Performance of corrosion protective epoxy blend-based nanocomposite coatings: a review

ABSTRACT

Epoxy is a thermosetting polymer with exceptional mechanical robustness, thermal stability, and chemical resistance. This article is devoted to updating development, processing, and physicochemical characterizations of epoxy-based anti-corrosion coatings. Incorporation of different polymers in epoxy matrix has motivated extensive research progress in the field of corrosion protection. Epoxy has been blended with polyaniline, polypyrrole, polythiophene, polyamide, polyester, polyurethane, poly(vinyl alcohol), and polydimethylsiloxane to form corrosion protective coatings. The addition of conducting polymer and nanofiller to epoxy matrix modified the nanocomposite morphology and facilitated the development of passive layer at metal/polymer interface. Consequently, nanocomposite coatings act as physical barrier to hinder the penetration of corrosive ions. Likewise, fine dispersion of nanocarbon and inorganic nanoparticles in compatible blends of epoxy/polyamide, epoxy/polyester, epoxy/polyurethane, and epoxy/poly(vinyl alcohol) has resulted in improved adhesion, wear, barrier and anticorrosion properties of the nanocomposite coatings. Design of epoxy blend-based nano-architectures may facilitate appropriate tailoring of overall performance of the resulting anti-corrosion coatings for advance technical applications including aerospace, automotive, construction, electronic devices, and biomedical relevances. New processing techniques may overcome challenges toward high performance future epoxy-based coatings.     

Holistic insights on polyimide nanocomposite nanofiber

ABSTRACT

Polyimides form an important class of high-performance polymers. Polyamides with aromatic macromolecular architecture have revealed excellent conducting, mechanical, and thermal properties for aerospace, automotive, electronics, and other technical industries. Recently, polyimide nanofiber and polyimide nanocomposite nanofiber have been focused for fabrication, essential physical features, and subsequent performance. Due to diversity of dianhydrides, diamines, and reinforced nanoparticles, various polyimide nanocomposite nanofibers have been judiciously designed. This comprehensive review highlights indispensable perspectives of polyimide nanocomposite nanofiber particularly polyimide/graphene, polyimide/carbon nanotube, and polyimide/inorganic nanoparticle-based nanofibers. It is envisioned that nanocomposite nanofibers have various high-value applications such as membranes, battery separators, electrodes, etc.     

Fire‐resistant effect of nanoclay on intumescent nanocomposite coatings

The aim of the study is the development of an intumescent nanocomposite coating to provide fire protection for the metallic substrate. Acrylic nanocomposites containing nanoclay and relative intumescent nanocoatings are prepared. The effect of nanoclay on the thermal degradation of an intumescent nanocomposite coating is analyzed by using differential thermal analysis, thermogravimetry, and X‐ray diffraction. The influence of the added content of nanoclay on fire performance is studied by a fire protection test and measurements of the limiting oxygen index and effective thermal conductivity. The distribution of nanoparticles in the acrylic nanocomposite is characterized by transmission electron microscopy. The flame‐retardant efficiency of the intumescent nanocomposite coating is improved by 1.5% well‐distributed nanoclay particles. However, 3% nanoclay produces a negative effect on the fire performance of the coating. Fire protection tests and scanning electron microscopy observations reveal that the fire‐retardant property of a conventional intumescent coating is destroyed by aging, whereas the nanocomposite coating modified with 1.5% nanoclay demonstrates good aging and fire resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1681–1689, 2007     

Effects of Ni content on microstructure,mechanical properties and Inconel 718 cutting performance of AlTiN-Ni nanocomposite coatings

AlTiN-Ni coatings with various Ni contents (0–3?at%) were deposited using cathodic arc evaporation. X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, a nanohardness tester, scratch-adhesion tester, and cutting tester were used to examine the microstructure, mechanical properties, and cutting performance of the coatings. The AlTiN coatings exhibited a columnar structure, while the AlTiN-Ni coatings exhibited a nanocrystal structure due to the formation of nc-AlTiN/Ni nanocomposite coatings. The nanohardness of the AlTiN-Ni coatings decreased from 26.2?GPa to 20.9?GPa as the Ni content increased from 0 to 3?at%. At an Ni content of 1.5?at%, the coating possessed a high toughness and sufficient adhesion strength; however, these dropped drastically for the AlTiN-Ni coating with 3?at% Ni owing to the presence of amorphous Ni. The results for the Inconel 718 turning indicated that the wear mode is adhesion at the rake face, abrasion and adhesion (built-up edge) at the flank face, and chipping at the cutting edge. Compared to AlTiN-Ni₃ and AlTiN-coated tools, the lifetime of the AlTiN-Ni_1.5 coated tool increased to 160% at a cutting speed of 40?m/min. This was attributed to less adhesion at the rake face and chipping at the cutting edge, due to the nanocrystal structure and higher toughness of the AlTiN-Ni_1.5 coating.     

Ultrasound assisted in situ emulsion polymerization for polymer nanocomposite: A review

This review covers an ultrasound assisted synthesis of polymer nanocomposites using in situ emulsion polymerization. First of all, surface modification of core nanoparticles with a coupling agent and surfactant has been employed for the synthesis of core–shell polymer nanocomposites. In addition to application of ultrasound for the synthesis of core–shell polymer nanocomposites, due to its influential efficiency, sonochemistry has been extensively used not only as an aid of dispersion for inorganic nanoparticles and organo-clay, but also acts as an initiator to enhance polymerization rate for synthesis of polymer nanocomposites. In situ emulsion polymerization of hydrophobic monomers, such as methyl methacrylate, butyl acrylate, aniline, vinyl monomers and styrene, using surfactant and water soluble initiator were carried out for a synthesis of core–shell polymer nanocomposite. This technique assists in preparation of stable and finely dispersed polymer nanocomposite with the loading of inorganic particles up to 5 wt.%. Recent developments in the preparation of core–shell polymer nanocomposites using an ultrasound assisted method with their physical characteristics such as morphology, thermal, and rheological properties and their potential engineering applications have been discussed in this review.     

Characterization and in vitro drug release properties of chitosan/acrylamide/gold nanocomposite prepared by gamma irradiation

A nanocomposite of (chitosan/polyacrylamide/gold) (Cs/AAm/Au) and (chitosan/polyacrylamide) (Cs/AAm) hydrogel were performed using gamma radiation and employed as a carrier for Cisplatin cancer drug. The structure and morphology were studied by FTIR and FE-SEM, respectively. XRD and TEM confirmed the formation of the nanoconposite. The average particle size ranged between 13 to 27?nm. EDX estimated that the concentration of Au⁰ nanoparticles in (Cs/AAm/Au) nanocomposite was 0.20%. Both (Cs/AAm) and (Cs/AAm/Au) have higher swelling percent and reached the swelling equilibrium within 6?h. The optimum pH of swelling was at pH 7.2. The maximum Cisplatin drug released was 33% for Cs/AAm hydrogel and 96% for Cs/AAm/Au nanocomposite at pH 7.2 through 320 and 410?min, respectively. The release mechanism was found to be followed the non-Fickian diffusion mechanism for both systems. The cytotoxicity against liver cancer (HepG2) was investigated. Cisplatin drug loaded samples (Cs/AAm) drug loaded hydrogel of concentration 100?μg/ml killed 76.4% of the cells and IC₅₀ reached 29?μg/ml whereas (Cs/AAm/Au) drug loaded nanocomposite killed 84.9 of the cells and IC₅₀ reached 22.7?μg/ml.     

改性胶体及其对高PVC内墙乳胶漆性能的影响

介绍了改性胶体改善乳胶漆性能的原理，讨论了使用改性胶体配制的高PVC乳胶漆的性能和改性胶体对乳胶漆性能的影响。改性胶体能够降低乳胶漆中分散剂、增稠剂和冻融稳定剂的用量，改善乳胶漆的流平性和涂膜的手感，提高抗分水性能，但对于涂膜的耐洗刷性没有明显的影响。     

Trends in graphene reinforced polyamide nanocomposite for functional application: a review

This review outlines significant aspects and vital progression from polyamide – to – polyamide/graphene nanocomposite – to – technical application. Polyamide forms an important class of engineering thermoplastic polymers with exceptional mechanical, abrasion, wear, barrier, and crystallinity properties. Graphene is a unique nanocarbon having exclusive electrical, optical, mechanical, thermal, and chemical performance. Consequently, polyamide/graphene nanocomposite has revealed multifunctional properties and high performance owing to the synergistic effect of polymer and graphene. Here, interfacial interaction, dispersion in matrix, and processing technique used affect the final nanocomposite performance. A range of technological fields have been profited using polyamide/graphene nanocomposites including non-flammable materials, membranes, coatings, textile, and packaging industries.     

Thermally conducting polymer/nanocarbon and polymer/inorganic nanoparticle nanocomposite: a review

ABSTRACT

This review addresses fundamentals and progress in field of thermally conducting polymer/nanocarbon nanocomposite. Upsurge in thermal conductivity of materials may lead to rapid heat diffusion, which in turn may prevent degradation. Thermally conductive nanofillers (carbon nanotube, graphene, nanodiamond, inorganics) have been effectively employed to form desired nanocomposite. In polymer/nanocarbon nanocomposites, thermal conductivity depends on nanofiller type, dispersion, loading level, polymer nature, morphology, and crystallinity. Thermal conductivity parameter has been significantly considered in aerospace, automotive, electronics, and energy-related industries, where thermal dissipation has become a challenging problem. In future, it is desired to design high performance nanocomposites with manageable thermal conduction.     

Copolymerization and polymer blending of trimethylene carbonate and adipic anhydride for tailored drug delivery

The copolymerization in bulk and solution of trimethylene carbonate (TMC) with adipic anhydride (AA) as well as the blending of homopolymers are described. We show experimentally that the components are not copolymerizable but partially miscible, forming a microscopic dispersion without any visible signs of phase separation. Poly(adipic anhydride) (PAA) functions as a plasticizer, permitting an increase in the erosion rate by increasing the porosity and hydration. Drug delivery from the blends was evaluated. A statistical factorial model was designed to explore the influence of three important blend parameters and their interactions, making it possible to predict the erosion and drug‐release behavior of the blend matrices. The PAA:poly(trimethylene carbonate) (PTMC) ratio and molecular weight of the polycarbonate component significantly influence the drug‐release performance, mass loss, and degree of plasticization. The interaction among these factors also influences the blend properties. Plasticization of PTMC enhances the drug release to an extent that is dependent on the amount of PAA used. We demonstrate that blending offers a convenient alternative to copolymerization for the preparation of polymer matrices with predictable drug delivery. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 227–239, 1999     

NiO-Ag2S复合纳米结构的合成及光催化性能研究

利用水热合成方法制备了一种由Ag2S纳米颗粒均匀填充在片层状NiO空隙内的NiO-Ag2S复合纳米结构,该复合结构中NiO与Ag2S均匀地融合在一起。通过SEM、二维EDX及XRD对该复合纳米结构的形貌、均一性、晶体特性进行了分析。以500 W氙灯为光源,考察了NiO2-Ag2S复合纳米结构光催化降解甲基橙能力。结果表明,NiO2-Ag2S复合纳米结构具有良好的光催化活性,不仅比单独的NiO2和Ag2S降解能力强,而且在光照180 min后的降解效率比NiO2和Ag2S的物理混合物(质量比为1:1)高30%。分析认为NiO-Ag2S复合纳米结构中形成的p-n结是其高效催化性能的重要因素。     

Dynamically bonded layer‐by‐layer films: Dynamic properties and applications

Layer‐by‐layer (LBL) assembly, a simple but versatile method for thin film fabrication, has been widely employed to fabricate nanoengineered films with controlled composition and thickness. Dynamically bonded LBL films are films fabricated using dynamic bonds, that is, chemical bonds which can undergo reversible breaking and reformation usually under equilibrium conditions, as driving forces. Because of the reversible, dynamic nature of the dynamic bonds, these films exhibit various dynamic properties, ranging from a small scale movement of the polymer chains within the films (chain rearrangement), to a large scale movement of the chains, which results in film disintegration. Usually an external stimulus is used to trigger the response of a dynamic film. Novel applications have been proposed by exploiting the dynamic properties of these films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40918.     

HPLC法测定建筑涂料及乳液中的苯甲醛

建立了建筑涂料及乳液中苯甲醛的液相色谱检测方法。样品经甲醇提取,用50%甲醇饱和氯化钙溶液(V/V)沉淀聚合物,离心后将上层清液过滤进样。采用C18色谱柱进行分离,甲醇-水为流动相洗脱,二极管阵列检测器进行目标物检测,外标法定量。结果表明:在0~10μg/mL范围内,质量浓度和峰面积呈现良好的线性关系(R=0.9998)。方法检出限0.44 mg/kg,定量限1.47 mg/kg,当添加水平在25 mg/kg、50 mg/kg、100 mg/kg时,加标回收率在87.60%~91.10%,相对标准偏差RSD(n=6)均小于1.5%,该方法可用于建筑涂料及乳液中的苯甲醛的快速检测。     

Controlled release on sand bed columns and biodegradability in soil of chitosan: Hydroxypropyl methylcellulose films

The main purpose of this work is to prepare and characterize films based on chitosan (Q) and hydroxypropyl methylcellulose (HPMC) blends to achieve adequate properties to be used as coating of conventional fertilizers to prolong their availability for crops. The films loaded with KNO₃ as model fertilizer were prepared by casting. Release of fertilizer was studied using sand bed columns. To quantify films durability in soil, their areas were measured in function of time. Results showed that chitosan substantially improved the durability of HPMC, lengthening its permanence in soil 900‰. Relative humidity had influence in mechanical properties. Comparing KNO₃ powder and that loaded in the film, the time of residence in the column was much lower for the powder than the second one: 4 and 56 days, respectively. Chitosan–HPMC film would be promising as polymeric coating for controlled release fertilizers taking into account field conditions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47532.     

Electrically conductive and mechanically tough graphene nanocomposite hydrogels with self‐oscillating performance

Conventional hydrogels are extremely brittle, fragile and poorly conductive, which limits their applications in a variety of aspects. In this study, we fabricated a novel kind of nanocomposite self‐oscillating hydrogel poly(AA‐co‐Fe(phen)₃)/PVA/RGO with high conductivity and good mechanical strength by dispersing reduced graphene oxide (RGO). Due to the synergetic effect of RGO dispersed in the hydrogels or dry gels and Fe metal which is the reduction product of the Fe(phen)₃ moiety by RGO, the hydrogels have a high conductivity of 18.2 S m^?1 with 0.67 wt% RGO content. The dispersed RGO in the hydrogels combined with the network structure by means of hydrogen bonding, π–π stacking and electrostatic interaction and was demonstrated to enhance the mechanical properties of the hydrogels. The elastic modulus achieves 65.2 kPa (1020% of the tensile strength) and 236.4 kPa (with 70% compression), respectively. In addition, the prepared hydrogels exhibit a self‐oscillating behavior in a Belousov–Zhabotinsky solution free of catalyst. These results can be broadly applied in the future in the development of an autonomous on–off switching, flexible/stretchable, graphene‐based soft electronic device. © 2019 Society of Chemical Industry     

The influence of coating with aminopropyl triethoxysilane and CuO/Cu2O nanoparticles on antimicrobial activity of cotton fabrics under dark conditions

A novel impregnation process for the fabrication of cotton nanocomposite with strong antimicrobial activity against antibiotics-resistant bacteria and yeast was developed. The impregnation process includes the sol–gel treatment of fabric with (3-aminopropyl)triethoxysilane in the first step, and synthesis of the CuO/Cu₂O nanoparticles (NPs) on the fabric surface in the second step. The in situ synthesis of the CuO/Cu₂O NPs was based on the adsorption of Cu²⁺-ions by the introduced amino groups of the sol–gel coating. The adsorbed Cu²⁺-ions are subsequently reduced in the alkaline solution of NaBH₄. X-ray diffraction measurements confirmed the formation of CuO/Cu₂O NPs. Scanning electron microscopy and atomic absorption spectrometry analyses indicate that the particle size, agglomeration, and amounts of synthesized NPs were highly affected by the initial concentration of CuSO₄ solution. The toxicity of nanocomposites to human keratinocytes (HaCaT) and antimicrobial activity against Gram-negative Escherichia coli ATCC 25922, E. coli ATCC BAA 2469, and Klebsiella pneumoniae ATCC BAA 2146, and Gram-positive bacteria Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 and yeast Candida albicans ATCC 24433 strongly depended on the copper content. In addition to excellent antimicrobial activity, controlled release of Cu²⁺-ions from the fabrics into physiological saline solution was obtained.     

Modification of hydrophilic polymer network to design a carrier for a poorly water-soluble substance

pH sensitive, nontoxic, and biocompatible poly(methacrylic) acid (PMAA) based soft networks have been extensively used in the design of systems for targeted drug delivery. Still, their highly hydrophilic nature limits their potential to be used as a carrier of poorly water-soluble substances. With the aim to overcome this limitation, the present study details a new approach for modification of PMAA based carriers using two amphiphilic components: casein and liposomes. The FTIR analysis revealed structural features of each component as well as the synergetic effect that originated from the formation of specific interactions. Namely, hydrophobic interactions between the poorly water-soluble model drug (caffeine) and casein enabled caffeine encapsulation and controlled release, while addition of liposomes ensured better control of the release rate. The morphological properties of the carriers, swelling behavior, and release kinetics of caffeine were investigated depending on the variable synthesis parameters (neutralization degree of methacrylic acid, concentration of caffeine, presence/absence of liposomes) in two different media simulating the pH environment of human intestines and stomach. The data obtained from in vitro caffeine release were correlated and analyzed in detail using several mathematical models, indicating significant potential of investigated carriers for targeted delivery and controlled release of poorly water-soluble substances.     

Poly(methyl methacrylate) nanocomposite reinforced with graphene,graphene oxide,and graphite: a review

Poly(methyl methacrylate) (PMMA) is an important transparent thermoplastic polymer having appropriate strength, chemical, weathering, heat, and UV resistance. However, essential properties of this versatile polymer need to be enhanced for high-tech applications. Graphene has opened up a new vista for developing functional polymeric nanocomposite. Therefore, reinforcement of PMMA with graphene and related nanofiller has been focused in literature. This review basically highlights the fundamentals and characteristics of the significant classes of PMMA/graphene, PMMA/graphene oxide, and PMMA/graphite nanocomposite. Recent developments in the applications of PMMA/graphene-based nanofiller nanocomposite in biomedical, sensor, supercapacitor, flame retardant, and electromagnetic interference shielding materials were also comprehended.     

Interpenetrating polymer network and nanocomposite IPN of polyurethane/epoxy: a review on fundamentals and advancements

This article presents state-of-the-art review on interpenetrating polymer network (IPN) formation by polyurethane/epoxy (PU/EP). PU is thermoplastic polymer with fine mechanical strength, chemical resistance, processability, and thermal stability. EP resins also possess unique chemical and physical properties, though it is rigid and brittle. Amalgamation of two polymers have resulted in improved mechanical, thermal, damping, and glass transition behavior. PU/EP IPN and nanocomposite containing carbon nanotube, graphene oxide, nanodiamond, nanoclay, and various other nanoparticles have been discussed. Commercial implication and future prospects of PU/EP-crosslinked network and nanocomposite IPN are foreseen in high-performance engineering materials, automotive and aerospace, and biomedical devices.     

Study on effect of duration of the ultrasonication process on solvent‐free polyurethane/organoclay nanocomposite coatings: Structural characteristics and barrier performance analysis

In this study, effect of duration of ultrasonication process on structural characteristics and barrier properties of solvent‐free castor oil‐based polyurethane (PU)/organically modified montmorillonite (OMMT) nanocomposites was investigated. A series of PU/OMMT composites were synthesized by in situ polymerization technique through an ultrasonication‐assisted process at various processing durations. Effect of ultrasonication duration on de‐agglomeration of clay stacks in castor oil dispersions was evaluated by optical microscopy, sedimentation test, and viscosity measurement. Wide angle X‐ray diffraction and Fourier‐transform infrared spectroscopy were employed to investigate the effect of processing time on degree of delamination of clay platelets and interfacial strength between clay layers and PU matrix. Also, surface morphology of the nanocomposites was analyzed by atomic force microscopy. The results showed that by increasing the ultrasonication time up to 60 min, the size of clay agglomerates decreased and the interlayer spacing of clay platelets increased. To evaluate the effect of ultrasonication duration on transport properties of the PU/OMMT composites, diffusion coefficient and permeability were determined through water uptake test. Electrochemical impedance spectroscopy was carried out to analyze the barrier properties and to evaluate the corrosion performance of these composite coatings on carbon steel panels. It was found that by increasing sonication time, the barrier property of nanocomposites against diffusion of water molecules improved, which is due to further separation of clay platelets, enhancement of the traveling pathways for water molecules and improvement of interactions between the two components. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012