Waterborne Polyurethane Emulsion Research Articles

Light-colored conductive fabric coatings using uniform ATO@TiO2 whiskers

In this work, one-dimensional conductive TiO2 whiskers coated with antimony-doped tin oxide (ATO@TiO2) were prepared with a method of hydrothermal coprecipitation. Specially, sodium hexametaphosphate (SHMP) was used as an interfacial reactor to form sufficient active groups on the surface of TiO2 whiskers, which not only increased the reaction sites, but also formed the electric double-layer structure to promote the dispersion of TiO2 whiskers in aqueous solution. Additionally, four kinds of ATO@TiO2 nanomaterials with different appearances were introduced into waterborne polyurethane (WPU) emulsion to prepare the conductive paint for the surface coating of polyester fabrics. During the process of curing reaction, ATO@TiO2 whiskers are located in the coating mold to organize a conductive network in the form of a rod-to-rod connection. Compared with particle-type ATO@TiO2, the percolation threshold was drastically decreased from 45 to 7.5 wt%, meanwhile, this conductive paint shows excellent covering performance and the whiteness is up to 83.

Synthesis of Castor Oil-based Cationic Waterborne Polyurethane Emulsion and Its Application

Castor oil-based cationic waterborne polyurethane (CWPU) was synthesized by pre-polymer process using castor oil (CO), poly(adipic acid-1,4-succinate diol) (PBA), isophorone diisocyanate (IPDI), and N-methyldiethanolamine (MDEA). The influences of the content of CO and MDEA on comprehensive performance and finished fabric properties of cationic waterborne polyurethane was investigated, especially the antibacterial properties of finished fabric. The CWPU latex particle size and its distribution decrease as the content of CO increased from 0wt% to 16.8wt%, and increases afterwards. The CWPU films show much higher thermal stability than cationic waterborne polyurethane without CO. The surface of fabrics was characterized by scanning electron microscope (SEM). The finished fabric surface is much smoother. In addition, the finished fabric with CWPU emulsion has better antibacterial property against E. coli and S. aureus. When MDEA content is 8%, the antibacterial rates of the two kinds of bacteria are 77.3% and 82.2%, respectively.

Effect of different carboxylic acid group contents on microstructure and properties of waterborne polyurethane dispersions

The waterborne polyurethane (WPU) with different carboxylic acid group contents were prepared by a prepolymer method, adopting polycarbonate diol (PCDL) as soft segments and isophorone diisocyanate (IPDI) as hard segments. The different amounts of 2,2-dimethylolbutyric acid (DMPA) as hydrophilic chain extender were introduced into polyurethane molecular for studying the effect on microstructure and properties. The solid content, pH value and viscosity measurement were used to characterize the performance of WPU emulsion. The fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), water contact angle tester and mechanical testing machine were utilized to measure the structure, crystallization performance, thermal stability, low temperature flexibility, wetting performance and mechanical properties of WPU films, respectively. The test value of impact, adhesive, flexibility and pencil hardness on tinplate of WPU coatings were obtained for observing film properties. The results indicated that the emulsification effect increase with the increased DMPA contents. The decomposition temperature of WPU films perform a slight decrease and the WPU films have excellence low temperature flexibility with the increased DMPA contents. The hydrophilic property of WPU films mainly are about 80°and the tensile strength value of 7 wt% WPU reaches 45 MPa and elongation at break at 420%.

Study on structure-induced heat transfer capabilities of waterborne polyurethane membranes

Structural induced heat transfer capability of waterborne polyurethane (WPU) membrane was investigated. Hereby, WPU emulsions were synthesized with series of combinations of 2,4-Diisocyanatotoluene (TDI), poly(propylene glycol) (PPG), Poly(ethylene glycol) (PEG), dimethylolpropionic acid (DMPA) and ethylene glycol (EG) for studied membranes preparation. In this study, optimal prepolymer components, hard segment content, hydrophilic fragments and thermal annealing treatment on membrane-forming process were performed to study the structural features of WPU and corresponding heat conduction. Regarding to the results of AFM, XRD and DSC analysis, we found heat conduction was tightly related to the status of phase behaviors in studied WPU membranes. That's because phonon propagation as one primary heat carrier in polymer matrix was closely depended on the morphology of polymer chains. Good phase separation behavior could conduce to form long-range, short-range and microcrystalline ordering in WPU through intermolecular force (e.g. hydrogen bond), further pave as a conductive path for heat transmitting.

Preparation and Properties of Polyaminosiloxane Modified Polyester Waterborne Polyurethane

Abstract In this study, a organosilicon modified waterborne polyurethane (WPU) is synthesized with polyethylene glycol 1,4-butanediol adipate ester diol (PBA) to form the soft segment, dimethylolpropionic acid (DMPA) as the hydrophilic chain extender, and isophorone diisocyanate as the hard segment to synthesize the WPU prepolymer, and aminoethyl aminopropyl dimethicone (AEAPS) as the graft chain extender. The properties of the formed WPU films are then characterized by using Fourier transform infrared spectrometry, thermogravimetric analysis, X-ray diffraction, and dynamic mechanical analysis. It is found that when the amount of AEAPS in the WPU is increased from 0 to 30 wt%, the particle size of the AEAPS modified WPU emulsion is increased from 84.8 nm to 271.9 nm and maintained high centrifugal stability. Moreover, the water absorption of the WPU film is reduced from 43.4% to 24.1%, and the hardness is enhanced from 3H to 5H, while the glass-transition temperature (Tg) of the soft segment of the modified WPU shifts from -37.4 °C to -44.3 °C, and the Tg of the hard segment shifts from 73.6 °C to 118.1 °C. Therefore, the overall performance of AEAPS modified WPU is improved.

Synthesis and Properties of Linear Polyether-Blocked Amino Silicone-Modified Cationic Waterborne Polyurethane

In this study, a waterborne polyurethane (WPU) is synthesized by using polytetramethylene ether glycol (PTMEG) to form the soft segment, 1,4-butanediol (BDO) as the chain extender, n-methyldiethanolamine (MDEA) as a hydrophilic chain extender, and isophorone diisocyanate (IPDI) to form the hard segment. Furthermore, the modified cationic WPU emulsion and its films are created through a reaction between the WPU and a linear polyether-blocked amino silicone (LEPS), which is an organosilicon compound that imparts flexibility. The properties of the structure and formed WPU films are then characterized by using Fourier transform infrared spectrometry, a thermogravimetric analysis, atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, as well as by measuring the water contact angle, testing the water absorption, etc. It is found that, with an increase in the LEPS content in the WPU, the particle size of the modified WPU emulsion is increased, the WPU films are more flexible, and the resistance of the modified WPU films to heat and water are increased, while the crystallinity is reduced. The polysiloxane chain segment, which is added to the LEPS-modified WPU emulsion, is significantly enriched on the surface of the modified WPU films, while there are no adverse effects of the LEPS-modified WPU emulsion on the adhesive force between the WPU and substrate. When the LEPS content of the WPU is 14.0 wt%, the modified WPU emulsion and film provide the best performance.

High-gravity-assisted emulsification for continuous preparation of waterborne polyurethane nanodispersion with high solids content

In this work, we developed a continuous preparation strategy for the production of high-solidscontent waterborne polyurethane (WPU) emulsions via high-gravity-assisted emulsification in a rotating packed bed (RPB) reactor. By adjusting the experimental parameters and formula, WPU emulsions with a high solids content of 55% and a low viscosity were prepared. Preliminary applications of the high-solids-content WPU as a thermally insulating material were demonstrated. RPB emulsification is an economical and environmentally friendly production strategy because of the low energy consumption, short emulsification time, and effective devolatilization. This study demonstrated an effective method for preparation of high-solids-content WPU, moving toward commercialization and industrialization.

Preparation of living and highly stable blended polyurethane emulsions for self-healing films with enhancive toughness and recyclability

Widely applied waterborne polyurethane (WPUs) are expected to be functionalized with excellent mechanical property, ideal self-healing performance and desired recyclability, but it is a great challenge to integrate these attractive properties into a one-pot WPU platform. Herein, a novel double ingredients waterborne polyurethane (2K-WPU-DA-x), found on the furan modified WPU-F and maleimide decorated WPU-M dispersions for Diels-Alder (DA) cross-linking reactions, was designed and projected which exhibited interesting enhanced-mechanical, self-healable and recyclable properties. The stability and appearance of these novel waterborne polyurethane emulsions were well studied. In the following, the reversible nature of direct DA/retroDA reactions within the 2K-WPU-DA-x was extensively analyzed via FT-IR, UV–vis, and DSC measurements. On account of the DA bonds resulted a cross-linked structure of 2K-WPU-DA-1/1, the stress and strain at the break increased by more than 20 MPa and 250% respectively compared with linear structural WPU-F. At the same time, relying on the thermal-responsive dissociation/reassociation of DA covalent bonds, 2K-WPU-DA-x films shown outstanding self-healing ability, with a self-healing efficiency beyond 95%. Moreover, owing to the reversibility of 2K-WPU-DA-x, the networks exhibited readily recyclable and reshaping properties, showing a desired thermoplasticity.

Aligned 3D porous polyurethane scaffolds for biological anisotropic tissue regeneration.

A green fabrication process (organic solvent-free) of artificial scaffolds is required in tissue engineering field. In this work, a series of aligned three-dimensional (3D) scaffolds are made from biodegradable waterborne polyurethane (PU) emulsion via directional freeze–drying method to ensure no organic byproducts. After optimizing the concentration of polymer in the emulsion and investigating different freezing temperatures, an aligned PUs scaffold (PU14) generated from 14 wt% polymer content and processed at −196°C was selected based on the desired oriented porous structure (pore size of 32.5 ± 9.3 μm, porosity of 92%) and balanced mechanical properties both in the horizontal direction (strength of 41.3 kPa, modulus of 72.3 kPa) and in the vertical direction (strength of 45.5 kPa, modulus of 139.3 kPa). The response of L929 cells and the regeneration of muscle tissue demonstrated that such pure material-based aligned 3D scaffold can facilitate the development of orientated cells and anisotropic tissue regeneration both in vitro and in vivo. Thus, these pure material-based scaffolds with ordered architecture have great potentials in tissue engineering for biological anisotropic tissue regeneration, such as muscle, nerve, spinal cord and so on.

Preparation and Characterization of Waterborne Polyurethane Modified by 4-Maleimidophenol to Enhance the Mechanical and Thermal Properties

A series of 4-maleimidophenol (4-HPM) modified waterborne polyurethane (MWPU) emulsions were successfully synthesized, using isophoronediisocyanate (IPDI), polycaprolactonediol (PCL, Mw = 1000), 1,4-butanediol (BDO), 2,2-dimethylolpropionic acid (DMPA), trimethylolpropane (TMP) and triethylamine (TEA) as raw material. The effects of 4-HPM content on the structure, morphology and physical properties of the MWPU were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscope, X-ray diffraction, thermogravimetric analysis, water absorption measurement, water contact angle measurement and tensile testing. The results revealed that with 4-HPM introduced into the WPUs backbones, the crystallinity, the hardness, tensile strength, water resistance and thermal stability of MWPU films were significantly augmented. Moreover, when the content of 4-HPM was 4.0 wt %, the tensile strength of the MWPU film was up to 46.4 MPa, improved about 134.19% (measurement error ±0.001) compared with WPU (19.8 MPa). When the content of 4-HPM was 6.0 wt %, the end decomposition temperature of the film was up to 489.6°C, improved 12.6% compared with WPU (434.8°C).

Robust, Transparent, and Superhydrophobic Coating Fabricated with Waterborne Polyurethane and Inorganic Nanoparticle Composites

We report the fabrication of a robust, transparent, and superhydrophobic organic–inorganic composite coating with simple, low-cost, effective, and environmentally friendly characteristics. First, a waterborne polyurethane (WPU) emulsion and silica fluoride (F-SiO2) nanoparticle dispersion were synthesized. Subsequently, the organic–inorganic superhydrophobic surfaces with low surface energy were constructed by spraying, in order, the WPU emulsion and F-SiO2 nanoparticle dispersion on substrates. The robust composite coating had superhydrophobicity and good optical transparency, in which the WPU provided a strongly adhesive elastic substance for the anchoring of superhydrophobic F-SiO2 nanoparticles to further construct a mechanically and chemically resilient nanocomposite coating. After 250 cycles of abrasion, a long period of ultraviolet irradiation, and oil-pollution and cross-cut tests, the nanocomposite coating still exhibited excellent properties including good self-cleaning, transparency, abrasion r...

Synthesis of waterborne polyurethane using snow as dispersant: Structures and properties controlled by polyols utilization

Waterborne polyurethane (WPU) dispersions have gained attention towards environmentally-friendly synthesis. In this article, a series of waterborne polyurethane emulsions was successfully synthesized and extensively characterized in terms of thermal, mechanical properties, hydrophilic behavior and morphology. Snow was chosen as dispersant instead of commonly used water. Preparation parameters such as intrinsic properties and molecular weight of polyols were discussed systematically. A chain structure was confirmed by Fourier transform infrared (FT-IR) spectroscopy. When comparing the nature of the polyols (PPG, PEG and PNA, 2000 g/mol) of this study, as-synthesized polyether waterborne polyurethane provided higher solid content, viscosity and water-resistance. However, polyester waterborne polyurethane performed differently and it exhibited higher thermal stability and crystallinity. When comparing the samples (WPU-N210, WPU-N220, WPU-N230 and WPU-N240) with different molecular weight of the same polyol (PPG) used as soft segment, the emulsion WPU-N220 with molecular weight of 2000 g/mol PPG provided the highest solid content and lowest viscosity. It was observed that particle size was uniform and highly dispersed for all samples from TEM images. Thermogravimetric, differential scanning calorimetry (DSC) and X-ray diffraction results demonstrated that the emulsion WPU-N230 with molecular weight of 3000 g/mol PPG possessed higher thermal stability and crystallinity than the other samples. The reason was that the Tg and thermal stability were increased with increasing molecular weight. When molecular weight increased, the arrangement of soft segment became more regular and so did the regularity of the molecular chains. This work demonstrated that different polyols as soft segment applied could lead to great differences in the structure and property of the resulting WPU.

Effects of soft segment and microstructure of polysiloxane modified cationic waterborne polyurethane on the properties of its emulsion and membrane

Cationic waterborne polyurethane (WPU) is limited in wider applications due to its poor water resistance and worse flexibility. However, polysiloxane is widely used because of the advantages in these two aspects. To improve the water resistance and the flexibility of cationic WPU, combining with the characteristics of organosilicon compound, the hydroxyalkyl-containing bifunctional group polysiloxane (PPC) and self-made trifunctional group modifier PPS were used to modify the cationic WPU. The particle size and size distribution of the modified cationic WPU emulsion, the water resistance and the surface moisture resistance of the corresponding membrane were investigated. The results indicated that the cationic WPU modified by PPC will show the moderate hydrophilicity, which had positive effect on the water resistance. Although PPS had a negative effect on the dispersion and the emulsification of the polymer, a small amount of introduction can greatly improve the water resistance and the water repellency of its membrane.

Effects of polyaminosiloxane on the structure and properties of modified waterborne polyurethane

ABSTRACTA waterborne polyurethane (WPU) prepolymer was synthesized with poly(tetramethylene glycol) to form the soft segment, dimethylolpropionic acid as a hydrophilic chain extender, and isophorone diisocyanate. Moreover, the graft and block copolymer emulsification of WPU–polysiloxane and their films was carried out through reactions between the WPU prepolymer, aminoethyl aminopropyl dimethicone (AEAPS), and a linear polyether‐blocked amino silicone (LEPS), respectively. The properties of the structure and formed films of the WPU were characterized with Fourier transform infrared spectrometry, gel permeation chromatography, X‐ray diffraction, thermogravimetric analysis, dynamic thermomechanical analysis, and X‐ray photoelectron spectroscopy; the measurement of the water contact angle; the testing of the water absorption; and so on. The WPU–polysiloxane emulsion showed a high stability, and the molecular weight of WPU increased. Moreover, the glass‐transition temperature (Tg) of the soft segment of polysiloxane that was incorporated into the WPU shifted to a lower temperature range, whereas the Tg of the hard segment shifted to a higher temperature range, and the crystallinity of the WPU–polysiloxane film was reduced. There was a greater degree of crosslinking and accumulation of polysiloxane segments on the surface of the WPU emulsion that was modified with AEAPS in comparison to the LEPS‐modified WPU emulsion. Therefore, the water resistance of the AEAPS‐modified WPU was higher than that of the LEPS‐modified WPU. The rigidity and elasticity of the WPU–polysiloxane film improved, whereas its tensile strength did not change much after AEAPS was used. However, this was not true after LEPS was used, as the tensile strength decreased significantly. Nevertheless, the flexibility and plasticity of the WPU–polysiloxane film were enhanced after LEPS was used. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47226.

Synthesis and properties of octadecylamine-graphene oxide modified highly hydrophobic waterborne polyurethane emulsion

A new type of environment friendly aqueous octadecylamine-graphene oxide modified water-based polyurethane-polyacrylate (ODA-GO/WPUA) emulsion was prepared by self-emulsification. Textural characterization of the synthesized films through FTIR, SEM, TGA and AFM revealed their smooth surface while hydrophobicity, waterproofing nature (as coating) and mechanical properties were disclosed by experimental findings. The optimized properties exhibited by the synthesized films at amount of 0.1 % ODA-GO and contact angle of 105.1°, were 17° higher than routine water-based polyurethane (WPUA). In addition, ODA-GOs/WPUA films were thermally more stable than GO/WPUA and WPUA films as indicated by a weight loss of 5% at 311 °C with an increase of 33 °C compared to WPUA films. AFM studies revealed that the Young's modulus of ODA-GO/WPUA film (30 MPa) and tensile strength (1.525 MPa) were significantly higher than those of GO/WPUA and WPUA films. Moreover, ODA-GO/WPUA film has 66% higher elongation at break than WPUA film and exhibited enhanced self-healing ability as well. The present approach based on the utilization of cost effective ODA-GO for the preparation of modified WPUA films with enhanced mechanical properties and self-healing ability could be of great interest on industrial level applications.

Synthesis and characterization of chitosan-based waterborne polyurethane for textile finishes

Chitosan has gained an increased interest of researchers due to its nontoxic, biodegradable, biocompatible and renewable properties as well as its antimicrobial activity. In this work, a series of chitosan-based waterborne polyurethane (CS-WPU) emulsions were synthesized. The synthesis was accomplished by using a two-step emulsion polymerization process. The pre-polymer was prepared using hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG; MW = 6 kDa). Afterwards, the chain extension step was performed by using different mole ratios of chitosan. Moreover, the effect of chitosan on physicochemical properties of the emulsion was studied. To evaluate textile performances such as tear strength, tensile strength and pilling, the CS-WPU emulsion was applied on different plain weave polyester cotton dyed and printed fabrics by using pad-dry cure techniques. The antimicrobial activity of the treated and untreated fabrics was also evaluated via the agar diffusion method. The results displayed that incorporation of chitosan has prominent effects on tensile tear strength, tear strength and antimicrobial activity of polyester cotton dyed and printed fabrics. Moreover, antimicrobial activity was considerably enhanced as the mole ratio of the chitosan was increased. The results emphasize that CS-WPU based on HDI exhibits a better performance as compared to IPDI.

Dispersion of multiwalled carbon nanotubes in waterborne polyurethane emulsions derived from alcoholysis products of waste PET and its effect on properties

Dispersion of multiwalled carbon nanotubes in waterborne polyurethane emulsions derived from alcoholysis products of waste PET and its effect on properties

Synthesis and characterization of waterborne polyurethane based on aliphatic diamine sulphonate and liquefiable dimethylol propionic acid

Abstract In this paper, aliphatic diamine sulphonate (AAS-Na) and liquefiable dimethylol propionic acid (LDMPA) were used together to synthesize waterborne polyurethane (WPU) with excellent property. The influence of -COOH/-SO 3 Na molar ratio on the structure and properties of the waterborne polyurethanes were characterized by IR, particle size analysis, DSC, DMA, apparent viscosity, water absorption, contact angle, tensile and peel strength tests. It was found that with decreasing -COOH/-SO 3 Na molar ratio from 10:0 to 3:7, (1) the particle size of the waterborne polyurethane emulsion decreased, while the apparent viscosity of the samples increased. (2) the water absorption of the WPU films decreased, while the contact angle of the films increased. (3) The tensile strength, elongation at break and peel strength of the samples increased. Furthermore, the results of DMA showed that incorporation of AAS-Na increased the storage modulus of the sample. And the results of DSC showed that with decreasing -COOH/-SO 3 Na molar ratio from 10:0 to 3:7, T g of soft segment shifted to lower temperature, which indicated that the micro-phase separation degree of the samples increased.

Preparation and Properties of High Solid Content and Low Viscosity Waterborne Polyurethane-Acrylate Emulsion with a Reactive Emulsifier.

High solid content waterborne polyurethane-acrylate (WPUA) emulsions have been successfully synthesized in two steps. Firstly, we prepared a waterborne polyurethane emulsion, then reacted it with acrylate monomer by emulsion polymerization using the semi-continuous seeded method. The effects of the type and amount of emulsifier, the amount of dimethylolpropionic acid (DMPA), the choice of capping group, the ratio of PU/PA, and the method of adding a water-soluble monomer to the properties of the composite emulsion were investigated. The reactive emulsifier replaced the traditional emulsifier and there were no metal ions introduced to the reaction, whether by the emulsifier or the initiator. Through a variety of tests, we proved that the prepared emulsion has the advantages of small particle size, narrow distribution, good stability, good performance of the film, and solid content of 46%.

Preparation and characterization of a novel low gloss waterborne polyurethane resin

A novel waterborne polyurethane (WPU) resin with low gloss and micro-roughness was synthesized by the prepolymer and self-emulsification method. It was achieved by introducing multi-hydroxyl castor oil and reactive bisphenol A-type epoxy E-44 or E-51 resin to polyurethane prepolymer to form a cross-linking network structural waterborne polyurethane emulsion, which demonstrated the distinctive characteristic of the shear-thinning pseudoplastic fluid with a yield stress. The chemical structures and rough surface morphologies of the WPU films were characterized by FTIR-ATR, LCRS, AFM, SPMS and SEM, respectively. The specular gloss values at 20°, 60° and 85° incident angles were measured, and the values of different kinds of roughness parameters were obtained. The relationship between the gloss and the castor oil content was also discussed in detail. In general, this WPU resin endowed the film with micro-roughness, moderate hardness and good adhesive strength, making it very prospective in substitution for the traditional low gloss coatings.