repellency.

Effective personal protective clothing for health care workers attending patients with severe acute respiratory syndrome

Background Optimal usability is crucial in providing protection for health care workers who are exposed to severe acute respiratory syndrome day and night while taking care of patients with the virus. No research study has yet tested the usability of personal protective clothing (PPC). Method The study was carried out in 3 stages. PPC available in Hong Kong were sorted by their physical properties in the first stage. The second stage was a single-blinded study examining the different usability aspects of the PPC. The third stage was a simulated viral load test. Results Four types were identified: good water repellency and water resistance, poor air permeability (Type A PPC); good water repellency and air permeability, poor water resistance (Type B PPC); poor water repellency, poor water resistance, and fair air permeability (Type C PPC); and good water repellency, poor air permeability, and fair water resistance (Type D PPC). Type D PPC had a significantly higher number of contamination sites on the subjects' dorsum and palm. Type C PPC had the highest contamination over the trunk. Findings in the viral load test showed that there was a significant difference in the contamination of the face (t = 4.69, df = 38, P<.00) between 1 and 2 strokes. Conclusion Type A PPC is effective in providing a desirable protective function against droplet splash, if a disposable PPC is required. Type C PPC, the surgical gown, is also appropriate, as the cost is low, air permeability is fair, and the level of possible hand contamination is lowest among the 4 groups in the current study.

Miscibility of poly(vinylidene fluoride) and atactic poly(methyl methacrylate)

AbstractDifferent results for the miscibility between poly(vinylidene fluoride) (PVDF) and atactic poly(methyl methacrylate) (at‐PMMA) have been reported. In this study, the interaction between PVDF and at‐PMMA was confirmed, although such a kind of force was weak. With increasing PVDF weight fraction, the blends exhibited more heterogeneous properties, and the films thus appeared more opaque. The difference spectra after subtraction of PVDF and poly(methyl methacrylate) (PMMA) showed that the interaction between the carbonyl groups of PMMA and the hydrogen atoms of PVDF increased as the stretch vibration of CO bonds band shifted to a lower frequency with higher PVDF content. From the computer analysis, the sum spectra of the blends could not be obtained by simple addition of the separate spectra of the homopolymers. The contact angle measurement demonstrated that the hydrophobicity against water increased with PVDF content and that contact angles against water were larger than 90° when the PVDF content exceeded 30%, indicating good water repellency. The contact angles against n‐hexane, however, could not be measured because of the complete wetting of the film by n‐hexane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1–5, 2004

Graft-polymerization of a hydrophobic monomer onto PAN textile by low-pressure plasma treatments

In order to confer a good and durable water and oil repellence to polyacrylonitrile (PAN) fabrics, the fluorinated monomer 1,1,2,2, tetrahydroperfluorodecyl acrylate (AC8) was graft-polymerized onto PAN samples using a low-pressure microwave (MW) plasma process. The property was achieved by creating covalent bonding between the PAN fabrics and the fluorinated polymer. The grafting and the polymerization processes were followed by weighing measurements, XPS, IR(ATR) spectroscopies and SEM. The impermeability of the fabrics and the durability of the coating were investigated by Schmerber tests. Moreover, these tests allowed us to appreciate the effect of a reorientation of the fluorinated chains at the surface and also the role played by the addition of a small amount of a cross-linking agent on the surface properties.

Trifluoromethylation by bis(trifluoroacetyl) peroxide of polymers bearing benzene rings

Bis(trifluoroacetyl) peroxide was prepared in good yield by the reaction between trifluoroacetic anhydride and sodium peroxide under anhydrous conditions. Polymers bearing benzene rings, polystyrene, poly(phenylene oxide) and poly(diphenylacetylene) were modified chemically by the peroxide. The resulting trifluoromethylated polymers have good solubilities in common organic solvents, and their cast films have good water repellency. The trifluoromethylated poly(diphenylacetylene)s have high gas and vapor permeabilities.

PEROXIDASE-CATALYZED POLYMERIZATION OF FLUORINE-CONTAINING PHENOLS

Peroxidase-catalyzed oxidative polymerization of fluorine-containing phenols has been performed in a mixture of a water-miscible organic solvent and buffer at room temperature under air. The monomers used were 2,6-difluorophenol, 3- and 4-fluorophenols. In the polymerization of 2,6-diflurophenol catalyzed by horseradish peroxidase (HRP), effects of an organic solvent, buffer pH, and their mixed ratio have been systematically investigated with respect to the polymer yield and molecular weight. The resulting polymer was soluble in common polar organic solvents and showed good water repellent property. From NMR and IR data, it was supposed that the polymer was of mainly 2,6-difluoro-1,4-oxyphenylene unit. Elemental analysis showed that the elimination of a small amount of the fluorine atom took place during the polymerization. HRP catalysis induced the polymerization of 3- and 4-fluorophenols, yielding a new class of fluorine-containing polyphenols.

Transparent Water-repellent Films Containing Fluoro-alkyl Functions by RF Plasma-enhanced CVD

SummaryTransparent water-repellent films containing fluoro-alkyl functions were prepared on polycarbonate, glass and Si substrates by rf plasma-enhanced CVD. The vapours of the fluoro-alkyl silanes were used as raw materials. The substrate temperature during deposition was around 50°C. The films obtained had good water repellency. The maximum contact angle for a water drop was 107 degrees. The contact angles obtained depended on the number of—(CF2)—in FAS molecules. FTIR and XPS were used to investigate the film properties. The existence of the fluoro-alkyl functions CP3—,—CF2—and >CF—was confirmed at the film surfaces. The transmittance of the PC substrate was improved by the coating. These films also have a function as anti-reflective coatings.

Formation of hydrophobic layers on biologically degradable polymeric foils by plasma polymerization

Biodegradable polymer foils made by extrusion of a mixture of potatoes and maize starch were coated by plasma polymerization of hexamethyldisilazane (HMDSN) and hexamethyldisiloxane (HMDSO) in order to prevent the direct action of water while retaining the biodegradability of the foils as much as possible. Foils coated at higher monomer concentrations in the argon feed (17% and 11% for the HMDSN and the HMDSO, respectively) and at higher RF power (5 W and 2 W, respectively) became highly hydrophobic (water contact angle 97° and 103°, respectively), i.e. they showed a good water repellency. Beside a small increase of the induction period, the biodegradability remained unaffected by the coatings.

Preliminary study on making of water resistance wood fiberboard

In the present study, described that preparation of oligoesterified wood fibre by the addition reaction of the wood Tibre with maleic anhydride (MA) and allyl glycidyl ether (AGE).Further, made of crosslinkable oligoesterified fiber board at high temperature and under high pressures, accompanying plasticization of the wood fibre components. The product exhibited the high the modulus of repture in bending (MOR), good water repellency and dimensional stability.