Hyperbranched Polyurethane Research Articles

Nanocomposites of Thermosetting Polymers and Graphene Quantum Dots—Physical Attributes and Ongoing Progressions

Thermosets, before hardening, consist of independent macromolecules similar to thermoplastics, however, chemical curing of these macromolecules via heat or radiations may form irreversibly crosslinked macromolecular networks between their main chains. Graphene quantum dots are inimitable spherical nano-entities having the advantages of extremely small sizes, of 5-10 nm, very high surface area, surface/edge effects, quantum confinements and a range of physical characteristics including semiconductivity, fluorescence and magnetic properties. Similar to other nanocarbons (like graphene, fullerene or nanodiamonds), graphene quantum dots have been examined as noteworthy nanofillers to enhance the essential physical features of various macromolecular matrices, such as thermosets, thermoplastics and rubbers. Consequently, this review article was intended to systematically discuss the existing scientific state of graphene quantum dots reinforced thermosetting macromolecular matrices for the formation of high performance nanomaterials. According to the literature reports, the type, amount and molecular weight of these macromolecules seemed to affect the epoxy-quantum dots interactions and physical properties, like strength and heat stability of the resulting nanomaterials. Moreover, including graphene quantum dots in thermosetting matrices, like epoxies, hyperbranched polyesters and hyperbranched polyurethanes, has positively influenced the engineering aspects (mainly mechanical and thermal attributes) of the resulting nanocomposites owing to their interactions, compatibility and interfacial tendencies toward these matrices. Principally, epoxy/graphene quantum dots nanocomposites have been fabricated and investigated for the effects of graphene quantum nano-entities on the physical property enhancements of these irreversibly crosslinked macromolecules due to their mutual matrix-nanofiller interfaces. As per our analysis, the literature hitherto on the graphene quantum dots reinforced thermosetting matrix nanocomposites has disclosed significant property improvements of these macromolecules and their promising technological applications for high performance anticorrosion coatings, electromagnetic interference shields and biomedical fields.

A review on carbon nanofiller-based hyperbranched polyurethane nanocomposites: synthesis strategies, applications and challenges

A review on carbon nanofiller-based hyperbranched polyurethane nanocomposites: synthesis strategies, applications and challenges

A sulfonated hyperbranched bio-based waterborne polyurethane sizing coating for the enhancement of mechanical properties and surface wettability of carbon fibres

Wet-weaving and cluster braiding in industrial production processes generate irreversible defects and grooves in carbon fibre (CF) filaments, which reduce the service life and mechanical properties of the fibres. Additionally, the fibre surface covered with numerous inactive carbon-containing groups and presents chemical inertness, which limits the prospects of CF applications. Hence, the hyperbranched bio-based waterborne polyurethanes (SWPU) possessing the synergism of sulfamate and carboxylate complex hydrophilic units were adopted as sizing coatings to improve the flexural and tensile strengths of CF, as well as fibre surface roughness and wettability. The SWPU is designed on dihydroxymethylbutyric acid and sulfamates (A95) as per- and post-chain extenders, respectively, trimethylolpropane (TMP) as an intramolecular cross-linker, and plant-extracts castor oil (CO) replacing petroleum-based petrochemicals as the soft-segments. The construction of CO-TMP hyperbranched cross-linking networks and the strengthened hydrogen-bonding effects of the polar sulfamates positively affect the intermolecular interactions and configuration stability of SWPU sizing coatings. SWPU revealed favourable thermo-mechanical properties achieving a T5% decomposition temperature and toughness of 297.83 °C and 35.24 MJ/m3. The coating effects of the bio-based sizing agents not only repaired defects and improved surface roughness on CF, but the polar groups in SWPU comprising SO3Na, carbamate and polyurea promoted the chemotactic activity and wettability of the fibres. The surface energy and tensile strength of the SWPU sized CF reached 43.75 mN/m and 5.68 GPa, respectively, which were 45.4 % and 30.7 % higher compared to original CF. The research contributes to the development and industrial production of high-performance, eco-friendly bio-based sizing coatings.

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.

Single-Step Synthesis and Characterization of Non-Linear Tough and Strong Segmented Polyurethane Elastomer Consisting of Very Short Hard and Soft Segments and Hierarchical Side-Reacted Networks and Single-Step Synthesis of Hierarchical Hyper-Branched Polyurethane.

Polyurethane elastomers are among the most versatile classes of industrial polymers-typically achieved through a two-step synthesis of segmented block copolymers, comprising very long and soft segments that provide elasticity and significantly long and hard segments that provide strength. The present research focused on the design of a single-step synthesis of a new segmented polyurethane consisting of very short soft and hard segments, crosslinked by preferentially side-reacted hierarchical tertiary oligo-uret network structures, thus exhibiting significant strength, elasticity, and toughness. Despite the theoretically linear structure, both FTIR and solid-state 13C NMR spectroscopy analyses indicated the quasi-equal presence of urethane groups and tertiary oligo-uret structures in the resulting polymer, indicating a preferential consecutive side reaction mechanism. Thermal analysis indicated the significant crystallization of soft segments consisting of only four ethylene oxide units, which was, hereby, demonstrated to occur via an extended chain mechanism. Tensile mechanical properties included significant strength, elasticity, and toughness. Increasing the soft segment length led to a decreased tertiary oligo-uret secondary crosslinking efficacy. The preferential hierarchical side reaction mechanism was, hereby, further confirmed through the synthesis of a completely new type of hyper-branched polymer via diisocyanate and a mono-hydroxy-terminated reagent. The structure-property relations and reaction mechanisms demonstrated in the present research can facilitate the design of new polyurethanes of enhanced performance and processing efficacy for a variety of novel applications.

A novel hyperbranched polyurethane solid electrolyte for room temperature ultra-long cycling lithium-ion batteries

Low room temperature ionic conductivity of solid polymer electrolytes (SPE) greatly constraints its application in the solid lithium-ion batteries. Hyperbranched polymer with unique topological structure as matrix of SPE is expected to solve this issue due to its low crystallinity and rich functional groups which helps dissociation of lithium salt. Herein, a hyperbranched polyurethane (HPU) solid electrolyte is prepared by the reaction of hyperbranched polyethylene glycol and isophoradione diisocyanate in the presence of lithium salt and ionic liquid for the first time. The obtained HPU1.5-IL1.5 electrolyte possesses a high room temperature ionic conductivity of 0.4 mS cm−1 and a wide electrochemical window of 4.95 V (vs Li/Li+). It is worth noting that the prepared HPU1.5-IL1.5 electrolyte can be adapted to multiple electrodes. Specifically, the assembled LFP half-cell can achieve long cycling up to 1000 cycles at 0.5 C with 83 % capacity retention at room temperature. Notably, the NCM811|HPU1.5-IL1.5|Li cells and LTO|HPU1.5-IL1.5|Li cells can deliver the initial discharge capacity of 148 mAh g−1 at 0.1 C for 160 cycles and the initial discharge capacity of 150 mAh g−1 at 0.2 C for 440 cycles at room temperature, respectively. Meanwhile, the safety of the pouch cell has been confirmed under some extreme conditions.

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.

Preparation of high-performance polyurethane-polyacrylate coatings based on hyperbranched structure and application in anti-ultraviolet film

An efficient, green UV-curable strategy is presented toward strong, flexible, and transparent polyurethane-polyacrylate coatings based on the acrylic-ended hyperbranched polyurethane (AHPU). AHPU was prepared and then blended with commercially available epoxy acrylate EB600 and UV absorbers silicomolybdic acid (SiMoA), followed by undergoing rapid UV curing to fabricate the anti-UV polymeric coatings. The polymeric coating exhibits outstanding mechanical properties including strength, toughness, adhesion, and pencil hardness, which are remarkably improved by the hyperbranched topological structure. Moreover, the uniform dispersion of SiMoA in the polymer matrix and the formation of charge-transfer complexes (CTCs) between SiMoA and AHPU have ensured excellent UV-protective performance. Furthermore, the compromise between the UV-shielding performance and visible transparency is overcome, since high visible transparency has also been achieved. This high-performance polymeric anti-UV composite coating has exhibited a huge application prospect in automotive glass film.

Synthesis of xylitol-based hyperbranched polyurethane acrylate and its application in self-matting acrylate coatings

Synthesis of xylitol-based hyperbranched polyurethane acrylate and its application in self-matting acrylate coatings

From nano to the macro: tuning hierarchical aggregation of thermoresponsive PEG/PCL-based polyurethanes via molar mass/composition control

Amphiphilic hyperbranched polyurethanes (HPUs) based on PEG and PCL are promising for several biomedical applications. However, the lack of control over the molar mass and composition hinders a deep understanding of the aqueous self-assembly of HPUs. In this paper, the control over the HPU molar mass and composition was provided by dynamic urea bond-mediated polymerization (DUBMP), enabling a careful evaluation of their aqueous self-assembly by 1H NMR, DLS, and Cryo-TEM. HPUs containing a single PCL block per chain self-assemble into nanoaggregates (Rh ≈ 10 nm) in water up to its cloud-point temperature (Tcp) of 34 °C. On the other hand, HPUs with more than one PCL block per chain self-assemble into nanoaggregates and their clusters below Tcp. In this case, the solution behavior can be tuned by the HPU molar mass. Increasing overline{{mathrm{M} }_{mathrm{w}}} from 4 to 19 kDa, HPUs of similar composition can form colloidally stable cluster suspensions (overline{{mathrm{M} }_{mathrm{w}}} = 4 kDa) and phase separate into a denser liquid aggregate–cluster phase (overline{{mathrm{M} }_{mathrm{w}}} = 7 kDa) or into a highly viscous aggregate-network phase (overline{{mathrm{M} }_{mathrm{w}}} = 19 kDa). This type of control over the hierarchical aggregation of HPUs was reported for the first time and is interesting for biomedical applications.Graphical abstractThe control of amphiphilic branched PU molar mass and architechture via isocyanate reversible deactivation provided the control over its aqueous phase behavior, tuning it from micelles to micelle-networks

Structure‐property relationships of waterborne polyurethane (WPU) in aqueous formulations

AbstractThis study provides an overview of the rheological properties of aqueous polyurethanes (WPU), as the main component, or as a thickening additive in aqueous formulations. Waterborne polyurethanes (WPU) have been proposed as an environmentally friendly alternative to conventional solvent‐based solutions in a variety of industrial applications such as coatings, adhesives, inks. In all these fields, the control of rheological properties became an important prerogative to determine the quality of the dispersion and its potential applicability. First, the effect of parameters such as components, particle size and content, temperature, and interactions on dispersion viscosity was reported. Then, the effect of two additives, i.e. thickeners and nanomaterials, on structure–property relationships of WPU‐base systems, was described. Thickeners are rheological modifiers, commonly used to stabilize the dispersion and prevent flocculation and sedimentation of the particles, or to change the flow behavior of dispersions from Newtonian to pseudoplastic. These species can interact with water and polymer particles to create a network structure that alters the flow resistance, and thus viscosity. The use of hyperbranched aqueous polyurethane as thickening agent in WPU formulations was also presented. On the other hand, nanostructured fillers (0D/1D/2D) or a combination thereof in waterborne polyurethane led to the formation of specific microstructures that prevented the penetration of water, oxygen, and corrosive substances, also improved mechanical and thermal properties, allowing the development of high‐performance WPU‐based products.

A highly stretchable and self-healable hyperbranched polyurethane elastomer with excellent adhesion

Polyurethane elastomers with outstanding mechanical properties were playing important roles in numerous fields. However, how to choose the tensile stress and strain of the material was a problem that we should consider. In order to solve the above difficulties, a hyperbranched way with hard and soft chain structure is proposed. Herein, we report a hydrogen bond rich strategy based on hyperbranched structure to address the above issue. The prepared polyurethane elastomer had excellent mechanical properties (tensile break strength to 41.8 MPa and stretchability to 2564.8%). Additionally, the self-healing efficiency of the material could reach 92.42% (70 °C). More importantly, PNHT shows a good adhesion strength (up to 730 KPa) due to the presence of TA. As a result, this work provided a reference for the preparation of high-toughness, high adhesion and healable elastomers.

Hyperbranched Polyurethanes with Flammability Resistance for Leather Retanning

In this study, diethyl bis(2-hydroxyethyl) aminomethyl phosphonate was modified by hexamethylene diisocyanate, and then was utilized to partly replace the isocyanates to prepare hyperbranched polyurethanes (HPU-DPAs). The hyperbranched polyurethanes were then employed in the retanning process of wet blue. The shrinkage temperature, average thickness as well as mechanical properties of leather before and after retanning were acquired. The flammability of retanned leather was measured by cone calorimeter test. The morphologies of wet blue and leather after retanning by HPU-DAP were obtained using a scanning electron microscope. Results showed that the average thickness, tensile strength and elongation at break of leather were all improved after retanning. Retanning by HPU-DAPs can effectively increase flame retardancy of final leather.

Correction to “Biobased Biodegradable Waterborne Hyperbranched Polyurethane as an Ecofriendly Sustainable Material”

Correction to “Biobased Biodegradable Waterborne Hyperbranched Polyurethane as an Ecofriendly Sustainable Material”

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.

Correction: A tough, smart elastomeric bio-based hyperbranched polyurethane nanocomposite

Correction for ‘A tough, smart elastomeric bio-based hyperbranched polyurethane nanocomposite’ by Suman Thakur et al., New J. Chem., 2015, 39, 2146–2154, https://doi.org/10.1039/C4NJ01989J.

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.