Series Of Waterborne Polyurethanes Research Articles

Enhancement of the adhesion strength of water-based ink binder based on waterborne polyurethane

Series of Waterborne Polyurethanes (WPUs) were synthesized by molecular structure design, using sodium 2-((2-aminoethyl) amino) ethanesulfonate (AAS) as the post-chain extender, and selecting poly-1,4-butanediol adipate (PBA) and isophorone diisocyanate (IPDI) as the soft segment and hard segment, respectively. The effects of changes in PBA molecular weight and AAS content on the properties of WPUs were investigated through analysis of adhesion, mechanical properties, and thermal properties. The result showed that the T-peel strength, shear strength, and adhesion of the film reached 7.75 ± 0.48 N/mm, 1.81 ± 0.08 MPa, and 1.45 ± 0.11 MPa, respectively, due to the higher hydrogen bond density in the molecular structure when the Mn of PBA was 2000 g/mol. Based on the selection, the introduction of sulfamate increased the urea bond content of the system, further increasing the intramolecular hydrogen bond density. When the content of AAS was 1.0 wt%, the T-peel strength, shear strength, and adhesion of the film were increased to the highest values of 10.63 ± 0.30 N/mm, 2.08 ± 0.09 MPa, and 2.41 ± 0.08 MPa, respectively. Therefore, WPU has a wide range of applications in the field of water-based ink binders due to its high adhesive strength.

In Situ Incorporation of Diamino Silane Group into Waterborne Polyurethane for Enhancing Surface Hydrophobicity of Coating

A series of waterborne polyurethanes (WPU) with crosslinked siloxane were obtained through introducing 3-(2-aminoethylamino)propyldimethoxymethylsilane (APTS) into WPU by in situ polymerization. The properties of WPU modified by APTS were studied through a variety of experimental methods. The water contact angle of the WPU coating surface increased from 64° to 86°, and the water resistance reduced to 3.90% when 3 wt% APTS was added, which improved the coating surface hydrophobicity. Firstly, Fourier transform infrared (FT-IR) and 1H-NMR spectra demonstrated the successful incorporation of APTS to polyurethanes and completed the hydrolytic condensation reaction-generated Si–O–Si crosslinking structure. Furthermore, the surface energy of the membrane was reduced when the crosslinking structure migrated and enriched on the surface of film. Besides, the crosslinking structure was abundant, and the distribution of siloxane in WPU was more uniform.

수분산 폴리우레탄 코팅의 미세상분리와 물성에 Isosorbide가 미치는 영향

Series of waterborne polyurethanes (WPUs) containing poly(tetra methylene glycol) (PTMG), 4,4-dicyclohexylmethane diisocyanate (HMDI), 2,2-dimethylolpropionic acid (DMPA), 2,2,4-trimethyl-1,3-pentanediol (TMPD), isosorbide (ISO) and ethylenediamine (EDA) were synthesized. The effects of ISO on the structure and properties of WPUs were studied by gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analyzer (DMTA), X-ray diffraction (XRD), thermogravimetry (TG), mechanical test, chemical resistance and hardness test. The deconvolution analysis of FTIR of WPUs revealed that the hydrogen bond interaction in the WPUs increased with the increase of ISO content. Furthermore, the degree of microphase separation was increased with the increase of hydrogen bond interaction, which was confirmed by DSC, XRD and DMTA test. The results demonstrated that the addition of ISO can increase the hydrogen bond interaction between the hard and hard segments in WPUs, which improved the mechanical properties of the WPU films. The highest tensile strength was obtained of 59.67 MPa when the content of isosorbide was 10.35 wt%. Moreover, the ISO was helpful to improve the chemical resistance and hardness of the coatings by the comprehensive performance analysis.

Synthesis and characterization of waterborne polyurethane based on covalently bound dimethylol propionic acid to e-caprolactone based polyester polyol

Abstract In this paper, a low temperature liquefiable dimethylol propionic acid (LDMPA) was designed by the condensation of e-caprolactone(CL) with dimethylol propionic acid (DMPA). A series of waterborne polyurethanes were successfully synthesized by using LDMPA. The structure and properties of the waterborne polyurethanes were characterized by IR, particle size analysis and tensile tests. It was found that with increasing LDMPA content, the particle size of the waterborne polyurethane emulsion decreased. The results of tensile tests showed that with increasing LDMPA content, the tensile strength and elongation at break of the samples increased at first and then deceased. DMA results showed that compared with samples using dimethylol propionic acid (DMPA), the introduction of LDMPA into WPU chain could reduce waterborne polyurethane’s micro-phase separation degree.

Synthesis and characterization of waterborne polyurethanes with alkoxy silane groups in the side chains for potential application in waterborne ink

Abstract In this study, a series of waterborne polyurethanes (WPUs) with alkoxy silane groups in the side chains were synthesized by the chain extension with diamine chain extender (3-(2-aminoethyl)aminopropyl)trimethoxysilane (AEAPTMS). The effects of AEAPTMS content on the properties of WPUs were investigated in terms of adhesion strength, mechanical property, crystallinity and thermal stability. FT-IR and 1 H NMR spectra demonstrated the successful incorporation of AEAPTMS to polyurethanes. The increase of AEAPTMS content produced a decrease in the surface tension of WPUs as well as the interfacial tension and contact angle between WPUs and oriented polypropylene (OPP) films, implying the improvement of wetting property of WPUs on OPP films. The increase of AEAPTMS content increased the hydrophobicity, tensile strength, glass transition temperature and thermostability of WPU films, and decreased the crystallinity and elongation at break of WPU films. The adhesion strength of WPUs initially increased and then decreased with the increase of AEAPTMS content, and was the highest when the AEAPTMS content was 2.0 wt%. Moreover, compared with 3-aminopropyltriethoxysilane (APTES), AEAPTMS could improve the property of WPUs more greatly. In summary, the synthesized WPU with 2.0 wt% AEAPTMS had low water absorption, high thermal stability, and good adhesion on OPP film, and could be potentially used in waterborne ink for OPP film.

Preparation and characterization of waterborne polyurethane containing PET waste/PPG as soft segment

ABSTRACTSoft drinks poly(ethylene terephthalate) (PET) bottles were depolymerized by glycolysis using a 1 : 3 molar ratio of PET repeating unit to glycols like neopentyl glycol (NPG) and dipropylene glycol (DPG). Further, a series of waterborne polyurethanes (WPUs) was synthesized using pure polypropylene glycol (PPG), and glycolyzed oligoesters/PPG blends in different molar ratios as soft segment. Thermal property of WPU was tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Moreover, viscosity and particle size of WPU were also investigated. The results show that introduction of a certain amount of glycolyzed oligoester to soft segment makes the degree of hard‐soft domain microphase separation smaller, and can also improve thermal stability of WPU. Furthermore, WPUs synthesised from glycolyzed oligoesters and PPG blends possess larger particle size, better particle size distribution, relative lower and more stable viscosity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42757.

Effects of crosslinking on adhesion behavior of waterborne polyurethane ink binder

Abstract A series of waterborne polyurethanes (WPUs) with different crosslinking densities were synthesized by varying the amount of trifunctional crosslinker trimethylolpropane (TMP). The effects of the TMP content on the adhesion behavior of WPUs were investigated in terms of the cohesive strength of WPUs, and the interface adhesion strength between WPUs and the substrate–polyethylene glycol terephthalate (PET) film. It was found that with the increase of TMP content, the interface adhesion strength decreased due to the decreased mobility of PU molecular chains, the cohesive strength of WPUs films increased because of the increase in the crosslinking density (υe), and the T-peel strength (T) initially increased and then decreased with the change of debonding failure from a cohesive failure to an interface failure. An empirical equation, revealing the relation between peel strength and TMP content (x), was found to be T = 1.94 + 0.81x − 0.22x2, and another empirical equation, T = 1.59 + 750.44 υ e − 128313.62 υ e 2 , showing the relation between peel strength and crosslinking density was obtained. Moreover, crosslinking density was mainly determined by TMP content, and it was found that the relationship between υe and x could be showed by the equation υe = 0.00045 + 0.0013x or υe = 0.00050 + 0.0013x. On the whole, crosslinking played an important role in the adhesion behavior of WPUs, and an optimal crosslinking density was a key for preparing the WPUs with outstanding adhesion property. In this study, the optimal υe was 0.00292 mol/cm3.

The effects of the molecular weight and structure of polycarbonatediols on the properties of waterborne polyurethanes

A series of waterborne polyurethanes (WPUs) were synthesized by a pre-polymer process from isophorone diisocyanate, 1,6-hexamethylene diisocyanate and polycarbonatediol with varying molecular weight (1000–2000 Da) and molecular structure (copolycarbonate and homopolycarbonate). The effect of polycarbonatediols on the performance of the emulsion was studied by means of apparent viscosity, particle size distribution and Zeta potential analysis. Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, physical and mechanical measurements and water droplet contact angle tests were employed to characterize the thermal stability, crystallinity, low temperature flexibility, physical and mechanical properties and wettability of the films derived from the emulsions. The results indicated that WPU dispersions with mean particle size in the range of 50–70 nm and Zeta potential value about −50 mV displayed excellent storage stability. It was found that the mean particle size, thermal stability, crystallinity, low temperature flexibility, mechanical properties and hydrophobicity increased and the particle distribution decreased with the increase of molecular weight of the polycarbonatediols. Moreover, copolycarbonate-based WPUs showed higher crystallinity of hard segments, thermal stability and wettability than the homopolycarbonate-based ones.

Effects of soft segments on the waterproof of anionic waterborne polyurethane

To study the waterproof of coating materials, a series of waterborne polyurethanes were prepared with different kinds and molecular weight of polyols. IR spectroscopy was used to check the end of polymerization reaction and characterization of polymer. The study was carried out by increasing the waterproof of various coating agents through variations of soft segments. We introduced laser-scattering equipment, Brookfield digital viscometer, JC2000C instrument, scanning electron microscope (SEM), and atomic force microscope (AFM) to investigate the particle size, viscosity, contact angle, and morphology of the coated fabric. In short, results displayed waterproof as follows: 3146~8200 mm H2O (IPDI = 30 %) in various polyols and 5421~8748 mm H2O (R = 1.6) of different molecular weight of poly(butylene adipate) (PBA). The higher water resistance belonged to PTMG-WBPU and WBPU-1000, respectively. Experimental results indicated that water resistance may be controlled by not only the types of soft segments, but also the molecular weight.

Synthesis and adhesion properties of waterborne polyurethane dispersions with long‐branched aliphatic chains

ABSTRACTIn this study, a series of waterborne polyurethanes (WPUs) with different contents of long‐branched aliphatic chains were synthesized through variation of the amount of diol chain extender trimethylol propane monooleate (TMPM). The effects of the TMPM content on the adhesion properties of the WPUs were investigated in terms of their surface tension, interfacial tension, contact angle, and adhesion strength. Fourier transform infrared and 1H‐NMR spectra demonstrated the successful incorporation of TMPM into the polyurethanes. An increase in the TMPM content produced decreases in the surface tension of the WPUs and the interfacial tension and contact angle between the WPUs and plastic films. This indicated that the wetting properties of the WPUs on the plastic films was improved. The improved wettability enhanced the adhesion strength of the WPUs, and this showed that the long‐branched aliphatic chains could effectively improve the adhesion performance of the WPUs on the plastic films. Moreover, TMPM, with its hydrophobic aliphatic chains, increased the hydrophobicity and thermal stability of the WPU films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41688.

Synthesis and adhesion property of waterborne polyurethanes with different ionic group contents

In this study, a series of waterborne polyurethanes (WPUs) with different ionic group contents were synthesized by varying the amount of the internal emulsifier 2,2-dimethylolpropionic acid (DMPA). The effects of the ionic group content on the stability and adhesion behavior of WPUs were investigated in terms of particle size, viscosity, surface tension, interfacial tension, contact angle, and adhesion performance. It was found that stable WPUs could be obtained when the DMPA content was larger than 3.5 wt% (with respect to the total solid content). Adhesion performance of WPUs to substrates was mainly affected by the wetting of WPUs on the substrates and the molecular interactions between them. With the increase of DMPA content, the surface tension of WPUs as well as the interfacial tension and contact angle between WPUs and polyethylene terephthalate (PET) films increased. Moreover, the adhesion strength of the WPUs firstly increased and then gradually decreased. The type of debonding failure of all the synthesized WPUs on PET films was cohesion failure due to their lower cohesion strength, which was theoretically testified by the comparison between the adhesion energy and cohesion energy.

Natural Dimer Fatty Acids Based Waterborne Polyurethane: Thermal, Mechanical and Antihydrolytic Properties

A series of waterborne polyurethanes (WPUs) based on polyester polyols derived from 0–70 wt% dimer fatty acids (DA) in dicarboxylic acid were prepared. The structures of WPU were characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. The effect of DA weight content on properties of WPU was systematically investigated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact meter, tensile tester and chemical experiments such as immersion in alkaline solution. The results indicated the degree of microphase separation increased with the DA content. The incorporation of DA to WPUs increased thermal stability, surface hydrophobicity, water resistance and hydrolytic resistance. The WPUs with 10–40 wt% DA had excellent mechanical properties (tensile strength and elongation at break were 13.1 MPa and 726% for the WPUs with 20 wt% DA relative to 6.8 MPa and 605% for the WPUs with no DA, respectively).

Synthesis and characterization of phosphorus‐containing waterborne polyurethanes: Effects of the organophosphonate content on the flame retardancy, morphology, and film properties

AbstractA series of waterborne polyurethanes (WPUs) with different contents of reactive organophosphonate were well prepared. Their structures were characterized by Fourier transform infrared and 1H‐NMR spectroscopy. Thermogravimetry and derivative thermogravimetry revealed that the WPU films containing phosphorus possessed lower onset and maximum degradation temperatures but higher char yields. Differential scanning calorimetry analysis suggested phase mixing of the hard and soft domains. The mechanical properties decreased with increasing amount of organophosphonate, whereas the limiting oxygen index results of the WPU films indicate that the flame retardancy was improved significantly by the incorporation of organophosphonate. The water uptake values of the organophosphonate‐containing WPU films were higher than those of the phosphorus‐free ones, whereas the static contact angles of the films indicated that the surface hydrophilic properties were not affected by segmenting in this phosphorus‐containing oligomer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis and characterization of waterborne polyurethane adhesives containing different amount of ionic groups (I)

AbstractA series of waterborne polyurethanes (WBPU) containing different amount of 2,2‐bis(hydroxymethyl) propionic acid (DMPA) were synthesized using prepolymer mixing process. Relationships between the DMPA content and physical, mechanical, and thermal properties as well as adhesive behavior at different condition were investigated. Stable aqueous dispersions of WBPU were obtained when the DMPA content was more than 10 mol %. At higher DMPA content, the particle size of the WBPU dispersion was lower but the viscosity of the dispersion was higher. Water swelling and tensile strength of the films increased with increasing of DMPA content. The optimum adhesive strength of WBPU adhesives was found to be depended on the DMPA content, pressing temperature, and pressure on adhesion process. The adhesive strength of WBPU adhesives increased with increasing DMPA content. The optimum pressing temperature decreased with increasing DMPA content. The adhesive strength of WBPU adhesives increased with increasing pressure up to 15 kg f/cm2 and then leveled off. The optimum pressing temperature of WBPU adhesives samples containing 24.02, 22.05, and 17.05 mol % DMPA was about 100, 120, and 140°C, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5684–5691, 2006

NMR studies of water-borne polyurethanes

A series of water-borne polyurethanes were prepared by prepolymerization process. Isophorone diisocyanate, polyester diol, and dimethylol propionic acid were used to conduct the reaction. 1H- and 13C-NMR spectra of the raw materials and products thereof were measured with a high-resolution spectrometer, and their chemical shifts were assigned. 1H- and 13C-NMR spectra of urethane group and urea group were compared. The chemical shifts of side products from the reaction between water and the isocyanate group were also analyzed. Much useful information may be obtained from the NMR analysis of this kind of polyurethanes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 257–260, 2003

Preparation and properties of waterborne polyurethanes based on triblock glycol (CL)4.5-PTMG-(CL)4.5 for water vapor permeable coatings: Effect of soft segment content

A series of waterborne polyurethanes (WBPU) were prepared from 4,4-dicyclohexylmethane diisocyanate (H12MDI), 2,2-bis(hydroxylmethyl) propionic acid (DMPA), ethylenediamine (EDA), triethylamine (TEA), and triblock glycol [TBG, (e-caprolactone)4.5-poly(tetramethylene ether) glycol (MW=2000)-(e-caprolactone)4.5: (CL)4.5-PTMG-(CL)4.5, MW=3000] as a soft segment. Two melting peaks of TBG at about 14°C and 38°C were observed indicating the presence of two different crystalline domains composed of CL and PTMG dominant component. The effect of soft segment content (60–75 wt%) on the colloidal properties of dispersion, and thermal and mechanical properties of WBPU films, the water vapor permeability (WVP) and water resistance (WR) of WBPU-coated Nylon fabrics, and the adhesive strength of WBPU-coated layer and Nylon fabrics was investigated. As soft segment contents increased, the water vapor permeability of WBPU-coated Nylon fabrics increased from 3615 to 4502 g/m2day, however, the water resistances decreased from 1300 to 500 mmH2O.