Water-dispersible Polyurethane Research Articles

Underwater fatigue behavior of cementitious mortar and a countermeasure using a water-dispersible polyurethane ether–Portland cement composite

The underwater fatigue behaviors of cementitious mortars are investigated with a focus on the mechanisms contributing to the deterioration of bridge foundations and possible countermeasures. This study analyzes the effects of water penetration during repetitive loading and unloading on the underwater fatigue lives of cementitious materials, highlighting the importance of considering dynamic water motion, in addition to the surface energy mechanism. Water penetration during underwater fatigue occurs even in water-saturated specimens, and water in- and egress within a few millimeters of the specimen surface can significantly reduce the fatigue life. This study proposes a novel approach using a water-dispersible polyurethane ether–Portland cement composite as a countermeasure to improve underwater fatigue resistance. Based on experimental analysis of fatigue in water and microstructural investigations of the composite, the presence of polyurethane compounds within the nano-to-micron-sized microstructures may mitigate water penetration and contribute to a corresponding increase in underwater fatigue life.

Water-Dispersible Polyurethanes Obtained by the Controlled Alternation of the Segments of Poly(propylene glycol), Poly(ethylene glycol) and Urethane

Water-Dispersible Polyurethanes Obtained by the Controlled Alternation of the Segments of Poly(propylene glycol), Poly(ethylene glycol) and Urethane

Surface characterization and paint bonding quality on chemically and thermally modified short rotation teak wood

ABSTRACT Chemical and thermal modification can change the hydrophilic properties of wood, and thus affect their coating performance. This study determined the surface characteristics of chemically and thermally modified short rotation teak wood. The characteristics studied were surface roughness, surface free energy (SFE), contact angle, wettability, and coating bonding quality. Results show that the surface of short rotation teak became smoother after chemical and thermal modifications; however, surface roughness increased after furfurylation. The total SFE of chemically and thermally modified teak wood decreased after treatment. The decrease in the total SFE caused the decrease in the constant contact angle change rate (K-value). The K-values for water-dispersed polyurethane and acrylic paints were nearly 0, which indicated their lower wettability. The paint bonding quality decreased after accelerated weathering. Short rotation teak with Glycerol-Maleic Anhydride (GMA)-thermal treatment can be considered for exterior applications with a proper selection of paint.

Microstructural properties and water penetration resistance of cementitious binder combined with water-dispersible polyurethane

To avoid the re-degradation of repaired regions and ensure the service lives of infrastructures, cementitious materials used for repair applications should possess excellent water penetration resistance. Organic polymers are widely used to enhance water resistance. In this study, the microstructural properties and water uptake of a cementitious material containing a newly developed water-dispersible polyurethane (PU) polymer were investigated. The results showed that the water uptake decreased significantly in the presence of PU. Microscopic observations and gas sorption isotherms indicated that submillimeter and capillary pores and the surfaces of calcium silicate hydrate were partially hydrophobized and/or blocked upon PU addition, which could contribute to the prevention of liquid water uptake. Nevertheless, based on a drying procedure performed prior to the water penetration tests, the specimens with and without PU exhibited similar water vapor uptakes owing to the eliminated difference in the volumes of their micro- and mesopores.

Characterization of a Water-Dispersed Biodegradable Polyurethane-Silk Composite Sponge Using 13C Solid-State Nuclear Magnetic Resonance as Coating Material for Silk Vascular Grafts with Small Diameters.

Recently, Bombyx mori silk fibroin (SF) has been shown to be a suitable material for vascular prostheses for small arteries. In this study, we developed a softer SF graft by coating water-dispersed biodegradable polyurethane (PU) based on polycaprolactone and an SF composite sponge on the knitted SF vascular graft. Three kinds of 13C solid-state nuclear magnetic resonance (NMR), namely carbon-13 (13C) cross-polarization/magic angle spinning (MAS), 13C dipolar decoupled MAS, and 13C refocused insensitive nuclei enhanced by polarization transfer (r-INEPT) NMR, were used to characterize the PU-SF coating sponge. Especially the 13C r-INEPT NMR spectrum of water-dispersed biodegradable PU showed that both main components of the non-crystalline domain of PU and amorphous domain of SF were highly mobile in the hydrated state. Then, the small-diameter SF artificial vascular grafts coated with this sponge were evaluated through implantation experiments with rats. The implanted PU-SF-coated SF grafts showed a high patency rate. It was confirmed that the inside of the SF grafts was covered with vascular endothelial cells 4 weeks after implantation. These results showed that the water-dispersed biodegradable PU-SF-coated SF graft created in this study could be a strong candidate for small-diameter artificial vascular graft.

Synthesis of Waterborne Polyurethane Using Phosphorus-Modified Rigid Polyol and its Physical Properties.

In this study, a phosphorous-containing polyol (P-polyol) was synthesized and reacted with isophorone diisocyanate (IPDI) to produce water-dispersed polyurethane. To synthesize waterborne polyurethanes (WPUs), mixtures of P-polyol and polycarbonate diol (PCD) were reacted with IPDI, followed by the addition of dimethylol propionic acid, to confer hydrophilicity to the produced polyurethane. An excess amount of water was used to disperse polyurethane in water, and the terminal isocyanate groups of the resulting WPUs were capped with ethylene diamine. P-polyol:PCD molar ratios of 0.1:0.9, 0.2:0.8, and 0.3:0.7 were used to synthesize WPUs. The films prepared by casting and drying the synthesized WPUs in plastic Petri dishes were used to test the changes in physical properties induced by changing the P-polyol:PCD molar ratio. The experimental results revealed that the tensile strength of PU-10, the WPU with a P-polyol:PCD molar ratio of 0.1:0.9, was 16% higher than that of the reference P-polyol–free WPU sample. Moreover, the thermal decomposition temperature of PU-10 was 27 °C higher than that of the reference sample.

Polyurethane based sizing agent for CFRP applications

In the production of carbon fiber reinforced plastic (CFRP), sizing agents are used to protect against fiber damage due to friction and to improve the affinity between the fiber and the matrix. The sizing agent improves the wettability between the fiber surface and the resin, reduces voids between the CFRP, and increases the physical properties. If the sizing agent is selected incorrectly, problems such as deterioration of physical properties and action as contaminants may occur. Therefore, it is necessary to develop a sizing agent having adhesiveness, workability, durability, water resistance and flexibility. Therefore, in this study, the water-dispersed polyurethane resin with the properties required above was synthesized and its properties were evaluated.

Bio-derived water dispersible polyurethane/rGO@α-MnO2/rGO@δ-MnO2 nanocomposite as a heterogeneous catalyst and anticorrosive material

Herein, we report the fabrication of rGO@α-MnO2/rGO@δ-MnO2 nanohybrid containing bio-derived water dispersed polyurethane (PU) nanocomposite (PUNH). Three nanocomposites of PU were fabricated with 0.5, 1.0 and 1.5 wt percentages of rGO@α-MnO2/rGO@δ-MnO2 and characterized by using various techniques including FTIR, XRD, BET, CV, FESEM, and TEM. Thermo-mechanical properties of PUNHs increase with the increase of nanohybrid content in the pristine PU. Chemical resistance and UV-aging capabilities of PUNHs increase, whereas biodegradation of them decreases with the increase of nanohybrid concentration in the pristine PU. The catalytic activities as well as anticorrosive performance of the nanocomposite were found to be excellent. PUNH1.5 showed proficient catalytic efficiency for the synthesis of N-(4-nitrobenzylidene)aniline with high yield (∼ 83 %). The used nanocomposite was recycled for five times without significant loss of activity. Furthermore, PUNH1.5 showed favorable corrosion current density (9.64 × 10−9A/cm2), corrosion potential (-0.318 V) and corrosion rate of 5.98 × 10-4 mm/yr after 8 days of exposure in 3.5 wt percentage NaCl aqueous solution.

Performance Behavior of Chitosan Based Water Dispersible Polyurethanes: Physicochemical Properties

The research work was carried out to synthesize a series of novel chitosan based water dispersible polyurethanes (CS-WDPUs). The three step synthesis involves the formation of end capped PU-prepolymer was formed through the reaction between polyethylene glycol (PEG) (Mn=600 g/mole, dimethylolpropionic acid (DMPA) and isophorone diisocyanate (IPDI) followed by the preparation of neutralized NCO terminated PU-prepolymer, which lead to the chain extension by using the chitosan. The dispersion of the obtained product was carried out by adding proper proportion of water. The synthesized CS-WDPUs were applied onto the different qualities of plain weave poly-cotton printed and dyed textile swatches by employing pad-dry-cure procedures. The textile assets of the treated and untreated textile swatches were assessed, as color fastness, pilling resistance, tear and tensile strength. The results showed that the chitosan incorporation into PU backbone has significant effect on the assets of treated textiles. These synthesized CS-WDPUs are eco-friendly bio-based finishes with potential applications for polyester/cotton textiles.

Synthesis and characterization of a novel thermally stable water dispersible polyurethane and its magnetic nanocomposites

In this work, a novel water dispersible polyurethane (WDPU) was synthesized from the reaction of hydroxyl-terminated polybutadiene (HTPB), 2,2 bis(hydroxymethyl) propionic acid (DMPA), and 1,5-naphthalene diisocyanate (NDI) and its magnetic nanocomposites were prepared by incorporation of modified Fe3O4 by 3-aminopropyltriethoxysilane (Fe3O4@APTS) nanoparticles (0.5, 1.5, and 3 wt%) via in situ polymerization method. Use of NDI as a high melting point diisocyanate by having the rigid naphthalene structure imparts physical strength as well as thermal stability to the resulted polyurethane. The synthesized WDPU based on NDI was characterized by using Fourier transform infrared spectroscopy (FTIR) technique. In addition, the morphology, mechanical, and magnetic features of the prepared polyurethane nanocomposites were investigated by X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), magnetic force microscopy (MFM), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMTA), and vibrating sample magnetometer (VSM) methods, respectively. Data from DLS experiment showed that the average particles size of the WDPU nanocomposites increased by increasing the nanoparticle contents in comparison with bare WDPU. AFM and MFM analyses indicated that the magnetic nanoparticles (MNPs) were well dispersed in the polyurethane matrices via the formation of covalent bonding between the functionalized magnetic nanoparticles and polymer chains. TGA results demonstrated that adding MNPs increased the temperature of the thermal degradation of the polyurethane nanocomposite. VSM analysis showed that the super paramagnetic behavior of the prepared nanocomposites depended on the Fe3O4@APTS nanoparticle content, as well.

Synthesis and Characterization of Aqueous Chitosan-polyurethanes Dispersion for Textile Applications with Multipurpose Performance Profile

As the use of high performance textiles has grown, the need for chemical finishes to provide the fabric properties required in the special applications has grown accordingly. In this project, a series of water dispersible polyurethanes dispersion (CS-PUs) with multipurpose performance profile was developed using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), 2,2-dimethylol propionic acid (DMPA) and chitosan (CS) for textile applications. In two step synthesis process, NCO functional PU prepolymers prepared by reacting IPDI, PEG, and DMPA were extended with varying molar quantities of chitosan followed by structural characterization through FTIR. The prepared CS-PU dispersions were applied onto the dyed and printed poly-cotton blend fabrics. The performance behavior of the treated fabric in terms of crease recovery, tear strength, tensile strength, and antibacterial properties was evaluated by applying standard test methods. These investigations show that the CS-PU dispersions can be applied as antibacterial textile finishes with significant improvement in the physical and mechanical properties of poly-cotton fabrics.

Synthesis, characterization of novel chitosan based water dispersible polyurethanes and their potential deployment as antibacterial textile finish

Our current research work comprised of synthesis of a series of novel chitosan based water dispersible polyurethanes. The synthesis was carried out in three steps, in first step, the NCO end capped PU-prepolymer was formed through the reaction between Polyethylene glycol (PEG) (Mn = 600), Dimethylolpropionic acid (DMPA) and Isophorone diisocyanate (IPDI). In second step, the neutralization step was carried out by using Triethylamine (TEA) which resulted the formation of neutralized NCO terminated PU-prepolymer, after that the last step chain extension was performed by the addition of chitosan and followed the formation of dispersion by adding calculated amount of water. The proposed structure of CS-WDPUs was confirmed by using FTIR technique. The antimicrobial activities of the plain weave poly-cotton printed and dyed textile swatches after application of CS-WDPUs were also evaluated. The results showed that the chitosan incorporation in to PU backbone has markedly enhanced the antibacterial activity of WDPUs. These synthesized CS-WDPUs are eco-friendly antimicrobial finishes (using natural bioactive agents such as chitosan) with potential applications on polyester/cotton textiles.

Preparation and Properties of Anionic Water-Dispersed Polyurethane Containing Polypropylene Glycol and Casein

In this study, analyzed the changes occurred after adding casein emulsions to water - dispersed polyurethane using polypropylene glycol (PPG). For this purpose, anionic water - dispersed polyurethane containing PPG, IPDI and DMPA and casein emulsion prepared by dissolving casein in distilled water using ammonia water were prepared. As a result of measuring the alkali resistance by using the prepared resin, there was no change in the physical properties. The tensile strength of the sample having a high casein content was measured to be 2.227 kgf / ㎟. Elongation was measured at 474% for samples containing less casein and The abrasion resistance was measured as 46.090 ㎎.loss of sample containing much casein as a result of the surface roughness measurement.

Organic/inorganic hybrid nanocolloids of water dispersible polyurethanes with antibacterial activity

We report an in-situ synthetic strategy to prepare water dispersible polyurethane (WDPU) from an organic/inorganic hybrid nanocolloids in which the organic component is dinitrobenzene-modified hydroxyl-terminated polybutadiene (HTPB-DNB)-based polyurethane and the inorganic part is TiO2 (core)–SiO2 (shell) nanoparticles. The shape, size, and polydispersity of the hybrid nanocolloids are determined using microscopic and light scattering studies and are found to be slightly dependent on the loading of core–shell nanofillers. FT-IR and solid-state NMR studies prove the presence of the interaction between the carbonyl functionality of the urethane linkage and the SiO2 present in the shell part of the particles, and this interaction is found to be the driving force for the formation of stable nanocolloids. The films, obtained from the nanocolloids of WDPU upon curing, display better thermal and mechanical properties, and also, these properties increase with increasing loading of nanofillers. Higher tensile strength and Young modulus are obtained in WDPU nanocolloids films compared to pristine WDPU films. The antibacterial activity of WDPU nanocolloids was studied on Staphylococcus aureus (Gram-stain-positive bacterium) and Escherichia coli (Gram-stain-negative bacterium) displayed significantly higher zone of inhibition in both the cases, indicating the potential use of these nanocolloids in antibacterial coating.

Эффективность действия пеногасителей для однокомпонентной полиуретановой системы

Чурикова Татьяна Николаевна – ведущий инженер сектора химико-технологических исследований отдела ПИТСиП, ОАО «РосНИТИ».454139, г. Челябинск, ул. Новороссийская, 30. E-mail:churikova@rosniti.ru Самкова Нина Петровна – начальник сектора химико-технологических исследований отдела ПИТСиП, ОАО «РосНИТИ». 454139, г. Челябинск, ул. Новороссийская, 30. E-mail: samkovanp@rosniti.ru Авдин Вячеслав Викторович – декан Химического факультета, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: avdinvv@susu.ru T.N. Churikova1, churikova@rosniti.ru N.P. Samkova1, samkovanp@rosniti.ru V.V. Avdin2, avdinvv@susu.ru 1 The Russian Research Institute of the Tube & Pipe Industries Joint Stock Company, Chelyabinsk, Russian Federation 2 South Ural State University, Chelyabinsk, Russian Federation

Synthesis and Properties of Cationic Polyurethane Dispersions

A series of water dispersible polyurethanes containing quaternary ammonium group as the hydrophilic group with different content of trimethylolpropane (TMP) as inner crosslinker were prepared. IR spectroscopy was adopted to demonstrate the polymerization reaction and structure of polymer. The effects of TMP content on PU properties were investigated. Particle size distribution (PSD) analysis and morphology of PU observed by TEM showed that particle size of PU dispersions initially decreased and then increased with increasing TMP content. The viscosity of the PU dispersions with TMP addition was bigger than the PU dispersions without TMP. TG analysis indicated thermal stability and microphase separation degree of PU was enhanced with increasing TMP content. Contact angle and gel content of PU also increased as increasing TMP content. Meanwhile, tensile strength increased and then decreased with the increment of TMP content.

Functionalized polybutadiene diol based hydrophobic, water dispersible polyurethane nanocomposites: Role of organo-clay structure

Abstract In this article, we report preparation and studies of water dispersible polyurethane (WDPU) nanocomposite which has high hydrophobic characteristics with contact angle greater than 100° and strong thermo-mechanical properties. An in-situ method is developed for synthesizing the WDPU nanocomposites where hydroxyl terminated polybutadiene (HTPB) functionalized at the terminal carbon atoms with dinitrobenzene (DNB), named as HTPB-DNB, is the diol source for the polyurethane chain, two types of organically modified clays namely Cloisite-30B and dimethyl sulfoxide (DMSO) intercalated Kaolinite (OKao) are the nanofillers and an ionic diol co-monomer e.g. dimethylol propionic acid (DMPA) is used to incorporate the ionic characteristics in the polymer chain to ensure the water dispersibility of the resulting nanocomposites. Microscopy and light scattering studies prove the formation particles of 100–200 nm size, and the particles size and the polydispersity of WDPU nanocomposites vary as the loading and type of clay are altered. In depth analysis of 13C CP-MAS NMR spectra using full width half maxima (FWHM) of carbonyl carbon peak of PU chains reveals the interactions between the polyurethane and organoclay that helped in preparing stable WDPU nanocomposites. Structural analysis of nanocomposites reveal the formation of intercalated morphology till 3 wt% loading of Closite-30B and exfoliated structure for higher loading whereas aggregated structure in case of OKao nanocomposites. Thermo-mechanical and tensile behaviour of resulting nanocomposites are largely influenced by the clay type and loading which can be attributed as the consequence of the different morphology and structure of nanocomposites. The surface hydrophobicity of nanocomposite films is determined by measuring the contact angle which increases with increasing clay loading and all samples show contact angle greater than 100° attributing good hydrophobic surface of nanocomposites.

Self-Decontaminating Fibrous Materials Reactive toward Chemical Threats.

Polymers that possess highly nucleophilic pyrrolidinopyridine (Pyr) and primary amino (vinylamine, VAm) groups were prepared by free-radical copolymerization of N,N-diallylpyridin-4-amine (DAAP) and N-vinylformamide (NVF) followed by acidic hydrolysis of NVF into VAm. The resulting poly(DAAP-co-VAm-co-NVF) copolymers were water-soluble and reacted with water-dispersible polyurethane possessing a high content of unreacted isocyanate groups. Spray-coating of the nylon-cotton (NYCO), rayon, and poly(p-phenylene terephthalamide) (Kevlar 119) fibers pretreated with phosphoric acid resulted in covalent bonding of the polyurethane with the hydroxyl groups on the fiber surface. A second spray-coating of aqueous solutions of poly(DAAP-co-VAm-co-NVF) on the polyurethane-coated fiber enabled formation of urea linkages between unreacted isocyanate groups of the polyurethane layer and the amino groups of poly(DAAP-co-VAm-co-NVF). Fibers with poly(DAAP-co-VAm-co-NVF) attached were compared with fibers modified by adsorption of water-insoluble poly(butadiene-co-pyrrolidinopyridine) (polyBPP) in terms of the stability against polymer leaching in aqueous washing applications. While the fibers modified by attachment of poly(DAAP-co-VAm-co-NVF) exhibited negligible polymer leaching, over 65% of adsorbed polyBPP detached and leached from the fibers within 7 days. Rayon fibers modified by poly(DAAP-co-VAm-co-NVF) were tested for sorption of dimethyl methylphosphonate (DMMP) in the presence of moisture using dynamic vapor sorption technique. Capability of the fibers modified with poly(DAAP-co-VAm-co-NVF) to facilitate hydrolysis of the sorbed DMMP in the presence of moisture was uncovered. The self-decontaminating property of the modified fibers against chemical threats was tested using a CWA simulant diisopropylfluorophosphate (DFP) in aqueous media at pH 8.7. Fibers modified with poly(DAAP-co-VAm-co-NVF) facilitated hydrolysis of DFP with the half-lives up to an order of magnitude shorter than that of the unmodified fibers. The presented polymers and method of multilayer coating can lead to a development of self-decontaminating textiles and other materials.

Preparation of a crosslinked coating containing fluorinated water-dispersible polyurethane particles

Abstract The development of new polyurethane (PU) derivatives can readily enhance the properties of a diverse range of polymeric materials. Herein, we report a novel crosslinked coating matrix, which contains uniformly distributed fluorinated water-dispersible PU particles both on its surface and interspersed throughout its matrix. The desirable distribution of the functional particles results in a coating with outstanding transparency, liquid repellency, and adherence to various substrates. In addition, the coating provides the substrates with excellent corrosion resistance as well as a high degree of glossiness. The developed structural design is anticipated to give an inspiration for the functionalization of PU-based materials with applications in various fields.

Hydrophobic, Water-Dispersible Polyurethane: Role of Polybutadiene Diol Structure

Preparation of stable, free-standing elastic film with hydrophobic surface from water-dispersible polyurethanes (WDPUs) is a challenging task. Here, we have prepared WDPUs from polybutadiene-based diols and the resulting PU films are satisfying the requisites. Two types of diols, namely, hydroxyl-terminated polybutadiene (HTPB) and terminal-functionalized HTPB with dinitrobenzene (DNB) [HTPB-DNB], were used to make WDPUs and the effects of diol structures were investigated. The synthesized WDPUs displayed particle morphology with size in the range of ∼130–270 nm and more than 1 year storage stability. WDPUs yielded stable and free-standing films upon curing and the resulting films showed high thermal and mechanical stabilities. The contact angle of the films is in the range of ∼80–100°, attributing the hydrophobic nature of the surface. Hard segment content of the PU varied from 30 to 40% (by weight) to tune the properties of WDPUs and the resulting films.