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Acrylic acid is commonly used to modify anionic waterborne polyurethanes, and little research has been done on the modification of cationic waterborne polyurethanes. In this study, the effect of acrylic acid addition at different levels on the performance of cationic waterborne polyurethanes was investigated. The experimental results showed that the stability, and chemical resistance of cationic waterborne polyurethane coatings were improved with the addition of acrylic acid, which has the advantages of better chemical resistance, high stability and low price, and the hardness of the coating gradually increased and the adhesion decreased with the increase of acrylic acid content, therefore, the acrylic acid content of 21% was the most suitable. In addition, the effect of amino acids as neutralizing agents on the performance of cationic waterborne polyurethane coatings was also explored. The addition of amino acids helped the cationic waterborne polyurethane to form a reticular crosslinked structure, and the experimental results showed that the mechanical properties of the cationic waterborne polyurethane coatings were greatly improved. Compared with the commonly used acids (hydrochloric acid and acetic acid), amino acids have the advantage of being environmentally friendly and non-toxic, which is more conducive to the industrial production and application of cationic waterborne polyurethane coatings. [ABSTRACT FROM AUTHOR]

In 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

High solid content CO2-based cationic waterborne polyurethanes (CWPUs) were prepared using CO2-polyols as soft segment and N-methyl diethanolamine (MDEA) as hydrophilic group. The resulting stable aqueous dispersion displayed a high solid content of 52% with a low MDEA loading of 3.52 wt%. This novel structural CWPU can provide excellent adhesive strength, whose T-peel strength could reach 173.48 N/5cm, 20% higher than that of ester-based cationic waterborne polyurethane (87.55 N/5cm). The CO2-based CWPU film showed only 2 wt% swelling percentage after 240 min immersion in water, and no change was observed during its immersion in 5 wt% sodium hydroxide solution. The tensile strength of CO2-WPUs dropped slowly to 91.2% after 480 min immersion in a 5 wt% sodium hydroxide solution, whereas that of ester-based CWPUs dropped quickly to 32% after 240 min and their mechanical properties were lost after 360 min immersion. Meanwhile, the retention of the tensile strength of the CO2-CWPUs was 81.5% even after 720 min immersion in 10 wt% H2O2 solution, while it was only ca. 38% for the ester-based CWPUs. These results indicated that the cationic CO2-based CWPU may be promising waterborne adhesive with outstanding ageing resistance due to its synergistic effect from carbonate and ether groups of CO2-polyol structure. [ABSTRACT FROM AUTHOR]

Cationic waterborne polyurethanes (CWPUs) bring in hydrophilic component to molecular chain, which inevitably deteriorates its water-resistant ability. Here, we synthesized a series of branched chain cationic waterborne polyurethanes (i.e., CWPUs-Si) that had been modified using a novel star-branched polydimethylsiloxane (SB-PDMS) to improve their water-resistant performance. The effects of SB-PDMS content on the properties of the CWPUs-Si polymers (e.g., crystallinity, emulsion stability, mechanical performance, surface element enrichment, surface topography, water resistance), together with the performance of coatings prepared by cathodic electrodeposition, were determined. The results showed that the introduction of SB-PDMS increased phase separation and surface roughness induced by hydrogen bonding while the surface energy decreased, both of which improved water resistance. The polymers showed improved rigidity due to increased content of the hard segments and enhanced physical crosslinking. Except for an increase in pencil hardness, SB-PDMS had no effect on the films prepared by cathodic electrodeposition. The results from this study may provide a strategy to improve the water-resistant properties of CWPUs. [ABSTRACT FROM AUTHOR]

The cationic waterborne polyurethanes (CWPU) exhibit excellent affinity towards various materials possessing negative surface charges owing to its positive charge. However, its limited heat resistance and flame retardancy greatly restrict its practical application. In this work, we synthesized a flame retardant, 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-hydroxyethoxyphenylene (DOPO-HQ-HE), and incorporated it into the skeleton of cationic waterborne polyurethanes to prepare flame-retardant cationic waterborne polyurethanes (CWPU-DHHxs). The obtained CWPU-DHHxs showed excellent flame retardancy, in which the LOI value of CWPU-DHH 12 reached over 26.9 vol% and passed UL-94 V-0 rating. The findings showed that CWPU-DHHxs exhibited remarkable efficacy in both the vapor and condensed phase during combustion. Moreover, the incorporation of DOPO-HQ-HE led to a significant improvement in heat resistance performance by facilitating enhanced microphase separation. Meanwhile, the major comprehensive performance of CWPU-DHHxs, including emulsion storage stability, thermal stability, mechanical performance, and transparency were effectively preserved. [Display omitted] • The intrinsic flame-retardant cationic waterborne polyurethanes (CWPU-DHHxs) were synthesized. • The presence of π-π stacking effects enhanced the microphase separation of CWPU-DHHxs. • CWPU-DHHxs exhibited higher mechanical strength and heat resistance. • The synergistic effect of gas and condensed phases allowed CWPU-DHHxs to exhibit good flame retardancy. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • The dyability and color fastness of leather treated with CWPU have been significantly improved. • The addition of CWPU supplements the organic chromium-free tanning system of leather and improves the practicality of leather. • This study provides an color fixing agent for chromium-free tanning system and has potential application to acid dyes. [ABSTRACT FROM AUTHOR]

In this study, a novel photo- and pH-sensitive cationic waterborne polyurethane containing side chain aromatic azo groups (Azo-CWPU) was synthesized by step-growth addition polymerization from polyether polylol, isophorone diisocyanate, N-methyl diethanolamine and a new aromatic azo-containing monomer, 2,2′-(4-((4-ethylphenyl)diazenyl)phenylazanediyl)diethanol (EDPD). Azo-CWPU showed a significant hypsochromic contrast to the azo monomer and rapid changes in UV-Vis absorption spectra at different irradiation times. Azo-CWPU dispersion displays bright yellow, orange and red color with the change of pH values. Regarding the orange dispersion, we assume that there is a mixture of the azoic form and the hydrazone form. Compared to cationic waterborne polyurethane dispersion without aromatic azo groups (CWPU), Azo-CWPU dispersion with smaller hydrodynamics radius and more narrow distribution shows good thermodynamic properties of polyurethane. [ABSTRACT FROM AUTHOR]

Cationic blocked waterborne polyurethane (CBWPU) as paper strength agent was prepared by the reaction of N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamino propanamide(DDP), isophorone diisocyanate(IPDI), polycaprolactone glycol(PCL) and bisphenol A, with imidazole as blocking agent and N-methyldiethanolamine as hydrophilic chain-extending agent. Effects of the blocked ratio and the dosage of CBWPU on the physical properties of the treated paper were studied. The chemical structure of CBWPU and the surface morphology of the paper surface are characterized by Fourier transform infared spectrometer(FT-IR) spectra and scanning electron microscopy(SEM). The results show that the paper strength, especially the wet tensile index and the wet strength of paper can be obviously improved with the increasing of the blocked ratio and the dosage of CBWPU. FT-IR result shows that structures of tertiary amine group, imidazole ring and urethane group are found in CBWPU molecular structure. SEM obsevation of the treated paper reveals that the exiestence of a lot of filamentous materials and films, which can improve the crosslinking between fibers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poly(hexamethylene guanidine hydrochloride) (PHMG) with 98 wt% type B was synthesized. • PHMG was introduced into anionic/cationic waterborne polyurethane (AWPU/CWPU). • PHMG incorporation resulted in higher particle sizes in AWPU, but in lower particle sizes in CWPU. • PHMG appeared no antibacterial activity in AWPU due to electronic attraction, but high antibacterial activity in CWPU. Antibacterial materials are widely used in various fields, and Poly(hexamethylene guanidine hydrochloride) (PHMG) is an effective broad-spectrum antibacterial agent with great potential in preparing antibacterial materials. Therefore, in this work, type B PHMG was prepared and incorporated into anionic waterborne polyurethane (AWPU) and cationic waterborne polyurethane (CWPU) following three incorporation ways (post-, in-situ and pre- methods). Subsequently, films were obtained by solvent-casting and their thermal, mechanical, contact angle and antibacterial properties were systematic studied. The results shown that owing to the strong electronic attraction between PHMG and AWPU, the stable PHMG modified AWPU (PAWPU) dispersions were obtained by pre-method only. However, PAWPU films has no antibacterial activity. In addition, the stable PHMG modified CWPU (PCWPU) dispersions were obtained by pre-method and in-situ -method. Unlike PAWPU films, PCWPU films exhibited excellent antibacterial activity, the antibacterial efficiency of PCWPU containing 2 wt% PHMG against E. coli is 98.4 % after 1 h incubation. Simultaneously, PHMG not leached from PCWPU films. [ABSTRACT FROM AUTHOR]

• The novel coating material from cWPU-eHTNR had long shelf life. • The cWPU-eHTNR had low electric conductivity of a good insulator • The polarity of cWPU-eHTNR led to good wettability, chemical resistance, and thermal stability. • cWPU-eHTNR has potential for coating applications and also an ecofriendly material. This report is the first one on a cationic waterborne polyurethane (cWPU) latex based on epoxidized hydroxyl telechelic natural rubber (eHTNR) polyol, providing potential for use as a coating made of renewable resources. A cWPU latex was synthesized by step growth emulsion polymerization from hydroxyl telechelic natural rubber (HTNR with M n = 3000 g.mol―1) with fixed N -methyl diethanol amine content of 5.6 wt% and 2,4-toluene diisocyanate (NCO index = 100). The effects of proportion of epoxide units on HTNR polyol from 0 to 30 % on preparing cWPU latex were investigated. Chemical structures of HTNR and eHTNR polyol were confirmed by 1H-NMR spectroscopy. The resulting HTNR and eHTNR polyols present a unimodal size exclusion chromatography trace. The viscosity increased with epoxide fraction. The synthesized cWPU latex based on eHTNR was a stable milky-blue emulsion with well-defined size dispersion. All cWPU-eHTNR films showed good wettability, good chemical resistance, and high thermal stability, improving with the proportion of epoxide units. The mechanical properties of cWPU-eHTNR films were studied from their stress-strain curves. Moreover, the electrical properties were investigated. The cWPU-eHTNR films showed relatively low conductivity. Wettability, chemical resistance, adhesion, thermal stability, and electrical properties of cWPU-HTNR films improved with the proportion of epoxide units on the HTNR polyol. These results demonstrate a new synthesis route to develop cWPU latex based on a biosource, for coating applications. [ABSTRACT FROM AUTHOR]

Renewable resource based cationic waterborne polyurethanes (cWPUs) have been prepared from hydroxyl telechelic natural rubber (HTNR) with a range of number average molecular weights (M n) (2820, 1800, and 950 g mol−1), toluene-2,4-diisocyanate (TDI), N -methyl diethanolamine (NMDEA), and ethylene glycol (EG). The chemical structure of the cWPUs was confirmed by FT-IR and 1H NMR. Particle size and zeta potential of prepared cWPUs were also characterized by ZS nanosizer. By varying the levels of M n of HTNR, the obtained cWPUs were stable with a milky blue appearance, forming yellowish films. The smallest particle sizes of 76.4 nm were achieved using M n of HTNR of 2820 g mol−1 while zeta potential value ranges from 67 to 71 mV were observed with increasing M n of HTNR. Lap shear testing of these WPUs indicates their potential in real cow leather adhesive applications, with the best adhesive result coming from cWPU based on an HTNR molecular weight of 1800 g mol−1. The results show the potential of natural rubber as a green adhesive material in suitable aqueous environments. Image 1 • New cationic waterborne polyurethane based on natural rubber was well successfully synthesized. • The effect of molecular weights of hydroxyl telechelic natural rubber was studied on their properties. • The adhesive application of cationic waterborne polyurethane based on natural rubber on real cow leather was studied. [ABSTRACT FROM AUTHOR]