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Article
Publication date: 22 May 2009

A.K. Khan, B.C. Ray, J. Maiti and S.K. Dolui

The purpose of this paper is to study the effect of monomer composition in core‐shell latex prepared from co‐polymer of styrene‐butylacrylate (BA)‐methyl methacrylate…

Abstract

Purpose

The purpose of this paper is to study the effect of monomer composition in core‐shell latex prepared from co‐polymer of styrene‐butylacrylate (BA)‐methyl methacrylate (MMA) and their paint properties.

Design/methodology/approach

The core‐shell latex was prepared by a stepwise semi‐batch emulsion polymerisation. A set of dispersion was made with the different core‐shell compositions. The core phase consists of a copolymer of styrene‐BA‐acrylic acid (AA) and the shell phase consists of a copolymer of MMA‐AA. The properties of latex were determined by solid content, viscosity, pH and particle size. Subsequently, emulsion paint (PVC‐37 per cent and NVM‐53 per cent) was prepared using core‐shell latex. The paint properties were determined by block resistance, gloss, elongation at break, etc. The particle morphology was characterised with transmission electron microscope (TEM).

Findings

Core‐shell structure of latex was confirmed by TEM. The performance of core‐shell latex has been optimised and the best combination achieved with 25‐40 per cent of hard phase in core‐shell latex.

Research limitations/implications

Although the core‐shell structured latex was prepared from co‐polymer of styrene‐BA‐MMA monomer, the system could be extended with other monomers depending on the end use of surface coating.

Practical implications

The paint industry may use this method to improve paint properties.

Originality/value

The paper shows that, by use of core‐shell latex, it is possible to achieve high‐block resistance, hardness, elasticity and gloss.

Details

Pigment & Resin Technology, vol. 38 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 2 November 2012

Q. Song, P. Yan, H. Wang, X. Zhu and Y. Xu

The purpose of this paper is to prepare a kind of novel multi‐layer core‐shell latex, and to evaluate the effect of the preparation methodology.

Abstract

Purpose

The purpose of this paper is to prepare a kind of novel multi‐layer core‐shell latex, and to evaluate the effect of the preparation methodology.

Design/methodology/approach

Core‐shell poly(siloxane)/polystyrene/polymethyl methacrylate (PSi/PSt/PMMA) latex particles were prepared by seeded‐emulsion polymerisation with three stages. The core of cured PSi was prepared with octamethyl cyclotetrasiloxane (D4) and tetraethoxysilane (TEOS) by co‐condensation. Using vinyltriethoxysilane (VTEOS) as coupling agent, functional PSi particles with vinyl groups on surfaces were prepared by hydrolysis and condensation of VTEOS in core formation stage. Then, the functional PSi particles were used as seeds to copolymerise with styrene and methyl methacrylate sequentially in shell stage I and stage II to form PSi/PSt/PMMA latex particles.

Findings

FTIR, TEM, DSC and XPS showed that the PSi/PSt/PMMA latex particles had multi‐layer core‐shell structure with cured PSi as core, PSt as shell I and PMMA as shell II.

Research limitations/implications

In the present work, PSi/PSt/PMMA latex particles having multi‐layer core‐shell structure with cured PSi as core, PSt as shell I and PMMA as shell II were prepared. This methodology can be employed to prepare new functional materials for various applications.

Practical implications

Multi‐layer core‐shell particles offer a new area of material science that has wide applications in coatings or modified polymer materials production.

Originality/value

The method developed in the study reported in this paper provides a new strategy to develop new types of core‐shell materials with multi‐layer structure.

Details

Pigment & Resin Technology, vol. 41 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 31 December 2015

Tereza Hájková and Andrea Kalendova

– This paper aims to synthesise anticorrosion pigments containing molybdenum for paints intended for corrosion protection of metals.

Abstract

Purpose

This paper aims to synthesise anticorrosion pigments containing molybdenum for paints intended for corrosion protection of metals.

Design/methodology/approach

The anticorrosion pigments were prepared by high-temperature solid-state synthesis from the appropriate oxides, carbonates and calcium metasilicate. Stoichiometric molybdates and core-shell molybdates with a non-isometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesised. The pigments were examined by X-ray diffraction analysis and scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration of 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications.

Findings

The molybdate structure of each pigment prepared was elucidated. The core-shell molybdates exhibit a non-isometric particle shape. The pigments prepared were found to impart a very good anticorrosion efficiency to the paints. A high anticorrosion efficiency was found with the pigments Fe2(MoO4)3 and Fe2(MoO4)3/CaSiO3 and with Mg and Zn molybdates.

Practical implications

The pigments can be used for the formulation of paints intended for the corrosion protection of metals. The pigments also improve the paints’ physical properties.

Originality/value

The use of the pigments in anticorrosion paints for the protection of metals is new. The benefits include the use and the procedure of synthesis of the anticorrosion pigments which are free from heavy metals and are acceptable from the aspect of environmental protection. Moreover, the core-shell molybdates, whose high efficiency is comparable to that of the stoichiometric molybdates, have lower molybdenum contents.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 7 September 2015

Andrea Kalendova and Tereza Hájková

– This paper aims to synthesize anticorrosion pigments containing tungsten for paints intended for corrosion protection of metals.

Abstract

Purpose

This paper aims to synthesize anticorrosion pigments containing tungsten for paints intended for corrosion protection of metals.

Design/methodology/approach

The anticorrosion pigments were prepared by high-temperature, solid-state synthesis from the respective oxides, carbonates and calcium metasilicate. Stoichiometric tungstates and core-shell tungstates with a nonisometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesized. The pigments were examined by X-ray diffraction analysis and by scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration (PVC) = 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications.

Findings

The tungstate structure of each pigment was elucidated. The core-shell tungstates exhibit a nonisometric particle shape. The pigments prepared were found to impart a very good anticorrosion efficiency to the paints. A high efficiency was demonstrated for the stoichiometric tungstates containing Fe and Zn and for core-shell tungstates containing Mg and Zn.

Practical implications

The pigments can be used with advantage for the formulation of paints intended for corrosion protection of metals. The pigments also improve the paints’ physical properties.

Originality/value

The use of the pigments in anticorrosion paints for the protection of metals is new. The benefits include the use and the procedure of synthesis of anticorrosion pigments which are free from heavy metals and are acceptable from the environmental protection point of view. Moreover, the core-shell tungstates, whose high efficiency is comparable to that of the stoichiometric tungstates, have lower tungsten content.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 8 May 2018

Nivin M. Ahmed, Mostafa G. Mohamed and Walaa M. Abd El-Gawad

New types of phosphate pigments which are appropriate alternatives for hazardous chromate pigments have been prepared and evaluated. These new pigments were prepared via a…

Abstract

Purpose

New types of phosphate pigments which are appropriate alternatives for hazardous chromate pigments have been prepared and evaluated. These new pigments were prepared via a new technique named core-shell. The core-shell materials consist of at least two separate phases with different chemical compositions. Recently, these materials have become more significant because they have the advantage of gathering the properties of both cores and shells that help to overcome the defects that they might possess individually. The purpose of this research is to develop a modified silica fume-phosphate core-shell pigment that contains 80-90 per cent of waste material (silica fume) and at the same time can offer promoted mechanical and anticorrosive properties than silica fume and they can also be compared with phosphates. The pigments have shells of Zn, Mn, Zn.Mn phosphates comprising about 10-20 per cent.

Design/methodology/approach

The prepared core-shell pigments have been characterized using several methods, which have then been integrated in alkyd paint formulations. The physical and mechanical properties of dry films and their corrosion prevention using accelerated laboratory test in 3.5 per cent NaCl for 28 days are estimated.

Findings

This study showed that the performance of these new pigments is highly efficient in corrosion protection, and it can be a suitable alternative to phosphate pigments despite containing phosphates which does not exceed 20 per cent of the composition.

Practical implications

Waste materials were reused in paints and only simple modification was used; their effectiveness was high and can be compared with well-known pigments.

Originality/value

Silica-phosphate core-shell pigments are environmentally friendly pigments that can replace other hazardous pigments (e.g. chromates and phosphates) with almost the same quality in their performance.

Details

Pigment & Resin Technology, vol. 47 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 25 May 2022

Nivin M. Ahmed, Mostafa G. Mohamed and Walaa M. Abd El-Gawad

Long time ago, multistructured materials showed great interest being considered as the bridge between bulk and atomic materials. Core-shell particles are kind of composite…

Abstract

Purpose

Long time ago, multistructured materials showed great interest being considered as the bridge between bulk and atomic materials. Core-shell particles are kind of composite materials that refer to multilayered structures with a core totally surrounded by shell(s) (onion-like structure). These new structures can offer an advantage of applying new adjustable parameters like shape, stoichiometry and chemical ordering, in addition to the opportunity of tailoring more complexed structures for different applications. Recently it was found that these structures can be tuned and taken for more advanced path with novel structures formed of core surrounded by multishells. The purpose of this study is to study the effect of the new anticorrosive pigments with its mutual shells and how each shell affects the performance of the pigment in protecting the metal and which shell will be more relevant in its effect.

Design/methodology/approach

The prepared pigments were characterized using X-ray fluorescence, X-ray diffraction, TEM and SEM/EDX to prove their core-shell structure, and then they were integrated in coating formulations to evaluate their anticorrosive activity using immersion test and electrochemical impedance spectroscopy (EIS).

Findings

The results showed that the prepared core-shell pigments possess a lot of unique characteristics and can offer improved anticorrosive performance in the generated coatings.

Originality/value

Core-mutual shells structured pigments were prepared for improving the corrosion resistivity of the organic coatings as a new trend in anticorrosive pigments.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 27 July 2018

Nivin M. Ahmed, Mostafa G. Mohamed, Reham H. Tammam and Mohamed R. Mabrouk

This study aims to apply novel anticorrosive pigments containing silica fume-phosphates (Si-Ph), which were prepared using core-shell technique by covering 80-90 per cent…

Abstract

Purpose

This study aims to apply novel anticorrosive pigments containing silica fume-phosphates (Si-Ph), which were prepared using core-shell technique by covering 80-90 per cent silica fume (core) with 10-20 per cent phosphates (shell) previously, to play dual functions simultaneously as anticorrosive pigments in coating formulations and as an anticorrosive admixture in concrete even if it is not present in the concrete itself. Two comparisons were held out to show the results of coatings on rebars containing core-shell pigments in concrete, and concrete admixtured with silica fume can perform a dual function as anticorrosive pigment and concrete admixture. The evaluation of corrosion protection efficiency of coatings containing core-shell pigments and those containing phosphates was performed.

Design/methodology/approach

Simple chemical techniques were used to prepare core-shell pigments, and their characterization was carried out in a previous work. These pigments were incorporated in solvent-based paint formulations based on epoxy resin. Different electrochemical techniques such as open-circuit potential and electrochemical impedance spectroscopy were used to evaluate the anticorrosive efficiency of the new pigments.

Findings

The electrochemical measurements showed that concrete containing coated rebars with core-shell pigments exhibited almost similar results to that of concrete admixtured with silica fume. Also, the anticorrosive performance of coatings containing Si-Ph pigments offered protection efficiency almost similar to that of phosphates, proving that these new pigments can perform both roles as anticorrosive pigment and concrete admixture.

Originality/value

Although the new Si-Ph pigments contain more than 80 per cent waste material, its performance can be compared to original phosphate pigments in the reinforced concrete.

Details

Pigment & Resin Technology, vol. 47 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 7 September 2015

Nivin M Ahmed, Walaa M. Abd El-Gawad, Elham A. Youssef and Eglal R. Souaya

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original…

Abstract

Purpose

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original ferrites which were also prepared. Core-shell structured particles are recently gaining lots of importance due to their exciting applications in different fields; these particles are constructed from cores and shells of different chemical compositions which show ultimately distinctive properties of varied materials different from their counterparts. The new core-shell pigment is based on shell of different ferrites that comprises only 10-20 per cent of the whole pigment on kaolin (cores) which is a cheap and abundant ore that comprises 80-90 per cent of the prepared pigment. The new pigments do not only comprise two different components, but they also contain pigment and extender in the same compound; their loadings in the paint formulations ranges from 50 and 75 per cent of the whole pigment. The work showed that these eco-friendly and cheap core-shell pigments are comparable in their efficiency to that of ferrites in protecting steel substrates.

Design/methodology/approach

The different ferrites and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDAX) and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods (ASTM). After evaluation, the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were determined.

Findings

The results of this work revealed that ferrite/kaolin core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel, and at the same time, they verified good physico-mechanical properties.

Practical implications

Treated kaolin can be applied in many industries beside pigment manufacture and paint formulations; it can be applied as reinforcing filler in rubber, plastics and ceramic composites. Also, it is applied in paper filling, paper coatings and electrical insulation.

Originality/value

Ferrite and ferrite/kaolin are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints, for example paper, rubber and plastics composites.

Details

Pigment & Resin Technology, vol. 44 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 10 July 2007

A. Kalendová and D. Veselý

To synthesise anticorrosion pigments of a lamellar and core‐shell type based on Zn, Ca and Mg ferrites for metal protecting paints.

1495

Abstract

Purpose

To synthesise anticorrosion pigments of a lamellar and core‐shell type based on Zn, Ca and Mg ferrites for metal protecting paints.

Design/methodology/approach

The anticorrosion pigments were synthesised from oxides or carbonates at high temperature. The pigments synthesised had particles with a pronounced lamellar‐tubular shape consisting of MgFe2O4; Mg0.8Zn0.2Fe2O4; Mg0.6Zn0.4Fe2O4; Mg0.4Zn0.6Fe2O4; Mg0.2Zn0.8Fe2O4; ZnFe2O4; Ca0.2Zn0.8Fe2O4; and CaFe2O4. The other type of synthesised ferrite pigments were core‐shell anticorrosion pigments where a layer corresponding to the compositions including MgFe2O4/KAl3Si3O11; Mg0.8Zn0.2Fe2O4/KAl3Si3O11; Mg0.6Zn0.4Fe2O4/KAl3Si3O11; Mg0.4Zn0.6Fe2O4/KAl3Si3O11; Mg0.2Zn0.8Fe2O4/KAl3Si3O11; ZnFe2O4/KAl3Si3O11; Ca0.2Zn0.8Fe2O4/KAl3Si3O11; and CaFe2O4/KAl3Si3O11 was applied onto the core – white mica – by a chemical reaction. The pigments prepared were characterised by means of X‐ray diffraction analysis, particle size distribution measurement, and scanning electron microscopy. The anticorrosion pigments synthesised were used to formulate alkyd paints that were tested in corrosion atmospheres.

Findings

Lamellar particles were detected in the pigments prepared, whereas quality coverage of the core was identified in the core‐shell ferrites. Good anticorrosion efficiency was detected in all of the pigments synthesised.

Practical implications

The pigments synthesised can be conveniently utilised in paints to protect metal bases from corrosion.

Originality/value

The method of using the ferrites synthesised as metal protecting anticorrosion paints is new. Of great benefit are the application and the method of synthesising the anticorrosion pigments that do not contain any heavy metals and are environmentally friendly.

Details

Pigment & Resin Technology, vol. 36 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 15 October 2021

Yanqiu Xia, Chuan Chen, Xin Feng and Zhengfeng Cao

The purpose of this paper is to synthesize a kind of core-shell Ag@polyaniline (Ag@PAN) as a lubricant additive to improve the friction reduction and anti-wear abilities…

108

Abstract

Purpose

The purpose of this paper is to synthesize a kind of core-shell Ag@polyaniline (Ag@PAN) as a lubricant additive to improve the friction reduction and anti-wear abilities of lithium-based complex grease.

Design/methodology/approach

The core-shell Ag@PAN was prepared by a simple method and was introduced into the lithium-based complex grease. The typical properties of Ag@PAN were investigated by scanning electron microscopy (SEM), Fourier transforms infrared spectrometer and thermal gravimetric analyzer. The tribological properties were evaluated under different conditions. After the tribological test, the worn surface was analyzed by SEM and X-ray photoelectron spectroscopy to probe the lubrication mechanisms.

Findings

The prepared Ag@PAN could greatly improve the friction reduction and wear resistance of the friction pair under different conditions. The preferable tribological performances were mainly attributed to the synergism of various lubrication mechanisms including “mending effect,” “rolling effect” and lubricating protective film, and so on.

Originality/value

This study synthesizes a new kind of core-shell Ag@PAN as a lubricant additive, and it possesses preferable friction reduction and anti-wear abilities.

Details

Industrial Lubrication and Tribology, vol. 73 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 266