Isocyanate-terminated Polyurethane Research Articles

Radical dendrimer: bis-indolyl polyurethane dendrimers containing TEMPO radicals for inhibition of cancer cell growth

Blocked isocyanate-terminated polyurethane dendrimers of first-generation (G1) to third-generation (G3) build-up with bis-indolyl units were subjected to urethane interchange reaction with 4-hydroxy-2, 2, 6, 6-tetramethylpiperidin-1-yloxyl (4-hydroxy TEMPO). The resulting free radical functionalized dendrimers were thoroughly characterized. The electron paramagnetic resonance (EPR)and vibrating sample magnetometer (VSM) results confirmed that these radical dendrimers are stable and paramagnetic. The cytotoxic effect of G1–G3 TEMPO-dendrimers was studied comprehensively across various cancer cell lines, encompassing human breast cancer (MCF-7 and MDA-MB-231), cervical cancer (SiHa), and lung cancer (A549 and NCI-H460), as well as normal lung epithelial cells (L132). It was observed that these TEMPO-dendrimers exerted cytotoxic effects in all cancer cell lines while demonstrating minimal impact on lung epithelial cells. Notably, MDA-MB-231 displayed heightened susceptibility to the TEMPO-dendrimers. Cell cycle analysis and morphological studies revealed that the TEMPO-dendrimers induced G1 phase cell cycle arrest and cell death specifically in breast cancer cells. Further investigations unveiled that these TEMPO-dendrimers triggered oxidative stress-mediated cell death specifically in breast cancer cells. All these findings suggest that the TEMPO radical dendrimers reported in this work exhibited cytotoxic effects in cancer cells by stimulating oxidative stress.

Solvent-free synthesis of pendant crosslinked polyurethane hot melt adhesive via dynamic Diels-Alder reaction

Pendant cross-linked polyurethane hot melt adhesive was synthesized without any solvents via Diels-Alder reaction (DA reaction) and was coded as DAPU. Firstly, a chain extender containing furan ring was synthesized via Michale addition reaction between hydroxyethyl acrylate (HEA) and furfuryl amine (FA). Secondly, the polyurethane prepolymer with pendant furan rings was synthesized from the reaction between the chain extender and isocyanate-terminated polyurethane prepolymer. Finally, the hot melt adhesive was cross-linked via DA reaction between furan rings and bismaleimide (BMI) without organic solvents due to the viscosity inhibition at higher temperature. DAPU exhibited a higher bonding performance (11.2 MPa) than the commercial reactive polyurethane hot melt adhesive (PUR-Ausbond 3550) and can reach 10.2 MPa after three times break as thermoplastic polyurethane hot melt adhesive (TPU-XJU83), due to the higher cross-linked density and the thermal reversibility of DA adducts. This confirmed that DAPU combined the merits of the two kinds of polyurethane hot melt adhesives successfully without involving solvents.

Self-Healing and shape memory reconfigurable Poly(urethane-urea-amide) elastomers containing multiple dynamic bonds for improving performance of 4D printout

As smart polymer material, 4D printed shape memory polymers (SMPs) can fix a temporary shape under a certain external stimulus and recover to the permanent shape under the same type of stimulus, which has attracted tremendous attention because of its potential applications in flexible electronics, biomedicine and other emerging fields. However, the traditional 4D printable polymer products in the practical multifunctional application usually have poor self-healing, shape memory, recyclability. Herein, a series of poly(urethane-urea-amide) elastomers (sPUUA) containing thiocarbamate, disulfide and carbamate dynamic bonds are successfully prepared by the copolymerization of isocyanate-terminated polyurethane prepolymer (OPU), polyetheramine and amino-terminated oligomeric polyamide-1212 (PA1212) in twin-screw extruder via reactive extrusion. Notably, sPUUA elastomers have self-healing, one-way/two-way and multiple shape memory functions. Damaged sPUUA-TU3 and sPUUA-TU3-H10 films with 0.9 wt% DBTDL can be healed by thermal treatment at 150 °C for 30 min and they also exhibit excellent micro-scratch elimination ability. Furthermore, sPUUA-TU3-H10 demonstrates a tensile stress of 9.6 MPa and an elongation at break of 402.3 % with a healing efficiency of 69 %, and exhibits the outstanding shape memory behavior based on supramolecular interactions and dynamic covalent bonds. Then the sPUUA elastomers were granulated, dried, extruded by single screw extruder, and then hot-stretched by pulling rollers into 1.75 ± 0.05 mm diameter wires for FDM 4D printing. The self-healing, macroscopic shape memory and reconfigurability of the as-printed objects were also demonstrated. Accordingly, sPUUA elastomers based on 4D printing will enable vast potential applications in the fields of multifunctional shape shifting devices, biomedicine, robotics and additive manufacturing.

Metal-free organocatalysts for high hydrolytic stability single component polyurethane adhesives and their application in decorative insulation facades manufacturing

We focused on developing polyurethane (PU) adhesives with superior ambient thermal and hydrolytic stability, a crucial factor for industrial productivity. Our approach involved creating PU prepolymers that can withstand varying temperatures in ambient conditions. These prepolymers consist of conventional isocyanate-terminated polyurethane and metal-free acid:base organic catalysts, with the stability of the adhesive relying on the organocatalyst employed. We tested a series of 11 latent organocatalysts derived from the reaction between 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and various acids. Among these, the catalyst based on 1-naphthoic acid exhibited exceptional stability, lasting at least 3 h at 60 °C and an average relative humidity of 65% under vigorous stirring. We assessed this stability using a fan-based stirrer and analyzed the curing conditions kinetically through DSC. Furthermore, our adhesive formulation is environmentally friendly as it is free of metals, specifically tin (typically present in catalysts such as dibutyltin dilaurate). This quality enhances its sustainability. To validate the practical applicability of the adhesives, we conducted tests using decorative facade models composed of siliciclastic sandstone extracted from a quarry in Vilviestre del Pinar (Burgos, Spain. Latitude: 41.951024° N, longitude: 3.078283° W) and extruded polystyrene (XPS). The results demonstrated the excellent hydrolytic and thermal stability of the adhesives, highlighting their significant potential for panel manufacturing in this context.

Eco-Friendly Epoxy-Terminated Polyurethane-Modified Epoxy Resin with Efficient Enhancement in Toughness

Polyurethane is widely used to toughen epoxy resins due to its excellent comprehensive properties and compatibility. However, some demerits of polyurethanes limit their applications, such as the harsh storage condition of isocyanate-terminated polyurethane (ITPU), the limited amount of ITPU in epoxy resin, and using solvents during the preparation of polyurethane-modified epoxy resins. To address these issues, in this study, we reported a facile and green approach for preparing epoxy-terminated polyurethane (EPU)-modified epoxy resins with different EPU contents. It was found that the toughness of the epoxy resin was significantly improved after the addition of EPU. When the EPU content was 30 wt%, the elongation at break and toughness were improved by 358.36% and 73.56%, respectively. In comparison, the toughening effect of EPU outperformed that of ITPU. Moreover, the high content of EPU did not significantly decrease the glass transition temperature and had little effect on the thermal stability of the epoxy resin.

Fabrication of nanocomposite membrane based on post-synthetic modification of two-dimensional metal-organic framework nanosheet

• Post-synthetic modification of two-dimensional metal-organic framework. • CuBDC-NH 2 nanosheet reacts with isocyanate-terminated polyurethane oligomer(PU). • The CuBDC-NH 2 /PU is conducted to prepare functional nanocomposite membrane. • The CuBDC-NH 2 /PU membrane shows over 93.0% removal rate for dye removal. Two-dimensional metal-organic framework (2D MOF) nanosheet is becoming as an attractive type of 2D materials. And Post-synthetic modification (PSM) provides a powerful method to modify the structure of MOF without altering its crystal topology, which can generate functional MOFs not accessible from direct synthesis and improve the compatibility between MOFs and other components in MOF-based composite materials, especially in MOF/polymer composite. In this work, a facile method based on PSM of 2D MOF with polymers is conducted to prepare functional nanocomposite membrane. First, the amino-functioned 2D MOF nanosheet, CuBDC-NH 2 (BDC-NH 2 is 2-amino-1,4-benzenedicarboxylate), has been prepared as PSM precursor. Then CuBDC-NH 2 nanosheet reacts with isocyanate-terminated polyurethane (PU) oligomer through PSM to obtain CuBDC-NH 2 /PU nanocomposite membrane, which show over 93.0% removal rate for dye removal, such as methylene blue, Rhodamine B and Eosin Y.

Multiple/Two-Way Shape Memory Poly(urethane-urea-amide) Elastomers.

Multiple and two-way reversible shape memory polymers (M/2W-SMPs) are highly promising for many fields due to large deformation, lightweight, strong recovery stress, and fast response rates. Herein, a semi-crystalline block poly(urethane-urea-amide) elastomers (PUUAs) are prepared by the copolymerization of isocyanate-terminated polyurethane (OPU) and amino-terminated oligomeric polyamide-1212 (OPA). PUUAs, composed of OPA as stationary phase and PTMEG as reversible phase, exhibit excellent rigidity, flexibility, and resilience, and cPUUA-C7 -S25 exhibits the best tensile property with strength of 10.3MPa and elongation at break of 360.2%. Besides, all the PUUAs possess two crystallization/melting temperatures and a glass transition temperature, which endow PUUAs with multiple and reversible two-way shape memory effect (M/2W-SME). Physically crosslinked PUUA-C0 -S25 exhibits excellent dual and triple shape memory, and micro chemically crosslinked cPUUA-C7 -S25 further shows quadruple shape memory behavior. Additionally, both PUUA-C0 -S25 and cPUUA-C7 -S25 have 2W-SME. Intriguingly, cPUUA-C7 -S25 can achieve a higher temperature (up to 165°C) SME, which makes it suitable for more complex and changeable applications. Based on the advantages of M/2W-SME, a temperature-responsive application scenario where PUUAs can transform spontaneously among different shapes is designed. These unique M/2W-SME and high-temperature SME will enable the applications of high-temperature sensors, actuators, and aerospace equipment.

In Situ-Formed Novel Elastic Network Binder for a Silicon Anode in Lithium-Ion Batteries.

High energy density lithium-ion batteries with preferable cycling stability are critical for the development of all-electric vehicles. Silicon (Si) has demonstrated a remarkable potential for application as anode materials due to its superior capacity performance and worldwide abundance. However, Si intrinsically undergoes substantial volume fluctuation during repeated lithiation/delithiation processes, which pulverizes the Si particles and undermines the integrity of the electrode structures, thus resulting in frustrating cycling stability. We developed a polymer binder with a highly stretchable and elastic network structure that can accommodate volume variation of Si. This was realized by an in situ cross-linking of polyacrylic acid (PAA) with isocyanate-terminated polyurethane oligomers that consist of polyethylene glycol (PEG) chains and 2-ureido-4-pyrimidinone (UPy) moieties through the reaction between isocyanate and carboxyl during the electrode preparation process. In this binder network, PAA could strongly adhere to the Si particles by forming hydrogen bonding with the surface hydroxyl groups. The PEG chains induce the flexibility of the polymer network, while the UPy moieties endow the polymer network with desirable mechanical strength through the formation of reversible and strong quadruple H-bonding cross-linkers. This binder not only can sufficiently accommodate the volume change of Si but can also provide a strong mechanical support to effectively sustain the integrity for the Si anode, consequently enhancing cycle stability and rate performance.

Synthesis of a coupling agent containing polyurethane chain and its influence on improving the dispersion of SiO2 nanoparticles in epoxy/amine thermoset

SiO2 nanoparticles (NPs) were modified with as-synthesized coupling agent containing isocyanate-terminated polyurethane (PUCA) to enhance the interaction between SiO2 NPs and DGEBA/DDM matrix in purpose of promoting the dispersion condition of the SiO2 NPs in cured resin. Uniform dispersion of the PUCA-SiO2 NPs was observed in the cured resin which was in obvious contrast with that of the raw SiO2 NPs and the IPTS-SiO2 NPs according to the visible light transmittance and TEM observation. The tensile behaviors of the PUCA-SiO2 composites were found obviously promoted than that of the raw SiO2 and IPTS-SiO2 composites. DMA results showed that the Tg of the PUCA-SiO2 composite was 8.9 °C and 5.8 °C higher than that of the raw, IPTS-SiO2 composite. SEM observation of the fracture surfaces showed that PUCA-SiO2 composite possessed the densest crack texture. This work showed that grafting the polyurethane chain to the surface of the inorganic NPs is an effective way to obtain uniform dispersion of the inorganic NPs in resin matrix.

Lignin-Based Phenolic Foam Reinforced by Poplar Fiber and Isocyanate-Terminated Polyurethane Prepolymer.

Phenolic foams (PFs) are lightweight (<200 kg/m3), high-quality, and inexpensive thermal insulation materials whose heat and fire resistance are much better than those of foam plastics such as polyurethane and polystyrene. They are especially suitable for use as insulation in chemical, petroleum, construction, and other fields that are prone to fires. However, PFs have poor mechanical properties, poor abrasion resistance, and easy pulverization. In this paper, a polyurethane prepolymer was treated with an isocyanate, and then the isocyanate-terminated polyurethane prepolymer and poplar powder were used to prepare modified lignin-based phenolic foams (PUPFs), which improved the abrasion resistance and decreased the pulverization of the foam. The foam composites were comprehensively evaluated by characterizing their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame-retardant properties. The pulverization ratio was reduced by 43.5%, and the thermal insulation performance and flame-retardancy (LOI) were improved. Compared with other methods to obtain lignin-based phenolic foam composites with anti-pulverization and flame-retardant properties, the hybrid reinforcement of foam composites with an isocyanate-terminated polyurethane prepolymer and poplar powder offers a novel strategy for an environmentally friendly alternative to the use of woody fibers.

Thermo-expandable microcapsules with polyurethane as the shell

Thermo-expandable microcapsules (TEMs) with polyurethane as the shell and n-hexane as the blowing agent were synthesized by interfacial reaction between isocyanate-terminated polyurethane prepolymer aqueous dispersion and polyamine chain extender. The synthetic process for the thermo-expandable PU-shelled microcapsules was established. The factors which affected the efficiency for blowing agent encapsulation were investigated by fourier transform infrared spectroscopy (FT-IR), laser particle size analyzer and thermo-gravimetric analysis (TGA). The foaming performances of the microcapsules were characterized by polarizing optical microscope with hot platform (POM) and thermo-mechanical analyzer (TMA). The results showed that PU-shelled thermo-expandable microcapsules were successfully synthesized and had good foaming performance. The NCO/OH ratio was found to have a significant effect on the encapsulation of n-hexane and the appropriate ratio was found to be 3:1. Diethylenetriamine (DETA), which is a polyamine chain extender, was found to be a more suitable chain-extender than other polyamine chain extenders in encapsulation the hexane. PU-shelled thermo-expandable microcapsules containing 25.8% blowing agent was fabricated. The onset expand temperature of TEMs was found to be 206 °C, and the maximum foaming temperature was at 235 °C, according to thermo-mechanical analysis. The volume expansion ratio of TEMs reached 27 times according to the measurement by polarizing optical microscope. The PU shelled TEMs showed good foaming performance in vinyl acetate-ethylene copolymer matrix.

Covalently introducing amino-functionalized nanodiamond into waterborne polyurethane via in situ polymerization: Enhanced thermal conductivity and excellent electrical insulation

Polymer-based thermal management nanocomposites with favorable electrical insulation have received increasing attention in the microelectronics industry. How to effectively disperse nanofillers and improve interfacial compatibility with polymer matrix is crucial to enhance comprehensive performance of nanocomposites. In this work, nanodiamond (ND) was first oxidized by hydrogen peroxide and then amino groups generated on its surface via hydrothermal reaction in the presence of ethylenediamine. Amino-functionalized ND particles (ND-NH2) were covalently incorporated into isocyanate-terminated polyurethane prepolymer chains via in situ polymerization, and a series of waterborne polyurethane (WPU)/ND-NH2 (WPN) nanocomposites with low loading levels (0.5, 1 and 2 wt%) were successfully prepared. ND functionalized with amino groups achieved excellent compatibility with the WPU matrix, improving the interfacial interactions between filler and matrix, and reducing the interface thermal resistances and phonon scatterings, further favoring the formation of thermal conductive paths. The highest thermal conductivity of the WPN nanocomposite with a lower ND-NH2 loading of 2 wt% was 0.369 W m−1 K−1, which is about 82% higher than that of the pure WPU film (0.203 W m−1 K−1). The excellent electrical insulation was also found at 2 wt% nanofiller content and the volume electrical resistivity reaches 2.525 × 1015 Ω·cm. Moreover, the incorporating and good dispersion state of ND particles in the WPU-based nanocomposites could increase the thermal stability and mechanical performance of the nanocomposite films. This method provides an effective and promising way to prepare environmentally friendly polyurethane nanocomposites reinforced with reactive surface of functionalized ND.

Evolution of Reaction‐Induced Phase Segregations in Bi‐Soft Segment Urethane Oligomers

AbstractOligomeric bi‐soft segment isocyanate‐terminated polyurethanes (ITPUs) are semi‐finished goods crucial for the fabrication of various polyurethane (PU) products such as foams, thermoplastics, adhesives, dispersions, and elastomers. Incompatibilities and thus phase segregation phenomena play an essential role in tailoring the properties of the final products. In this work, the evolution of reaction‐induced phase segregation (RIPS) in ITPUs is explored in terms of composition and morphology of the phase segregated products as well as competing second order kinetics of the reaction. The results suggest that mechanism and extent of the phase segregation are thermodynamically controlled following the ternary phase diagram of the reactants. A comprehensive description of the phase behavior during the reaction is provided demonstrating excellent control over the morphology of ITPUs by means of appropriate adjustment of the initial reactant composition. These results are fundamental for tailored morphology design as it is employed for instance in membrane synthesis.

Synthesis and characterization of castor oil-based branched polyols from renewable resources and their polyurethane-urea coatings

The chemical modifications of castor oil (CO) to develop branched polyols and their polyurethane-urea coatings have been investigated. For this purpose, castor oil-based branched polyols (COBPs) were synthesized from CO by modifying with succinic anhydride followed by reaction with hydroxyl group moieties like petrochemical-based pentaerythritol, trimethylolpropane and bio-based glycerol. The COBPs were characterized by using Fourier transform infrared, 1H and 13C nuclear magnetic resonance spectroscopies, gel permeation chromatography and differential scanning calorimetry. These COBPs were further urethanized with isophorone diisocyanate at OH/NCO ratio of 1:1.6 to get the isocyanate-terminated polyurethane prepolymers. The surplus isocyanate groups of the prepolymer were cured with atmospheric moisture at ambient temperature condition to form uniform film with fast surface drying. The thermo-mechanical, viscoelastic and swelling properties were evaluated for the cured coating films. Properties have been discussed from the viewpoint of branched network and also the urethane segment present in the structure. The glass transition temperatures of the coating films were found to be in the range of 32–64°C. The modified castor oil coating films show better thermo-mechanical and viscoelastic properties in comparison with control (unmodified castor oil) coating films. This work delivers an effective and promising way to synthesize branched moieties in plant oil-based high performance coatings.

Preparation of novel marine antifouling polyurethane coating materials

Polyurethane coating materials with different compositions of low surface energy polydimethylsiloxane and degradable poly(l-lactic acid) were synthesized by three major steps. Initially, the hydroxylation-terminated poly(l-lactide)-functionalized graphene (G-g-PLLA) was prepared by ring-opening polymerization of l-lactic acid using the phenol-functionalized graphene (G-f-OH), which was prepared by 1,3-dipolar cycloaddition reaction of graphene and 3,4-dihydroxybenzaldehyde when N-methylglycine and tin octoate were used as initiator and catalyst, respectively. Subsequently, isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane was obtained by condensation polymerization of polydimethylsiloxane and isocyanate-terminated polyurethane prepolymer that was obtained by the condensation polymerization of 4,4′-diphenylmethane diisocyanate and 1,4-butane diol. Finally, the novel polyurethane coating materials were prepared by the condensation polymerization of G-g-PLLA and isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane. These synthesized materials were carefully analyzed with Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectra (1H NMR), field-emission scanning electron microscopy (SEM), and high-resolution transmission (TEM). In addition, the water contact angles were measured. It was found that the surface free energy of the polyurethane coating materials decreased from 52.19 to 11.74 N/m2 with the increase of polydimethylsiloxane content from 0 to 20% and the water contact angle of the polyurethane coating materials increased from 71° to 108°. Moreover, the mechanical property was investigated. The studies also demonstrated that functionalized polyurethane was able to hydrolyze in seawater and the hydrolysis rate decreased as the PDMS content increased. At the same time, simulative ocean hanging plate experiment confirmed that the novel polyurethane coating materials exhibited a good antifouling performance, which indicated that the functionalized polyurethane has a potentiality in marine antifouling coating application.

Reaction‐induced phase separation in hexamethylene diisocyanate‐based poly(propylene oxide)/poly(ethylene oxide) bi‐soft segment oligomers

AbstractOligomeric bi‐soft segment isocyanate‐terminated polyurethanes (ITPUs) are semi‐finished materials crucial for the synthesis of various PU products like foams, thermoplastic parts, dispersions or elastomers. Incompatibilities and thus phase separation phenomena play an essential role in tailoring the properties of the final products. Therefore, a detailed knowledge of these phenomena is mandatory in order to design products with properties meeting the requirements of a given application. In this study the reaction‐induced phase separation during the formation of ITPUs by application of two partially miscible soft segments is presented. The physicochemical basics of this process as well as the extent of the resulting phase separation are discussed on the basis of the initial phase diagram of the reactants. Reaction monitoring by NCO content titration and UV–visible spectroscopy reveals a dependency between the onset of phase separation and conversion. It is found that an increase of the initial content of hexamethylene diisocyanate delays the onset of phase separation. Differential scanning calorimetry reveals further that the phase separation is a direct consequence of the incompatibility of the soft segments. Overall, the findings support the hypothesis that the mechanism and the extent of phase separation are closely related to the ternary phase diagram of the reactants. © 2018 Society of Chemical Industry

Evidence of Liquid-Liquid Demixing During Bi-Soft Segment Polyurethane Prepolymerization

Bi-soft segment isocyanate-terminated polyurethanes (ITPUs) currently play a major role in the industrial production of high performance polyurethanes (adhesives, coating, foams, thermoplastics, nanoparticles, dispersion). The present contribution reports on the investigation of liquid-liquid demixing phenomena during the synthesis of bi-soft segment ITPUs. For this purpose, a dedicated experimental setup based on coupled in-line reaction monitoring via UV/Vis and FTIR technique was developed. It was used to monitor phase separation and reaction progress in the course of a prepolymerization using 1,6-hexamethylene diisocyanate and a polyether polyol mixture. Such phenomena may have a great impact on reaction kinetics and product quality. Furthermore, in-line FTIR analysis appeared to be sensitive to phase separation processes in the way that it predominantly detects the continuous phase rather than the dispersed droplets.

Chemically Cross-Linked MOF Membrane Generated from Imidazolium-Based Ionic Liquid-Decorated UiO-66 Type NMOF and Its Application toward CO2 Separation and Conversion.

Carbon dioxide capture and transformation are of great importance to make cuts in greenhouse gas emissions. Nanometal-organic frameworks (NMOFs) could serve as ideal fillers for polymer membranes owing to their structural diversity and regulable microenvironment of the nanocage. Herein, a bifunctional, robust, and chemically cross-linked NMOF-based membrane was successfully constructed by the postsynthetic polymerization of imidazolium-based ionic liquid (IL)-decorated UiO-66 type nanoparticles (NPs) and the isocyanate-terminated polyurethane oligomer under mild conditions. The IL-modified MOF-polymer membranes exhibit a highly selective adsorption for CO2 over N2 and CH4. In addition, the obtained membrane can also be a highly active heterogeneous catalyst for CO2 transformation by cycloaddition with epoxide under an ambient pressure.

Effect of Monomers in Vinyl Urethane Macromonomers on Dispersion Polymerization of Polystyrene

The four different vinyl monomers in the reaction of isocyanate-terminated polyurethane prepolymer were used for the preparation of macromonomers and successfully employed in the dispersion polymerization of styrene. The chemical structures of vinyl monomer in macromonomers influenced on the polystyrene particle characteristics, such as the conversion, weight average molecular weights (Mw), polydispersity index (PDI), weight average diameter (Dw), and uniformity. The conversion of polystyrene increased with amounts of methyl group in vinyl monomer. Also the uniformity of polystyrene particles increased with amounts of methyl group in vinyl monomer.

Polyurethane encapsulated carbon black particles and enhanced properties of water polyurethane composite films

Abstract Polyurethane-encapsulated carbon black (ECB) particles were synthesized successfully through a facile method by encapsulating carbon black (CB) particles in the presence of an amphiphilic isocyanate-terminated polyurethane pre-polymer. Fourier transform infrared spectroscopy demonstrated the existence of a polyurethane layer on the surface of encapsulated CB, and thermo-gravimetric analysis indicated the encapsulation percentage reached 15.77 wt.%. The results of dynamic light scattering, transmission electron microscopy, and UV–vis spectroscopy analyses revealed that the ECBs exhibited better dispersibility and stability in water in comparison with the dispersant-dispersed carbon black (DCB) prepared by simply dispersing CB particles using a polymer super-dispersant. In particular, scanning electron microscope observation of PUB/ECB composite films obtained by blending ECB particles with a waterborne polyurethane binder (PUB), showed enhanced dispersibility and compatibility of the ECBs in the PUB matrix. Therefore, as test results demonstrated, PUB/ECB composite films showed better mechanical, water resistance, and color properties compared with those of PUB/DCB composite film. It is expected that this effective encapsulation method for preparing functional CB dispersions will be used to make waterborne coatings in the leather and textile finishing fields.