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Article
Publication date: 1 June 2003

A. Krysztafkiewicz, S. Binkowski, A. Kaczmarek and T. Jesionowski

Two types of amorphous silica namely, the precipitated silica and the pyrogenic silica, were studied. The surfaces of such silica were modified with silane coupling agents…

Abstract

Two types of amorphous silica namely, the precipitated silica and the pyrogenic silica, were studied. The surfaces of such silica were modified with silane coupling agents such as 3‐aminopropyltriethoxysilane, N‐2‐(aminoethyl)‐3‐aminopropyltrimethoxysilane and 3‐ureidopropyltrimethoxysilane. Pigments were obtained by the adsorption of organic dyes, C.I. Reactive Blue 19 and C.I. Acid Green 16, onto the modified silica surface. Structural properties of the modified silica and the pigments obtained were evaluated using scanning electron microscopy, zeta potential analysis and particle size measurement techniques. Moreover, colour of the pigments obtained was evaluated using the CIE L *a*b* colour space system. The specific surface area of the pigment obtained was estimated using the BET method.

Details

Pigment & Resin Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 October 1999

Andrzej Krysztafkiewicz and Slawomir Binkowski

Surface of precipitated silica was modified with 3‐aminopropyltriethoxysilane. The optimum solvent was selected, in which the silane coupling agent was deposited on silica

Abstract

Surface of precipitated silica was modified with 3‐aminopropyltriethoxysilane. The optimum solvent was selected, in which the silane coupling agent was deposited on silica surface. Basic physicochemical properties of the modified silica were estimated. Methods of evaluating silica surface modification extent were presented, taking advantage first of all of its altered hydrophilicity and of differences in condensation extent of surface silanol groups. The modified silica was used as adsorbent capable of trapping water soluble organic amines.

Details

Pigment & Resin Technology, vol. 28 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 9 November 2010

Peter Greenwood

The purpose of this paper is to investigate epoxysilane‐modified silica sols as surfactant‐free inorganic pigments dispersants and as co‐binders/reinforcing agents for…

Abstract

Purpose

The purpose of this paper is to investigate epoxysilane‐modified silica sols as surfactant‐free inorganic pigments dispersants and as co‐binders/reinforcing agents for silicate paints.

Design/methodology/approach

The performance of epoxysilane‐modified silica sols as dispersants for titania was studied using a polyacrylate‐based dispersant as reference. Furthermore, the effect of the addition of silica sols, with or without silane modification, to potassium silicate on binder properties was investigated.

Findings

Significant improvements were obtained in stability towards settling in water‐based titania pigments pastes and in light‐scattering efficiency (as much as 50 per cent) for the optimal size of the silica particle of 5 nm. The number of silane molecules per nm2 silica particle surface must exceed a critical value of at least 1 molecule of epoxysilane per nm2 particle surface. Additionally, improved stability towards gelling, water resistance and film‐forming properties of sol‐silicate binder mixes were achieved for epoxysilane‐modified silica sols.

Research limitations/implications

Only epoxysilane‐modified silica sols were studied in this report. Titania pigment was examined but other important pigments (e.g. iron oxides) remain to be studied. In addition, only sol‐silicate mixes were investigated and not fully formulated silicate paints.

Practical implications

A method that produces stable, high‐performing, surfactant‐free inorganic pigments pastes. Furthermore, stable, high‐ratio, sol‐silicate binders can be obtained with improved water resistance and film properties for use in silicate paints.

Originality/value

The present method provides an easy route to obtain stable surfactant‐free inorganic pigments pastes, as well as makes stable, high‐ratio, sol‐silicate mixes/paints.

Details

Pigment & Resin Technology, vol. 39 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 6 March 2017

Zhiling Ma, Yanjun Qiao, Yajing Wen, Xianling Wang and Jing Wang

This paper aims to evaluate the effect of precursors on the anticorrosion property of silica encapsulated waterborne aluminium pigments (WBAPs).

Abstract

Purpose

This paper aims to evaluate the effect of precursors on the anticorrosion property of silica encapsulated waterborne aluminium pigments (WBAPs).

Design/methodology/approach

The silica encapsulated WBAPs were prepared using different siloxanes as precursors. The anchorage and compactness of silica films on aluminium flakes were characterized by optical microscopy, scanning electron microscopy and N2 adsorption-desorption. The anticorrosion property and glossiness of WBAPs were evaluated.

Findings

The effect of precursors on anticorrosion property of silica encapsulated WBAPs is reflected from the anchorage and the compactness of silica on aluminium flakes surface. Furthermore, the structure of γ-aminopropyl triethoxysilane benefits the anchorage and the compatibility between pigment and acrylic resin. Neither high nor low ratio of tetraethoxysilane/γ-aminopropyl triethoxysilane is favourable to the anchorage and formation of dense silica film on the aluminium flakes surface. To obtain perfect WBAP, the precursors of silica must be carefully selected.

Research limitations/implications

Only four kinds of precursors were used in this work; other precursors could also be studied.

Practical implications

The investigation results provide theoretical basis to obtain excellent WBAPs.

Originality/value

The method to investigate anticorrosion property of WBAPs that is based on the effect of precursors on the performance of silica was novel.

Details

Pigment & Resin Technology, vol. 46 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 18 May 2012

E. Yan, Y. Wang, T. Jing, D. Zhang, C. Wang and J. Zhang

The purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid…

Abstract

Purpose

The purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow nanospheres.

Design/methodology/approach

A simple method coupling sol‐gel process and in situ self‐assembly was used to prepare CS‐silica nanospheres from the solution containing chitosan‐poly (acrylic acid) (CS‐PAA) nanoparticles, tetraethoxyorthosilicate (TEOS) and polyvinylpyrrolidone (PVP). The morphology of CS‐silica hybrid hollow nanospheres was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The chemical structures of CS‐PAA nanoparticles and CS‐silica nanospheres were characterised by FT‐IR spectra.

Findings

The size and morphology of CS‐silica nanospheres was largely dependent on the starting amounts of TEOS, PVP and ammonia. Moreover, the reaction time can also affect the structures of the hybrid nanospheres.

Research limitations/implications

The dispersibility of CS‐silica nanospheres was not good enough and the conglutination was inevitable to some extent.

Practical implications

The coupling of sol‐gel technology and in situ self‐assembly opened a new gateway for preparing other organic/inorganic composite nanoparticles. This kind of material could be used as a slow release agent for biocides in coatings/paints.

Originality/value

The hybrid CS‐silica nanospheres showed obvious hollow structures. The morphology of nanospheres can be efficaciously controlled via adjusting the starting amounts of PVP, TEOS and ammonia, and the stirring time. The obtained CS‐silica hybrid nanospheres will have potential applications in such as drug delivery and controlled release.

Details

Pigment & Resin Technology, vol. 41 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 April 1998

E.A.M. Youssef, Nivin M. Ahmed and M.A. Abd El‐Ghaffar

Silica waste fume is a byproduct produced in the manufacture of ferrosilicon. The sample, which was very fine and rich in silica, was characterized using chemical and…

Abstract

Silica waste fume is a byproduct produced in the manufacture of ferrosilicon. The sample, which was very fine and rich in silica, was characterized using chemical and spectrophotometric measurements (XRD and electron microscope). The silica fume was incorporated in anticorrosive paint formulations based on alkyd resin to replace partially or completely the imported diatomaceous silica. The various paint formulations were evaluated and the physico‐mechanical properties as well as the corrosion protection properties of the painted films have been studied. Promising results were achieved, which showed that silica fume can replace satisfactorily the imported diatomaceous silica from the economical and environmental points of view.

Details

Pigment & Resin Technology, vol. 27 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 June 2004

A. Andrzejewska, A. Krysztafkiewicz and T. Jesionowski

Studies were carried out on the modification of silica with 3‐aminopropyltriethoxysilane in various solvents. The modified silica obtained was subjected to comprehensive…

Abstract

Studies were carried out on the modification of silica with 3‐aminopropyltriethoxysilane in various solvents. The modified silica obtained was subjected to comprehensive evaluations of physicochemical properties, including the bulk density and the capacities to absorb water, dibutyl phthalate and paraffin oil. Particle size, particle size distribution, uniformity of the particles, tendency to form agglomerates, as well as particle surface morphology, were also examined using SEM and dynamic light scattering (DLS) techniques. The properties of the modified silica obtained were compared to evaluate the effects of the solvents used during the surface modification of the silica.

Details

Pigment & Resin Technology, vol. 33 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 25 May 2010

Peter Greenwood, Börje S. Gevert, Jan‐Erik Otterstedt, Gunnar Niklasson and William Vargas

The purpose of this paper is to develop methods to produce white composite pigments consisting of a silica core with a titania shell.

Abstract

Purpose

The purpose of this paper is to develop methods to produce white composite pigments consisting of a silica core with a titania shell.

Design/methodology/approach

Silica cores were coated with titanium dioxide (TiO2) via forced hydrolysis of a solution prepared from titanium tetrachloride (TiCl4). The morphology, surface charge and particle size of obtained composite particles were studied.

Findings

Dispersions of well‐dispersed composite particles, having silica cores of uniform size in the range from 300 to 500 nm with a homogeneous titania coating are obtained. The coating thickness corresponded to 150‐400 per cent by weight of titania based on the core. Modification of the silica core by incorporation of 1.5 aluminosilicate sites per square nanometre of core surface proves to be favourable in achieving a homogeneous coating on the silica core. Deposition of such titania coating is also favoured by agitating the dispersion well, keeping electrolyte content low, maintaining pH at 2.0 and the temperature at 75°C during the coating process.

Research limitations/implications

Only TiCl4 is used as titania source. In addition, only silica cores obtained by Stöber synthesis are used while commercially available silica solutions made from sodium silicate are not used.

Practical implications

The process offers a method of producing a white composite pigment with a narrow particle size distribution in order to maximise light scattering as well as using a core with lower density than the shell. This kind of particle would be of interest for coating applications and white inorganic inks.

Originality/value

The developed method provides a straightforward process to produce well‐defined composite particles.

Details

Pigment & Resin Technology, vol. 39 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 16 June 2021

Zrinka Buhin Šturlić, Mirela Leskovac, Krunoslav Žižek and Sanja Lučić Blagojević

The purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition…

Abstract

Purpose

The purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition and surface modification on the polyacrylate properties.

Design/methodology/approach

Improving the properties of the composite can be achieved by optimizing the compatibility between the phases of the composite system with improving the interactions at the matrix/filler interface. Therefore, the silica surface was modified with nonionic emulsifier octylphenol ethoxylate, cationic initiator 2,2'-azobis-(amidinopropane dihydrochloride) and 3-methacryloxypropyltrimethoxysilane and polyacrylate/silica nanocomposites were prepared via in situ emulsion polymerization. Particle size distribution, rheological properties of the emulsions and morphology, thermal properties and mechanical properties of the film prepared from the emulsions were investigated.

Findings

Polyacrylate/silica systems with unmodified silica, silica modified with nonionic emulsifier and cationic initiator have micrometer, while pure PA matrix and systems with silica modified with silane have nanometer particle sizes. Addition and surface modification of the filler increased emulsion viscosity. Agglomeration of silica particles in composites was reduced with silica surface modification. Silica filler improves thermal stability and tensile strength of polyacrylate.

Originality/value

This paper provides broad spectrum of information depending on filler surface modification and latex preparation via in situ emulsion polymerization and properties with high amount of filler and monomer/water ratio with the aim that prepared latex is suitable for film formation and final application.

Details

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

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Article
Publication date: 3 August 2020

Salwa H. El-Sabbagh, Nivin M. Ahmed, Doaa Samir Mahmoud and Wael S. Mohamed

The purpose of this paper is to evaluate the efficiency of commercial silica, silica fume-waste (SF) and modified silica fume-waste (mSF) as reinforcing filler in…

Abstract

Purpose

The purpose of this paper is to evaluate the efficiency of commercial silica, silica fume-waste (SF) and modified silica fume-waste (mSF) as reinforcing filler in acrylonitrile-butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) through the mixing process of rubber. The composites were prepared using different loadings of silica fume and commercial silica in EPDM and NBR composites. Structural characterization of silica and SF was done using X-ray fluorescence and scanning electron microscopy (SEM). The surface of silica fume waste was modified using poly methyl methacrylate/butyl acrylate through emulsion polymerization to increase the interaction between silica and rubber, then consequently better dispersion in rubber matrix was obtained. The mSF waste was characterized using FT-IR spectra and transmission electron microscopy.

Design/methodology/approach

The investigated rubber mixes and vulcanizates were evaluated by measuring the curing characteristics, mechanical testing, thermogravimetric analysis and morphological studies (SEM). The mechanical properties of composites including tensile strength, elongation at break and modulus were estimated and analyzed.

Findings

The results revealed that the composites (NBR and EPDM) containing mSF as filler exhibited better rheological and mechanical properties compared to unmodified silica waste and commercial silica. The SEM analysis indicated that the mSF was homogeneously dispersed through the surface of NBR and EPDM composites. Also, results showed that (NBR and EPDM) composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of mSF; they also showed an increase in the thermal stability. This means that the treatment of surface SF can improve its dispersion in rubber.

Research limitations/implications

Silica cannot be applied in rubber matrix without surface modification because of their incompatibility; their dispersion is not good without surface modification.

Practical implications

The modified silica surface is considered as effective reinforcing filler which can replace other fillers because of its lower surface energy and enhanced intercalating behavior in rubber.

Social implications

This study is just a start in establishing rubber projects with wide applications in the industry and providing a cheap local product while preserving the quality and that is the use of factory waste, which helps in protecting the environment from pollution.

Originality/value

mSF is cheap with relatively high purity, which make rubber/mSF composites appear as new grade of material that can be used in different media rather than rubber.

Details

Pigment & Resin Technology, vol. 50 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

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