Ashraf M. EL-Saeed

Tailored design of Cu2O nanocube/silicone composites as efficient foul-release coatings

Environmental concerns about the use of toxic antifoulants have increased the demand to develop novel, environmentally-friendly antifouling materials. Silicone coatings are currently the most effective non-toxic alternatives. This study focused on developing a model for silicone foul-release nanocomposites that were successfully designed, fabricated, characterized, and tailored toward foul-release (FR) coatings. A series of elastomeric polydimethyl-siloxane (PDMS)/Cu2O nanocube composites with different nanofiller concentrations was successfully synthesized, for the first time, as FR coatings via solution casting technique. Emphasis was given to the study of the physicomechanical and surface properties, as well as the easy release efficiency of the elastomer PDMS enriched with Cu2O nanocubes. The bulk properties of the nanocomposites appeared unchanged after adding low amounts of nanofillers. By contrast, surface properties such as contact angle and surface free energy were improved, and the settlement resistance and easy release behavior of the nanocomposites were enhanced. The surfaces were further proven to have reversible tunable properties and are thus renewable in water. The antifouling property of the nanocomposites was investigated by laboratory assays involving microfoulants such as Gram-positive and Gram-negative bacteria, as well as yeast organisms, for 30 days. Exposure tests showed that lower surface energy and elastic modulus of coatings resulted in less adherence of marine microfouling. The most profound effect recorded was the reduction of fouling settlement with nanofiller loadings of up to 0.1% Cu2O nanocubes. Thus, the good foul release and long-term durability confirmed that the present strategy was an attractive nontoxic and environmentally-friendly alternative to the existing antifouling systems.

Sunflower oil-based hyperbranched alkyd/spherical ZnO nanocomposite modeling for mechanical and anticorrosive applications

Approaches for designing advanced nanomaterials with hyperbranched architectures and lack of volatile organic content (VOC) have attracted considerable attention. In this study, eco-friendly hyperbranched alkyd resins for mechanical and anticorrosive coatings with high solid content were successfully synthesized based on sunflower oil (SFO) via a polyesterification approach. These resins are characterized by energy-efficient polymer synthesis, lack of gelation properties, high functionality, and low viscosity. A chemical precipitation process was used to fabricate zinc oxide (ZnO) spherical nanostructures with controlled diameters and morphologies. A series of conformal, novel, low-cost SFO-based hyperbranched alkyd/spherical ZnO nanocomposites were fabricated through an ex situ method. Various nanofiller concentrations were distributed to establish synergetic effects on the micro–nano binary scale performance of the materials. The features of the nanocomposites, including the molecular weight, acid and hydroxyl values of the prepared alkyd resins, were concomitantly assessed through various standard tests. The nanocomposites were also subjected to various tests to determine their surface adhesion and mechanical properties, such as impact, T-bending, crosscut, and abrasion resistance tests. Furthermore, the physico-mechanical properties, anticorrosive behavior, thermal stabilities and cellular cytotoxicities of the fabricated materials were assessed. The anticorrosive features of the nanocomposites were investigated through salt spray tests in 5 wt% NaCl. The results indicate that well-dispersed ZnO nanospheres (0.5%) in the interior of the hyperbranched alkyd matrix improve the durability and anticorrosive attributes of the composites; thus, they exhibit potential applications in eco-friendly surface coatings.

Data on photo-nanofiller models for self-cleaning foul release coating of ship hulls.

The data presented in this article are related to the research article entitled “Smart photo-induced silicone/TiO2 nanocomposites with dominant [110] exposed surfaces for self-cleaning foul-release coatings of ship hulls” (Selimet al., 2016) [1]. This article reports on successfully designing and controlling TiO2 spherical single crystal photo-nanofillers and indicating evidence of fouling resistance after stimulation through UV radiation exposure. These data also reveal that the influence of well-dispersed spherical TiO2 nanoparticles (NPs) into the polymer matrix surface features on the prepared fouling release (FR) coating. Single crystal TiO2 nanospheres have played a large role in the scenario of photocatalysis due to its cost effectiveness, inert nature and photo stability. The model output and the surface and mechanical behavior data of the fabricated UV-irradiated silicone-based FR nanocoatings are made publicly available through analyzing nanocomposite topology, superhydrophilicity and self-cleaning efficiency in order to enable critical analysis of the tailored model. It also investigates the photo-bactericidal effect confirmed through biofilm coverage data disability. The modeled nanocomposites were subjected to comparable studies with other published models so as to understand how different UV-irradiated nano-scale parameters propagate and affect bulk film response.

Preparation and application of crosslinked poly(sodium acrylate)--coated magnetite nanoparticles as corrosion inhibitors for carbon steel alloy.

This work presents a new method to prepare poly(sodium acrylate) magnetite composite nanoparticles. Core/shell type magnetite nanocomposites were synthesized using sodium acrylate as monomer and N,N-methylenebisacrylamide (MBA) as crosslinker. Microemulsion polymerization was used for constructing core/shell structures with magnetite nanoparticles as core and poly(sodium acrylate) as shell. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanocomposite chemical structure. Transmittance electron microscopy (TEM) was used to examine the morphology of the modified poly(sodium acrylate) magnetite composite nanoparticles. These particle will be evaluated for effective anticorrosion behavior as a hydrophobic surface on stainless steel. The composite nanoparticles has been designed by dispersing nanocomposites which act as a corrosion inhibitor. The inhibition effect of AA-Na/magnetite composites on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Polarization measurements indicated that the studied inhibitor acts as mixed type corrosion inhibitor. EIS spectra exhibit one capacitive loop. The different techniques confirmed that the inhibition efficiency reaches 99% at 50 ppm concentration. This study has led to a better understanding of active anticorrosive magnetite nanoparticles with embedded nanocomposites and the factors influencing their anticorrosion performance.

Application of magnetite nano-hybrid epoxy as protective marine coatings for steel

The present work aims to develop a method for preparation of porous iron oxide nanomaterials and to investigate the applicability as smart self-healing protective coatings for steel. In this respect, iron oxide nanoparticles doped with iodine and capped with natural modified rosin surfactant were prepared and applied as self-healing materials to repair the cracks of epoxy coats. The mechanism of self-healing characteristics of porous nanomaterials was elucidated using different analyses. The results suggested the formation of stable thin films on the cracks and holes of epoxy coats. Polarization and electrochemical impedance spectroscopy showed an improvement in the corrosion resistance of the epoxy coating. The presence of nanoparticles was found to be an effective in restricting the penetration of aggressive ions by forming a strong barrier layer at coating metal interface.

Preparation and Application of Nonionic Polypropylene Oxide-graft-Polyethylene Glycol Copolymer Surfactants as Demulsifier for Petroleum Crude Oil Emulsions

This work aims to prepare new water soluble nonionic amphiphilic graft copolymers based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(propylene oxide) (PPO) at ambient temperature and normal atmospheric pressure. In this respect, poly(propylene oxide) were prepared and grafted with different molar ratios of maleic anhydride (MA) in the presence of dibenzoyl peroxide as an radical grafting initiator to produce PPO-MA grafts. The produced grafts were esterfied with different molecular weights of poly(ethylene glycol) momomethyl ether to produce PPO-MA-PEGME nonionic surfactants. The chemical composition and molecular weights of the prepared copolymers were determined from 1HNMR analyses. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 60°C. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations.

Effect of Montmorillonite Nanogel Composite Fillers on the Protection Performance of Epoxy Coatings on Steel Pipelines

Montmorillonite (MMT) clay mineral is widely used as filler for several organic coatings. Its activity is increased by exfoliation via chemical modification to produce nanomaterials. In the present work, the modification of MMT to form nanogel composites is proposed to increase the dispersion of MMT into epoxy matrices used to fill cracks and holes produced by the curing exotherms of epoxy resins. The dispersion of MMT in epoxy improved both the mechanical and anti-corrosion performance of epoxy coatings in aggressive marine environments. In this respect, the MMT surfaces were chemically modified with different types of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) nanogels using a surfactant-free dispersion polymerization technique. The effect of the chemical structure, nanogel content and the interaction with MMT surfaces on the surface morphology, surface charges and dispersion in the epoxy matrix were investigated for use as nano-filler for epoxy coatings. The modified MMT nanogel epoxy composites showed excellent resistance to mechanical damage and salt spray resistance up to 1000 h. The interaction of MMT nanogel composites with the epoxy matrix and good response of AMPS nanogel to sea water improve their ability to act as self-healing materials for epoxy coatings for steel.

Salt-controlled self-healing nanogel composite embedded with epoxy as environmentally friendly organic coating

Smart nanogel capsules are attracting great attention to act as self-healing materials for polymers and epoxy coating and as anticorrosion materials. The present work aimed at incorporating nanogel among silicate layers of sodium montmorillonite (Na-MMT) to increase its dispersibility into an epoxy matrix so as to be used as self-healing nanocomposites. For this purpose, N-isopropyl acrylamide (NIPAm) as a salt-sensitive monomer was selected to prepare smart nanogels to disperse the Na-MMT layers. The chemical structure, surface morphology, particle size distribution, surface charge, and degree of exfoliation of Na-MMT with NIPAm nanogel were investigated. The ability of Na-MMT/NIPAm to modify the mechanical, surface, and self-healing characteristics of epoxy matrix was studied. The corrosion inhibition and self-healing mechanism were discussed in light of salt spray resistance of epoxy nanocomposites to protect steel from corrosive environments.

Preparation and Evaluation of Epoxy Binders Based on Rosin as Organic Coating for Steel

Abstract: In this work, modification of rosin as epoxy organic coating was reported. Epoxy resins were prepared from modified rosin, rosin Diels-Alder adducts, rosin formaldehyde and their ketone. These adducts were reacted with epichlorohydrine in the presence of NaOH as a catalyst to produce epoxy resins. The preparation of the curing agents for the epoxy resins based on rosin poly (amideimide) was investigated. The recent advances in manipulating patterned rosin arrays and patents are reviewed with a focus on the progress of production of epoxy resins based on biopolymer and natural products and their epoxy organic coating applications. Keywords: Rosin, corrosion protection, organic coatings, epoxy resins, coating characteristics. 1. INTRODUCTION Epoxy resins have been widely used in many industrial applications because of their good heat and chemical resistance, superior mechanical and electrical properties and excellent process capabilities [1]. Intensive research efforts have been devoted to develop new epoxy resins through chemical and physical modifications of the classical resins in the last few years [2, 3]. It was also noted that the epoxy resin based paints generally offer very good corrosion protective properties and are widely used for different applications. Rosin is a complex mixture of mainly twenty carbon atom fused rings, mono-carboxylic acids and a small amount of nonacidic components, where the resin acid molecule has double bonds and the carboxylic acid group, which may be possible for a derivative to be used that maintains the carboxylic acid group. Several patents used rosin in epoxy resin formulation as linking agents [4-8]. Modified epoxy resins comprising the reaction product of rosin and a linking molecule reacted with an epoxy resin are disclosed. Aqueous dispersions and coatings comprising these resins are also reported [4, 5]. On the other hand, rosin was modified and used as a solid curing agent in a composition for coating a substrate with a powder coating comprising a solid polyepoxide resin [6]. Rosin as crosslinking agent is essentially free of active hydrogen functional groups. Methods for preparing rosin as crosslinking agents for aminoplast formulation were investigated