Polyurethane Emulsion Research Articles

Nanofibrous scaffold from electrospinning biodegradable waterborne polyurethane/poly(vinyl alcohol) for tissue engineering application

A series of nanofibrous scaffolds, free of organic solvents, are prepared by electrospinning biodegradable waterborne polyurethane (BWPU) emulsion blending with aqueous poly(vinyl alcohol)(PVA). Tuning the proration of BWPU to PVA, various nanofibers with diameter from 370 to 964 nm are obtained. Strong intermolecular interaction existing between them benefits to the electrospun of BWPU emulsion, which is demonstrated by dynamic thermomechanical analysis and Fourier transform infrared spectroscopy. The nontoxic nanofibrous scaffolds with porous structure, which is similar to the natural extracellular matrix, favor to the attachment and proliferation of the L929 fibroblasts. Thus, the scaffolds are promising to be used as biomaterials for many natural tissues repair.

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 polyurethane emulsions based on poly(butylene itaconate) ester

Waterborne polyurethane (WPU) prepolymer was synthesised by the reaction of poly(butylene itaconate) ester (PBI, Mn = 1109 g/mol), 1,6-hexanediol, dimethylol propionic acid (DMPA), 2,4-toluene diisocynate (TDI), hydroxyethyl acrylate (HEA), and absolute ethanol as blocking agent, triethylamine as neutralizer. Cross-linked WPU was synthesized by trimethylolpropane (TMP) as crosslinker. The influences of PBI, DMPA, and TMP content on WPU emulsions and films were investigated. The structure of WPU was determined by Fourier transform infrared (FTIR) spectra, thermal properties and glass transition temperature of WPU films were determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively, and morphology of the emulsion particles was observed by transmission electron microscopy (TEM). Through TGA, the heat resistance of the cross-linked WPU film was better than WPU film. By DSC analysis, glass transition temperature of cross-linked WPU film (21 °C) was higher than WPU film (10 °C).

Enhanced mechanical and barrier properties of polyurethane nanocomposite films with randomly distributed molybdenum disulfide nanosheets

Lithium intercalated molybdenum disulfide (LixMoS2) was synthesized using a simple one-step solvothermal technique, followed by the formation of few-layer suspension of chemically exfoliated molybdenum disulfide (c-MoS2) in aqueous solution. The c-MoS2 was introduced into the waterborne polyurethane (WPU) emulsions to obtain the nanocomposite films by a simple blending method. As a comparison, MoS2/WPU composite film was prepared by directly blending bulk MoS2 particles into WPU. The incorporation of chemically exfoliated MoS2 significantly enhanced the thermal stability and mechanical properties of WPU film: with the incorporation of 4 wt% of c-MoS2, the 5% mass loss temperature of WPU nanocomposite film was increased by 30 °C relative to neat WPU; the tensile strength and Young's modulus were increased by 140% and 85%, respectively. Furthermore, the moisture permeability coefficient was reduced by about 37% at a MoS2 content of 4 wt%. These results demonstrate that such a facile and rapid technique presented herein will provide an effective and promising strategy to design and fabricate high barrier MoS2/polymer nanocomposite films.

One-pot synthesis and control of aqueous soluble and organic soluble carbon dots from a designable waterborne polyurethane emulsion.

Carbon dots (CDs) have a wide range of applications and have drawn great interest in the recent decade. The fabrication and control of CDs with different solubilities are still urgent problems for their practical use. In this paper, aqueous soluble and organic soluble CDs (ACDs, OCDs) were produced by one-pot hydrothermal treatment of a designable waterborne polyurethane (WPU) emulsion. The difference in the solubility and fluorescence of these two kinds of CDs was attributed to the various functional groups on the surface, which were derived from the different segment fragments formed by hydrothermal treatment of a block polymer. It was found that the yields of the ACDs and OCDs could be regulated by means of selecting different soft segments in WPU. The more hydrophobic soft segments could result in an increase of the OCDs and a decrease of the ACDs. While the soft segments were hydrophilic or hydrolysable under hydrothermal conditions, only ACDs were obtained. The ACDs had good fluorescence and showed low cytotoxicity for use in multicolour bio-imaging. The OCDs processed good solubility in a wide range of organic solvents and were suitable for preparing fluorescent composite films with polymers.

Preparation and properties of paper–plastic laminating adhesive used for medical packaging materials

Paper–plastic packaging materials have become important materials in the printing industry. Water‐based paper–plastic laminating adhesive is a new type of adhesive that has been widely applied in the modern packaging and printing industry. The adhesive used for medical packaging materials asked for higher performance, such as stability, peel strength, and aging resistance, so there is a large necessity in developing an environment‐friendly paper–plastic laminating adhesive with excellent performance. Wax emulsion, natural latex and waterborne polyurethane emulsion are mixed in the experiment, while epoxy resin emulsion was added to blending modification. The paper discusses the influence of the dosage of epoxy resin emulsion, wax emulsion, and waterborne polyurethane emulsion for T‐peel strength and paper breakage rate; also, the storage stability of the emulsion, partical size, and partical size distribution and differential scanning calorimeter are tested to determine the best prescription of the paper–plastic adhesive. Copyright © 2015 John Wiley & Sons, Ltd.

Studies on waterborne polyurethanes based on new medium length fluorinated diols

Abstract A novel fluorinated diol 3-(bis-( N , N -dihydroxyethyl)) dodecafluoroheptyl acrylate (DEFA) was for the first time synthesized via Michael addition reaction between diethanolamine and dodecafluoroheptyl acrylate, followed by a series of waterborne fluorinated polyurethane emulsions IPDI-DEFA-PU synthesis using isophorone diisocyanate (IPDI), poly(tetramethylene oxide glycol) (PTMG), dimethylolpropionic acid (DMPA) and 1,4-butanediol (BDO) as main starting materials, and DEFA as a chain extender. The structure of DEFA and IPDI-DEFA-PU was confirmed by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance ( 1 H NMR). It was found that the fluorine content increased from 0 to 15.1%, and the particle size of emulsion increased from 102 nm to 260 nm, whereas the surface tension of latex film decreased from 42.9 mN/m to 16.5 mN/m; while the water contact angle increased from 71° to 104°, the swelling ratio of latex film in water and cyclohexane decreased from 15.8% to 1.1% and from 28.8% to 3.4%, respectively. Meanwhile, water/organic solvent resistance and thermal stability, mechanical properties of IPDI-DEFA-PU were all improved. As tensile strength increased from 9 MPa to 15 MPa, extensibility decreased from 520% to 280%.

Study on Synthesis of IPDI-Based Waterborne Polyurethane

An IPDI-based waterborne polyurethane emulsion(WPU) was synthesized by the reaction of polyester glycol(PBA), di-methylol propionic acid(DMPA) with isophorone diisocyanate (IPDI) instead of toluene di-isocyanatotoluene(TDI) because of its low toxicity, low saturated vapor pressure. The factors influencing the properties of IPDI -based WPU were discussed. It was observed that the appearance and properties of the IPDI -based WPU were nearly related with the ratio of NCO/OH(R) and the amount of DMPA.

Study on the Modification of Waterborne Polyurethane by Tung Oil Anhydride-Ester Polyol

Waterborne polyurethane (WPU) emulsions were prepared with Tung oil anhydride-ester polyol (TOAEP) as modifier via the acetone process. The structure, morphology, emulsion particle size, thermal property and mechanical property of the Modified WPU were investigated by FT-IR, SEM, Laser particle size analysis, TG and tensile test, respectively. The experimental results show that the modified WPU emulsion particle size increases along with the growth of weight content of TOAEP. Compared with the unmodified WPU emulsion film, water and toluene absorption of the modified WPU emulsion film have decreased significantly, indicating that water and solvent resistance are remarkably improved after the modification. Tensile test shows that the tensile strength of the modified WPU emulsion film increases with the content of TOAEP while the reverse is true for the elongation at break. The characteristic thermo-decomposition temperatures of WPU have been increased notably after modification by the introduction of TOAEP which indicates that the heat resistance has been improved after modification. Morphology analysis shows that the soft segment phase and hard segment phase in the WPU are more compatible after modification.

Synthesis and Properties of Naphthalimide Fluorescent Dye and Covalent Fluorescent Polyurethane Emulsion

The reactive fluorescent dye 4- methoxy- N-(2- hydroxy- 1- hydroxymethylethyl) naphthalimide(MHHNA) was first synthesized by imidization and substitution reactions using 4-bromo-1,8-naphthalic anhydride,2- amino- 1,3- propanediol, and sodium methoxide as initial materials. A series of covalent fluorescent polyurethane(PU)(PU-MHHNA) emulsions were then fabricated using MHHNA as the chain extender through a phase inverse self-emulsification process. The chemical structure of the synthesized fluorescent dyes and the properties of PU-MHHNA emulsions and their latex films were characterized by1 H nuclear magnetic resonance(1H NMR) spectroscopy,13 C nuclear magnetic resonance(13C NMR) spectroscopy, Fourier transform infrared(FTIR) spectroscopy, elemental analysis, ultraviolet- visible(UV- Vis) absorption spectroscopy,fluorescent spectroscopy, particle size analysis, and xenon arc aging measurements. The fluorescent quantum yields of MHHNA and PU-MHHNA were 0.73 and 0.92, respectively. The amount of MHHNA had no obvious influence on the colloidal properties of the PU-MHHNA emulsions. The maximum wavelength(λmax) of the UVVis absorption spectra was 360.6 nm, and fluorescent spectroscopy analysis indicated that the maximum excitation wavelength(λex) and maximum emission wavelength(λem) of PU-MHHNA in acetone were 362 and435 nm, respectively. In addition, the fluorescence intensity of PU- MHHNA decreased with increasing temperature. The light fastness and solvent fastness of the PU-MHHNA film were much better than those of the non-covalent fluorescent polyurethane(PU/MBNA) film.

Synthesis and characterization of waterborne polyurethane thickeners based on hyperbranched polyester

Octahydroxyl-terminated and hexadecahydroxyl-terminated hyperbranched polyesters (HPE-8 and HPE-16) were synthesized from 2,2-dimethylol propionic acid and 1,4-butanediol. The hyperbranched waterborne polyurethane (HWPU) thickeners containing different branching structure and length of hydrophilic chain were prepared with hexamethylene diisocyanate, polyethylene glycol (PEG), cetyl alcohol, and HPE. The structures of HPE and HWPU were characterized by Fourier transform infrared spectra and nuclear magnetic resonance (1H NMR and 13C NMR). The rheological properties of polyurethane emulsion thickened by HWPU were measured using Brookfield LVDV-III rheometer, and the effects of HPE structure and PEG molecular weight on the thickening property of HWPU were studied. The results showed that HWPU with HPE branching number of 8 and PEG molecular weight of 4000 exhibited an excellent thickening effect in the aqueous polyurethane emulsion.

New thermal deblocking characterisation method of aqueous blocked polyurethane

Purpose – The mechanisms of the deblocking reaction of the polyurethane with blocking agent were investigated in detail relatively using thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS). This kind of method for polyurethane as the application of wood adhesives can provide the conditions of application and the main theoretical basis. Design/methodology/approach – The blocking rate and latex particle size distribution were determined using the titrimetric analysis and the laser particle analysis, respectively. TGA, FTIR, XPS and differential scanning calorimetry were used to investigate the deblocking temperature and time of the blocked isocyanate in detail. Findings – The results indicated that the blocking rate was approximately 97 per cent and the average particle size was 360 nm. The results of laser particle analysis have confirmed that the dispersivity of the blocked polyurethane emulsion was good. XPS results showed that the amount of –O = C-N-benzyl groups increased with an increasing deblocking temperature and subsequently reached equilibrium. In summary, the blocked isocyanate was deblocked at temperatures ranging from 50 to 90°C. Research limitations/implications – An important approach in future wood adhesive work would be to gain access to man-made board application data. Practical implications – The paper provided some useful information about deblocking mechanisms of blocked polyurethane that would be helpful to guide applied practical applications as wood adhesive. Social implications – To promote China’s wood processing technology progress and solve the problem of shortage of the natural quality of wood is of important practical significance. Originality/value – The paper is the first to use the XPS characterisation method to characterise deblocking polyurethane solution.

Synthesis and Properties of Polypropylene Carbonate Polyol-Based Waterborne Polyurethane

Different kinds of anionic polyhydric alcohols water-borne polyurethane (WPU) emulsion and films were prepared by separately taking polypropylene carbonate polyol (PPC), polyethylene-1,4-buthylene adipate glycol (PBA) and polytetramethylene ether glycol (PTMG) with the same molecular weight as soft segment. Their structure and properties were characterized with Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), rigidity, adhesive power, contact angle and water absorption. Comparing their properties, it was found that the rigidity, adhesive power and water resistance of PPC WPU were similar to those of PBA WPU.

불소화 폴리아크릴레이트-폴리우레탄 라텍스 혼성필름의 그레디언트 구조와 표면성질

In order to investigate the characteristics of the gradient fluorinated polyacrylate and polyurethane latex blend films, the fluorinated polyacrylate emulsion and the polyurethane emulsion were synthesized, and then the both emulsions were blended at a series of ratios. The effects of content of the fluorinated polyacrylate on the gradient structure and surface property of the blended films were assessed by AFM, XPS, SEM-EDX and surface free energy measurements. It appeared that, while the content of the fluorinated polyacrylate latex was up to 30%, the fluorinated polyacrylate particles were selectively gathered on the film-air (F-A) and film-glass (F-G) interfaces at room temperature. When the content of the fluorinated polyacrylate was under 30%, the gradient structure of fluorinated component was not evident. The further increasing of fluorinated polyacrylate in the mixed system facilitated the formation and enlargement of gradient structure, but the adhesion of film decreased a little.

Effect of poly(sodium 4-styrenesulfonate) modified carbon black on the dispersion and properties of waterborne polyurethane nanocomposites

In this work, the poly(sodium 4-styrenesulfonate) modified highly hydrophilic carbon black (PCB) have been successfully prepared by one-step in situ ball milling method. The resulting PCB exhibited an excellent dispersion in water with an encapsulation of 14.9wt%. The results of laser particle analyzer showed that the PCB exhibited the smallest particle size of 127nm at the pH of 5 in water. The PCB was firstly used to prepare blend films with waterborne polyurethane (WPU) emulsion and the effect of PCB content on the structure and properties of the resultant films were discussed. The excellent dispersibility of PCB in WPU emulsion through electrostatic repulsion was observed, which played an important role in improving the homogeneous structure of blend films. Compared with the neat WPU films, the tensile strength of the WPU/PCB hybrid films increased from 39.8 to 54.2MPa and the break elongation decreased from 1200 to 827%.

Preparation of High Solid Content Polyurethane Emulsion with Sulfonate Hydrophilic Chain-Extending Agents

A series of novel stable polyurethane emulsion with high-solid-content and low-viscosity were prepared by self-emulsification. They were prepared by the reaction of poly (tetrahydrofuran-co-oxidation of propylene) glycol (Ng210), isophorone isocyanate (IPDI) with 1,2-dihydroxy-3-propanesulfonic acid salt (DHPA) as hydrophilic chain-extending agents. Influence of the content of DHPA on properties of polyurethane emulsion and film were analyzed .The results show that obtained emulsion were multivariate distribution in particle size and were spherical particles by measurement of grain size and electron microscopic photo. It is noticed that with increasing content of DHPA and, average particles diameter of polyurethane emulsion became smaller, poly-dispersion became narrower and solid-content became bigger. when the content of DHPA is 7%, solide-concent of emulsion reaches 61%. In addition, Polyurethane emulsion are endowed stability of emulsion are good at high temperature and low temperature as well as storage stability.

Properties and paper sizing application of waterborne polyurethane emulsions synthesized with isophorone diisocyanate

In this work, a two-step synthesis methodology has been used to synthesize a series of waterborne polyurethane (WPU) emulsions with isophorone diisocyanate (IPDI), poly-caprolactone diol (PCL) and dimethylol propionic acid (DMPA) as monomers and ethylenediamine (EDA) as the chain extender, respectively. The influences of the NCO/OH molar ratio, DMPA content, chemicals-adding sequence, and acetone content on the physical properties of the resultant emulsions have been investigated in detail. The results show that the emulsion viscosity increases with an increase in the NCO/OH molar ratio or DMPA content whereas it declines sharply as the acetone amount increases. The emulsion particle size is seen to increase with the NCO/OH molar ratio but it decreases as the DMPA content increases. The chemicals-adding sequence is observed to strongly affect the particle size and viscosity of the resultant emulsions. For cast films, with an increase in the NCO/OH molar ratio, the elongation monotonically decreases while the tensile strength is seen to increase at first and then deceases. The film water absorption capacity is found to go up as the DMPA content increases. Furthermore, after sized with the emulsions, the paper water resistance is markedly improved and the 30s Cobb value is seen to decrease by 63% as compared to the unsized counterpart. The paper folding resistance and the tensile index are also improved to certain extents. For producing well-performed WPU emulsions for sizing paper sheets, an NCO/OH molar ratio of 1.6–1.8 and a DMPA content of 6.0–7.0 wt.% are preferably chosen.

Preparation and Property of Waterborne Polyurethane Waterproofing Composites

Waterborne polyurethane waterproofing composite has been prepared using polyurethane emulsion, cement, sand, and distilled water as raw materials, respectively. The compression performance of the samples has been determined by tensile testing machine. The microstructure of the samples has been observed by metallographic microscope. At the same time, the water resisting property of samples has been presented. The result shows that the surface of samples becomes the more smoothing with the increase ratio of cement to sand. The best compressive strength and water resisting property have been obtained when the weight of polyurethane emulsion to distilled water was 1:5 and the ratio of sand to cement was 2.1:1.

Waterborne Polyurethane–Polyacrylic Ester Hybrid Emulsion for Humidity-Controlling Coatings

Methyl methacrylate, butyl acrylate, acrylic acid and diacetone acrylamide were used as main monomers to prepare polyacrylic ester emulsion (PA). Isophorone diisocyanate, polypropylene glycol and 2,2-dimethylolpropionic acid were used as main monomers to prepare waterborne polyurethane emulsion (PU). Then, a new kind of waterborne polyurethane–polyacrylic ester hybrid emulsion (PUPA) was prepared successfully by physical blend of PA and PU. The structure and chemical components of the waterborne polyurethane–polyacrylic ester hybrid nanoparticles were investigated by transmission electron microscopy, FT–IR spectra and thermogravimetric analysis, respectively. The film properties of PUPA were measured and showed excellent hardness, gloss, water resistance and water absorption. The humidity-sensitive coating (PUPA-C) was prepared from PUPA, pigments and fillers. The basic properties of humidity-controlling coating were investigated, with particular attention to the effects of humidity-controlling. The humidity-controlling coating showed excellent properties of humidity sensitivity and humidity retention.

Micromorphology and mechanism of polyurethane/polyacrylate membranes modified with epoxide group

Polyurethane/polyacrylate (PUA) composite emulsions were synthesized based on the presence of preformed polyurethane chains. Glycidyl methacrylate (GMA), an acrylate monomer, was introduced into the system. Surface tension measurements assured the surface activities of the polyurethane emulsion. Dynamic light scattering (DLS) result showed that the average diameters and polydispersity were increased with the increment of GMA content. X-ray photoelectron spectroscopy (XPS) result indicated that the upper surface was rich in PU phase. The peak deconvolution results of XPS also confirmed the formation of PUA. The crosslinking degree and tensile strength were both enhanced due to the reaction between the carboxyl groups and the epoxide groups. Thermo gravimetric analysis (TGA) of the membranes showed that the thermal stability enhanced and the decomposition temperature was much higher than the pure PU membrane. X-ray diffraction (XRD) analysis, together with differential scanning calorimetry (DSC) results, demonstrated the amorphous nature of the PU matrix. Atomic force microscopy (AFM) observation performed the extremely flat membrane.