Two-component water reducible polyurethane coatings

Historically, polyurethane coatings have been formulated as two-component organic solvent based systems. These polyurethane coatings provide room temperature cure characteristics as well as an excellent combination of abrasion resistance, flexibility, adhesion, chemical resistance and appearance. However, the coatings industry is under increasing pressure to reduce the environmentally undesirable emission of volatile organic compounds (VOC). One way of doing this is to replace some or all of the organic solvent with water. However, in the case of isocyanate crosslinked polyurethane coatings this is not a straightforward matter due to the fact that unmodified isocyanates are not only reactive with water, but are hydrophobic and non-dispersible.     

水性聚氨酯涂料的制备与性能研究

以甲苯-2,4-二异氰酸酯(TD I)、聚醚Ng 210和二羟甲基丙酸(DMPA)为主要原料,制得不含或含少量有机溶剂的水性聚氨酯乳液,研究了NCO/OH的摩尔比、DMPA含量等对水性聚氨酯乳液性能的影响。结果表明,当NCO∶OH(摩尔比)=2.5∶1,DMPA=5%时,乳液性能最佳。     

聚氨酯地坪涂料的发展现状

介绍了聚氨酯树脂地坪涂料的组成、特性、分类,综述了溶剂型、无溶剂型、水分散型和粉末型聚氨酯地坪涂料的发展和应用进展。     

聚氨酯涂料研究现状及发展

聚氨酯是世界六大具有发展前途的合成材料之一,聚氨酯涂料具有良好的粘结性、耐磨擦性,光泽度高,是涂料行业中占有非常重要的位置的主要品种之一。综述了聚氨酯涂料用单体、预聚物和环保型聚氨酯涂料的研究进展,介绍了环保型聚氨酯涂料性能与应用,指出了聚氨酯涂料的发展趋势。     

Novel polyurethane insulating coatings based on polyhydroxyl compounds,derived from glycolysed PET and castor oil

To prepare versatile polyurethane material suitable as insulating coatings, novel kinds of polyhydroxy compounds (PHCs) were prepared via transesterification reaction of poly(ethylene terphthalate), different molecular weight of poly(ethylene glycol)s (PEGs), and castor oil. The final networks were prepared via crosslinking of PHCs with a novel blocked isocyanate curing agent (BPI) made from trimethylol propane (TMP), toluene diisocyanate (TDI), and N‐methyl aniline (NMA). Polyols and curing agent were characterized by conventional methods and the curing condition was optimized via gel content measurements. Curing kinetic of the polyurethane network formation was investigated by differential scanning calorimetric method and the kinetic parameters were derived. Crosslink density of the samples was determined via equilibrium swelling method and by using Flory‐Rehner equations. Effects of crosslink density on electrical, physical, mechanical, and dynamic mechanical (DMTA) properties of the polyurethane coatings were investigated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1222–1233, 2006     

Mechanical and thermal properties of phenolic/glass fiber foam modified with phosphorus‐containing polyurethane prepolymer

Phenolic foam exhibits outstanding flame, smoke and toxicity properties, good insulation properties and low production costs. However, the brittleness and pulverization of phenolic foam have severely limited its application in many fields. In this study, a novel phosphorus‐containing polyurethane prepolymer (DOPU) modifier was firstly synthesized, and then the foaming formula and processing of toughening phenolic foam modified with DOPU and glass fiber were explored. The structure and reactive behavior of prepolymer and phenolic resin were investigated using Fourier transform infrared spectroscopy. The effects of DOPU and glass fiber on the apparent density, compressive strength, bending strength and water absorption were investigated. The results suggested that the apparent density, compressive strength and bending strength of modified phenolic foam tended to increase irregularly with increasing content of DOPU. The addition of DOPU led to lower water absorption of glass fiber‐filled foam. Thermal stability and flame retardancy were examined using thermogravimetric analysis and limiting oxygen index (LOI) tests. It was found that foam with 3% DOPU and 0.5% glass fiber added exhibited good thermal stability and high char yields. The LOI value of modified phenolic foams decreased with increasing DOPU content, but it still remained at 41.0% even if the amount of modifier loaded was 10 wt%. © 2012 Society of Chemical Industry     

聚氨酯预聚体增韧酚醛泡沫保温板的性能

研究了聚氨酯改性剂改性酚醛泡沫,测试了改性酚醛泡沫的性能,采用热重、红外光谱、扫描电子显微镜分析改性酚醛泡沫的微观结构,最终得到一种保温效果好、力学性能优异的新型酚醛泡沫。改性后酚醛泡沫具有如下特点:保温效果好,导热系数为0.030 W/(m·K);硬度大,表观密度可达40~60 kg/m3;韧性好,弯曲强度达2.1MPa,压缩强度提高16.5%,可达0.134 MPa。     

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。     

Synthesis and characterization of eco-friendly siloxane-semifluorinated polyurethane coatings for underwater application

Siloxane-semifluorinated polyurethane coatings were prepared for robust underwater application. Initially, acrylic polyol (FS-GPTACP)-containing fluoroalkoxysilane (1H,1H,2H,2H-Perfluorooctyltrimethoxysilane) pendant group was synthesized by the free-radical polymerization method. Different weight percentages of polydimethylsiloxane (0, 10, and 20 wt %) were added to the polyol to tune the mechanical and the surface energy of the coating. Subsequently, this polyol mixture was cured with 4, 4′-methylenebis(cyclohexyl isocyanate) (H₁₂MDI) to prepare a series of siloxane-semifluorinated polyurethane–urea hybrid coatings (APUS 0%, APUS 10%, and APUS 20%). The synthesized coating showed low surface energy, hydrophobicity with exceptional water, and alkali resistance. Moreover, the coating displayed excellent mechanical properties with low pseudobarnacle adhesion strength. The coatings also showed nontoxicity against gram-positive and gram-negative bacterial strains. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47720.     

Removal of phenol from coupling of talc and peroxidase. Application for depollution of waste water containing phenolic compounds

The degradation of phenol by a combination of horseradish peroxidase/hydrogen peroxide in the presence of talc, a natural abundant and low cost mineral, was investigated. Adsorption of the reaction products on the talc effectively protected the biocatalyst against contamination by oxidative products, thereby prolonging its catalytic action and leading to almost complete elimination of phenols in aqueous media. Suitable conditions for depollution of waste water containing phenolic substances were developed after optimization of various parameters (type and amount of talc, reaction duration).     

Fabrication of active corrosion protection waterborne polyurethane coatings using cerium modified palygorskite nanocontainers

The development of eco-efficient and environmental friendly active anti-corrosion coatings for metallic substrates represents a fundamental milestone in many engineering applications. Herein, a new type of active corrosion protection coating was successfully synthesized simply based on waterborne polyurethane (WPU) and nanocontainer of Ce³⁺ modified palygorskite (Ce-PAL). Particularly, the nanocontainer of Ce-PAL was achieved via a facile and green process by cation exchange in water. Inductively coupled plasma atomic emission spectrometry (ICP) revealed that Ce³⁺ had successfully incorporated into PAL nanofibers with a loading amount of 10.334 g/kg. The salt immersion test, electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy (EIS) demonstrated that the incorporation of Ce-PAL only with 2 wt% into WPU led to a significant improvement of their corrosion protection properties. Finally, according to the results of scanning electron microscopy with energy dispersive X-ray spectroscopy, the active anti-corrosion mechanism of Ce-PAL/WPU coating was proposed.     

聚氨酯改性环氧树脂耐磨涂料的研制

以2,4-甲苯二异氰酸酯和蓖麻油为原料,合成了聚氨酯预聚体。使用该聚氨酯预聚体对环氧树脂进行了改性。对各种固化剂进行了筛选。最后研制了一种双组分常温固化耐磨涂料。通过正交实验和单因素实验确定了涂料的最佳配方:聚氨酯5 g,环氧树脂10 g,填料3 g,固化剂2．3 g。由此获得的耐磨性优良的涂膜性能为:表干时间10 h,实干时间不到40 h;耐磨性实验中,磨痕弦长5．4 mm;附着力0级,硬度5 H。     

Preparation and physical properties of two-component polyurethane flame-retardant coatings using trichloro modified polyesters

Trichloro modified polyester polyols were synthesized by two-step condensation reactions. An intermediate compound was synthesized by the esterification of trichloroacetic acid with trimethylolpropane in the first step. In the next step, polycondensation of the intermediate, 1,4-butanediol and trimethylolpropane with adipic acid was carried out. Two-component flame-retardant polyurethane coatings were prepared by blending these modified polyester polyols and polyisocyanate. The physical properties of these new coatings were comparable to non-flame-retardant coatings. They showed a drying time of 3–4 h and a pot life time of 10–13 h, which could belong to the flame-retardant coatings with long pot life times. Coating with 20 wt % trichloroacetic acid showed a self-extinguishing property in the vertical burning test. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 913–920, 1998     

Antioxidant properties of phenolic compounds in macadamia nuts

Phenolic compounds in macadamia nuts and shells were identified, and their antioxidant activities were evaluated in refined macadamia nut oil. Thin-layer chromatography of oil extracted from macadamia nut kernels and shells indicated the possible presence of catechol, phrogallol, and 3,4,5-trihydroxy phenolic compounds. Four phenolic compounds were tentatively identified as 2,6-dihydroxybenzoic acid, 2′-hydroxy-4′-methoxyacetophenone, 3′,5′-dimethoxy-4′-hydroxyacetophenone, and 3,5-dimethoxy-4-hydroxycinnamic acid. Adding 0.01% of 2′-hydroxy-4′-methoxyacetophenone, 3′,5′-dimethoxy-4′-hydroxyacetophenone, or 3,5-dimethoxy-4-hydroxycinnamic acid to the oil significantly increased the Rancimat induction time against the control (P<0.0001). At this concentration, 3′,5′-dimethoxy-4′-hydroxyacetophenone was the most effective compound added. Although induction times of oils with 0.01%, 2,6-dihydroxybenzoic acid were not significantly different from the control, at 0.1% there was a significant difference from the control (P<0.0001). The activity was the same as that of 2′-hydroxy-4′-methoxyacetophenone at 0.1%.     

外墙高光纯丙乳胶漆助剂的选择研究

以具有代表性的外墙纯丙乳液为基础,对国内外著名厂商的各类助剂进行平行试验,对各牌号的助剂进行考评得出数据。     

Synthesis,characterization, and properties of PCDL aliphatic hyperbranched polyurethane coatings

The isocyanate‐terminated polyurethane pre‐polymer (PPU) was synthesized via the step‐growth polymerization approach by using polycarbonate diol (PCDL, Mn = 2000) and isophorone disocyanate (IPDI) as monomers, dibutyltin dilaurate (DBTDL) as the catalyst. Subsequently, the hyperbranched polyurethane (HBPU) was synthesized by graft copolymerization using PPU, hyperbranched poly(amide–ester) polyol (HPAE) and 1,4‐butanediol (BDO). The molecular structure of HBPU was characterized by means of FTIR, ¹H‐NMR, and ¹³C‐NMR. It was observed that HBPU was synthesized as anticipated. The thermal and mechanical properties, the microstructure, and morphologies of the filmed HBPU and LPU (linear polyurethane) were tested, respectively. The filmed HBPU, revealed better thermal stability, and higher T_g accompanied with lower viscosity than those of filmed LPU. Additionally, the mechanical experiment showed that the filmed HBPU exhibited enhanced mechanical properties because it contained certain amounts of HPAE. Compared with its linear analog (LPU) specimen, the tensile strength of the filmed HBPU containing 10 wt % HPAE increased by 1.9 times (up to 28.15 MPa), and its elongation at break increased by 1.5 times (up to 543.8%), resulting from the dual effects of the hydrogen bonding and the crosslinking density in the HBPU system. The morphologies of filmed HBPU were characterized by means of WAXD and SEM, which indicated that increasing the content of HPAE lowers the crystallinity of HBPU. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2671–2679, 2013     

PANI/TIO复合材料的制备及其在聚氨酯涂料中的应用

采用原位聚合的方法在锑掺杂氧化锡/氧化钛复合材料（TIO）上包覆一层完整的聚苯胺（PANI）膜,成功制备了PANI/TIO复合材料,将其作为水性聚氨酯涂料的填料,制备了水性聚氨酯导电涂料。利用X射线粉末衍射、透射电镜、红外光谱等分析方法对复合材料进行表征,利用涂层机械性能测试对导电涂料进行了测试。同时得到了制备PANI/TIO三元复合材料的最佳工艺条件：苯胺（An）包覆量为15%、m(An)/m[磺基水杨酸（SSA）]=0.4、m(An)/m[过硫酸铵（APS）]=3。在最佳工艺条件下,得到的PANI/TIO复合材料体积电阻率为15.3Ω·cm。实验结果表明：当填料比为15%时涂层机械性能最佳,硬度为2B、耐冲击力为50 cm、附着力为1级、涂层表面电阻为3.56×105Ω/m2,该导电涂料有较好的应用前景。     

Polyaniline‐grafted polyurethane coatings for corrosion protection of mild steel surfaces

We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10^?2 to 10^?3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45806.     

Application of a silicone-modified acrylic emulsion in two-component waterborne polyurethane coatings

Two-component waterborne polyurethane (2K WBPU) coatings were prepared using a silicone-modified acrylic emulsion as the hydroxyl component, and hydrophilically-modified polyisocyanate as the curing agent. The effects of the levels of silicone monomer and hydroxyl values on the film properties of the 2K WBPU coatings were investigated. Infrared spectroscopy characterized its structure. Scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to study the surface morphology and the thermal stability of the film. The results showed that the performance of the coatings and the thermal stability of the film of 2K WBPU were improved after silicone modification.     

非均相Fenton催化降解酚类化合物的研究进展

非均相Fenton催化法是去除水中难降解有机污染物的一种重要高级氧化技术,近些年以其效率高、污染少、材料来源广泛而受到人们更多的重视。介绍了现今主要的非均相Fenton催化降解酚类化合物的催化剂研究进展,包括零价铁、Fe3O4、Fe2O3、以碳、黏土、柱撑黏土、沸石、介孔二氧化硅等为载体的催化剂。最后提出了三个非均相Fenton反应的研究方向。