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Progress in Organic Coatings 77 (2014) 725– 732

Contents lists available at ScienceDirect

Progress in Organic Coatings

jou rn al hom ep age: www.elsev ier .com/ locate /porgcoat

ovel water based coatings containing some conducting polymersanoparticles (CPNs) as corrosion inhibitors

oha Elhalawanya,∗, Michael A. Mossadb, Magdy K. Zahranc

Polymers and Pigments Department, National Research Center, Cairo, EgyptEagle Chemicals Company, 6th October, EgyptHelwan University, Cairo, Egypt

r t i c l e i n f o

rticle history:eceived 10 March 2013eceived in revised form6 December 2013ccepted 27 December 2013

a b s t r a c t

A new type of anticorrosive water-based paints containing some conducting polymers nanoparticles(CPNs) such as poly anisidine (PAns), poly toluidine (PTol) and their copolymer (CCPNs) have been pre-pared and evaluated. The CPNs and CCPNs have been synthesized via miniemulsion polymerization. Theprepared materials have been characterized by GPC, FTIR, TEM and DSC. The prepared CPNs and CCPNs ofdifferent weight percentages (wt.%) have been incorporated into paint formulations. It has been found that

eywords:nticorrosive water-based paintsonducting polymers nanoparticles

the presence of the prepared CPNs and CCPNs in the paint formulations highly enhanced the resistanceof the formed paint films against washability, weathering and corrosion.

© 2014 Elsevier B.V. All rights reserved.

aint formulations and miniemulsionolymerization

. Introduction

Corrosion is considered as the silent enemy which threatenshe endurance of steel and infrastructures in all countries with-ut exception, leading to plant shutdowns, waste of valuableesources, loss or contamination of products, reduction in effi-iency, costly maintenance, and expensive over design. In addition,t also jeopardizes safety and inhibits technological progress, andhis involves annual losses of billion dollars worldwide. The con-entional anticorrosive coatings which are based on heavy metalsuch as chromium, zinc and copper are toxic to the environment.o there has been a need to find suitable coatings which are envi-onmentally friendly and effective to inhibit corrosion of steels.nvironmentally friendly nature and high effectiveness make con-ucting polymers a suitable replacement of conventional coatingso combat corrosion in different environments. Conducting poly-

ers can interact with the metal substrate and form a passivexide layer to inhibit corrosion process due to their redox proper-ies. Among these polymers is polyaniline which has been widelytudied due to its low cost, ease of process, high conductivity, envi-

onmental stability and redox properties [1,2]. Polymeric coatingsontaining polyaniline, polypyrrole and polythiophene have beensed to protect steel against corrosion [3,4]. Corrosion protection of

∗ Corresponding author. Tel.: +20 2 33371499; fax: +20 2 33370931.E-mail addresses: nohaelhalawany1@yahoo.com, elhalawany1970@hotmail.com

N. Elhalawany).

300-9440/$ – see front matter © 2014 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.porgcoat.2013.12.017

steels using coating containing polypyrrole/clay nanocomposite [5]and alkyd coatings containing polyaniline [6] has been well stud-ied. The formation of coating on active metals is rendered difficultby the general lack of solubility of conducting polymers. Thougha popular route, the electrodeposition of conducting polymersis a difficult process involving a complicated mechanism [7].The mechanism of protection of steels using conducting poly-mers has been well described [8,9]. One of the important factorsis the homogeneous distribution of conducting polymers in thecoating material. In order to obtain the homogeneous dispersionof conducting polymers inside of paint, a substituent is incor-porated to facilitate the solubility of the conducting polymers[10].

The present study reports the synthesis and characterization ofsome CPNs based on polytoluidine, polyanisidine and their copoly-mer (CCPNs) using miniemulsion polymerization technique. Theprepared CPNs and CCPNs dispersed in an aqueous media have beenincorporated into water based paint. The basic properties as wellas anticorrosion studies of the blank paint films and paint filmscontaining the prepared CPNs and CCPNs have been investigatedand evaluated. No literature is available on the synthesis of Polytoluidine, poly anisidine and their copolymer via miniemulsion ortheir use as anticorrosive inhibitors in water based paints. Hencean attempt has been made to synthesize them and to study their

anticorrosion properties. Thus, this paper should pave the way forthe development of new coating technologies based on the intro-duction of polytoluidine, poly anisidine and their copolymer asanticorrosive additives.

7 Organic Coatings 77 (2014) 725– 732

2

2

(aSumaGtSfs(pAAnsahACaiS

2

2

pvfsuatiac

2

pcobo

2(

m(otdoAbb

gas conditions according to the recipe shown in Table 1. The pro-duced latex has been filtered, cooled below 30 ◦C and then kept forfurther use.

26 N. Elhalawany et al. / Progress in

. Experimental

.1. Materials

O-toluidine (99.5%) (Tol) and dodecyl benzene sulfonic acidDBSA) have been supplied from Sigma–Aldrich Company, USA. O-nisidine (99.5%) (Ans) has been supplied from MERCK, Germany.tyrene (St) has been supplied from (ARKEMA CANADA Inc.) andsed as essential monomer. Butyl acrylate monomer (BA), Sodiumetabisulfite (SMBS) and Plurafac LF 901 (nonionic fatty acid

lkoxylate surfactant) have been supplied from BASF Company,ermany. Emulsogen EPA 073 (Sodium alkyl ether sulfate surfac-

ant) has been supplied from Clariant International Ltd., Muttenz,witzerland. Ammonium persulphate (APS, 99%) has been suppliedrom AKKIM Company, Turkey. Calcium carbonate filler has beenupplied from Al-Faltas Company, Cairo, Egypt. Titanium dioxideunder the trade name rutile R-902), has been supplied from Du-ont Company, Wilmington, USA and used as the main pigment.mmonia has been used as pH stabilizers and supplied from CHIMIRT Chemicals Company, Cairo, Egypt. Tylose (under the tradeame Tylose® H 30000 YP2) has been used as thickening agent andupplied from GmbH & Co.KG Company, Kapfenberg, Austria. Tex-nol, WD-EAGLE (AS 40/40) and Tetra potassium pyrophosphateas been supplied from Eastman Chemical Company, Melbourne,ustralia, Eagle Chemicals Company, 6th October, Egypt and Energyhemical Company, China respectively. Anti-foaming agent andntibacterial agent (Acticide HF) have been purchased from Münz-ng Chemie, Germany and Clariant International Ltd., Muttenz,witzerland respectively.

.2. Preparation of the CPs

.2.1. Synthesis of poly toluidine (PTol)Tol and DBSA of ratio (1:1) have been mixed in water and iso-

ropanol (IPA) mixture of ratio (3:1) respectively under continuousigorous stirring using a homogenizer at 10,000 rpm for 5 min toorm the miniemulsion. A 25 ml of (1%) ammonium persulfate (APS)olution has been added dropwisely to the former miniemulsionnder continuous vigorous stirring at 10,000 rpm for further 10 mint room temperature. A color change from white to brownish redhen to dark pink has been observed. At the final stage of polymer-zation, a dark pink stable PTol/DBSA dispersion has been obtaineds shown in Fig. 1. The produced stable dispersion of PTol has beenooled below 25 ◦C and then kept for further use.

.2.2. Synthesis of polyanisidine (PAns)The same procedure as previously mentioned has been made to

repare a stable dark green colloidal dispersion of PAns. A colorhange from white to pale green then to dark green has beenbserved. Finally, a dark green stable PAns/DBSA dispersion haseen obtained as shown in Fig. 2. The produced stable dispersionf PAns has been cooled below 25 ◦C and then kept for further use.

.2.3. Synthesis of the conducting copolymer nanoparticlesCCPNs)

(Tol) and (Ans) monomers of feed composition (1:1) have beenixed in 1% DBSA surfactant dissolved in water and isopropanol

IPA) mixture of ratio (3:1) respectively under continuous vigor-us stirring at 10,000 rpm for 5 min using a homogenizer to formhe miniemulsion. A 25 ml of (1%) APS solution has been addedropwisely to the former miniemulsion under continuous vigor-

us stirring at 10,000 rpm for further 10 min at room temperature.

color change from white to pale brown then to dark brown haseen observed. At the final stage of copolymerization, a brown sta-le P(Tol-co-Ans)/DBSA dispersion has been obtained as shown in

Fig. 1. Stable dark pink PTol/DBSA colloidal dispersion.

Fig. 3. The produced stable dispersion has been cooled below 25 ◦Cand kept for further use.

2.2.4. Synthesis of (St/BA) emulsionSemi-continuous emulsion copolymerization has been carried

out on a semi-pilot scale at Research and development depart-ment, Eagle chemicals company, Egypt, in three Liters stainlesssteel reactor equipped with a reflux condenser, a thermometer,three dropping funnels and a mechanical stirrer. Only 8% of the totalmonomer mixture has been introduced at the beginning of the reac-tion at 65 ◦C and the remaining monomer mixture has been addeddropwisely at 80 ± 2◦ during the remaining time. Redox system ofTetra butyl hydroperoxide and Sodium metabisulfite (SMBS) havebeen added after 30 min from addition of monomers at 65 ◦C. Emul-sion copolymerization has been carried out for 4 h under nitrogen

Fig. 2. Stable dark green PAns/DBSA colloidal dispersion.

N. Elhalawany et al. / Progress in Organ

2

a(nTTDmE

2

po

2

mSMui

TR

Fig. 3. Stable dark brown P(Ans-co-Tol) DBSA colloidal dispersion.

.3. Characterization of the prepared materials

FT-IR analysis of the prepared materials has been carried outt Infra-Red unit, Central service labs, National Research CenterNRC) using FT-IR-6100, Japan. The molecular weight determi-ation has been made using GPC, Agilent 1100 series, Germany.hermal analysis for the prepared materials has been carried out athermal Analysis unit, Central service labs, (NRC) using DiamondSC Perkin Elmer, USA. Samples have been measured using trans-ission electron microscope TEM + DEM Joel-JEM 1230, Japan at

lectron Microscope Lab, Physics Department (NRC).

.4. Paint film testing

Paint film testing has been used to confirm some basic physicalroperties of the coatings after it is applied and dried. The resistancef the paint films to corrosion has been also examined.

.4.1. Physical propertiesThe gloss, whiteness, and opacity of paint films have been

easured in accordance with ASTM D 523-89 (1999) usingpectromatch Gloss 45/0◦ from Sheen-Instruments Company.

andrel-Bending tester from BYK-Gardner Company has been

sed to measure a range of elongation of a dry paint filmn accordance with ASTM D 522-93a (2001). The hardness of

able 1aw materials of emulsion copolymerization.

Raw materials Wt. in grams

Initial reactor chargeDe-ionized water 600Plurafac LF901 10Emulsogen EPA 073 4

Monomer mixtureWater 350Plurafac LF901 35Emulsogen EPA 073 32Styrene 620Butylacrylate 530

Initiator mixtureTetra butyl hydroperoxide 0.7Sodium metabisulphite 0.5

ic Coatings 77 (2014) 725– 732 727

paint has been evaluated in accordance with ASTM D 4366-95with Pendulum Hardness Rocker tester; model 707 KONIG fromSheen-Instruments. The adhesion power of paint film to the basesubstrates has been tested in accordance with ASTM D 3359-97using the cross-cut test instrument-Sheen Company. CHOC Vari-able – Impact Tester from – Braive Instruments has been used tomeasure resistance of organic coatings to the effects of rapid defor-mation (Impact) in accordance with ASTM D 2794 – 93 (1999).

2.4.2. Weathering resistance testWeathering-resistance and light stability test has been mea-

sured in accordance with ISO 4892-3 by Accelerated WeatheringTester, Model QUV/Spray with solar eye Irradiance control from Q-Lab Corporation, USA. To simulate outdoor weathering, the QUVtester exposes materials to alternating cycles of UV light and mois-ture at controlled elevated temperatures. It simulates the effects ofsunlight using special fluorescent UV lamps (Type: UVA 340) whichgive the best simulation of sunlight in the critical short wavelengthregion from 365 nm down to the solar cut-off of 295 nm. It simulatesdew and rain with condensing humidity and/or water spray.

2.5. Corrosion studies

The corrosion study has been carried out with hand-madeequipment developed in Research and Development Department,Eagle Chemical Company, Egypt. Air bubbles have been allowedto go through an aggressive solution medium which consists ofan aqueous solution of NaCl (3.5 wt.%). The painted steel panelshave been scratched with a sharp blade to obtain X-cut throughthe coating under test. The panels have been immersed in the abovesolution medium (artificial seawater) for 28 days. At this time, thesepanels have been washed with distilled water and dried.

3. Results and discussion

The prepared (CPNs) and their copolymer (CCPNs) should bedissolved in water/alcohol mixture to be compatible and suitablefor use in waterborne systems. Solubility of conducting polymers(CPs) has gained special importance, both scientifically and com-mercially. Cao et al. [11] in 1992 used functionalized protonicacids to convert polyaniline (PANI) into the metallic form and,simultaneously, render the resulting PANI complex soluble in com-mon organic solvents. The functionalized counter ion acts like a‘surfactant’ in that the charged head group is ionically bound tothe oppositely charged protonated PANI chain, and the ‘tail’ ischosen to be compatible with nonpolar or weakly polar organicliquids [12–14]. This approach is also known as ‘counter-ion-induced processability’. In this manuscript, the polymerization ofaniline derivatives (toluidine and anisidine) and their copolymerin presence of protonic acid such as DBSA has been described inSchemes 1 and 2, respectively.

The molecular weight (M.wt) determination of the prepared(CPNs) and their copolymer (CCPNs) has been done using GPC tech-nique. It has been found that the prepared PTol, Pans and theircopolymer (CCPNs) have low molecular weight of (7307, 6878 and8195) and a polydispersity index (Dw/Dn) of (1.9, 1.3 and 1.5),respectively. Where Dw is the weight average particle diameter andDn is the number average particle diameter.

3.1. Characterization of the prepared materials

3.1.1. FT-IR spectra of the prepared CPs

Fig. 4 shows the FT-IR of the prepared CPNs and their CCPNs.

It shows the main peaks characteristic of PTol and PAns as thosedescribed in literature for poly aniline [15,16]. The peaks charac-teristic of PTol and PAns can be assigned as follows: C C stretching

728 N. Elhalawany et al. / Progress in Organic Coatings 77 (2014) 725– 732

omaroOcm

3C

agnaihbi

Scheme 1. Polymerization of toluidine and/or anisidine in presence of DBSA.

f benzene rings at 1400 and 1440 cm−1, C N stretching of aro-atic amines at 1255 cm−1 and the bands at 1660 and 1661 cm−1

ssigned to the non-symmetric benzene ring stretching mode (theing stretching in quinoid unit and ring stretching in benzenoidne). The bands at 2926 and 1497 cm−1 are assigned to CH3 andCH3 groups of PTol and PAns, respectively. FT-IR spectrum of theopolymer has shown the same characteristic peaks as previouslyentioned but they are slightly shifted due to copolymerization.

.1.2. Transmission electron microscope (TEM) of the preparedPs and their copolymer

Fig. 5a–c shows the TEM micrograph of the prepared PTol, Pansnd their copolymer, respectively. It is clearly seen from the micro-raphs 5a and 5b that the morphology of the prepared PTol hasano-sphere structure in the size ranging from 62 nm to 115 nmnd the morphology of the prepared PAns has nano-rod structuren the size ranging from 96 nm to 114 nm. Finally, micrograph 5c

as confirmed that the morphology of the prepared copolymer hasoth the nanosphere and nano-rod structures at the same time

ndicating the formation of the copolymer.

Scheme 2. Copolymerization of toluidine (Tol)

Fig. 4. FT-IR spectra of the prepared CPNs and their copolymer.

3.1.3. Differential scanning calorimetric analysis (DSC)Fig. 6 shows the DSC analysis of CE containing the prepared

CCPNs. It is well known from the literature that the DSC exothermicpeak corresponding to decomposition temperature of the tradi-tional styrene/butylacrylate copolymer is low [17]. As a result ofthe presence of the conducting copolymer nanoparticles (CCNs)higher decomposition temperature has been obtained. The DSC dia-

gram shows one exothermic peak indicating the compatibility ofthe St/BA emulsion with the present CCPNs.

and anisidine (Ans) in presence of DBSA.

N. Elhalawany et al. / Progress in Organic Coatings 77 (2014) 725– 732 729

Fig. 5. TIM of the stable colloidal dispersions of (a) PToL, (b) PAns and (c) P(Ans-co-ToI).

3

5hciCcdt

TS

Table 3Blank paint formulation.

Composition Weight (g)

Water 200Tetra potassium pyrophosphate 2WD-EAGLE (AS4/40) 3Texanol 4Antifoaming agent 6Tylose H30,000 3Ammonia 2Titanium dioxide 150CaCo3 25Binder 50% 600

CE1, CE2 and CE3 samples after one week from dryness have beenmeasured and tabulated in Tables 7–9. The data shown in the tablesindicate that the presence of CPNs and CCPNs in the film paintshas not affected too much the basic properties of the resultant

Fig. 6. DSC diagram of CE containing CCPNs.

.2. Water based paint formulations

The binder used here is the St/BA emulsion (solid content0%). St/BA latex specification is shown in Table 2. St/BA emulsionas been simply blended with the prepared PTol, PAns and theiropolymer (1:1 composition) to give the corresponding compos-te emulsions CE1, CE2 and CE3, respectively. Blank, CE1, CE2 andE3 samples have been incorporated into paint formulations. Each

omposite emulsion consists of four different samples having fourifferent concentrations (1.5%, 3%, 6% & 9%) of total paint formula-ion respectively. The detailed paint formulations of the blank, CE1,

able 2t/BA latex specifications.

Latex specification

State LiquidColor Milky whiteAv. (M.wt.) 289,360 g/molNon-volatile content by weight (%) 50% ± 1Viscosity (Brookfield) Spindle4 at 23 ◦C ( C Ps) 1000-5000pH 7-8MFFT, (◦C) (minimum film forming temperature) 18Specific gravity (g/ml) 1.06Particle size (�m) 0.1Water solidification temperature 0 CWater vapor temperature 100 C

HF antibacterial agent 5Total 1000

CE2 and CE3 samples are represented in Tables 3–6, respectively.Each paint has been applied on steel, tin and glass panels and driedat room temperature for 1 week before the measurements.

3.3. Physico-mechanical tests

The physico-mechanical test results of the paint films of blank,

Table 4Emulsion paint formulations of CE1 samples.

Composition CE1

A1 A2 A3 A4

Water 185 170 140 110Tetra potassium pyrophosphate 2 2 2 2WD-EAGLE (AS4/40) 3 3 3 3Texanol 4 4 4 4Antifoaming agent 6 6 6 6Tylose H30,000 3 3 3 3Ammonia 2 2 2 2Titanium dioxide 150 150 150 150CaCo3 25 25 25 25St/BA emulsion 600 600 600 600HF antibacterial 5 5 5 5Poly toluidine (PTol) 15 30 60 90Total 1000 g 1000 g 1000 g 1000 g

730 N. Elhalawany et al. / Progress in Organic Coatings 77 (2014) 725– 732

Table 5Emulsion paint formulations of CE2 samples.

Composition CE2

B1 B2 B3 B4

Water 185 170 140 110Tetra potassium pyrophosphate 2 2 2 2WD-EAGLE (AS4/40) 3 3 3 3Texanol 4 4 4 4Antifoaming agent 6 6 6 6Tylose H30,000 3 3 3 3Ammonia 2 2 2 2Titanium dioxide 150 150 150 150CaCo3 25 25 25 25St/BA emulsion 600 600 600 600HF antibacterial agent 5 5 5 5Poly anisidine (PAns) 15 30 60 90Total 1000 g 1000 g 1000 g 1000 g

Table 6Emulsion paint formulations of CE3 samples.

Composition CE3

C1 C2 C3 C4

Water 185 170 140 110Tetra potassium pyrophosphate 2 2 2 2WD-EAGLE (AS4/40) 3 3 3 3Texanol 4 4 4 4Antifoaming agent 6 6 6 6Tylose H30,000 3 3 3 3Ammonia 2 2 2 2Titanium dioxide 150 150 150 150CaCo3 25 25 25 25St/BA emulsion 600 600 600 600HF antibacterial agent 5 5 5 5Poly(toludiene-co-anisidine) (1:1) 15 30 60 90Total 1000 g 1000 g 1000 g 1000 g

Table 7Physico-mechanical properties of paint films of the blank and CE1 samples.

Test Blank A1 A2 A3 A4

Adhesion 4B 5B 5B 5B 5BHardness 60 65 73 76 79Bending Pass Pass Pass Pass PassImpact 100/15 100/15 100/15 100/15 100/15Gloss 51.3 50.5 49 51.8 50Opacity 93.8% 95.3 96% 98% 98.1%Whiteness 79.3 70.1 66.9 64.5 62.1Washability 1100 1350 2500 3500 3450

Table 8Physico-mechanical properties of paint films of CE2 samples.

Test B1 B2 B3 B4

Adhesion 5B 5B 5B 5BHardness 68 77 82 80Bending Pass Pass Pass PassImpact 100/15 100/15 100/15 90/9Gloss 49 47 47 45Opacity 94% 94% 95% 96.2%Whiteness 75.6 68.7 67.2 66.7Washability 1750 3000 3700 3750

Table 9Physico-mechanical properties of paint films of CE3 samples.

Test C1 C2 C3 C4

Adhesion 5B 5B 5B 5BHardness 75 78 80 80Bending Pass Pass Pass PassImpact 100/15 100/15 100/15 100/15Gloss 49 48 49 47Opacity 94% 95.2% 94.5% 95.2%Whiteness 70.7 62.1 61 60.2Washability 2100 2800 3500 3300

Table 10Weathering test results of the tested film paints.

Sample After 250 h After 500 h�E �E

Blank 2.44 7.73A1 4.1 6.84A2 1.36 4.84A3 1.65 3.9A4 1.9 6.84B1 3.87 7.2B2 0.84 2.3B3 0.64 1.82B4 0.75 3.12C1 1.69 2.87C2 1.19 2.66

C3 1.03 1.92C4 1.75 3.45

final paint. In addition, washability is highly increased due to thepresence of the prepared CPNs and CCPNs.

3.4. Weathering resistance test

Most weathering damage is caused by three factors: light, hightemperature and moisture. Any one of these factors may cause dete-rioration. Together, they often work synergistically to cause moredamage than any one factor alone.

Weathering test results of the paint films of blank, CE1, CE2 andCE3 samples are shown in Table 10. It is obvious from Table 10 thatthe color differences �E increase as the time of exposure increases.It is also obvious that the best results are for the paint formu-lations of samples A3, B3 and C3 where the color differences �Ebetween the tested sample and the standard sample are the least.This confirms that incorporation of the prepared CPNs and CCPNs inthe blank paint formulation makes the paint films acquire higherweathering resistance than those of paint formulations based onSt/BA emulsion alone.

3.5. Corrosion resistance test

To examine the corrosion resistance, different steel panels havebeen painted with different paint formulations based on the blank,CE1, CE2 and CE3 samples. After drying for one week, they havebeen immersed in artificial seawater for 28 days. The results aregiven in Table 11. The painted metal plates have been detected forblistering resistance of coating films and degree of rusting of metalsurface under paint films. Corrosion progress on metal plates underpaint films of the blank, CE1, CE2 and CE3 samples is representedphotographically in Figs. 7–11, respectively. As shown from the fig-ures and data given in Table 11, the corrosion resistance of the steelpanels painted with all the tested samples increases as the concen-tration of the CPNs and CCPNs in the paint increases up to (6%)and after that the corrosion resistance starts to decrease. Coatingscontaining the CPNS and CCPNs function as both a barrier and anoxidant for the steel substrate, i.e. formation of passive oxide filmon the steel surface results from redox reaction at the steel andpolymer interface [18].

When the concentrations of the CPNs and CCPNs reach the max-imum of 9%, the anticorrosion properties decrease and this may beattributed to the formation of intermolecular crosslinks betweenthe polymeric chains which hinder the flow of electrons and conse-quently the redox reaction at the steel and polymer interface. Whenthe paint contains 6% of the prepared CPNs and/or CCPNs corrosion,

resistance maximizes. This explains why the steel panels have lit-tle tarnished surface, while the other paint formulations especiallywith lower concentrations (1.5, 3%) of CPNs and CCPNs show weakcorrosion resistance as shown in Figs. 8 and 9. Maximum failure is

N. Elhalawany et al. / Progress in Organic Coatings 77 (2014) 725– 732 731

Table 11Corrosion resistance tests of the painted steel panels.

Test Blank Group CE1 Group CE2 Group CE3

A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4

Degree of rustinga 2.5 5.5 6 9.8 9 6.5 7.5 9.8 8 6.5 8 9.9 9.5Degree of blisteringb D MD 4MD 9F MD 7F 9F 9F 7F 6MD 8F 9F 8.5FTotal anticorrosion efficiency (%) 25 55 60 98 90 65 75 98 80 65 80 99 95

a It is rating of rust as area percentage; it is graded on a scale from 10 to 0, where 10 < 0.01% and 0, 100% according to ASTM D 610 (2001).b It is graded on a scale from 10 to 0, where 10 no blistering and 0 for largest blisters an

according to ASTM D 714-87 (2000).

Fig. 7. Corrosion test of steel panel painted with blank paint sample.

Fig. 8. Corrosion test of the steel panels painted with CE samples. ((

Fig. 9. Corrosion test of the steel panels painted with the CE sample

d frequently denoted by F, M, MD, and D (few, medium, medium dense and dense)

obviously obtained with the blank paint sample, where severe cor-rosion (rating 2.5) and D blisters have been observed as seen fromFig. 7 and Table 11.

With respect to the panels painted with A3, B3 and C3 samples,the results show that maximum corrosion resistance is for the pan-els painted with sample C3. They have very little tarnished surface(rating 9) with negligible blisters of 9F degree, as shown from Fig. 10and data in Table 11.

It is worth mentioning that all panels painted with the sam-ples containing the CCPNs have much better corrosion resistancethan those painted with samples containing the neat PAns or neatPTol nanoparticles. The enhanced corrosion protection effect of theCCPNs in the form of coating on steel surface is attributed to thegreater barrier performance and the more involvement of CCPNsin the oxide formation due to combination of the redox catalyticproperty of PAns and PTol at the same time. The porosity of thecoating is another important factor that affects the initiation and

progress of corrosion under the coating [19]. The enhanced barrierperformance of the CCPNs coatings is attributed to the dense filmof the CCPNs coating on the steel substrate.

a) Ai, (b) Bi and (c) Ci having the same concentration of 1.5%.)

s. ((a) A, (b) B and (c) C having the same concentration of 3%.)

732 N. Elhalawany et al. / Progress in Organic Coatings 77 (2014) 725– 732

Fig. 10. Corrosion test of the steel panels painted with the CE samples. ((a) Ai, (b) B3 and (c) C3 having the same concentration of 6%.)

mples

4

hastaaratrrtittahcC

A

mge

[[[

[

[

[[

[17] H.J. Nagash, A. Karimzadeh, A.R. Momeni, A. Reza, M.H. Alian, Turkish Journalof Chemistry 31 (2007) 257–269.

Fig. 11. Corrosion test of the steel panels painted with the CE sa

. Conclusion

In this work, a new type of anticorrosive water-based paintsas been prepared by incorporation of the prepared (CPNs)nd their (CCPNs) in the blank paint formulation based ontyrene/butylacrylate emulsion as a binder. It has been found fromhe data given in the tables and figures that incorporation of CPNsnd their CCPNs in the blank paint formulation make the paint filmscquire higher resistance against washability, weathering and cor-osion than those of paint formulation based on St/BA emulsionlone. The anticorrosion properties of the painted films containinghe CCPNs have given the best results due to their enhanced bar-ier effect and greater involvement in oxide film formation whichesults from dual redox catalytic effect of the CCPNs. It is expectedhat such a new type of emulsion paint containing CPNs and CCPNss to be used as an architectural paint to reduce the consumption ofhe petroleum resources in the field of paint industry and to pavehe way for the development of new coating technologies. As fars we know, none of the commercial paints developed up to dateas achieved any of these characteristics and no applied usage ofomposite emulsions containing PTol or PAns nanoparticles or theirCPNs has been reported.

cknowledgement

The authors wish to thank Research and development depart-ent, Eagle Chemicals Company, 6th October City, Egypt for

enerous and sincere assistance in carrying out some of the nec-ssary investigations and analysis in this work.

[[

. ((a) A4, (b) 64 and (c) C4 having the same concentration of 9%.)

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