Anticorrosive properties of an epoxy-Meldrum acid cured system catalyzed by erbium III trifluromethanesulfonate

New low curing temperature powder epoxy coatings cured with Meldrum's acid and catalyzed by the use of erbium III trifluoromethanesulfonate have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin) and with an epoxy powder coating homopolymerized by erbium III trifluoromethanesulfonate. Three different tests of anticorrosive properties (EIS, AC/DC/AC and salt fog spray) have been used together with an adherence test, in order to establish the best system. Results show that systems crosslinked with Meldrum's acid and catalyzed with erbium triflate present very fast curing kinetics and very good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly and much faster than other techniques the anticorrosive properties of powder coatings.     

Application of electrochemical techniques to study the effect on the anticorrosive properties of the addition of ytterbium and erbium triflates as catalysts on a powder epoxy network

New low curing temperature epoxy powder coatings cured with o-tolylbiguanide and catalyzed by the use of erbium(III) and ytterbium(III) trifluoromethanesulfonates have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin). Three different tests for measuring anticorrosive properties (EIS, AC/DC/AC, and salt fog spray) have been used together with an adherence test, in order to establish the ideal system. Results show that a system using 1 phr of ytterbium triflate presents good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly and much faster than other techniques the anticorrosive properties of powder coatings with similar results.     

催化剂对环氧树脂/酚类固化剂体系反应性的影响

采用三氟甲磺酸铒和三氟甲磺酸镱作为环氧树脂/酚类固化剂的催化剂,筛选了固化剂的最佳用量,采用胶化时间研究了催化剂的催化活性,并采用差热分析法对环氧树脂/酚类固化剂/三氟甲磺酸铒动力学参数进行了研究。结果表明,酚类固化剂的最佳质量分数为9%(以环氧树脂计),三氟甲磺酸铒的催化活性最强,环氧树脂/酚类固化剂/三氟甲磺酸铒体系的活化能为79.53 kJ/mol,反应级数为0.95。     

Preparation and anticorrosive performances of polysiloxane-modified epoxy coatings based on polyaminopropylmethylsiloxane-containing amine curing agent

In this article, polysiloxane-modified epoxy coatings were prepared using the mixture (CPSA) of polyaminopropylmethylsiloxane (PAPMS) oligomer/N-(2-hydroxyethyl)ethylenediamine as a curing agent and cardanol as a compatibilizer. The PAPMS oligomer was prepared from the controlled hydrolysis and condensation of (γ-aminopropyl)methyldimethoxysilane. Conventional epoxy coatings based on commercial phenalkamine epoxy curing agent (PECA) were also fabricated for comparison. The compatibility between the CPSA amine curing agent and epoxy resin was investigated by SEM and element-mapping measurements. The anticorrosive performances of the CPSA- or PECA-based epoxy coatings were thoroughly examined by electrochemical impedance spectroscopy (EIS), salt fog tests, and immersion experiments in acid (25 wt% H₂SO₄), alkali (25 wt% NaOH), and saline (3 wt% NaCl). It was found that cardanol can dramatically improve the miscibility of CPSA with epoxy resins. Polysiloxane-modified (namely, CPSA-based) epoxy coatings have much better corrosion resistance than conventional (namely, PECA-based) epoxy coatings.     

Effect of molecular weight of phenalkamines on the curing,mechanical, thermal and anticorrosive properties of epoxy based coatings

The present investigation deals with the study of effect of molecular weight and structures of phenalkamine curing agents on the curing, mechanical, thermal and anticorrosive properties of epoxy based coatings. The phenalkamines were prepared by varying the composition of formaldehyde and diamine in the formulation. The structural characterization confirmed successful preparation of high molecular weight phenalkamines. These were then used as curing agents for air drying and thermally curable epoxy coatings. The effect of these phenalkamines on curing properties of epoxy resin as well as mechanical, chemical, thermal and dynamic thermo-mechanical properties of the resultant coatings was studied and compared with commercial phenalkamine. The anticorrosive properties of the coatings were evaluated by salt spray test and electrochemical impedance spectroscopy. The study revealed that high molecular weight phenalkamines resulted in faster surface drying due to rapid molecular weight build-up. The anticorrosive performance also improved as indicated by higher modulus and electrochemical potential values.     

柔性陶瓷重防腐涂料的研制及性能研究

探讨了树脂和固化剂类型、颜基比以及陶瓷粉类型对柔性陶瓷涂料性能的影响。结果表明:选择酚醛环氧树脂与双酚F树脂混合使用,以异佛尔酮二胺为固化剂,颜基比选择3.5:1,以不同细度的碳化硅粉搭配氧化铝粉和云母粉作为陶瓷粉所制备的柔性陶瓷涂料的性能最佳。对该涂料各种性能进行测试并与进口陶瓷涂料进行性能对比,发现该涂料的性能与进口陶瓷涂料性能相当,具备良好的耐磨性能、耐温性能、耐化学品性能及其他物理机械性能。     

钢结构用超薄型水性环氧防火防腐涂料的研制

以液体环氧树脂为基料树脂,以水性胺为固化剂;以聚磷酸铵、三聚氰胺、季戊四醇、氯化石蜡为膨胀阻燃体系;以纳米TiO2、可膨胀石墨为增效剂;以复合铁钛粉为防锈颜料,制备了钢结构用超薄型防火防腐涂料。当环氧涂层的交联度达到理论交联度的50％～70％时,涂层既有优良的防火隔热性能,又有优良的防腐蚀性及机械性能。     

Optimization of deposition voltage of cataphoretic automotive primers assessed by EIS and AC/DC/AC

The dependence of the anticorrosive properties of a cataphoretic paint with the applied deposition voltage was studied by the so-called EIS tests; an accelerated cyclic test used in the automotive industry; and a rapid electrochemical test (AC/DC/AC) which combines EIS measurements with cathodic polarizations. DSC and TGA were employed for the coating characterisation. The traditional accelerated cyclic test was unable to distinguish the influence of the deposition voltage on the anticorrosive properties while electrochemical tests found an optimal range of deposition voltage between 270 and 320 V. The AC/DC/AC test obtained the same results as EIS tests but in only 24 h instead of months of evaluation. The technique AC/DC/AC is suggested as an accelerated technique able to determine the optimum range of deposition voltages to obtain the higher anticorrosive properties of an epoxy cataphoretic primer.     

无溶剂环氧输油气管内低表面处理防腐减阻涂料的研制

以液态环氧树脂、稀释剂为基体树脂,以腰果壳液改性酚醛胺为固化剂,以复合铁钛粉、磷酸锌、氧化铁红、聚四氟乙烯、沉淀硫酸钡、陶瓷微珠等为填料,在多种功能助剂的配合下制备成无溶剂环氧输油气管内低表面处理防腐减阻涂料.集带锈带油、带湿涂装为一体,具有防腐、减阻、耐磨等特性.     

Lanthanide triflates as curing initiators for solid DGEBA resin: Thermal and mechanical characterization

A new class of cationic initiators, lanthanide triflates, has been studied in the curing of diglycidyl ether of bisphenol‐A (DGEBA). Two metal salts (Erbium and Ytterbium (III) trifluoromethanesulfonate) in various proportions (0.5, 1, and 2 parts per hundred of resin) have been used and the thermal and mechanical properties of the thermosets compared to a common solid epoxy system (crosslinked with o‐tolylbiguanide). The kinetics of these processes has been evaluated by the isoconversional method that has been proved to be an excellent tool to predict the principal curing parameters (conversion/time/temperature). Their mechanical properties have been evaluated by dynamic mechanical thermal analysis (DMTA), stress‐strain curves, impact resistances and adhesion to metallic substrates, and the thermal characteristics were measured by calorimetry (DSC) and thermogravimetry (TGA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The use of nanoclay in preparation of epoxy anticorrosive coatings

Epoxy/clay nanocomposites (NC) have become a very interesting topic among researchers in the past two decades because nanoclays have a positive effect on the mechanical, thermal and especially barrier and anticorrosive performances of the polymers. In this study epoxy NCs and NC-based epoxy coatings were prepared by the solution intercalation method using Cloisite 30B as nanoclay. WAXD and SEM analyses revealed that a mainly exfoliated structure was obtained in epoxy NC with 1 wt% clay content, while higher clay loadings reduced the number of exfoliated clay nanolayers and produced a mainly intercalated structure. EIS, TGA and DMA analyses showed that epoxy NCs with clay content below 5 wt% exhibited increased corrosion stability, thermal stability, glass transition temperature (T_g) and storage modulus (G′), in both glassy and rubbery states due to the nanoscale dispersion of Cloisite 30B and the barrier effect of individual nanolayers. Enhanced mechanical properties were also noticed at higher clay loadings, but the rate of improvement was lower. The highest extent of exfoliation and the most homogeneous macromolecular network was found for NC with 1 wt% of clay, leading to the highest improvement of thermal and anticorrosive properties. The salt spray test results showed that anticorrosive properties of epoxy coatings in the presence of 3 wt% and especially 1 wt% of Cloisite 30B were significantly better, thus indicating that nanoclay efficiently modifies the commercial epoxy coatings.     

水性环氧防腐涂料的研制

以自制的环氧树脂乳状液为漆基、磷酸锌作为活性防锈颜料合成了水性环氧防腐涂料。研究了涂料中颜基比、固化剂与环氧树脂的当量比等对涂膜性能的影响。结果表明,颜基比小于1,固化剂CEN-537与环氧树脂E-44的当量比为1或稍大于1时,所得涂膜的各项性能指标可达到较好的平衡;涂料的防绣性能与以硅铬酸铅为防绣颜料的传统涂料相当。新研制的水性环氧防腐涂料性能达到了国外同类产品的水平。     

石墨烯改性环氧锌基防腐涂料的制备与性能研究

针对传统环氧富锌涂料环保性差、质量大、成本高等问题,利用石墨烯优异的导电性与独特的二维片层结构可增强涂层防腐性能的特性,取代传统环氧富锌涂料中的部分锌粉,以期制备低锌含量的石墨烯环氧锌基涂料。首先将石墨烯材料与环氧树脂预混合,掺杂天然高分子表面活性剂,制备一种高分散性石墨烯 /环氧树脂浆料;然后将其与计量的环氧树脂、锌粉、其他功能颜填料复配,通过高速分散与砂磨的制备方式相结合,得到石墨烯改性环氧锌基防腐涂料;最后通过力学性能、连接强度、交流阻抗、耐中性盐雾等方法探索涂层关键性能。研究结果表明：该石墨烯涂层防腐性能优异, 2 000 h盐雾划痕腐蚀扩展 0.9 mm,且力学性能与施工性能好,可广泛应用于船舶、海工设备、桥梁等大型钢结构装备领域。     

几种新型富锌涂料的研究进展

介绍了氧化石墨烯改性水性环氧富锌涂料、石墨烯纳米片/环氧富锌(Gnps/ZRE)复合涂料、高柔韧性、高附着力水性无机富锌涂料、石墨烯硅酸盐富锌防腐蚀涂料、水性聚苯胺/氧化石墨烯改性低锌粉含量防腐涂料、还原-氧化石墨烯(r-GO)改性环氧富锌涂料、耐盐雾双组分水性环氧富锌涂料、石墨烯浆料改性水性环氧富锌涂料、双电层水性无机富锌涂料、SnCl2/EtOH溶液法还原氧化石墨烯环氧富锌涂料、有机-无机杂化水性富锌涂料、水性富锌铝涂料、低锌含量石墨烯长效防腐涂料、自固化醇溶性无机富锌底漆和冷镀锌喷漆等几种新型富锌涂料的研究进展。     

管道防腐用环氧粉末涂料及其新进展

介绍了管道防腐用环氧粉末涂料的组成及固化体系,综述了其在国内外的发展状况。结合国产管道防腐用环氧粉末涂料存在的问题和粉末技术的最新发展,探讨了提高国产管道防腐用环氧粉末涂料综合性能的技术途径。     

环氧粉末涂料用酚类固化剂的研制

详细介绍了ＥＢ－ ３０ 型酚类固化剂的制备、性能及其应用。     

A comparative study between the results of different electrochemical techniques (EIS and AC/DC/AC): Application to the optimisation of the cataphoretic and curing parameters of a primer for the automotive industry

Companies producing organic coatings for the automotive industry often need to test newly formulated products, which may have used different production or application parameters, to determine their actual behaviour before large-scale production and use of the coating. Proper choice of the test for this characterisation and the method of evaluation are critical. The results must be obtained in relatively short times so it is impracticable for manufacturers to wait for the completion of outdoor exposure tests. To reduce lead times in the development process, the use of an accelerated aging test (such as salt spray resistance) to predict durability of the coating is essential. Yet, the time needed to perform such tests is usually at least 500 h. This article proposes the use of electrochemical impedance spectroscopy (EIS) and an electrochemical test, AC/DC/AC, which consists in a combination of impedance results and cathodic polarisations, in order to optimise in a very short time the cataphoretic process parameters (mean applied voltage) and the curing temperature needed for a primer in order to obtain the maximum anticorrosion performance. Results show very good degree of concordance between the two electrochemical tests although the AC/DC/AC method is much faster. The accelerated electrochemical test lasted 24 h to differentiate anticorrosive coatings performance, while same conclusions were obtained after more than 100 days by electrolyte immersion and evaluated by EIS.     

无溶剂玻璃鳞片重防腐涂料的研制

采用低分子环氧树脂、脂肪胺和多氨基酰胺固化体系,加入适量玻璃鳞片,利用玻璃鳞片优异的抗渗透性能,研制出高效长久无污染的防腐涂料。     

低温固化环氧树脂粉末涂料的制备及性能研究

通过双螺杆挤出机用E-12型环氧树脂和YLT-118固化剂及其他助剂在90℃下熔融混合10 min,然后在平板硫化机上冷压3 min,最后经过粉碎机粉碎,过筛制得环氧粉末涂料。采用差示扫描量热法和红外光谱表征粉末涂料,并讨论了填颜料用量、固化条件等对涂料性能的影响。结果表明：该粉末涂料可实现低温固化,固化条件为120℃下恒温固化30 min;固化剂用量为环氧树脂的16.7%时,m（环氧树脂）∶m（填颜料）为150∶135时,得到的涂膜各项物理性能最好。     

Evaluation of cure temperature effects in cataphoretic automotive primers by electrochemical techniques

Companies producing organic coatings for the automotive industry frequently need to test newly formulated products or materials, habitually according to different production parameters, in order to determine their actual behaviour before large-scale production of the coating is implemented. Proper choice of the test for this characterisation and the method of evaluation are critical. On the one hand, the choice is important because it is often necessary to distinguish coatings with very similar performance. On the other hand, results must be obtained in relatively short times, for it is impracticable for the manufacturers to wait for the completion of outdoor exposure tests. To reduce lead times in the development process, the use of accelerated aging tests to predict durability of the coating is essential (the time needed to perform them, however, is usually at least 500 h). This article proposes the use of EIS and an electrochemical test, AC/DC/AC, which consists in a combination of impedance results and cathodic polarisations, in order to find out the performance of coatings with precision and in a very short time. These techniques have been used to determine the optimum range of curing temperatures of a primer in order to obtain the maximum anticorrosion properties. Results show very good degree of concordance between the two electrochemical tests, although the AC/DC/AC method is much faster.