Hyperbranched Waterborne Polyurethane Research Articles

Collaboration of Fenton reaction with a tannin acid-based hyperbranched waterborne polyurethane sizing agent for synergistic enhancement of the CF/PA6 composite interfacial properties

The adhesive strength between the sizing agent and carbon fiber (CF) plays a pivotal role in determining the interfacial properties of composites. Unfortunately, this critical aspect has been consistently overlooked. In this study, a hyperbranched waterborne polyurethane (HWPU) sizing agent was prepared by biogenetic derived raw materials including gallic acid as well as tannic acid. Meanwhile, iron ion was introduced onto the surface of CF by Fenton reaction, forming a heterogeneous structure to elevate the mechanical interlocking between the CF and resin. Chelation of TA with iron ion on the fiber surface effectively enhanced the adhesion between sizing agent and CF. The mechanical properties of the newly designed composites were systematically investigated. The results showcase a significant enhancement in both flexural strength and interlaminar shear strength (ILSS) compared to untreated CF, marking improvements of 54.3% and 60.0%, respectively. Furthermore, the interfacial shear strength (IFSS) test exhibited a 71.2% augment. In conclusion, this approach presented a highly promising concept aimed at improving the interfacial performance of CF composite materials.

Synthesis of a fully bio-based self-catalyzed hyperbranched waterborne polyurethane as a sizing agent for enhancing the interfacial properties of CF/PA6 composites

Reinforcement mechanism introduced by the fully bio-based HWPU sizing agent.

Hybridization of cellulose nanocrystals modified ZnO nanoparticles with bio-based hyperbranched waterborne polyurethane sizing agent for superior UV resistance and interfacial properties of CF/PA6 composites

The interface of carbon fiber (CF) reinforced composites has been a long challenging issue that restricts the full utilization of its excellent properties in industrial applications. In present work, a green solvent γ-valerolactone and biogenetic derived gallic acid and tartaric acid were used to prepare a hyperbranched waterborne polyurethane (HWPU) sizing agent. Meanwhile, cellulose nanocrystal modified zinc oxide (CNC–ZnO) nanohybrids were successfully synthesized using a facile one-pot method to improve the dispersibility and specific surface area of ZnO nanoparticles. The hybridization of CNC–ZnO substantially enhanced the thermostability and UV resistance of bio-based HWPU. The mechanical properties of the modified composites were thoroughly examined, revealing remarkable enhancements in flexural strength and interlaminar shear strength, with improvements of 46.5 % and 48.1 % compared to pristine CF. Additionally, the interfacial shear strength test demonstrated a significant increase of 63.6 %. Remarkably, the modified carbon fiber composites retained more than 97 % of their mechanical properties after being subjected to continuous xenon irradiation for a week, highlighting the exceptional ultroviolet resistance derived from the hybrid HWPU sizing agent.

A novel bio-based hyperbranched waterborne polyurethane sizing agent with superior UV-resistance and interfacial properties for CF/PA6 composites

On account of environment concerns and the gradually depletion of fossil resources, a hyperbranched waterborne polyurethane (HWPU) serving for sizing agent of carbon fibers (CF) was designed based on bio-based materials. Hyperbranched chain extender named CAG was synthesized by citric acid (CA) and glycerol as HWPU precursor. Tartaric acid (TA) was coordinated with nano titanium dioxide (TiO2) through two –COOH groups, which was introduced to HWPU as the chain extender, leading to a significant improvement in ultraviolet (UV)-resistant of the sizing agent. The interfacial performance promotion of CF reinforced nylon 6 (CF/PA6) composites contributed by the HWPU sizing agent were systematically investigated. In contrast to the untreated CF composites, the mechanical performance arrived the best improvement after sizing by concentration of 1.5 wt%, which exhibited a dramatic promote of 44.9% in interlaminar shear strength (ILSS), 58.7% in interfacial shear strength (IFSS) and 43.3% in flexural strength. Extraordinary, the treated CF composites remained over 98% of mechanical performance after a week of unremitting ultraviolet irradiation, signifying the outstanding UV-resistance of the TiO2 modified HWPU sizing agent.

Synthesis of hyperbranched polyurethane sizing agent with high-solid content via self-catalytic method for improving interfacial adhesion of CF/PA6 composites

To improve the unsatisfactory interfacial adhesion of carbon fiber/polyamide-6 (CF/PA6) composites, a hyperbranched waterborne polyurethane (HWPU) sizing agent with high-solid content was designed. As a carboxy chain extender for HWPU, carbic anhydride-tris(hydroxymethyl)methyl aminomethane (CA-THAM) with a self-catalytic capacity was synthesized to accelerate the chain extension. The synthesized hyperbranched polyurethane exhibited low viscosity, along with a strong double-electron layer conformation after dispersing in water. The electrostatic repulsion between the latex particles effectively prevented agglomeration, delivering a high solid content of 58% for the sizing agent. The influence of different sizing agent concentrations on the wettability of CF as well as the interfacial properties of composites was systematically studied. Compared with unsized CF/PA6 composites, the interlaminar shear strength and flexural strength of CF-1.5 wt%/PA6 composites were up to 60.3 MPa and 508.4 MPa, with an increment of 50.3% and 27.7%, respectively. Furthermore, the interfacial strengthening mechanism of sizing agent was discussed. The preparation of this high-solid content sizing agents was facile and environmentally friendly, which would hopefully reduce costs during the transportation.

A novel moisture-controlled siloxane-modified hyperbranched waterborne polyurethane for durable superhydrophobic coatings

Superhydrophobic coatings have attracted extensive interest owing to their excellent water repellence property. However, low durability, environmentally harmful fabrication methods, and complex fabrication methods severely limit their widely practical applications. In this work, we demonstrate an eco-friendly, robust, superhydrophobic matrix coating based on siloxane-modified hyperbranched waterborne polyurethane (Si-HBPU) in combination with fluorinated silica nanoparticles (F-SiO2). The superhydrophobic coating was constructed by convenient process of casting Si-HBPU onto the substrate, which was regulated by a moisture-controlled model, and then F-SiO2 nanoparticles were uniformly seeded onto the surface of semi-cured Si-HBPU. The Si-HBPU covalently bonds to F-SiO2 nanoparticles for the reason that Si-HBPU possesses many polar groups (such as Si-OH), which utilized the silanol groups to chemically bond with the surface hydroxyl of the substrate and F-SiO2 nanoparticles to form a solid SiOSi cross-linking network. The resulted coating exhibited an excellent water repellency with contact angles of ∼ 163° and sliding angles of ∼ 3°. And benefiting from the establishment of the stable SiOSi binding, the modified coating demonstrates excellent mechanical robustness, and is capable of maintaining superhydrophobicity after 140 cycles of sandpaper abrasion. The resultant coating shows excellent anti-icing/deicing performance: the water-freezing time can be postponed to 2205 s at −20℃ and the ice adhesion is significantly lower than that of a pure copolymer coating (∼21.2 KPa). Moreover, the Si-HBPU/ F-SiO2 coating also demonstrated excellence in scratch resistantance, anti-fouling and anti-corrosion performances. These remarkable performances may promote the development of large-scale operation and practical application.

Synthesis of salt-resistant hyperbranched waterborne polyurethane associative thickener and its application in textile printing

To improve the thickening effect of polyurethane thickener, hyperbranched waterborne polyurethane associative thickener (HWPUAT) was successfully synthesized and the 3 wt% HWPUAT aqueous solution (HAS) was prepared. The viscosity of HAS at the rotating speed of 6 and 60 rpm was 12,118 and 4207 mPa·s, respectively. After adding 1.3 wt% NaCl, the viscosity retention rates of HAS and anionic polyacrylic acid thickener (APAT) aqueous solution with the same mass fraction were 90.5% and 27.5%, respectively. In addition, HWPUAT was used in textile printing with three different reactive dyes. The penetration ratios (PRs) and the paste removing rates (PRRs) of the cotton fabrics were equal to or greater than 75.91% and 74.23%, respectively. And the color unevenness (CU) of the cotton fabrics was equal to or less than 0.19. The comprehensive performance of the printed fabric was good.

Effects of the molecular structure on the vibration reduction and properties of hyperbranched waterborne polyurethane–acrylate for damping coatings

ABSTRACTA series of hyperbranched waterborne polyurethane–acrylate (HWPUA) hybrid emulsions were prepared with isocyanate‐terminated PU prepolymers, hyperbranched polyol (HP), and acrylate monomers. The HP as crosslinker was synthesized with isophorone diisocyanate, dimethylol propionic acid, and diethanol amine. The influence of the HP content on the chemical structure, particle size, morphology, damping properties, and thermal stability of the HWPUA hybrid emulsions and films were investigated by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, dynamic mechanical analysis (DMA), and thermogravimetric analysis, respectively. The results show that the addition of HP obviously improved the damping and thermal properties of the HWPUA films. However, the addition of excessive HP had a detrimental impact on the performance of films. The DMA curves indicated that when the HP content was 1%, tan δ was 0.3 or greater and spanned the broadest temperature range, with a maximum value of 0.65. The HWPUA hybrid emulsions could be used as damping coatings. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47733.

Synthesis and properties of quick-drying UV-curable hyperbranched waterborne polyurethane coating

Ultraviolet light (UV)-curable hyperbranched waterborne polyurethane (UVHWPU) resins were synthesized using polypropylene glycol (PPG)-1000, dimethylol propionic acid (DMPA), trimethylol propane (TMP), isophorone diisocyanate (IPDI) as core moiety, and 2-hydroxyethyl methacrylate (HEMA) as capping agent. The preparation methods of the UVHWPU resins were studied and an optimum recipe was given by selecting the proper dosage of DMPA, PPG-1000 and TMP. The structure of hyperbranched resins was characterized by C13-NMR spectra and Fourier transform infrared (FTIR) spectroscopy. The type and dosage of photoinitiator were determined, and the properties of UVHWPU coating with excellent performance were examined.

High performance polyurethane dispersion synthesized from plant oil renewable resources: A challenge in the green materials

A series of hyperbranched polyesters were incorporated by the chemical reaction of the dimethylolpropionic acid with trimethylolpropane, pentaerythritol, and glycerol as the core group. The castor oil-based fatty acids were also successfully prepared in order to examine the impact of the biopolyols on the thermo-mechanical characteristics of the hyperbranched waterborne polyurethane. The chemical structure of the polyols and the resulting polymer were characterized. Developing −OH functionality of the polyols the polyurethanes represented an improvement in crosslinking density, leading to increasing Tg, tensile modulus, and tensile strength and a decrease in elongation and toughness. Thus, the overall results forward the synthesized HBWPU as a potent sustainable and eco-friendly polymeric material by a simple approach that possesses a higher degree of sustainability over a purely petrochemical route.

Synthesis and characterization of hyperbranched waterborne polyurethane/Ag nanoparticle composites

The hyperbranched waterborne polyurethane (HWPU)/Ag nanocomposites were prepared by incorporation of silver sol into the HWPU. Formation of Ag nanoparticles in different generation hyperbranched polyesters was confirmed by UV–vis spectra, particle size distribution, and transmission electron microscope. The structures and properties of HWPU and its nanocomposites were measured with X‐ray diffraction, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and thermogravimetric analysis, etc. SEM images revealed that the Ag nanoparticles were well dispersed in the HWPU matrix with an increasing of generation number. The DMA analysis results showed that the HWPU/Ag nanocomposites had higher glass transition temperature and dynamic storage modulus than that of pure HWPU, especially incorporation of Ag nanoparticles protected by the third generation polyester. Incorporation of Ag nanoparticles into HWPU not only increased the mechanical properties but also enhanced thermal properties. Furthermore, the Young's modulus, tensile strength, and the initial decomposition temperature of HWPU/Ag nanocomposites are increased with increase in generation number. POLYM. COMPOS., 39:1967–1977, 2018. © 2016 Society of Plastics Engineers

Study on associating thickening mechanism and structure–efficiency relationship of hyperbranched waterborne polyurethane

Abstract The rheological behavior of waterborne polyurethane dispersion (PUD) thickened by the hyperbranched waterborne polyurethane (HWPU) was studied by rheological measurements. The results showed that the flow activation energy depended on the structure and concentration of HWPU. Based on the relationship between the structure, concentration and flow activation energy, we could infer that during HWPU associating thickening process PUD experienced Duckweed state (appropriate HWPU-latex particles linker), 3D network structure (HWPU-latex particles three-dimensional network) or Bead-like texture (HWPU monomolecular micelles or multi-molecular micelles). The role of interaction between particles in the structure of thickening system was explored by dynamic light scattering, refraction analysis and fluorescence spectroscopy. The combination of hydrophobic groups of HWPU with latex particles resulted in associating thickening, while the intramolecular or intermolecular association of HWPU might lead to a decrease in thickening efficiency or no thickening.

Bio-based waterborne polyurethane/carbon dot nanocomposite as a surface coating material

Abstract Waterborne surface coating materials with low volatile organic compounds (VOCs) are environmentally friendly and hence the most desired materials for the modern society. The present study reports in situ fabricated thermosetting hyperbranched waterborne polyurethane (WPU)/carbon dot (CD) nanocomposites as surface coating materials. CD was used as a nanoreinforcing agent (at 0.25, 0.5 and 1.0 weight percentages) in the nanocomposites. The structures of the waterborne polyurethane and its fabricated thermosetting nanocomposites were analyzed by using different spectroscopic and analytical tools like Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, UV–visible spectroscopy and X-ray diffractometry. The mechanical properties of the pristine thermosetting WPU were significantly improved after incorporation of CD (tensile strength from 4.5 to 8.5 MPa, elongation at break value from 96 to 136%, scratch hardness from 3 to 9 kg, impact strength from 70 to 100 cm). The thermal stability of WPU also enhanced from 250 to 280 °C after incorporation of CD in the matrix. Interestingly, the fabricated nanocomposites demonstrated an excitation wavelength and concentration dependent photoluminance behavior as well as exhibited good transparency. Thus, the fabricated WPU nanocomposites show great potential as low VOC containing environment friendly transparent surface coating material.

Preparation and Film Properties of Hyperbranched Waterborne Polyurethane

Preparation and Film Properties of Hyperbranched Waterborne Polyurethane

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.

Unique viscosity mutation of multi-generation hyperbranched waterborne polyurethane

Abstract Different generation hyperbranched polyurethanes (HBPUs) were synthesized through the A2+B’B2 strategy. The molecular structures and viscosity were characterized by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The NMR results confirmed the formation of the branched units between the segments contained in the HBPU structure. The GPC with a four-capillary bridge design differential viscometer and the Ubbelohde viscometer showed a different viscosity. For the HBPUs, the viscosity first increased to higher values then decreased to lower values, and finally increased with increasing weight, which can be attributed to the spherical structure. The growth degree of HBPUs spherical structure depends on the forming hydrogen bonds; when the hydrogen bonds reach a certain degree, the spherical structure becomes compact.

Preparation and Properties of Waterborne Polyurethane Containing Hyperbranched Polyester Linkages

Different generations of hydroxyl-terminated hyperbranched polyesters (HBPEs) were synthesized in sequence, all of the HBPEs based on methyl methacrylate (MMA) and diethanolamine (DEA) as AB2 monomer and trimethylolpropane (TMP) as core molecule. Then a series of hyperbranched waterborne polyurethane dispersions (HPUs) were prepared with the 3rd generation hyperbranched polyester (HBPE-3) used as an original cross-linking agent in this article. The intrinsic viscosity of each HBPE vs temperature and properties of HPUs was studied. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersion exhibited larger particle size and higher surface tension, when the hydroxyl-ratio was 1:6, the HPU achieved maximum particle size of 78.0 nm and surface tension of 52.48 mN/m, respectively. For the hyperbranched HPU films, the thermal stability and mechanical properties increased, resulting from the effects of the cross-linking structures in the HPU system.

Study on synthesis and thickening property of hyperbranched waterborne polyurethane

A series of hyperbranched waterborne polyurethanes (HWPU-4, HWPU-6 and HWPU-12) containing hydrophobic end groups were prepared by the hyperbranched core and the polyurethane prepolymer. The core was polyol including pentaerythritol (PE-4), hyperbranched polyester with six hydroxyl end groups (HPE-6) and hyperbranched polyester with 12 hydroxyl end groups (HPE-12). The polyurethane prepolymer was synthesized by hexamethylene diisocyanate (HDI), polyethylene glycol (PEG) and hexadecanol. The structures of the hyperbranched cores and HWPUs were characterized by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance spectra (1H NMR and 13C NMR) and gel permeation chromatography (GPC). The influences of HWPU content and structure on its thickening property were studied by the measurement of rotary viscosity. The results showed that the thickening effect of HWPU enhanced with the increase of HWPU content in the aqueous polyurethane emulsion. The thickening effect of HWPU-6 was superior to that of HWPU-4 and HWPU-12 with the same length of hydrophilic chain. In addition, the thickening effect of HWPU with the same core was related to the length of hydrophilic chain and the relative content of hydrophobic end groups.

Investigation of Hyperbranced Polyesters with Different Generation and their Application in Waterborne Polyurethanes

The 1st, 2nd and 3rd generations of hydroxyl-terminated hyperbranched polyesters (HBPE-1, HBPE-2, and HBPE-3) were synthesized. A3rd generation hyperbranched polyester (HBPE-3) was used as original crosslinking agent to prepared hyperbranched waterborne polyurethane dispersions (HPU). FTIR spectra confirmed that this reaction really took place. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersions exhibited lower viscosity, and larger particle size. For the hyperbranched HPU films, mechanical properties were obviously enhanced.