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.     

一种高固体分环氧防腐涂料的研制

采用小分子量环氧树脂和大分子量环氧树脂复配作为基料,以腰果壳油改性酚醛胺为固化剂,研制了一种高固体分环氧防腐涂料,并进行了性能检测。讨论了环氧树脂、环氧稀释剂、颜填料、流变助剂和固化剂对涂料性能的影响。     

Epoxy resin from cardanol as partial replacement of bisphenol-A-based epoxy for coating application

With continuous depletion of petrochemical feedstock and their rising prices, the chemical industry is now looking for alternative renewable and sustainable materials. Such materials could be processed with various chemistries to produce high performance functional materials for a range of applications, such as plastics, coatings, constructions, pharmaceuticals, and food applications. Cardanol derived from cashew nut shell liquid has a reactive phenolic group and aliphatic double bond that could be exploited to produce novel functional materials for polymer and coating applications. It has previously been used for preparation of phenolics, epoxy, and phenalkamine hardeners. In this study, we report on the preparation of novel epoxy resin from cardanol via simple a two-step reaction. The prepared resin with epoxy equivalent weight of 210–220 gm/eq was analyzed using FTIR and NMR spectroscopy. The epoxy resin was then used as binder along with bisphenol-A-based epoxy resin (DGEBPA) at various weight proportions and cured with different amine hardeners. The cured coatings were analyzed for physical, mechanical, and chemical properties for optimization of the coating formulation. The study conducted showed that 40–60% of DGEBPA resulted in comparable properties to that of completely DGEBPA-based system. Further, thermal and anticorrosive properties of the optimized coatings were also evaluated.     

Preparation of a light color cardanol-based curing agent and epoxy resin composite: Cure-induced phase separation and its effect on properties

A light color cardanol-based epoxy curing agent (MBCBE) was synthesized from cardanol butyl ether, formaldehyde and diethylenetriamine. In comparison, a phenalkamine with a similar structure was also prepared. The chemical structures were confirmed by GC–MS and FTIR. The cure behaviors of diglycidyl ether of bisphenol A (DGEBA) with these two curing agents was studied by differential scanning calorimetry (DSC). The morphology, mechanical properties, thermal properties of the cured epoxies were also investigated. The DSC results indicated that MBCBE is less reactive than the phenalkamine. The morphology of the cured MBCBE/DGEBA consisted of cavities dispersed within a continuous epoxy matrix. The cavities markedly improved the lap shear strength and impact strength of the cured resin. Both the two cured resins indicated a two-stage decomposition mechanism. Compared with PKA/DGEBA, the weight loss of MBCBE/DGEBA at the first stage was mainly resulted from the dispersed phase in the epoxy matrix.     

Synthesis of rosin‐based flexible anhydride‐type curing agents and properties of the cured epoxy

BACKGROUND: Although rosin acid derivatives have received attention in polymer synthesis in recent years, to the best of our knowledge, they have rarely been employed as epoxy curing agents. The objective of the study reported here was to synthesize rosin‐based flexible anhydride‐type curing agents and demonstrate that the flexibility of a cured epoxy resin can be manipulated by selection of rosin‐based anhydride‐type curing agents with appropriate molecular rigidity/flexibility. RESULTS: Maleopimarate‐terminated low molecular weight polycaprolactones (PCLs) were synthesized and studied as anhydride‐type curing agents for epoxy curing. The chemical structures of the products were confirmed using ¹H NMR spectroscopy and Fourier transform infrared spectroscopy. Mechanical and thermal properties of the cured epoxy resins were studied. The results indicate that both the epoxy/anhydride equivalent ratio and the molecular weight of PCL diol play important roles in the properties of cured resins. CONCLUSION: Rosin‐based anhydride‐terminated polyesters could be used as bio‐based epoxy curing agents. A broad spectrum of mechanical and thermal properties of the cured epoxy resins can be obtained by varying the molecular length of the polyester segment and the epoxy/curing agent ratio. Copyright © 2009 Society of Chemical Industry     

环保节能型水性环氧地坪涂料的研制

采用水性环氧固化剂制备色漆和低相对分子质量的液态环氧树脂作为水性环氧地坪涂料的成膜物质,考察了环氧值与胺氢值物质的量比、颜填料的选择、消泡剂用量、固化干燥时间等对漆膜性能的影响。结果表明：当环氧值与胺氢值物质的量比为1∶0.8,消泡剂用量为0.1%,固化干燥时间为7 d时,漆膜的综合性能最佳。     

颜填料体积浓度对水性环氧导静电防腐蚀涂层性能的影响

考察了颜填料体积浓度（PVC）对水性环氧导静电防腐蚀涂料涂层导静电性能和防腐蚀性能的影响,运用X射线能谱（EDX）分析了导电填料的元素组成,采用电化学阻抗谱（EIS）、扫描电镜（SEM）等手段对不同颜填料体积浓度的涂层进行了性能测试及表征,根据不同颜填料体积浓度涂层的物理机械性能、盐水浸泡实验结果和电化学阻抗谱分析,确定该水性环氧导静电防腐蚀涂料的最佳颜填料体积浓度为35%。     

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.     

无溶剂绝缘防腐防水涂料的研发

采用聚天门冬氨酸酯树脂、助剂、绝缘导热填料、阻燃剂、憎水剂及颜料等制备了无溶剂绝缘防腐防水涂料 A组分,与脂肪族异氰酸酯 NX-100固化剂 B组分以质量比 4∶1配合制备了无溶剂绝缘防腐防水涂料。通过对树脂、阻燃剂、消泡剂、导热填料和憎水剂的筛选,该涂料可快速固化,绝缘性、导热性能优良,阻燃效果好,憎水性及防腐效果持久,机械性能优异,符合绿色环保涂料要求,满足在电力工业中的使用要求。     

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。     

高抗流挂厚浆型环氧重防腐涂料的制备

以双酚A环氧树脂为主体树脂,酚醛胺和聚酰胺为固化剂,制备了一种具有高抗流挂性的厚浆型环氧重防腐涂料。该涂料不仅具有低VOC(挥发性有机化合物)含量,而且通过触变剂的合理搭配,一次喷涂湿膜厚度达到500μm而不流挂,大大改善了施工环境,提高了施工效率。涂层性能的测试结果表明:该涂料具有良好的附着力、优异的耐腐蚀性,综合性能优异。     

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.     

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.     

环氧树脂固化剂对高强玻璃纤维复合防弹板的力学性能影响分析

为高强玻璃纤维复合防弹板的环氧树脂固化剂进行研究。重点研究了三种不同固化剂的种类、用量及环氧树脂分子量对纤维复合板力学性能的影响。研究表明不同牌号、不同分子量的环氧树脂，对纤维复合板力学性能有一定影响。综合考虑选用间苯二胺作为高强玻璃纤维复合防弹板的固化剂。     

Electrochemical and mechanical studies on influence of curing agents on performance of epoxy tank linings

Effect of different curing agents on the mechanical, chemical resistance and anticorrosive properties of tank linings based on phenolic + novolac epoxies has been studied. Proportion of two epoxies was chosen by monitoring the processing viscosity of the coating. Parts of hardener required for 100 g of the above resin (phr) was scrutinized using differential scanning calorimetry and flexibility measurements. As a result, five coatings were finalized and their mechanical properties were investigated by dynamic mechanical analyzer. Anticorrosive properties of these coatings were studied using electrochemical impedance measurements and neutral salt spray exposure test. Chemical resistance of these coatings was investigated by monitoring the weight change of the coating during immersion. Coatings cured with modified cycloaliphatic amine (amine value = 350), in spite of lower cross-link density, exhibited superior anticorrosive properties and reasonably good chemical resistance. Electrochemical impedance results correlated fairly well with actual solvent resistance property of the coating.     

Effect of molecular weight of curing agents on properties of nanocomposites based on epoxy resin and organoclay with reactive modifier

Nanocomposites of epoxy resin and clay modified with half neutralized salt of Jeffamine D400 were prepared by curing separately with three polyetheramines curing agents of different molecular weights and reactivity. The molecular weight of curing agents and their structural similarity with modifier played an important role in deciding the curing behavior, thermomechanical, and morphological properties of epoxy/clay nanocomposites. Morphological analysis carried out by X‐ray diffraction (XRD) and transmission electron microscope (TEM) clearly show that the dispersion of clay layers in epoxy matrix decreases with decreasing molecular weight of the curing agents. Curing study done by using temperature modulated differential scanning calorimetry (MDSC) demonstrates that extragallery reaction rate increases with decreasing molecular weight of curing agents. Dynamic mechanical analysis (DMA) of epoxy/3 wt % modified clay composite prepared by curing with curing agent of higher molecular weight shows around 270% improvement in storage modulus (glassy) as compared with its neat epoxy network. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44595.     

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。     

环氧改性有机硅耐高温防腐隔热涂料的研制

以环氧改性有机硅树脂为成膜物,以复合铁钛粉为防锈颜料,以六钛酸钾晶须、海泡石、膨胀蛭石、空心玻璃微珠等轻质材料为填料,在多种助剂和低相对分子质量聚酰胺的配用下,制得一种综合性、实用性、经济性较好的双组分耐高温防腐隔热涂料。     

固化剂对有机改性凹凸棒石/聚苯胺环氧树脂复合涂层性能的影响

固化剂对涂层的防腐、力学性能起着至关重要的作用.以环氧树脂为成膜物质,采用原位复合法在环氧树脂体系中合成有机改性凹凸棒石/聚苯胺(OAT/PAn)复合涂层,分别使用改性脂肪胺固化剂593、酚醛胺固化剂T-31以及聚酰胺固化剂650对上述涂层进行固化,讨论了不同种类固化剂对涂层的化学结构、防腐和力学性能以及耐水性能的影响.利用FTIR 对比了各涂层的固化结构,证明了三种固化剂均可使复合涂层固化;SEM结果表明,593固化剂固化涂层的致密性最好;电化学实验结果表明,593固化剂的固化涂层防腐性能最佳,腐蚀电位达到了Ecorr=-318 mV,腐蚀电流密度Icorr=1.193×10-6 A·cm-2;通过划格法评价了各涂层的附着力,发现593固化剂固化效果最好,附着力可达5B;对比浸泡168 h后涂层的耐水性发现,593固化剂耐水性最好.     

Investigation of cardanol-based reactive polyamide as a crosslinker in epoxy zinc-rich primer

Cardanol-based reactive polyamides with different amine functionalities were successfully developed by conventional polycondensation mechanism. The synthesis involved 2-step processes of functionalization of cardanol by maleic anhydride followed by its condensation with diethylenetriamine in the second step. The polyamides with different molecular weights were prepared by varying the mole ratios of acid and amine components in the formulation. The developed polyamides were characterized for structural confirmation by FTIR and NMR spectroscopy. These polyamides were then used as crosslinker in conventional epoxy zinc-rich primer. The effect of molecular weights of these polyamides on mechanical, chemical, and solvent resistance properties of conventional epoxy zinc-rich primer was studied and compared with that of commercial polyamide. The anticorrosive properties of the primers were evaluated by humidity resistance test, salt spray test and electrochemical impedance spectroscopy. The study revealed that the epoxy zinc-rich primers cured with cardanol-based polyamide resulted in improved mechanical, chemical, and anticorrosive properties as evaluated by various methods.