Editorial

3 pages, 180 KiB

Open AccessEditorial

Special Issue: “Advances in Organic Coatings 2018”

by Flavio Deflorian

Coatings 2020, 10(6), 555; https://doi.org/10.3390/coatings10060555 - 10 Jun 2020

Cited by 4 | Viewed by 2135

Organic coatings have shown an impressive evolution in recent years, both scientifically and technologically. Nanotechnology and surface science allows the development of multifunctional materials combining different properties, such as corrosion protective actions, aesthetical functions, hydrophobic properties, and self-healing ability. In addition, recent advances [...] Read more.

Organic coatings have shown an impressive evolution in recent years, both scientifically and technologically. Nanotechnology and surface science allows the development of multifunctional materials combining different properties, such as corrosion protective actions, aesthetical functions, hydrophobic properties, and self-healing ability. In addition, recent advances in experimental techniques and the attention to environmental issues are pushing to develop new systems, joining advanced performance with high sustainability. The aim of this Special Issue is to provide an update on the most advanced research in this area, showing the innovation trends and promoting further research for better properties of new coatings materials. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

Research

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7 pages, 3437 KiB

Open AccessCommunication

Control of Polydimethylsiloxane Surface Hydrophobicity by Plasma Polymerized Hexamethyldisilazane Deposition

by Virginija Jankauskaitė, Pranas Narmontas and Algirdas Lazauskas

Coatings 2019, 9(1), 36; https://doi.org/10.3390/coatings9010036 - 11 Jan 2019

Cited by 29 | Viewed by 4848

Abstract

The properties of a polydimethylsiloxane (PDMS) surface were modified by a one-step deposition of plasma polymerized hexamethyldisilazane (pp-HMDS) by the arc discharge method. Scanning electron microscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy analytical techniques were employed for morphological, structural, and chemical characterization [...] Read more.

The properties of a polydimethylsiloxane (PDMS) surface were modified by a one-step deposition of plasma polymerized hexamethyldisilazane (pp-HMDS) by the arc discharge method. Scanning electron microscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy analytical techniques were employed for morphological, structural, and chemical characterization of the pp-HMDS modified PDMS surface. The changes in PDMS substrate wetting properties were evaluated by means of contact angle measurements. The unmodified PDMS surface is hydrophobic with a contact angle of 122°, while, after pp-HMDS film deposition, a dual-scale roughness PDMS surface with contact angle values as high as 170° was obtained. It was found that the value of the contact angle depends on the plasma processing time. Chemically, the pp-HMDS presents methyl moieties, rendering it hydrophobic and making it an attractive material for creating a superhydrophobic surface, and eliminating the need for complex chemical routes. The presented approach may open up new avenues in design and fabrication of superhydrophobic and flexible organosilicon materials with a self-cleaning function. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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11 pages, 2705 KiB

Open AccessArticle

Properties of Post-Consumer Polyethylene Terephthalate Coating Mechanically Deposited on Mild Steels

by Elisângela Silva, Michele Fedel, Flavio Deflorian, Fernando Cotting and Vanessa Lins

Coatings 2019, 9(1), 28; https://doi.org/10.3390/coatings9010028 - 05 Jan 2019

Cited by 18 | Viewed by 4160

Abstract

An anticorrosive coating of post-consumer polyethylene terephthalate (PET) was applied on carbon steel by using an industrial press. The PET layer showed a good adhesion on the substrate, evaluated by using a pull off test, when compared with the traditional organic coatings. In [...] Read more.

An anticorrosive coating of post-consumer polyethylene terephthalate (PET) was applied on carbon steel by using an industrial press. The PET layer showed a good adhesion on the substrate, evaluated by using a pull off test, when compared with the traditional organic coatings. In addition, scanning electron microscopy (SEM) analysis showed that the PET layer was uniform, homogeneous, and free of cracks or defects. The Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) proved that the PET properties were not affected by the deposition process. The PET organic coating is a promising coating, due to its corrosion resistance evaluated by using salt spray tests, even though the applied thickness of 65 µm was considered thin for a high-performance coating. The electrochemical impedance spectroscopy (EIS) showed that the PET coating has a capacitive effect and its electrochemical behavior was not affected as the exposure time increased, resulting in an impedance modulus value of 10¹⁰ Ω·cm², after 576 h of immersion in an aqueous solution of NaCl 3.0 wt %. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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20 pages, 10307 KiB

Open AccessArticle

Studies on Synthesis and Characterization of Aqueous Hybrid Silicone-Acrylic and Acrylic-Silicone Dispersions and Coatings. Part I

by Janusz Kozakiewicz, Joanna Trzaskowska, Wojciech Domanowski, Anna Kieplin, Izabela Ofat-Kawalec, Jarosław Przybylski, Monika Woźniak, Dariusz Witwicki and Krystyna Sylwestrzak

Coatings 2019, 9(1), 25; https://doi.org/10.3390/coatings9010025 - 03 Jan 2019

Cited by 11 | Viewed by 5006

Abstract

The objective of the study was to investigate the effect of the method of synthesis on properties of aqueous hybrid silicone-acrylic (SIL-ACR) and acrylic-silicone (ACR-SIL) dispersions. SIL-ACR dispersions were obtained by emulsion polymerization of mixtures of acrylic and styrene monomers (butyl acrylate, styrene, [...] Read more.

The objective of the study was to investigate the effect of the method of synthesis on properties of aqueous hybrid silicone-acrylic (SIL-ACR) and acrylic-silicone (ACR-SIL) dispersions. SIL-ACR dispersions were obtained by emulsion polymerization of mixtures of acrylic and styrene monomers (butyl acrylate, styrene, acrylic acid and methacrylamide) of two different compositions in aqueous dispersions of silicone resins synthesized from mixtures of silicone monomers (octamethylcyclotetrasiloxane, vinyltriethoxysilane and methyltriethoxysilane) of two different compositions. ACR-SIL dispersions were obtained by emulsion polymerization of mixtures of the same silicone monomers in aqueous dispersions of acrylic/styrene copolymers synthesized from the same mixtures of acrylic and styrene monomers, so the compositions of ACR and SIL parts in corresponding ACR-SIL and SIL-ACR hybrid dispersions were the same. Examination of the properties of hybrid dispersions (particle size, particle structure, minimum film forming temperature, T_g of dispersion solids) as well as of corresponding coatings (contact angle, water resistance, water vapour permeability, impact resistance, elasticity) and films (tensile strength, elongation at break, % swell in toluene), revealed that they depended on the method of dispersion synthesis that led to different dispersion particle structures and on composition of ACR and SIL part. Generally, coatings produced from hybrid dispersions showed much better properties than coatings made from starting acrylic/styrene copolymer dispersions. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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15 pages, 5723 KiB

Open AccessArticle

Assessing of New Coatings for Iron Artifacts Conservation by Recurrence Plots Analysis

by Paola Roncagliolo Barrera, Francisco Javier Rodríguez Gómez and Esteban García Ochoa

Coatings 2019, 9(1), 12; https://doi.org/10.3390/coatings9010012 - 26 Dec 2018

Cited by 9 | Viewed by 3514

Abstract

Cast iron has stood for centuries of invention. It is a very versatile and durable material. Coating systems are a low-maintenance protection method. The purpose of this research is to increase the Paraloid coating’s resistance when applied to iron in high humidity atmospheres, [...] Read more.

Cast iron has stood for centuries of invention. It is a very versatile and durable material. Coating systems are a low-maintenance protection method. The purpose of this research is to increase the Paraloid coating’s resistance when applied to iron in high humidity atmospheres, with the addition of caffeine (1,3,7-dimethylxanthine) and nicotine (S)-3-(1-methylpyrrolidin-2-yl) pyridine as corrosion inhibitors; the resistance of protection versus exposure time will be evaluated by using electrochemical noise. A statistical analysis of the electrochemical noise signals was carried out. Recurrence plots were used as a powerful tool in the analysis to complement the data obtained and they predicted the evaluation of coatings behaviors performance versus time. The outcomes show that the addition of inhibitors increases and improves the performance as a temporary protection of Paraloid and that protection in high relative humidity was improved. Recurrence plots and parameter quantification show the variances in the surface corrosion dynamics. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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11 pages, 4721 KiB

Open AccessArticle

Determination of Optimum Concentration of Benzimidazole Improving the Cathodic Disbonding Resistance of Epoxy Coating

by Saghar Nabavian, Reza Naderi and Najmeh Asadi

Coatings 2018, 8(12), 471; https://doi.org/10.3390/coatings8120471 - 19 Dec 2018

Cited by 3 | Viewed by 3130

Abstract

This study is aimed to evaluate the effect of concentrated benzimidazole (BIM) on the cathodic disbonding (CP) of an epoxy coating applied on steel substrate. For this purpose, the polymeric coatings, formulated with different concentrations of BIM (0 wt.%, 0.5 wt.%, 0.75 wt.%, [...] Read more.

This study is aimed to evaluate the effect of concentrated benzimidazole (BIM) on the cathodic disbonding (CP) of an epoxy coating applied on steel substrate. For this purpose, the polymeric coatings, formulated with different concentrations of BIM (0 wt.%, 0.5 wt.%, 0.75 wt.%, and 1 wt.%, were subjected to the CP test at the potential of −1.2 V vs. Ag/AgCl during 24 h immersion in 3.5 wt.% NaCl solutions. The optimum formulation was found through taking advantage of the CP test results, FESEM/EDX, and EIS data. Moreover, a pull-off test was used to measure the wet adhesion strength. For insight into the inhibition function of the organic inhibitor, the behavior of steel in the sodium chloride solutions, with and without BIM, was compared using EIS and surface analysis. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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11 pages, 5033 KiB

Open AccessArticle

Spectroscopic and Structural Analyses of Opuntia Robusta Mucilage and Its Potential as an Edible Coating

by Aurea Bernardino-Nicanor, José Luis Montañez-Soto, Eloy Conde-Barajas, María de la Luz Xochilt Negrete-Rodríguez, Gerardo Teniente-Martínez, Enaim Aída Vargas-León, José Mayolo Simitrio Juárez-Goiz, Gerardo Acosta-García and Leopoldo González-Cruz

Coatings 2018, 8(12), 466; https://doi.org/10.3390/coatings8120466 - 15 Dec 2018

Cited by 14 | Viewed by 4033

Abstract

Mucilage extracted from the parenchymatous and chlorenchymatous tissues of Opuntia robusta were obtained using water or ethanol as the extraction solvent. The changes in the different tissues by using different extraction solvents were evaluated via scanning electron microscopy (SEM) and Fourier transform infrared [...] Read more.

Mucilage extracted from the parenchymatous and chlorenchymatous tissues of Opuntia robusta were obtained using water or ethanol as the extraction solvent. The changes in the different tissues by using different extraction solvents were evaluated via scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) and Raman spectroscopy; in addition, the effect of mucilage coating on the various quality characteristics of tomato (Lycopersicum sculentum) was evaluated. The SEM results showed that the mucilage extracted from the parenchyma had a higher aggregation level that the mucilage extracted from the chlorenchyma. The presence of three characteristic bands of pectic substances in the FT-IR spectra between 1050 and 1120 cm⁻¹ indicated that the mucilage extracted from the parenchymatous tissue had a higher content of pectic compounds than the mucilage extracted from the chlorenchymatous tissue. It was also observed in the Raman spectra that the level of pectic substances in the mucilage extracted from the parenchymatous was higher than that in the mucilage extracted from the chlorenchymatous tissue. The mucilage extracted from the parenchymatous tissue was more effective as an edible coating than the mucilage extracted from the chlorenchymatous tissue. Tomatoes covered with mucilage showed significantly enhanced firmness and reduced weight loss. The uncoated tomatoes showed higher lycopene content than the coated tomatoes on the 21st day. This study showed that the Opuntia robusta tissue and extraction solvent influence mucilage characteristics and that Opuntia robusta mucilage is a promising edible coating. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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14 pages, 5083 KiB

Open AccessArticle

Self-Stratification of Ternary Systems Including a Flame Retardant Liquid Additive

by Agnes Beaugendre, Stephanie Degoutin, Severine Bellayer, Christel Pierlot, Sophie Duquesne, Mathilde Casetta and Maude Jimenez

Coatings 2018, 8(12), 448; https://doi.org/10.3390/coatings8120448 - 06 Dec 2018

Cited by 9 | Viewed by 4121

Abstract

Particular coating compositions based on incompatible polymer blends can produce coatings having complex layered structures after film formation. The most traditional approaches to their structural modification are the introduction of additives (extenders, inorganic pigments, surface active agents, etc.). As minor additives, some are [...] Read more.

Particular coating compositions based on incompatible polymer blends can produce coatings having complex layered structures after film formation. The most traditional approaches to their structural modification are the introduction of additives (extenders, inorganic pigments, surface active agents, etc.). As minor additives, some are capable of substantially accelerating the phase separation process with a moderate or negligible influence on the composition equilibrium of solutions. In contrast, in order to be effective, some have to be introduced in significant amounts, thereby substantially changing the resulting distribution of components through the film. Up to now, most of the liquid additives that have been tested destabilized the solutions while impacting the layering process. In this work, two phosphorus based liquid fillers have been introduced (at 2.5 and 5 wt.%) in a partially incompatible polymer blend based on a silicone resin and a curable epoxy resin to fire retard a polycarbonate matrix. Self-stratification was evidenced by microscopic and chemical analyses, flammability by Limiting Oxygen Index (LOI) and UL-94 tests, fire performances by Mass Loss Calorimetry and thermal stability by using a tubular furnace and ThermoGravimetric Analysis. The ternary compositions including 5 wt.% of additives exhibit the best stratification and excellent adhesion onto polycarbonate. Improvements of the fire resistant properties were observed (+7% for the LOI compared to the virgin matrix) when a 200 µm wet thick coating was applied, due to reduced flame propagation and dripping. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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12 pages, 2249 KiB

Open AccessArticle

Bio-Inspired Fluorine-Free Self-Cleaning Polymer Coatings

by Lionel Wasser, Sara Dalle Vacche, Feyza Karasu, Luca Müller, Micaela Castellino, Alessandra Vitale, Roberta Bongiovanni and Yves Leterrier

Coatings 2018, 8(12), 436; https://doi.org/10.3390/coatings8120436 - 28 Nov 2018

Cited by 7 | Viewed by 3632

Abstract

Bio-inspired fluorine-free and self-cleaning polymer coatings were developed using a combination of self-assembly and UV-printing processes. Nasturtium and lotus leaves were selected as natural template surfaces. A UV-curable acrylate oligomer and three acrylated siloxane comonomers with different molecular weights were used. The spontaneous [...] Read more.

Bio-inspired fluorine-free and self-cleaning polymer coatings were developed using a combination of self-assembly and UV-printing processes. Nasturtium and lotus leaves were selected as natural template surfaces. A UV-curable acrylate oligomer and three acrylated siloxane comonomers with different molecular weights were used. The spontaneous migration of the comonomers towards the polymer–air interface was found to be faster for comonomers with higher molecular weight, and enabled to create hydrophobic surfaces with a water contact angle (WCA) of 105°. The replication fidelity was limited for the nasturtium surface, due to a lack of replication of the sub-micron features. It was accurate for the lotus leaf surface whose hierarchical texture, comprising micropapillae and sub-micron crystalloids, was well reproduced in the acrylate/comonomer material. The WCA of synthetic replica of lotus increased from 144° to 152° with increasing creep time under pressure to 5 min prior to polymerization. In spite of a water sliding angle above 10°, the synthetic lotus surface was self-cleaning with water droplets when contaminated with hydrophobic pepper particles, provided that the droplets had some kinetic energy. Full article

(This article belongs to the Special Issue Advances in Organic and Polymeric Coatings )

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