Preparation and properties of UV‐curable waterborne polyurethane–acrylate emulsion

Polyurethane–acrylate oligomer terminated with multiple unsaturated bonds was prepared using isophorone diisocyanate, (IPDI), methylene diphenyl diisocyanate, and polyols as monomers, using 2,2‐dimethylol propionic acid as hydrophilic chain extender, together with pentaerythritol triacrylate (PETA) as end‐capper. The UV‐curable waterborne polyurethane–acrylate (UV‐WPUA) composite emulsion was obtained by mixing the PUA oligomer with certain content of reactive diluents and then dispersing the mixture in water. The molecular structure of the polyurethane prepolymer, PUA oligomer, and UV‐cured polymer was investigated by Fourier transform infrared spectroscopy. The influence of the composition and content of the diluents and end‐capper on UV‐WPUA properties, including the emulsion stability, thermal property, water resistance, adhesion, hardness, glossiness of polymer film were studied. The results show that the WPUA emulsion has excellent stability, and the UV‐cured film features good hardness and remarkable water resistance when PETA is used as end‐capper and the end‐capping ratio of the polyurethane prepolymer is 70% and dipentaerythritol hexaacylate/dipropylene glycol diacrylate (mass ratio 1:1) is used as diluent. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45208.     

Synthesis and characterization of UV-curable waterborne polyurethane–acrylate ionomers for coatings

A new kind of ultraviolet (UV)-curable waterborne polyurethane–acrylate (PUA) ionomer, prepared from toluene diisocyanate (TDI), polyethylene glycol (PEG), dimethylolpropionic acid (DMPA), triethylamine (TEA), and 2-hydroxyethyl methacrylate (HEMA), was synthesized by the modified prepolymer mixing process in which water serves as a chain-extender and dispersant. Fourier transform infrared (FTIR) spectra demonstrated the formation of the PUA ionomers both in dispersions and in their corresponding cured films. Surface tension of the PUA dispersions decreased as the DMPA-to-PEG mole ratio increased. The investigation of rheological behavior of the PUA dispersions suggested that all the dispersions belong to pseudoplastic fluid and display the characteristic of common polymer dispersions. Differential scanning calorimetry (DSC) analysis showed that the increasing DMPA-to-PEG mole ratio may result in a higher T_g and a broader transition zone for the hard segment. The results of TGA for the PUA-cured films indicated good thermal stability with no appreciable weight loss until well above 200°C. Measurement of physical properties showed that all the PUA-cured films exhibited excellent adhesion, gloss, flexibility, and impact strength, as well as pendulum hardness, depending upon hard segment content. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2869–2876, 1999     

丙烯酸酯改性水性聚氨酯的合成及应用研究

以异氰酸酯、聚醚多元醇及二羟甲基丙酸(DMPA)为主要原料,合成了水性聚氨酯(WPU)预聚体;然后采用扩链、交联和丙烯酸酯复合改性等方法制备了丙烯酸酯改性水性聚氨酯(PUA)。结果表明:水性PUA具有丙烯酸酯和聚氨酯(PU)的双重优点,而且其低温成膜性较好、综合性能较优、成本及VOC含量较低;由PUA配制的木器漆,其主要性能均达到HG/T36082-1999标准。     

Preparation and performance of waterborne UV‐curable polyurethane containing long fluorinated side chains

Novel waterborne UV‐curable polyurethane containing long fluorinated side chains (WUVFPU) was prepared and the fluorinated component was incorporated by two novel fluorinated macromolecular diols (FDO) with different chain length as chain extender. FDO was synthesized via free radical polymerization of hexafluorobutyl methacrylate (HFBMA) using 1‐thioglycerol (TG) as chain transfer agent. Extremely low dosage of FDO incorporated could change the surface property significantly. The influence of both the content and chain length of FDO on the surface energy, surface composition and morphology were investigated by contact angle measurement, XPS and AFM. Surface energy significantly decreased at extremely low concentration of FDO. The hydrophobicity was enhanced with increasing both the content and the chain length of FDO. XPS and AFM results revealed the enhancing hydrophobicity was attributed to the enrichment of F atoms and rougher surface morphology. Gel content, pencil hardness, adhesion, and optical transmittance tests were employed to investigate the coating properties of the UV‐cured films. The preparation and investigation of WUVFPU might provide better understanding of the influence of fluorinated chain length on the properties of polyurethane for theory. Moreover, it might provide a facile and effective route to prepare polyurethane materials with low surface energy for engineering and industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44506.     

Structure‐property relations in UV‐curable urethane acrylate oligomers

Four urethane acrylate oligomers were synthesized by a reaction of an excess of isophorone diisocyanate (D) with polypropylene glycol Acclaim 4200N (P) with a subsequent reaction of nonreacted D with a hydroxy acrylate Tone M100 (A). The latter has a common name caprolactone acrylate. Oligomers were prepared by different ways of addition of P to D or D to P and at different ratio of [D]/[P]. The fifth oligomer ADA was prepared as an individual compound. Viscosities, GPC traces, T_g's of oligomers were taken alongside with other physical properties of cured oligomers. It was demonstrated that oligomers with P consist of ADPDA, ADA, and of a chain‐extended product A… P_n… A, which has two or more Ps in a molecule. Additive contributions of these three components essentially determine properties of the liquid and cured oligomers. Structure‐property relations of urethane acrylate oligomers are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:489–494, 2006     

High‐performance waterborne coatings based on epoxy‐acrylic‐graft‐copolymer‐modified polyurethane dispersions

Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent‐based products and also because PUDs exhibit almost the same high performance levels as solvent‐borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy‐acrylic graft copolymer blocks. The epoxy‐acrylic graft copolymers were first modified with ethylene diamine to give amine‐terminated blocks which in turn reacted with isocyanate‐terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain‐extenders. The physico‐chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy‐acrylic copolymer blocks. Copyright © 2004 Society of Chemical Industry     

Preparation,mechanical properties of waterborne polyurethane and crosslinked polyurethane‐acrylate composite

The waterborne polyurethane (PU) prepolymer was first prepared based on isophorone diisocyanate, polyether polyol (NJ‐210), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate via in situ method. The crosslinked waterborne polyurethane‐acrylate (PUA) dispersions were prepared with the different functional crosslinkers. The chemical structures, optical transparency, and thermal properties of PU and PUA were confirmed by Fourier transform infrared spectrometry, ultraviolet–visible spectrophotometry, and differential scanning calorimetry. Some physical properties of the aqueous dispersions such as viscosity, particle size, and surface tension were measured. Some mechanical performances and solvent resistance of PUA films were systemically investigated. The experimental results showed that the particle sizes of the crosslinked PUA aqueous dispersions were larger than the PU and increased from 57.3 to 254.4 nm. When the ratios of BA/St, BA/TPGDA, and BA/TMPTA were 70/30, PUA films exhibited excellent comprehensive mechanical properties. The tensile strength and elongation at break of the film were 2.17 MPa and 197.19%. When the ratio of BA/St was 30/70, the film had excellent water resistance and was only 6.47%. The obtained PUA composites have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings, and wood finishes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Ink and moisture sorption study in UV‐curable polyurethane acrylate

A study of the interaction of commercial black ink with a UV‐curable polyurethane acrylate (PUA) is presented. Diffusivity and solubility in PUA cured using different UV dosages, and subjected to different post‐UV curing conditions, were studied, as was the swelling produced by such sorption. Experiments were also conducted using water, to serve as a benchmark and compare with the effect of ink. The percentage ink absorption was found to decrease with higher degree of cure. In addition, through desorption measurements, ink induced swelling of PUA processed under different conditions was determined. The degree of swelling per unit solvent uptake was observed to increase with the degree of cure. PUA was determined to be more prone to moisture rather than solvent uptake. However, the coefficient of moisture expansion (CME) was found to be ～ 35% lower than the coefficient of ink expansion (CIE) for a fully cured PUA. © 2006 Wiley Periodicals, Inc. JAppl PolymSci 103: 1985–1991, 2007     

环保节能型水性聚氨酯建筑涂料研究进展

综述了近几年来环保型、节能型水性聚氨酯涂料的研发和应用情况。主要包括:水性聚氨酯(WPU)保温隔热涂料,以聚氨酯为壳层材料的相变储能材料,UV固化WPU工艺,提高水性聚氨酯涂料的耐水性和防霉抗菌性等。     

电子束固化水性聚氨酯丙烯酸酯的制备及性能

研究了一种制备水性聚氨酯丙烯酸酯的新方法,通过在扩链剂分子结构中组装离子基团来改善亲水性,解决了聚氨酯丙烯酸酯与水难相溶的问题。采用这种方法制备了一种聚氨酯丙烯酸酯产物,使用FTIR和1H NMR对产物结构进行了表征。对产物与水的储存稳定性、黏度、电子束固化行为及固化后性能进行了研究。结果表明,分散乳液储存稳定性好,经电子束固化后性能(如硬度、附着力、光泽度、柔韧性、热稳定性)优良。     

Synthesis and characterization of flame retarding UV‐curable organic–inorganic hybrid coatings

UV‐curable, organic–inorganic hybrid materials were synthesized via sol–gel reactions for tetraethylorthosilicate, and methacryloxypropyl trimethoxysilane in the presence of the acrylated phenylphosphine oxide resin (APPO) and a bisphenol‐A‐based epoxy acrylate resin. The sol–gel precursor content in the hybrid coatings was varied from 0 to 30 wt %. The adhesion, flexibility, and hardness of the coatings were characterized. The influences of the amounts of inorganic component incorporated into the coatings were studied. Results from the mechanical measurements show that the properties of hybrid coatings improve with the increase in sol–gel precursor content. In addition, thermal properties of the hybrids were studied by thermogravimetric analysis in air atmosphere. The char yield of pure organic coating was 32% and that of 30 wt % silicate containing hybrid coating was 30% at 500°C in air atmosphere. This result demonstrates the pronounced effect of APPO on the flame retardance of coatings. Gas chromatography/mass spectrometry analyses showed that the initial weight loss obtained in thermogravimetric analysis is due to the degradation products of the photoinitator and the reactive diluent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1906–1914, 2006     

Novel hyperbranched waterborne polyurethane‐urea/silica hybrid coatings and their characterizations

Thermally resistant and mechanically stable novel hyperbranched waterborne polyurethane‐urea/silica hybrid coatings were prepared by using 3‐aminopropyltriethoxysilane as a coupling agent with SiO₂ as a crosslinker. The extent of hydrogen bonding was investigated to show a dependence on SiO₂ concentration, which increased the glass transition temperature of the polymers with increasing SiO₂ concentration. Thermal decomposition profiles and the corresponding stability data suggest two‐step decomposition for the hybrids; further, their stability increased with increasing concentration of SiO₂.Copyright © 2011 Society of Chemical Industry     

UV‐curable sol–gel based protective hybrid coatings

UV‐curable, novel, fluorinated polyether ether ketone urethane acrylate oligomer (FPEEKUA) has been synthesized and used as corrosion‐protector in sol–gel hybrid coatings for metallic substrates. Incorporation of FPEEKUA and sol–gel in the formulations improved coatings’ physical properties such as gel content, hardness, adhesion, gloss, flexibility, and contact angle. Due to strong interaction between acrylate and highly crosslinked structures, mechanical properties improved drastically with homogenously dispersed structures throughout the organic matrix, while water uptake values decreased and thermal stability and char yields increased. Highest contact angle values were measured up to 94° with shinny coatings. The results are important for two reasons. First, polyether ether ketone (PEEK) immiscibility problem are overcome by using reactive oligomer and benefitted from high performance properties of poly(arylene ether ketones) (PAEK)s in hybride coating applications. Second, Coatings combine the advantages of sol–gel with poly(arylene ether ketone urethane acrylate) (PAEKUA) oligomer and they can be used as barrier coatings in metal corrosion protection. Performance tests in corrosive mediums at room temperature of chlorine solution (bleach) for 24 h and also in a 10 wt% HCl solution for 92 h produced promising results for use in corrosion mitigation applications in highly corrosive downstream oil and gas industry. POLYM. ENG. SCI., 59:E146–E154, 2019. © 2018 Society of Plastics Engineers     

Chain‐extended polyurethanes—Synthesis and characterization

Chain‐extended polyurethanes (PUs) were prepared using castor oil and different diisocyanates such as toluene‐2,4‐diisocyanate and 4,4′‐methylene bis(phenylisocyanate) as a crosslinker and different aromatic diamines like 4,4′‐diaminodiphenyl methane and 4,4′‐diaminodiphenyl sulphone as chain extenders. The effect of aromatic diamines on the swelling and thermal degradation behavior of PU have been discussed. A thermogravimetric analyzer (TGA) curve shows that all the chain‐extended PUs are stable up to 194°C and that maximum weight loss occurs at 490°C. The TGA thermograms show that the thermal degradation of the PUs was found to proceed in two steps. The average molecular weight between crosslinks (M?_c) was determined by swelling studies. The properties imparted by the aromatic chain extenders are explained on the basis of groups present in the diamines. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 359–369, 2002; DOI 10.1002/app.10347     

Synthesis of self‐matting waterborne polyurethane coatings with excellent transmittance

The effect of structural factors, including the type of diisocyanates and glycols, degree of crosslinking, hard‐segment content, crystallinity and hydrophilic group content, on optical properties of waterborne polyurethane (WPU) was investigated. Based on the relationship between structure and properties, a series of self‐matting WPUs with excellent transmittance were synthesized. Results demonstrated that refractive index of constituent groups was an important factor to influence the optical properties of coatings. For multiphase polyurethane, aromatic ring, ester bond, ? NH? COO? and urea groups with high refractive index could decrease the matting effect and transmittance. Higher hard‐segment content resulting in an increase of the number of ? NH? COO? or urea bonds also decreased the matting effect and transmittance. The aggregation structure of WPU was another factor to influence the optical properties of coatings. Crystalline soft and hard segment domains could decrease the transmittance and matting effect, whilst non‐crystalline segments, pendent groups and crosslinking destroyed the regularity or crystallinity of macromolecules, behaving as an auxiliary function to improve the transmittance. The particle size of WPU was of great importance for the matting effect. Smaller particle size (<5.0 µm) would endow the coating with a smoother surface and higher reflected light ratio, and thus the expected matting effect was hard to be achieved. A larger particle size could improve the matting effect but impart to the coating a coarse surface and hand‐feel. When the 2,2‐bis(hydroxymethyl)propionic acid content was 1.6 wt%, spherical particles with a size distribution of 7–8 µm were aggregated on the coating surface, giving the coating an excellent matting effect and hand‐feel. © 2017 Society of Chemical Industry     

Study on electrochemical behavior of Nano‐ZnO modified alkyd‐based waterborne coatings

A nano‐composite coating was formed using nano‐ZnO as pigment in different concentrations, to a specially developed alkyd‐based waterborne coating. The nano‐ZnO modified composite coatings were applied on mild steel substrate by dipping. The dispersion of nano‐ZnO particles in coating system was investigated by scanning electron microscopic and atomic force microscopic techniques. The effect of the addition of these nano‐pigments on the electrochemical behavior of the coating was investigated in 3.5% NaCl solution, using electrochemical impedance spectroscopy. Coating modified with higher concentration of nano‐ZnO particles showed comparatively better performance as was evident from the pore resistance (R_po) and coating capacitance (C_c) values after 30 days of exposure. In general, the study showed an improvement in the corrosion resistance of the nano‐particle modified coatings as compared with the neat coating, confirming the positive effect of nano‐particle addition in coatings. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and property of waterborne UV‐curable chain‐extended polyurethane surface sizing agent: Strengthening and waterproofing mechanism for cellulose fiber paper

Waterborne UV‐curable polyurethane (UWPU) dispersions with different hydrophilicity and functionalities were prepared by varying the content of dimethylol butanoic acid (DMBA) and pentaerythritol triacrylate (PETA). And linear and cyclic chain extenders with different functionalities were also incorporated into the UWPU backbone, including isophorone diamine (IPDA), diethylene triamine (DETA), and ethylene diamine (EDA). Effects of DMBA content, PETA content, photoinitiator content, UV curing time, chain extender on the properties of UWPU dispersions and films, as well as the properties of the unsized and sized paper were investigated. The water resistance and mechanical properties of sized paper were greatly relied on the particle size, the molecular weight, the croslinking density, and penetrability of UWPU. UWPU dispersion chain extended with IPDA (IPDA‐UWPU) displayed smaller particle size than that of UWPU. The paper sized with IPDA‐UWPU was endowed with best water resistance, tensile strength, folding strength and surface strength. XPS depth analysis revealed that IPDA‐UWPU exhibited better penetrability into the paper substrate than UWPU. SEM and AFM demonstrated that the smoothness of sized paper was improved, and the bond strength between fibers was enhanced. The obtained UWPU could be directly used as an effective and fast drying surface sizing agent for cellulose fiber paper. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42354.     

建筑用水性聚氨酯涂料的研究进展

综述了建筑用水性聚氨酯(WPU)涂料的改性技术的研究进展,其改性技术包括交联改性、丙烯酸酯改性、环氧树脂改性、植物油改性和纳米材料改性等,并对建筑用WPU涂料的发展前景作了展望。     

Effects of starch nanocrystal‐graft‐polycaprolactone on mechanical properties of waterborne polyurethane‐based nanocomposites

Based on a “graft from” strategy, the surface of starch nanocrystals (StN) were functionalized by grafting with polycaprolactone (PCL) chains via microwave assisted ring‐opening polymerization (ROP). The modified natural nanoparticles were then compounded into a PCL‐based waterborne polyurethane as matrix. The structural and mechanical properties of the WPU/StN‐g‐PCL nanocomposites were characterized by XRD, FTIR, SEM, DSC, DMA, and tensile testing. It was interesting to note that a loading‐level of 5 wt % StN‐g‐PCL resulted in a simultaneous enhancement of tensile strength and elongation at break, both of which were higher than those of neat WPU. This enhancement was attributed to the uniform dispersion of StN‐g‐PCL because of its nano‐scale size, the increased entanglements mediated with grafted PCL chains, and the reinforcing function of rigid StN. Increasing the StN‐g‐PCL content however caused the StN‐g‐PCL to self‐aggregate as crystalline domains, which impeded improvement in tensile strength and elongation at break, but significantly enhanced Young's modulus. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and physical properties of functionalized graphene/waterborne polyurethane UV‐curing composites by click chemistry

Functionalized graphene nanoplatelets (f‐GNS) were modified with (3‐mercaptopropyl)trimethoxysilane (MPTMS) to enhance their compatibility with the polyurethane coating matrix. The results of Fourier transform infrared spectroscopy, AFM, Raman and XRD showed that the MPTMS was successfully attached onto the surface of the graphene nanoplatelets. Functionalized graphene/waterborne polyurethane acrylate (f‐GNS/WPUA) nanocomposites were fabricated by UV‐curing technology. The SEM and TEM images indicated that f‐GNS could be well dispersed in the polymer matrix and improved the interfacial adhesion. With the incorporation of 1 wt% f‐GNS, the thermal decomposition temperature of the composites was increased by 25 °C. Meanwhile, the conductivity, hydrophobicity and tensile strength were increased. When the load was further increased, the performance of the composites showed varying degrees of reduction. However, the dielectric loss tangent (tan δ) could be maintained at 0.08 or less and the electromagnetic shielding factor of the composites reached from 5 to 36 dB, showing a good electromagnetic shielding effect at a high content (2.5 wt% f‐GNS). It was considered that f‐GNS could disperse in the waterborne polyurethane well and crosslink with the polyurethane. © 2016 Society of Chemical Industry