Comparison of Nanofibrillated Cellulose and Hydroxyethyl Cellulose in Improving the Storage Stability of Waterborne Coatings

Waterborne coatings often delaminate and settle during long-term storage,requiring the addition of thickeners.The effects of nanofibrillated cellulose(NFC)and the commonly used thickener,hydroxyethyl cellulose(HEC),on the storage stability of waterborne coatings were compared in this study.The morphology of NFC was characterized using infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM).The rotational viscosity and rheological properties of the waterborne coatings with NFC and HEC were tested.Stationary settling experiments were also conducted at different temperatures to compare the difference of NFC and HEC on improving the storage stability of the waterborne coatings.The results showed that the waterborne coating with NFC exhibited pseudoplastic fluid characteristics;a small addition of NFC can achieve the same improvement effect on the storage stability of waterborne coatings as HEC.Further,the improvement effect of NFC was not affected by temperature.The waterborne coating with NFC still exhibited good storage stability at high temperatures,which was significantly superior to that of HEC.Therefore,NFC is a feasible agent for improving the prolonged storage stability and warming-induced delamination of waterborne coatings.

Preparation and Characterization of Two-component Waterborne Polyurethane Comprised of Water-soluble Acrylic Resin and HDI Biuret

A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU parti-cles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI iso-cyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction be-tween HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.

Effect of Nano Al Pigment on the Anticorrosive Performance of Waterborne Epoxy Coatings

This paper presents the results regarding the effect of nano aluminum powder pigment concentration on the protective properties of waterborne epoxy films in 3.5 wt pct NaCl solution. The anticorrosive performance of the coatings with 0.5, 1, and 3 wt pct pigments and none pigment were investigated using electrochemical impedance spectroscopy （EIS）, scanning electron microscopy （SEM） and Raman spectroscopy techniques. The results show that adding appropriate amount of nano-aluminium powder pigment can enhance the barrier properties of the epoxy coating, which is attributed to the surface effect of nanoparticles and the compatibility of the pigment with the waterborne epoxy coatings.

Waterborne Polyurethane from Polycaprolactone and Tetramethylxylene Diisocyanate: Synthesis by Varying NCO/OH Ratio and Its Characterization as Wood Coatings

Environmentally friendly, polyacrylic-based polyurethane dispersion (PUD) was synthesised using various molar ratios of polycaprolactone, dimethylolpropionic acid and tetramethyl xylene diisocyanate. Synthesis was carried out in flowing nitrogen atmosphere. The PUD’s preparations are free of NMP (n-methyl pyrrolidone), a toxic processing solvent generally used during the preparation of PUD’s. The performance of the synthesised polyurethane dispersions with varying NCO/OH molar ratio was tested on wood surface. The physical, chemical, thermal and mechanical properties such as viscosity, particle size, chemical resistance, thermal stability and taber abrasion of applied polyurethane dispersion were carried out as a function of NCO/OH molar ratio. The PUD’s preparation with NCO/OH ratio of 1.4 or 1.6 showed better performance as a wood finish and the results are described in the present study.

Preparation and Properties of Two-Component and Double-Crosslinking Waterborne Polyurethane-Acrylic Dispersions

In this paper, isophorone diisocyanate (IPDI), polyethylene glycol (PEG), dimethylolpropionic acid (DMPA) and internal crosslinking agent trimethylolpropane (TMP) were used to prepare waterborne polyurethane. And then double-crosslinked polyurethane-acrylic composite aqueous dispersion was prepared in which polyacrylate was adopted to modify waterborne polyurethane and some special external crosslinking agents were added including silicone and trifunctional aziridine. The influence of the amounts of internal and external crosslinking agents, emulsifier, initiator on the particle size, particle size distribution, viscosity, molecular weight, as well as water adsorption ratio were studied.

Effect of Perlite on Fire Protection of Waterborne Coatings for Steel Structure

In this paper, perlite was used as a kind of modifier to prepare waterborne fire resistive coatings for steel structure. The influence of perlite on the properties of the fire resistive coatings was investigated with the help of thermogravimetric analysis (TGA), micro-scale combustion calorimetry (MCC) and fire protection test. The TGA results showed that the char residue weight of the coatings was increased when perlite was loaded and the anti-oxidation performance was enhanced as well and MCC data indicated the addition of perlite reduced the peak heat release rate and total heat release. After the fire protection test, the results confirmed that the fire resistant time of the coating coated with 5 wt% perlite increased up to 114.4 min when the temperature of the sample boards’ backside reached 500?C.

Synthesis of Waterborne Polyurethane Modified by Nano-SiO_2 Silicone and Properties of the WPU Coated RDX

A series of nano silica/silicone modified waterborne polyurethane(WPU) have been synthesized from polytetramethylene glycol and isophorone diisocyanate, dihydroxymethyl propionic acid and triethylamine, ethylenediamine, trimethylolpropane, nano-SiO2 and the silane coupling agent KH550. The effect of the dosage of nano-SiO2 on the WPU-Si membrane and the coated RDX(cyclotrimethylenetrinitramine) particles have been studied in terms of their surface properties, mechanical properties, and thermal stability. The results showed that with the increase of Si content, the stability of the emulsion reduced gradually. The material with more Si content displayed an increased thermodynamic stability, an increased high temperature resistance, an increased tensile strength and a decreased elongation at break. With the increase of Si content, the surface tension of the material decreased, the bibulous rate reduced, and the contact angle increased gradually, so that the surface tension of the polyurethane and RDX are close to each other which could improve the performance of coating.

Advancements and Prospects of Waterborne Coatings in the Coating Industry: A Comprehensive Analysis

This paper presents an overview of resins used in coatings,categorizing them into commonly used cross-linking agents such as methyl etherified melamine formaldehyde resin,and matrix resins including acrylic resin,polyurethane,epoxy resin,and alkyd resin.It further examines the demand and market size trends of these matrix resins in China over the recent seven years(2016-2022).The analysis reveals that in terms of both demand and market size,polyurethane resin ranks highest,followed by alkyd resin,acrylic resin,and epoxy resin.Additionally,the paper provides a comprehensive analysis of the development status,advantages,and macro-environment of the waterborne coatings industry.The competitive landscape within the industry is also discussed.The application of water-based coatings has shown significant potential to reduce the emission of pollutants such as volatile organic compounds(VOCs).Moreover,water-based coatings exhibit excellent performance characteristics.Market data from 2011 to the present indicates a consistent growth trend in the market size of waterborne coatings.However,intense competition among coating enterprises has led to a high level of product homogenization.In response to increasingly stringent national environmental protection policies,companies are accelerating the development and adoption of water-based coatings and other environmentally friendly products.This strategic shift towards waterborne coatings is expected to drive significant advancements and growth in the industry.

Plant Oil-Based Waterborne Polyurethanes: A Brief Review

The increasing pressure from consumers and policy makers to reduce the use of synthetic polymers,whose production contributes to the depletion of non-renewable resources and are usually non-biodegradable,has prompted the efforts to find suitable bio-based sources for the production of polymers.Vegetable oils have been a frequently spotted in this search because they are versatile,highly available and a low cost liquid biosource,which can be used in the synthesis of a wide plethora of different polymers and reactive monomers.Following the same idea of reducing the environmental stress,the traditional polyurethanes that are soluble in organic solvents have been targeted for replacement,particularly in applications such as adhesives and coatings,in which the solvent is released to the atmosphere increasing the air pollution.Instead,waterborne polyurethanes(WBPU),which are polyurethane dispersions(PUD)prepared in aqueous media,release benign water to the atmosphere during use as supported or self-standing films for different applications.In this brief review,the contributions to the development of WBPUs based on vegetable oils are discussed,focusing mainly on the contributions of the last decade.The synthesis of ionic and nonionic PUDs,their characterization and the properties of the resulting dried materials,as well as derived composite materials are considered.

软模板法制备聚苯胺干凝胶及在水性防腐涂料中的应用

分别以双十八烷基二甲基氯化铵和双十二烷基二甲基氯化铵为软模板,采用化学氧化法制备聚苯胺干凝胶。通过傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)等对聚苯胺干凝胶进行结构表征;将制备的聚苯胺干凝胶应用于水性防腐涂料中,考察其对水性涂料防腐性能的影响。结果表明,制得的聚苯胺水性防腐涂料具有较好的耐水、耐酸、耐碱、耐中性盐雾性。

水性无机耐高温防腐涂料的研制

以硅烷KH560、甲基三甲氧基硅烷偶联剂、气相二氧化硅和氢氧化钾为主要原料合成水性无机耐高温树脂,为提高涂料的耐热性,选择铜铬黑、磷酸锌、碳酸镁作为主要颜填料,并选用抗开裂粉料、消泡剂、分散剂等提高涂层外观及涂料的施工性能等。结果表明,该涂料有机挥发物低于100mg/L,涂层能在200℃固化成膜,700℃煅烧2h仍具有良好的防腐性能,且附着力好、耐盐雾性能良好。

水性醇酸树脂涂料在严寒地区电站锅炉的应用

介绍了水性醇酸树脂涂料的发展历程及水性醇酸树脂的主要分类及特点。根据锅炉产品的特点及防锈要求,论证了水性醇酸树脂在锅炉产品应用的可行性及应用范围,并提出水性漆在严寒地区的施工工艺特点及注意事项。

水性可剥离涂料在海洋工程建造中应用的可行性研究

对水性可剥离涂料的性能进行试验测试,通过模拟现场施工环境,验证水性可剥离涂料的各项性能指标,为在海洋工程建造过程中推广应用提供数据和效果参考。

水性丙烯酸阻燃涂料的研究进展

水性丙烯酸树脂涂料是一类近年来发展迅速的水性涂料,由于具有耐光性、耐候性、耐热性良好且环保无毒的特点,在汽车、家具、建筑等行业得到了广泛应用。其中利用水性丙烯酸树脂制备阻燃涂料的研究呈快速增长的态势,得到了木材、家具、建筑、钢材阻燃等领域有关学者的高度关注。简述了水性丙烯酸阻燃涂料的阻燃机理,从原料配比、原料种类、反应温度三方面阐述了水性丙烯酸阻燃涂料的制备工艺及其应用,并对其研究发展方向提出了建议。

石墨烯的分散方法及在水性环氧富锌涂料中的应用进展

石墨烯具有高的比表面积、高的机械强度、优异的导热和导电性、低的化学反应活性、良好的物理阻隔性能等特性,在提升涂料/涂层防腐性能方面具有很大的潜力,因而受到了广泛关注,石墨烯水性环氧富锌涂料是其中的研究热点。但是,石墨烯较大的比表面积及层间范德华力的相互作用导致其在水性溶剂或聚合物基体中极易发生团聚,直接影响了其在水性涂料/涂层中性能的发挥。因此,如何改善石墨烯在水性溶剂或聚合物基体中的分散性是待解决的首要问题。本文综述了石墨烯在水性环氧富锌涂料中的研究进展,对比讨论了单一或多种分散方法对石墨烯在水性涂料特别是水性环氧涂料中分散效果的影响规律及适用范围,对现有文献中石墨烯环氧富锌涂料的防腐性能进行了汇总,分析了石墨烯类型、含量及其与锌粉的相对比例对涂料/涂层性能的影响规律及选择原则。最后,本文介绍了石墨烯在提高涂层屏蔽性能及阴极保护方面的作用机理,并对石墨烯水性环氧富锌涂料在工业化制备和应用方面面临的挑战和未来研究方向进行了简要讨论。

衣康酸聚乙二醇单醚酯封端水性聚氨酯织物涂层剂的制备及其性能

为丰富水性聚氨酯亲水单体的来源与种类,从而提高涂层织物水蒸气透过率,以聚乙二醇单醚(MPEG)和衣康酸(IA)为原料,通过酯化反应合成含碳碳双键的衣康酸聚乙二醇单醚酯(IM)。将IM和甲基丙烯酸羟乙酯型水性聚氨酯(HWPU)混合,经紫外线接枝得到IM封端水性聚氨酯织物涂层剂(WPU-IM),采用直接涂覆法将其涂布于涤纶织物。通过吸水率、拉伸、耐静水压和水蒸气透过率测试对WPU-IM涂膜、织物涂层的性能进行分析。结果表明:当IM质量分数为2.1%时,WPU-IM涂膜断裂强度为8.61 MPa,断裂伸长率为325%,吸水率为17.4%,水接触角为79.2°;WPU-IM涂层织物耐静水压值为18.86 kPa,透湿率为4086.3 g/(m^(2)·d),综合性能达到最佳。

阻燃超细纤维合成革贝斯的制备及性能研究

为了解决添加型阻燃水性聚氨酯稳定性差的问题,以脂肪族多异氰酸酯、聚醚多元醇和阻燃含磷多元醇为原材料,通过预聚体法合成一系列具有阻燃性能的水性聚氨酯。将该阻燃水性聚氨酯应用于超细纤维合成革贝斯(超纤贝斯)的含浸工艺中,探讨其对超纤贝斯力学、品质、阻燃、热分解性能的影响。结果表明,随着含磷阻燃多元醇含量的增加,燃烧速率从115.00 mm/min降低至60.79 mm/min,极限氧指数从21.00%提高到24.20%。然后在超纤贝斯表面喷涂不同浓度的磷氮阻燃剂,经过测试发现,超纤贝斯在燃烧过程中出现自熄现象,极限氧指数提升到27.00%。与未经阻燃整理的超纤贝斯相比,经过阻燃整理超纤贝斯的热释放速率峰值、总释放热分别降低了42.29%,20.01%。通过扫描电镜和拉曼光谱分析可得,经过阻燃整理的炭层石墨化程度提高,结构更为致密,表明阻燃剂利用凝聚相阻燃机理发挥重要作用。

咪唑啉季铵盐缓蚀剂改性蒙脱土/水性环氧纳米复合涂料

以油酸、二乙烯三胺和氯化苄为原料,合成了油酸基咪唑啉季铵盐缓蚀剂。通过FTIR、^(1)HNMR对其结构进行了表征,并离子交换至钠基蒙脱土(DK0)层间,制备了缓蚀剂改性蒙脱土(QACDK0)。通过XRD、TGA和UV-Vis对其结构、组成及层间缓蚀剂释放性能进行了表征。结果表明,咪唑啉季铵盐缓蚀剂约占QACDK0质量的38.96%,并将蒙脱土层间距由1.28 nm(DK0)扩大至3.98 nm(QACDK0)。利用DLS及Zeta电位对添加有QACDK0的水性环氧树脂进行了稳定性测试,其Zeta电位为–27.8 mV,具有较高的稳定性。电化学阻抗谱(EIS)测试表明,在腐蚀介质中浸泡30 d后,基于QACDK0制备的清漆漆膜仍具有2.29×10^(8)Ω·cm^(2)的高阻抗,表明涂层具有较好的耐腐蚀性。并且在耐中性盐雾测试中,QACDK0对应的防腐色漆耐盐雾时间最长,验证了该涂层具有良好的耐盐雾性能。

可紫外固化的水性聚氨酯耐沾污涂层

耐沾污涂层固化时需要长时间的高温烘烤,限制了其在热敏基材上的应用。为解决以上问题,以单端双羟基聚二甲基硅氧烷(PDMS)作为疏水组分,乙氧化三羟甲基丙烷三丙烯酸酯(EOTA)作为交联剂,制备了一种可紫外固化的水性聚氨酯耐沾污涂层。使用傅立叶变换红外光谱仪(FT-IR)、接触角测量仪、X射线光电子能谱仪(XPS)和原子力显微镜(AFM)等对涂层进行表征,同时对涂层进行了自清洁、防涂鸦和耐腐蚀测试。结果表明:作为支链的PDMS能够在固化时富集在涂层表面形成疏水层,使涂层水和二碘甲烷的接触角分别从(70.0±2.4)°/(33.6±2)°提高到(93.8±1.2)°/(62.2±1.1)°,降低了污染物的润湿和铺展性;交联剂EOTA的引入,一方面可有效包裹聚氨酯的极性基团,降低涂层表面极性,削弱污染物小分子与涂层间的相互作用力,因而水和油性液滴能够轻松地从涂层表面滑落,显示出涂层良好的自洁性;另一方面,致密的交联网络阻碍了油墨等污染物分子向聚合物骨架渗透,使得油墨等污染物停留在涂层表面并收缩成细小的液滴,很容易被纸巾擦拭干净,展现出涂层优异的防涂鸦性能。另外,涂层经过10%NaCl溶液5 d的浸泡,表面依然光滑平整并保持着防涂鸦性能,展现出涂层良好的耐腐蚀性和耐沾污持久性。

聚乙二醇改性水性环氧丙烯酸酯的合成及其光固化动力学研究

为克服水性环氧丙烯酸酯脆性高的缺点,首先采用不同相对分子质量的聚乙二醇(PEG)对环氧树脂E51进行柔韧性改性,生成低黏度环氧树脂,将其与丙烯酸反应,得到低黏度环氧丙烯酸酯树脂,再引入丁二酸酐基团,然后用三乙胺中和成盐,加水乳化,合成了PEG改性水性环氧丙烯酸酯(PEG-WEA)乳液;将PEG-WEA乳液涂覆在聚对苯二甲酸乙二醇酯(PET)基材上。通过傅立叶变换红外光谱仪(FT-IR)和凝胶渗透色谱仪(GPC)表征PEG改性环氧树脂,探究PEG相对分子质量对PEG-WEA乳液粒径、光固化动力学行为、光固化膜热稳定性、力学性能以及涂层性能的影响。结果表明:PEG相对分子质量为600时,制得的PEG-WEA乳液粒径最小(77.96 nm),双键转化率得到提升,光固化膜热稳定性良好且呈现良好的韧性断裂特征,断裂伸长率提高7.54%,同时固化后涂层硬度达3H,柔韧性1 mm,附着力2级。