Cationic Waterborne Polyurethane Research Articles

Preparation of cationic waterborne polyurethane and its application in leather dyeing

The development of organic chromium-free tanning agents is currently a major research focus in leather tanning. However, these agents decrease the electrical potential of the tanned leather, which hampers the absorption of subsequent anionic dyes and fatliquoring agents. Consequently, issues such as lower color fastness, poor dyeing effects and environmental pollution arise. To address these challenges, this study proposes the utilization of anionic polyurethane (CWPU) as a dye fixing agent to enhance its performance and application in the leather preparation process. CWPU was successfully synthesized using polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), polypropylene glycol (PPG), and N-methyldiethanolamine (MDEA) as raw materials, and the optimal synthesis conditions were optimized. The experimental results showed that the synthesized CWPU color fixing agent exhibited excellent emulsion properties and comprehensive performance when the PCDL: PPG ratio was 1:1 and the MDEA addition amount was 6 wt%. When applied to leather color fixation, the leather not only achieved improved dry and wet rubbing fastness levels of 4–5 but also demonstrated significant improvements in solvent wash resistance and perspiration fastness. Furthermore, the leather treated with CWPU color fixing agent exhibited deeper color and improved physical and mechanical properties and tactile quality. Therefore, this study provides an effective choice of color fixing agent for environmentally friendly chromium-free tanning systems and has broad prospects for the application of acid dyes.

Preparation and performances of cationic waterborne polyurethane coating co-modified with acrylic and amino acid

Preparation and performances of cationic waterborne polyurethane coating co-modified with acrylic and amino acid

Synthesis and application of multifunctional lignin-modified cationic waterborne polyurethane in textiles

Waterborne polyurethanes (WPUs) often have limitations like inadequate weathering resistance and thermal stability. To overcome these shortcomings, lignin has been selected as a modifier for its abundant availability, renewability, and biocompatibility. This study synthesized a cationic WPU using isophorone diisocyanate and polyethylene glycol as raw materials. Hydrophilicity was attained through the inclusion of dihydroxyethyl dodecylamine as a chain extender, while the introduction of epoxy monomers and lignin served to modify the polyurethane. Furthermore, a dye dispersion for cotton fabric dyeing was prepared by combining the synthesized polyurethane, chitosan, and dyes. The cationic nature of the polyurethane played a crucial role in facilitating dye adhesion and uptake on the fabric surface, resulting in improved dyeing performance. The incorporation of epoxy side chains and chitosan cross-linking contributed to the excellent color fastness of the dyed fabrics. Moreover, the incorporation of lignin and chitosan endowed the fabric with antibacterial properties. Simultaneously, it provided effective UV protection, characterized by a high UV protection factor value for the fabrics. This lignin-modified WPU exhibits tremendous potential in applications such as textile coatings, adhesives, and color fixation agents. It effectively addresses the limitations of traditional WPUs and offers notable advantages, including a renewable source, cost-effectiveness, and biocompatibility.

Synthesis and Properties of Cationic Core-Shell Fluorinated Polyurethane Acrylate.

Vinyl-capped cationic waterborne polyurethane (CWPU) was prepared using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), N-methyldiethanolamine (MDEA), and trimethylolpropane (TMP) as raw materials and hydroxyethyl methacrylate (HEMA) as a capping agent. Then, a crosslinked FPUA composite emulsion with polyurethane (PU) as the shell and fluorinated acrylate (PA) as the core was prepared by core-shell emulsion polymerization with CWPU as the seed emulsion, together with dodecafluoroheptyl methacrylate (DFMA), diacetone acrylamide (DAAM), and methyl methacrylate (MMA). The effects of the core-shell ratio of PA/PU on the surface properties, mechanical properties, and heat resistance of FPUA emulsions and films were investigated. The results showed that when w(PA) = 30~50%, the stability of FPUA emulsion was the highest, and the particles showed a core-shell structure with bright and dark intersections under TEM. When w(PA) = 30%, the tensile strength reached 23.35 ± 0.08 MPa. When w(PA) = 50%, the fluorine content on the surface of the coating film was 14.75% and the contact angle was as high as 98.5°, which showed good hydrophobicity; the surface flatness of the film was observed under AFM. It is found that the tensile strength of the film increases and then decreases with the increase in the core-shell ratio and the heat resistance of the FPUA film is gradually increased. The FPUA film has excellent properties such as good impact resistance, high flexibility, high adhesion, and corrosion resistance.

Synthesis of a Reactive Cationic/Nonionic Waterborne Polyurethane Dye Fixative and Its Application Performance on Viscose Fiber Fabrics.

A series of cationic waterborne polyurethane (CWPU) emulsions was synthesized with isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI) as hard segments; polyol (N210) and polyethylene glycol (PEG-2000) as soft segments; N-methyldiethanolamine (MDEA) as a hydrophilic chain extender; and trimethylolpropane (TMP) as a crosslinker. Then, the effects of the R-value, MDEA content, and TMP content on the properties of the CWPU emulsion, film, and fabric treatment were investigated. The results indicated that when the R-value was 3.0, the MEDA content accounted for 4.0% of the solid and the TMP content accounted for 1.0% of the solid. CWPU has excellent storage stability. Applying it to the fixing treatment of the viscose fiber fabrics can effectively improve the color fastness to rubbing, elasticity, surface smoothness, and anti-static properties.

Preparation and characterization of high solid content cationic waterborne polyurethane with core‐shell structures

AbstractIn this study, core‐shell structured cationic waterborne polyurethane (WPU) dispersions with high solid content were prepared. To this end, prepolymer A was synthesized from polytetramethylene ether glycol (PTMG), isophorone diisocyanate (IPDI), castor oil (CO) and 1,4‐butanediol (BDO) without integration of the hydrophilic groups. Prepolymer B with hydrophilic groups was prepared from PTMG, IPDI, CO, BDO and N‐methyldiethanol amine (MDEA). WPU dispersion with a core‐shell structure could be generated by mixing, neutralizing, and emulsifying of the prepolymer A and the prepolymer B. The results indicated that the generation of WPU dispersions through this technique exhibited a milky appearance while the pH values range from 5.30 to 5.60. The optimal combination of prepolymer A and prepolymer B (at a ratio of 5:5) resulted in a dispersion with the highest solid content (50.4%), lowest viscosity (69 mPa·s), and narrowest particle size distribution. As the proportion of prepolymer A to prepolymer B decreases, the tensile strength of WPU film reduces while the elongation at break and glass transition temperature increases. Moreover, initially the contact angle with water was decreased instead of increase. However, modifications in a ratio of prepolymer A and B was not showed any significant impact on the thermal stability performance of the WPU films.

Sustainable Strategies for Synthesizing Lignin-Incorporated Bio-Based Waterborne Polyurethane with Tunable Characteristics.

In this study, we introduce a novel approach for synthesizing lignin-incorporated castor-oil-based cationic waterborne polyurethane (CWPU-LX), diverging significantly from conventional waterborne polyurethane dispersion synthesis methods. Our innovative method efficiently reduces the required solvent quantity for CWPU-LX synthesis to approximately 50% of that employed in traditional WBPU experimental procedures. By incorporating lignin into the polyurethane matrix using this efficient and reduced-solvent method, CWPU-LX demonstrates enhanced properties, rendering it a promising material for diverse applications. Dynamic interactions between lignin and polyurethane molecules contribute to improved mechanical properties, enhanced thermal stability, and increased solvent resistance. Dynamic interactions between lignin and polyurethane molecules contribute to improved tensile strength, up to 250% compared to CWPU samples. Furthermore, the inclusion of lignin enhanced thermal stability, showcasing a 4.6% increase in thermal decomposition temperature compared to conventional samples and increased solvent resistance to ethanol. Moreover, CWPU-LX exhibits desirable characteristics such as protection against ultraviolet light and antibacterial properties. These unique properties can be attributed to the presence of the polyphenolic group and the three-dimensional structure of lignin, further highlighting the versatility and potential of this material in various application domains. The integration of lignin, a renewable and abundant resource, into CWPU-LX exemplifies the commitment to environmentally conscious practices and underscores the significance of greener materials in achieving a more sustainable future.

Synthesis and properties of castor oil–based cationic waterborne polyurethane modified by epoxy resin

Synthesis and properties of castor oil–based cationic waterborne polyurethane modified by epoxy resin

Thermal-driven cationic waterborne polyurethane crosslinker with oxime-based and catechol structure for the preparation of soybean protein-based adhesive with excellent adhesion properties

Recently, the research of waterborne polyurethane (WPU) as toughening matrix of soybean protein-based adhesives has attracted much attention. However, the intermolecular interaction between polyurethane and protein molecules is too weak to construct a compact crosslinking system to achieve strengthening and toughening adhesive systems. In this work, a thermal-driven cationic waterborne polyurethane (CWPOU) with oxime-isocyanate groups and catechol groups was synthesized. The obtained CWPOU emulsion was introduced into soybean meal (SM) matrix to fabricate a SM/CWPOU bio-adhesive. Thermal-driven elements in polyurethane molecules released isocyanate groups, increasing covalent crosslinking between crosslinker and protein molecules, synergies with non-covalent forces formed between catechol structures to improve the comprehensive bonding properties of the adhesives. As a result, the dry/wet bonding strengths of the modified adhesives were noticeably enhanced with the highest values observed (SM/CWPOU-4) reaching 169.6% and 191.4% that of pure SM adhesives, respectively. Furthermore, the hydrogen bonding provided by hard segments of polyurethane and noncovalent forces between catechol groups and wood substrates contributed to excellent cold-pressing performance of the bio-adhesives with a maximum value pleasantly reaching 298% that of pure SM. The mildew resistances of SM/CWPOU adhesives were attributed to bactericidal performance of the cationic structures and catechol groups in CWPOUs. This work provides an effective method to prepare the “green” and high-performance protein-based adhesives.

Developing a highly-conductive and strength cotton yarn through dual shell architecture of graphene for smart wearable devices

The development of textile-based flexible wearable electronics has received increased attention owing to its potential application in personalized thermotherapy, human health monitoring, and human-interactive sensing. Cotton yarn is an inexpensive, extensively used material suitable for the above applications. However, the use of commercial cotton yarn presents issues regarding electrical insulation and tensile properties. Functionalizing pristine cotton yarn and simultaneously improving its electrical conductivity and mechanical properties remains a challenge. In this study, a graphene-cotton yarn with a dual shell interfacial structure was designed by the interface modulation strategy. Cationic waterborne polyurethane was introduced into the functionalization interface and played an interfacial linking molecule role. The inner shell (reduced graphene oxide, rGO) exhibits electrostatic attraction to the modified cotton yarn substrate, while the outer shell (graphene) generates a continuous and effective conductive network. The resultant graphene-cotton yarn exhibits a high electrical conductivity of 5.50 × 103 S·m−1. The conductive yarn exhibits an extraordinary tensile strength of 194.36 ± 19.82 MPa and a toughness of 32.66 ± 1.13 MJ m−3, which are 2.1 and 3.6 times higher than that of pristine cotton yarn, respectively. Additionally, we have demonstrated the capabilities of the designed graphene-cotton yarn in prototype textile-based applications, such as personalized thermotherapy, human health monitoring, and braille identification. This research expands the prospects of electronic textiles in the field of flexible wearable applications.

Construction and Performance Evaluation of Functional Coating with Multi-Layered Structure on the Surface of Cashmere Fibers Based on Dispersed Graphene by Cationic Waterborne Polyurethane

ABSTRACT In order to revise the problem of inferior hand-feeling of cashmere textile anti-filling finished with “addition” or “subtraction-addition” technology and indicate the effects of graphene distributed state in the surface on antistatic properties of cashmere fibers, A couple of flexible hydrophilic cationic polyurethanes used as a dispersion medium for graphene purposefully are designed and prepared. In addition, the state of polymer coating and graphene on the fiber is effectively controlled by foam micro-coating technology. The admirable pilling resistance, static resistance, and hand-feeling of cashmere textile attributed to two-layer polyurethane membranes realized through “bottom coating (BC)” and “surface coating (SC)” are definite and reliable. The results show that the cashmere textile obtained 1.0% (o.m.f. on mass of fabric) weight gain rate (WGR) under the foam bottom coating process, correspondingly, obtained 3–4% (o.m.f.) weight gain rate (WGR) under traditional dipping process, the pilling resistance grade of cashmere textile is improved to Grade 4–5 from Grade 1–2. The semi-embed state of graphene in the “surface coating” resin film on cashmere surface results in the decrease of static voltage half-life from 180 s to about 2 s. Clearly, the foam microcoating technology scheme of “BC+ SC@graphene” has achieved good expected results.

Study on Castor Oil-based Cationic Waterborne Polyurethane and Its Application

The raw material for polyurethane synthesis is mainly polyols, while traditional polyols come from fossil resources. With the decrease of fossil resources, the synthesis of polyurethane by vegetable oil-based polyols has gradually gained more attention. Castor oil is a kind of plant oil-based polyols, which are the most suitable plant oil polyols because of its non-toxic, biodegradable and trihydroxy structure. Polyurethane synthesized with castor oil as a polyol has many special properties, such as good antibacterial properties, anti-UV properties, good biocompatibility and biodegradable properties. This paper explores the performance and application of castor oil-based cationic waterbased polyurethane (CWPU), which is helpful to promote its performance research and wider application.

Antibacterial and Alkali-responsive Cationic Waterborne Polyurethane Based on Modification of Aloe Emodin.

Cationic water-based polyurethane(CWPU) was synthesized to explore aloe-emodin modifies to obtain CWPU materials with better comprehensive performance. It provides a simple way to synthesize antibacterial waterborne polyurethane, which is to introduce the end-blocking group of herbal extracts into the structure. It contains synergistic antibacterial effect of herbal antibacterial and quaternary ammonium ion on Escherichia coli. It makes the material resist the erosion of bacterial, and increase the service life of materials. When the pH value of the environment changes, the UV absorbance of the aloe-emodin modified cationic water-based polyurethane(AE-CWPU) also changes. Therefore, within a certain detection range, AE-CWPU has great applications in the field of smart response materials. The modified thermodynamic properties have been improved, and the mechanical properties basically maintained the maximum stress, and the elongation at break was reduced.

Synthesis and property of room-temperature self-healable cathodic electrophoretic deposition coatings based on cationic waterborne polyurethane

Synthesis and property of room-temperature self-healable cathodic electrophoretic deposition coatings based on cationic waterborne polyurethane

Bioinspired dual-crosslinking strategy for fabricating soy protein-based adhesives with excellent mechanical strength and antibacterial activity

Plant-derived biomass adhesives are increasingly in demand to replace traditional non-biodegradable petrochemical materials. However, the insufficient mechanical strengths and poor antibacterial activities of biomaterials severely limit their applicability. Inspired by the amphiphilic characteristics of mussel protein, a dual-crosslinking strategy is reported here for preparing soy meal (SM)-based adhesives with excellent adhesion and antibacterial properties. Specifically, castor oil containing abundant hydroxyl groups was used to prepare the cationic waterborne polyurethane (WPU) dispersion. Subsequently, the dynamic glue bridges were synthesized from the tannic acid-functionalized borax (TA@BA) complexes via multiple coordination bonds. Finally, the enhanced cross-linking network system was then constructed in the protein matrix based on the synergy of dynamic covalent bonds, electrostatic interactions, and hydrogen bonds. As a result, the wet strength of the resultant adhesive significantly increased by 154.77% compared to the SM adhesive. Additionally, the resultant adhesive exhibited remarkably enhanced thermal stability, flame retardancy, and water resistance. Based on the synergistic effect of the cationic WPU, polyphenol components, and borate groups, the SM/WPU/TA@BA adhesive exhibited desirable anti-mildew and antibacterial properties. This biomimetic dual-crosslinking design therefore provides a novel and facile strategy for the preparation of high-performance biopolymer adhesives used in the fields of biology and engineering.

Synthesis of cationic waterborne polyurethane via thiol-ene click reaction and catechol chemistry to improve the performance of soybean meal adhesives

The development of bio-based adhesives comprised of low-cost, renewable, and accessible biomass resources with high adhesion and toughness is needed in wood-based panel industry. Herein, a novel cationic waterborne polyurethane (CWPU) emulsion was prepared with a hydrophobic long alkyl chain and catechol structure via thiol-ene click reaction and direct emulsification. Then, the obtained emulsions were applied as efficient crosslinkers to enhance the bonding performance of soybean meal (SM) adhesives. The catechol group on polyurethane acted as a secondary reaction platform that formed multiple hydrogen bonds with protein molecules to optimize the mechanical strength and adhesion toughness of the SM resins. In addition, the hydrophobic alkyl chains grafted intertwine and served as a “water-proofer” that hindered the intrusion of water molecules. Consequently, the modified SM/HD@CCWPU resin presented an impressive improvement in its wet bonding strength and toughness to 165.9% and 378.1%, respectively, compared with the pure SM resin. This efficient, ecofriendly, and low-cost design enables the utilization of agricultural byproducts instead of traditional formaldehyde-based products to prepare high-performance adhesives.

Improvement of Mechanical and Thermal Properties of Cationic Waterborne Polyurethane by Using an Amino-Rich Multifunctional Macromolecular Crosslinking Agent

Improvement of Mechanical and Thermal Properties of Cationic Waterborne Polyurethane by Using an Amino-Rich Multifunctional Macromolecular Crosslinking Agent

Synthesis and application of aminosiloxane‐modified cationic waterborne polyurethane as fixing agent for nylon fabric

AbstractIn order to make up for the lack of washing fastness and chlorinated water fastness of nylon dyed with acid dyes, an aminosiloxane modified cationic waterborne polyurethane (KWPU) with the ability to reversibly adsorb chloride ions was synthesized. N‐methyldiethanolamine and ethylenediamine was used as chain extender. N‐aminoethyl‐γ‐aminopropyltrimethoxysilane was used to block the remaining isocyanate groups and provide secondary amine groups for reversible adsorption of chloride ions. The structure of KWPU was characterized by Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), 1H NMR, and differential scanning calorimetry (DSC). Particle size and zeta potential were tested to evaluate the emulsion stability. The research results showed that when the N‐methyl diethanolamine content was 14%, the water absorption rate of KWPU film was 82.1%, and when the KH‐792 content was 6%, the water absorption rate of KWPU was 34.8%. The addition of siloxane can significantly improve the thermal resistance of the KWPU film. The color fastness of the dyed nylon fabric treated with KWPU emulsion was significantly improved, the rubbing fastness was improved by 0.5 or 1 grade, the washing fastness was improved by 1 grade, and the fastness to chlorinated water was improved by 1.5 or 2 grade.

Cationic waterborne polyurethane–chitosan based on natural rubber as new green antimicrobial coating

This is the first report on developing new methodologies to synthesize hydroxytelechelic natural rubber (HTNR), a bio-polyol based on natural rubber (NR), by mechanical and chemical degradation. The mechanical degradation of NR from shear during mastication leads to a lower molecular weight before oxidative cleavage by periodic acid. The effects of the molar ratio of periodic acid/isoprene unit ([H5IO6]/[isoprene unit]) on properties of HTNR were investigated. The end-functionality was determined by 1H NMR spectroscopy and the molecular weight was determined by SEC. The HTNR polyol with 3000 g/mol molecular weight and H5IO6 at 0.07 ratio were used as precursors to synthesize cationic waterborne polyurethane (cWPU). The cWPU had a well-defined size distribution and was stable for at least 3 months. The chemical structure of cWPU was confirmed by 1H NMR spectroscopy. Moreover, the hydrophilic properties and antimicrobial properties of cWPU improved when mixed with 1% solution of protonated chitosan (PCS). In addition, the effects of PCS content were studied. The investigations showed that increasing PCS gave a more hydrophilic surface with a low contact angle and a high surface free energy for the cWPU-PCS film. Furthermore, PCS at over 3%wt content inhibited E. coli growth. Hence, the new cWPU mixed with chitosan could serve as an alternative antimicrobial coating material.

Preparation and properties of rosin-based cationic waterborne polyurethane dispersion

Preparation and properties of rosin-based cationic waterborne polyurethane dispersion