Polyurethane Surface Research Articles

The grafted carbendazim and 2,4,6-tris(dimethylaminomethyl)phenyl group onto polyurethane to improve its antifungal effectiveness and hydrophilicity

The antifungal agent carbendazim and the water-compatible functional group 2,4,6-tris(dimethylaminomethyl)phenol (TDMP) were jointly grafted to polyurethane (PU) to develop a water-compatible antifungal PU. The water compatibility of the PU surface improved strikingly after the protonation of TDMP, as confirmed by water contact angle tests. The combined grafting of carbendazim and TDMP affected the melting and glass transition of soft segments and sharply increased the tensile stress and shape recovery capability. Carbendazim was selected as a grafted antifungal functional group due to its wide effective range of antifungal activity and its large production volume. PUs with grafted carbendazim and TDMP completely suppressed the growth of a mixture of fungi, unlike ordinary PU. Therefore, the joint grafting of both carbendazim and TDMP led to improved water compatibility, breaking tensile stress, shape recovery capability, and antifungal activity.

Preparation and properties of fluorinated silicon two‐component polyurethane hydrophobic coatings

AbstractA polyurethane (PU) hydrophobic coating was prepared by the two‐component method, polycarbonate diol and isophorone diisocyanate becoming a two‐phase composition. The PU films with hydrophobic surface were prepared by establishing a rough structure on the surface of silica (SiO2) modified with silane coupling agents (γ‐(2,3‐epoxypropoxy)propytrimethoxysilane (KH560) and (heptadecafluoro‐1,1,2,2‐tetradecyl)trimethoxysilane (FAS)). First, the surface of SiO2 was covered by a layer of hydrophobic methyl and fluorocarbon (C–F) groups. Then, the SiO2 and modified SiO2 were obtained by the introduction of KH560 and FAS with the silanol reaction by ultrasonic stirring. The effect of SiO2 and modified SiO2 on the structure and hydrophobic properties of PU was investigated by a series of test instruments. The results showed that the introduction of SiO2 and modified SiO2 was beneficial for increasing the roughness of the PU coating surface; the roughness of FAS/SiO2‐PU could reach up to 14.790 nm, four times better than pure PU. A hydrophobic modified PU coating with water contact angle 123° was fabricated by using the hydrophobic C–F group FAS as a low surface energy material and establishing a micro rough structure on the surface of PU. Moreover, PU modified with KH560 and FAS can reduce the glass transition temperature (Tg) of soft segments, resulting in improvement of micro‐phase separation. © 2020 Society of Chemical Industry

Lanthanum phenylphosphonate–based multilayered coating for reducing flammability and smoke production of flexible polyurethane foam

In the present work, lanthanum phenylphosphonate (LaPP)–based multilayered film was fabricated on the surface of flexible polyurethane (PU) foam by layer‐by‐layer self‐assembled method. The successful deposition of the coating was confirmed by scanning electron microscopy (SEM) and energy‐dispersive X‐ray (EDX). Subsequently, the thermal decomposition and burning behavior of untreated and treated PU foams were investigated by thermogravimetric analysis (TGA) and cone calorimeter, respectively. The TGA results indicated that Tmax2 of treated PU foams were increased by approximately 15°C to 20°C as compared with untreated PU foam. The peak heat release rate (PHRR) and total heat release (THR) of PU‐6 (with 19.5 wt% weight gain) were 188 kW/m2 and 20.3 MJ/m2, with reductions of 70% and 15% as compared with those of untreated PU foam, respectively. Meanwhile, the smoke production of treated PU foam was suppressed after the construction of LaPP‐based coating.

Well-Defined Gold Nanorod/Polymer Hybrid Coating with Inherent Antifouling and Photothermal Bactericidal Properties for Treating an Infected Hernia.

Biomedical device-associated infection (BAI) is a great challenge in modern clinical medicine. Therefore, developing efficient antibacterial materials is significantly important and meaningful for the improvement of medical treatment and people's health. In the present work, we developed a strategy of surface functionalization for multifunctional antibacterial applications. A functionalized polyurethane (PU, a widely used biomedical material for hernia repairing) surface (PU-Au-PEG) with inherent antifouling and photothermal bactericidal properties was readily prepared based on a near-infrared (NIR)-responsive organic/inorganic hybrid coating which consists of gold nanorods (Au NRs) and polyethylene glycol (PEG). The PU-Au-PEG showed a high efficiency to resist adhesion of bacteria and exhibited effective photothermal bactericidal properties under 808 nm NIR irradiation, especially against multidrug-resistant bacteria. Furthermore, the PU-Au-PEG could inhibit biofilm formation long term. The biocompatibility of PU-Au-PEG was also proved by cytotoxicity and hemolysis tests. The in vivo photothermal antibacterial properties were first verified by a subcutaneous implantation animal model. Then, the anti-infection performance in a clinical scenario was studied with an infected hernia model. The results of animal experiment studies demonstrated excellent in vivo anti-infection performances of PU-Au-PEG. The present work provides a facile and promising approach to develop multifunctional biomedical devices.

Effects of Tetraethyl Orthosilicate on Improving Adhesion Between Polyurethane Sponge/Hydrophobic Silica Gel Composite Materials for Oily Wastewater Treatment

The environmental disposal of oily wastewater is a challenge to household and food industries. Cost-effective oil absorbent materials for oily wastewater treatment have been developed by various methods, one of which, the modification with hydrophobic particles. However, the oil absorbents still suffer high cost and low reusability because of the insufficient adhesion between supported material and the hydrophobic particles. Herein, a low cost and simple method to fabricate oil absorbents were reported by immersing commercial polyurethane (PU) sponge in hydrophobic silica gel. The adhesion between hydrophobic silica gel to the 3D surface of PU was assisted with the use of tetraethyl orthosilicate (TEOS) as a silane coupling agent. Only 0.5% TEOS was required for up to 73% improvement of adhered calculated from % silica loading. The use of TEOS showed adhesion enhancement between the surface of PU and the silica which in turn improve reusability. Reusability test mimics the real situation of squeezing the PU/silica sponge to demonstrate good mechanical properties and flexibility. Furthermore, the PU/silica sponge displayed good and rapid absorption capacity. Results from Water Contact Angle (WCA), Scanning Electron Microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) were also used to confirm successful modification of PU with hydrophobic silica gel.

Morphology and Physicochemical Properties of Branched Polyurethane/Biopolymer Blends.

The aim of this study is the analyze the structure of branched polyurethanes based on synthetic poly([R,S]-3-hydroxybutyrate) and their blends with biopolymers and montmorillonite. The properties which would predict the potential susceptibility of these materials to degradation are also estimated. Fourier-transform infrared spectroscopy with attenuated total reflection analysis shows that poly([d,l]-lactide) is on the surfaces of polyurethanes, whereas chitosan and starch are included inside the blend network. Atomic force microscopy images have shown that the surfaces of investigated samples are heterogenous with the formation of spherulites in case of pure polyurethanes. The presence of biopolymers in the blend reduced the crystallinity of polyurethanes. Thermal stability of blends of polyurethanes with poly([d,l]-lactide) and polysaccharides decreased in comparison to pure polyurethanes. Although the tensile strength is reduced after the blending of polyurethanes with biopolymers, the elongation at break increased, especially in the case of polyurethane/poly([d,l]-lactide) blends. The presence of polysaccharides in the obtained blends caused the significant reduction of contact angle after one minute from water drop immersion. This hydrophilizing effect is the highest when montmorillonite has been incorporated into the chitosan blend. The estimated properties of the obtained materials suggest their potential sensitivity on environmental conditions.

Nitric Oxide-Generating Antiplatelet Polyurethane Surfaces with Multiple Additional Biofunctions via Cyclodextrin-Based Host-Guest Interactions.

A nitric oxide-generating polymeric coating was prepared by copolymerization of the hydrophilic monomer 2-hydroxyethyl methacrylate (HEMA) and the comonomer 1-adamantan-1-ylmethyl methacrylate (AdaMA) with subsequent incorporation of selenocystamine. The coating was applied to polyurethane (PU) as a substrate. In the presence of a NO donor, the PU-PHA-Se surface generated nitric oxide (NO). This surface was shown to inhibit platelet adhesion and human umbilical vein smooth muscle cell adhesion and proliferation. The poly(AdaMA) on the modified surface was designed to allow the incorporation of functional units into the PU-PHA-Se surface via host-guest interactions between the adamantane groups and cyclodextrin (CD) derivatives. In this work, two functional CD complexes containing lysine (CD-L) and sulfonate (CD-S) groups were incorporated into the PU-PHA-Se surface. CD-L conferred fibrinolytic activity, whereas CD-S promoted human umbilical vein endothelial cell proliferation. This NO-generating antiplatelet polymeric coating has potential as a platform for modifying surfaces with multiple additional biological functions via host-guest interactions, thus providing an alternative approach for the preparation of biomaterials with multifunctionality.

Thermal-triggered insulating fireproof layers: A novel fire-extinguishing MXene composites coating

Abstract The use of intumescent flame-retardant (IFR) coatings is one of the most highly effective methods for polymeric materials to improve their fire safety. However, organic IFR coatings show “negative effect” in a large amount of heat and smoke release during the char-forming process. Developing nanocomposite coatings that can reduce their “negative effect” and simultaneously enhance the barrier effect of fireproof char layer is particularly desirable. Herein, a novel UV-curable IFR/MXene nanocomposite coating was developed by incorporation of surface-modified MXene nanosheets in the IFR coating system, and then constructed on the surface of rigid polyurethane (RPU) foam to fabricate coated RPU foams via spray-coating and UV-cured process. The IFR/MXene coated RPU foams show a fast self-extinguished behavior and a remarked decrease in heat and smoke production, indicating the great improvement of RPU fire safety in building. The fireproof layers combined with expanded char and MXene jammed networks generated rapidly during combustion can serve as physical shield to effectively delay the release of heat and volatile products, protecting the underlying substrate from further burning. Moreover, the mechanical properties and dispersion are enhanced due to the co-cross-linking networks between the IFR coating and MXene nanosheets. As a new member of the 2D nanomaterials, MXene nanosheets have potential to be a new choice for developing high-performance nanocomposite coating for polymers to reduce their risk of fire hazard.

Layer-by-layer assembled nanocoating containing MoS2 nanosheets and C60 for enhancing flame retardancy properties of flexible polyurethane foam

A novel three bilayers nanocoating containing MoS2 nanosheets and C60 was constructed on the surface of flexible polyurethane (FPU) foam by a layer-by-layer assembly method. MoS2 nanosheets were prepared by ultrasonic-assistant exfoliation method in a mixed solvent of N-Methyl-2-pyrrolidinone (NMP) and aqueous hydrogen peroxide (30% H2O2). MoS2-C60/FPU foam was prepared by alternately submerging the FPU foam into C60/guargum and MoS2/sodium alginate suspensions. Scanning electron microscopy (SEM) characterization showed that MoS2 nanosheets and C60 nanoparticles were uniformly distributed on the surface of FPU foam matrix. Thermogravimetric analysis demonstrated that MoS2-C60/FPU foam exhibited better thermal stability than the control FPU foam. Cone calorimeter test results revealed that MoS2-C60/FPU foam with the incorporation of 5.24 wt% MoS2-C60 nanocoating had a remarkable reduction in peak heat release rate (pHRR, 47.5% reduction), total heat released (THR, 51.1% reduction) and total smoke production (TSP, 33.1% reduction) compared with those of the control FPU foam. Furthermore, the morphology and structure of char residue after cone calorimeter test were investigated by SEM and Raman spectroscopy. The possible flame-retardant mechanism of MoS2-C60/FPU foam was proposed, and this significant improvement in flame retardancy could be ascribed to the insulating barrier and adsorption effect of MoS2 nanosheets, free radicals-trapping ability of C60 in condensed phase, and the catalytic carbonization effect of the MoS2-C60 nanocoating. This work provides a new approach for producing high quality flame retardant polyurethane foam materials.

Anchored quaternary ammonium salts adsorbed on polyurethane film surfaces

A flexible, thermoset and transparent polyurethane (PUR) film with high glass transition temperature, has been deployed as a substrate for anchoring anti-bacterial molecular layers. These layers are formed by adsorbing, from an aqueous solution, a silyl anchoring quaternary ammonium salt (AQAS) with a long alkyl chain (C18) onto the PUR film surface, followed by thermal curing at 160 °C. The presence of AQAS adsorbed on the PUR film surface is confirmed by the appearance of a distinctive N1 s level XPS peak at 402 eV, attributed to quaternary nitrogen (N+). The carbonyl groups on the PUR surface appear to be the main surface binding sites for the adsorbed AQAS molecules. This interpretation is validated by the relative decrease in the intensities observed for the ν (CO) at 1700 cm−1 in the infrared spectra, and decreases in the intensity of the C1 s binding energy peak for CO at 289 eV in the XPS spectra of the PUR following AQAS adsorption. Leaching studies suggest a chemisorbed first layer and several leachable higher layers of oligomeric forms of AQAS. A PUR surface incorporating a blended polydimethylsiloxane additive exhibits similar adsorptive capacity to pristine PUR. However exposing the PUR films to oxygen plasma treatment prior to AQAS adsorption leads to a higher coverage of the adsorbate on the PUR surface. The anchoring quaternary ammonium salt (AQAS) in this current work has established potencies against a wide range of critical organisms. Antibacterial assays adapted from the JIS 2801 wet fomite method confirm the potency (3-log reduction) of these PUR-AQAS films against Staphylococcus aureus and Escherichia coli.

Types of Errors Made During Breast Augmentation with Polyurethane Implants: A Systematic Review.

Implementation of polyurethane-covered (PU) implants into practice requires a reassessment of the experience and a learning curve period. Occasional publications describe a few difficulties in this regard. However, there are no publications covering the spectrum of errors. The absence of definite information and contradictory findings makes the learning curve longer leading to many unsatisfactory results. The systematization is based on the 12years of experience with over 1000 patients and previously published data. A literature review was conducted using PUBMED with the following keywords: polyurethane or foam or sponge and breast and implant. A total of 285 articles were found (last accessed 08/13/2019). All articles concerning polyurethane implants were studied along with any articles found describing the surgical techniques applied to them. Additional references found in the above-mentioned articles were also included in the study. All errors can be divided into planning errors, errors in pocket development and surface-dependent errors, for which the polyurethane surface is the main reason. Surface-dependent errors include the errors connected to positioning and biointegration. The possible causes of late seroma with PU implants are discussed. The polyurethane surface should not be considered textured in the clinical point of view. Previous experience with non-PU implants cannot be transferred to PU implants. The learning curve is unavoidable. The systematization of errors with PU implants facilitates a decision-making process during the primary and secondary surgery and lowers the risk of the unsatisfactory results. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266.

Polydopamine as reinforcement in the coating of nano-silver on polyurethane surface: Performance and mechanisms

Polyurethane (PU) is a popular medical polymer material and plays a vital role in many artificial organs and medical devices. The antibacterial properties of medical polyurethanes have always been a research hotspot for scientists. We studied the effect of polydopamine (PDA) modification and dopamine (DA) concentration on the coating of nano-silver on polyurethane surface, and investigated the bonding mechanism between nano-silver layer and modified polyurethane. We found that the polydopamine-modified polyurethane has a better nano-silver coating on the surface and a uniform distribution.We also found that the catechol groups in the PDA film could chelate with Ag+ or [Ag(NH3)2]+ and in situ reduce the Ag+ or [Ag(NH3)2]+ to Ag0 without extra reducing agent.

Facile UV-curable fabrication of robust, anti-icing superhydrophobic coatings based on polyurethane

Abstract A novel robust, anti-icing, self-cleaning superhydrophobic coating was prepared via a simple, environmentally, friendly and efficient strategy which bond nanoparticles SiO2 to the polyurethane surface under UV-curing. By controlling the content of nano-silica, a superhydrophobic coating with sliding angle (SA) of 2° and water contact angle (WCA) of 165° was constructed. The coating can be widely applied to various substrates with excellent anti-fouling properties and acid/alkali resistance. Meanwhile, the surface of coating is robust, can maintain superhydrophobic after 750 cycles of friction. In addition, the coating has a good anti-icing property which maintains excellent superhydrophobic after being placed at −10 °C for 100 h. Hence, the coating could be widely used on the surface of transmission lines and wind turbines.

Formation of biofilms of the salmon pathogen Flavobacterium psychrophilum in differents surfaces using the CDC biofilm reactor

Aquaculture settings present a number of surfaces that can potentially act as a reservoir for Flavobacterium psychrophilum, resulting in a serious threat to the health of farmed salmonids. The aim of this study was to employ the CDC Biofilm Reactor to evaluate the capacity of F. psychrophilum to form biofilms on stainless steel, polystyrene, polyurethane, and polycarbonate. Scanning electron microscopy and confocal laser scanning microscopy were used to assess biofilm formation, while epifluorescence and qPCR methods were effectively used to determine cell contents. After a 72 h incubation period, F. psychrophilum had formed mature biofilms composed by dense, multilayered clusters of short bacilli on stainless steel, polystyrene, and polycarbonate. Nevertheless, biofilms formed on stainless steel presented a significantly higher cell density than those formed on polyurethane. Biofilm growth was poor on polyurethane surfaces. These findings will facilitate the design of appropriate guidelines for more efficiently managing F. psychrophilum and controlling the persistence of this pathogen in fish-farming environments.

Enhancing the biocompatibility of siliconepolycarbonate urethane based implant materials

Abstract Polyurethane-bases block copolymers (TPCUs) are block-copolymers with systematically varied soft and hard segments. They have been suggested to serve as material for chondral implants in joint regeneration. Such applications may require the adhesion of chondrocytes to the implant surface, facilitating cell growth while keeping their phenotype. Thus, aims of this work were (i) to modify the surface of soft biostable polyurethane-based model implants (TPCU and TSiPCU) with high-molecular weight hyaluronic acid (HA) using an optimized multistep strategy of immobilization, and (ii) to evaluate bioactivity of the modified TPCUs in vitro. Our results show no cytotoxic potential of the TPCUs. HAbioactive molecules (Mw =700kDa) were immobilized onto the polyurethane surface via polyethylenimine (PEI) spacers, and modifications were confirmed by several characterization methods. Tests with porcine chondrocytes indicated the potential of the TPCU-HA for inducing enhanced cell proliferation.

Growth of islet carbon coating on nitrogen-activated polyurethane surface

Development of discontinuous (islet) plasma coatings is of interest in the design of materials with non-uniform (selective) surface properties. In comparison with similar continuous coatings, they are more resistant to a damage induced by deformation of an elastic substrate. In this work, a formation of carbon islet coating obtained by a pulsed magnetron sputtering of a graphite target on the surface of nitrogen-activated elastic polyurethane is studied. Roughness, stiffness and surface energy of the polymer substrate are increased after the activation. High surface energy makes possible the adhesion of carbon islets (the size is ~100 μm and the thickness is 4…30 nm). The structure of such coatings depends both on the activation time and on the number of pulses of the magnetron discharge. At the initial stage of formation, the islets consist of individual shards ~1 μm in plane, further carbon deposition covers them by a continuous layer. Certain areas of the islets with a thickness > 10 nm have an inhomogeneous wrinkled surface. The folds are formed at the initial stage of the islet growth, and the subsequent carbon deposition flattens them. Preliminary studies of stretched samples up to 20% showed good fracture toughness of the given coatings.

Antibacterial superhydrophobic polyvinyl chloride surfaces via the improved phase separation process using silver phosphate nanoparticles

This study aims to induce antibacterial and superhydrophobic properties on the surface of thermoplastic polyurethane (TPU) sheets via an improved phase separation process through application of polyvinyl chloride (PVC) thin films. Porous PVC thin films were produced using different amounts of ethanol as nonsolvent. However, the created porosity was not sufficient to achieve superhydrophobicity. To improve the phase separation process, the silver phosphate nanoparticles were first synthesized and then added to the solution. According to scanning electron microscopy and X-ray photoelectron spectroscopy results, the nanoparticles were majorly localized at the bulk of PVC films. A direct relationship was found between the level of porosity and superhydrophobicity. An exceedingly high amount of nanoparticles had a deteriorating influence on porosity and superhydrophobicity. The optimum sample was found to be durable against liquids with different pH values. In contrast to the good resistance of superhydrophobic sample at elevated temperatures (80 °C), a sticky behavior was obtained upon exposure to 120 °C. The level of bacterial adhesion for the superhydrophobic sample was drastically declined (>99%) with respect to the pure PVC film in case of S. aureus and E. coli bacteria after an incubation time of 24 h. In conclusion, the hybrid of superhydrophobic behavior and an antibacterial material such as silver phosphate nanoparticles exhibited a promising potential in achieving antibacterial surfaces.

Creating orientated cellular structure in thermoplastic polyurethane through strong interfacial shear interaction and supercritical carbon dioxide foaming for largely improving the foam compression performance

This work presented a novel strategy for enhancing foam compressive properties through structuring orientated cells introduced by combining barrier film and supercritical CO2 foaming. The low permeability and the strong interface bonding of barrier films were employed to hinder the CO2 escaping from thermoplastic polyurethane (TPU) surface and induce the bubble orientation growth, respectively. The compressive modulus and strength of TPU foamed with films constraints increased by as much as 355% and 121%, respectively, relative to the freely foamed counterparts. The polyimide (PI) films, which possessed higher bonding strength with TPU due to the molecular diffusion at the interface, could boost more cell nucleation, improve the cell uniformity and increase the orientation degree and compressive performance, compared to the poly(ethylene terephthalate) (PET) films. A modified constitutive model for assessing the compressive modulus of closed-cell foams was developed to uncover the positive effect of cell orientation on compressive behavior.

Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum

BackgroundCorynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.MethodsC. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.ResultsEleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.ConclusionsGenotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.

A Facile Activation Method for Improving the Wettability of Polyurethane Surfaces

This work reports the activation of polyurethane film surfaces in order to enrich them with polar groups such as -NH2, -OH, -COOH or radicals, which further allows immobilization of several bioactive compounds. UV-activation was used to introduce new groups on the polymer surface without affecting the bulk properties. The current arising species improve the wettability of the PU surfaces as it was observed from the static contact angle measurements. The structure and composition of the new PU surfaces were analyzed by using ATR-FTIR spectroscopy. The results suggested the possibility of modifying the PU surfaces in a shorter time periods, in order to provide many sites to attach other biomacromolecules by polar interaction or hydrogen bonding.