UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersion

Preparation and Characterization of Fluorinated Acrylate and Epoxy Co-Modified Waterborne Polyurethane

Conventional waterborne polyurethane (WPU) has poor water resistance and poor overall performance, which limits its application in outdoor coatings. A solution to this problem is urgently needed. The introduction of fluorine-containing groups can effectively improve the water resistance of WPU. In this study, a new fluorinated chain extender (HFBMA-HPA) synthesized by free radical copolymerization and epoxy resin (E-44) were used to co-modify WPU, and five waterborne fluorinated polyurethane (WFPU) emulsions with different fluorine contents were prepared by the self-emulsification method. The effects of HFBMA-HPA content on the emulsion particle properties, coating surface properties, mechanical properties, water resistance, thermal stability, and corrosion resistance were investigated. The results showed that the WFPU coating had excellent thermal stability, corrosion resistance, and mechanical properties. As the content of HFBMA-HPA increased from 0 wt% to 14 wt%, the water resistance of the WFPU coating gradually increased, the water contact angle (WCA) increased from 73° to 98°, the water absorption decreased from 7.847% to 3.062%, and the surface energy decreased from 32.8 mN/m to 22.6 mN/m. The coatings also showed impressive performances in the adhesion and flexibility tests in extreme conditions. This study provides a waterborne fluorinated polyurethane material with excellent comprehensive performance that has potential application value in the field of outdoor waterproof and anticorrosion coatings.

Fabrication of Perfluoropolyether Microfluidic Devices Using Laser Engraving for Uniform Droplet Production

A perfluoropolyether (PFPE)-based microfluidic device with cross-junction microchannels was fabricated with the purpose of producing uniform droplets. The microchannels were developed using CO2 laser engraving. PFPE was chosen as the main material because of its excellent solvent resistance. Polyethylene glycol diacrylate (PEGDA) was mixed with PFPE to improve the hydrophilic properties of the inner surface of the microchannels. The microchannels of the polydimethylsiloxane microfluidic device had a blackened and rough surface after laser engraving. By contrast, the inner surface of the microchannels of the PFPE-PEGDA microfluidic device exhibited a smooth surface. The lower power and faster speed of the laser engraving resulted in the development of microchannels with smaller dimensions, less than 30 μm in depth. The PFPE and PFPE-PEGDA microfluidic devices were used to produce uniform water and oil droplets, respectively. We believe that such a PFPE-based microfluidic device with CO2-laser-engraved microchannels can be used as a microfluidic platform for applications in various fields, such as biological and chemical analysis, extraction, and synthesis.

UV LED Curable Perfluoropolyether (PFPE)-Urethane Methacrylate Transparent Coatings for Photonic Applications: Synthesis and Characterization

The contribution aims to bring forth a novel synthesis route in developing transparent UV LED-curable coatings accounting for various exposure options. A selection of perfluoropolyether (PFPE)-urethane methacrylate and acrylate resins, free-radical photo-initiator Omnirad 2100, and two distinct silane-based crosslinking agents were blended under a weight ratio of 75:20:5 (without crosslinker) and 70:15:5:10, respectively. The coatings were cured under a UV LED 4 × 3 matrix light emitting source, in a chamber under a controlled atmosphere, by means of an in-house developed conveyor belt type platform, at different conveyor belt speeds (5, 50, 150, 250, and 500 mm/s). The morphologies of fabricated coatings were characterized by FTIR revealing high conversion rates (e.g., from 98 to 100%) for increased exposure time as a result of the 5 or 50 mm/s values, on all combinations. Dynamic-mechanical and optical properties of UV LED-cured transparent coatings were also investigated. A negative shift of the glass transition temperature values with a decrease in exposure time, in all combinations, from about 60 °C to 30 °C, along with storage moduli lowering in the glassy plateau further favors higher exposure times for curing. The refractive indices of poly-mers were from 1.38 to 1.40, whereas the thermo-optic coefficients are showing minor changes around the value of 2.55∙10^-4 K^-1.

Bulk Modification of Thermoplastic Polyurethanes for Self-Sterilization of Trachea Intubation

Implantable medical devices are widely used, but biomaterial-associated infections (BAIs) impose a huge economic burden and increase the mortality of patients. Therefore, BAIs are a serious concern that must be urgently resolved. Materials with antibacterial properties have become hotspots of current research and development. In the present work, quaternized chitosan (QCS) is used as an antibacterial agent and blended with thermoplastic polyurethane (TPU) to create an antibacterial material for tracheal intubation tubes. The modified TPU material (QCS-TPU) exhibited good mechanical properties and excellent long-term antibacterial performance. Under in vitro hydrodynamic conditions, QCS-TPU retained its strong antibacterial properties. QCS-TPU also possessed a low hemolysis rate and cytotoxicity. The current work is expected to provide a facile and feasible strategy for the preparation of antibacterial catheters and aid in the discovery of promising clinical applications to prevent BAIs.

Integrated compositional and nanomechanical analysis of a polyurethane surface modified with a fluorous oxetane siliceous-network hybrid

Investigating the surface characteristics of heterogeneous polymer systems is important for understanding how to better tailor surfaces and engineering specific reactions and desirable properties. Here we report on the surface properties for a blend consisting of a major component, a linear polyurethane or thermoplastic elastomer (TPU), and a minor component that is a hybrid network. The hybrid network consists of a fluorous polyoxetane soft block and a hydrolysis/condensation inorganic (HyCoin) network. Phase separation during coating formation results in surface concentration of the minor fluorous hybrid domain. The TPU is H12MDI/BD(50)-PTMO-1000 derived from bis(cyclohexylmethylene)-diisocyanate and butane diol (50 wt %) and poly(tetramethylene oxide). Surface modification results from a novel network-forming hybrid composed of poly(trifluoroethoxymethyl-methyl oxetane) diol) (3F) as the fluorous moiety end-capped with 3-isocyanatopropylriethoxysilane and bis(triethoxysilyl)ethane (BTESE) as a siliceous stabilizer. We use an integrated approach that combines elemental analysis of the near surface via X-ray photoelectron microscopy with surface mapping using atomic force microscopy that presents topographical and phase imaging along with nanomechanical properties. Overall, this versatile, high-resolution approach enabled unique insight into surface composition and morphology that led to a model of heterogeneous surfaces containing a range of constituents and properties.

Preparation and properties of novel ultraviolet-cured waterborne polyurethanes

A new ultraviolet (UV)-cured waterborne polyurethane (WPU) mainly composed of ionic soft segments, imide groups, and a new water-soluble UV-cured cross-linking agent containing both C=C bond and carboxy group was prepared. The ionic soft segments were prepared by 1,6-hexamethylene diisocyanate , poly(propylene glycol)-600, and dimethylol butanoic acid. The imide groups were introduced into polyurethane by extending them with pyromellitic dianhydride (PMDA). The new water-soluble UV-cured cross-linking agent (MLGLY) was synthesized by hydrophilic maleic anhydride and glycerol oligomer. The particle size and the viscosity of the new anionic WPU as well as the water swelling, gel content, mechanical properties, and thermal stability of the UV-cured WPU cast films were investigated. The results showed that the best performance of WPU was obtained with 0.024 mol of PMDA and 5 wt% of MLGLY.

Modelling the surface free energy parameters of polyurethane coats-part 1. Solvent-based coats obtained from linear polyurethane elastomers

Polyurethane elastomers coating were synthesised by using typical diisocyanates, polyether and polyester polyols and HO-tertiary amines or diols as a chain extenders. Mole fractions of structural fragments (κ_exp) responsible for the polar interactions within polyurethane chains were calculated by ¹H NMR method. Obtained results were confronted with the analogous parameter values (κ_theor) calculated on the basis of process stoichiometry, considering the stage of the production of isocyanate prepolymers and reaction of their extension for polyurethanes. Trials of linear correlation between the κ_exp parameters and surface free energy (SFE) values of investigated coatings were presented. SFE values were determined by Owens–Wendt method, using contact angles measured with the goniometric method. Based on achieved results, another empirical models, allowing for prediction the influence of the kind of polyurethane raw materials on SFE values of received coatings were determined. It was found that it is possible to regulate the SFE in the range millijoules per cubic metre by the selection of appropriate substrates. It has been found that use of 2,2,3,3-tetrafluoro-1,4-butanediol as a fluorinated extender of prepolymer chains is essential to obtain coatings with increased hydrophobicity, applied among others as biomaterials—next to diphenylmethane diisocyanate and polyoxyethylene glycol.