24 Corrosion Protection on Copper by Polyvinylimidazole Fred P. Eng and Hatsuo Ishida
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Macromolecular Science Department, Case Western Reserve University, Cleveland, OH 44106
Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS) is applied to the study of corrosion protection of copper by an organic coating. Poly-N-vinylimidazole (PVI(1)) and poly-4(5)-vinylimidazole (PVI(4)) are demonstrated to be effective new polymeric anti-corrosion agents for copper at elevated temperatures. Oxidation of copper is suppressed even at 4 0 0 C. PVI(1) and PVI(4) are more effective anti-oxidants than the most commonly used corrosion inhibitors, benzotriazole and undecylimidazole, at elevated temperatures. These new polymeric agents are water soluble and easy to treat the metal surface. ˚
Azole compounds such as benzotriazole, benzimidazole, indazole and i m i d a z o l e s a r e e f f i c i e n t a n t i - c o r r o s i o n agents f o r copper and c o p p e r - b a s e alloys [1-10]. Many experimental techniques [11-15] have been used t o study the corrosion i n h i b i t i o n mechanisms, however, t h e mechanisms a r e s t i l l n o t w e l l understood. It i s believed t h a t t h e complex f o r m a t i o n between c o p p e r and n i t r o g e n atoms would inhibit oxygen a d s o r p t i o n on copper surface [ 1 6 - 2 0 ] . I n h i b i t o r s mentioned above a r e s m a l l molecules i n nature. Recently, there have been great emphases i n u s i n g polymers a s corrosion i n h i b i t o r s [21-37]. However, these inhibitors, which included different heterocyclic polymers, polythiopropinate, polymaleic acid and p o l y a l k y l o l a m i d e / a l k e n y l copolymers, were developed f o r protecting steel i n s e a water [ 2 1 , 2 g J , tap water [22] and i n a c i d i c e n v i r o n m e n t s [ 2 0 , _ 2 J , 2 3 J . Relatively v e r y few or no p o l y m e r i c inhibitors f o r copper, aluminum, and i r o n [ 2 8 , 3 4 - 2 J ] have been reported, especially i n high temperature studies. In t h i s study, we w i l l p r e s e n t p o l y - N - v i n y l i m i d a z o l e ( P V I ( D ) and p o l y - 4 ( 5 ) - v i n y l i m i d a z o l e ( P V I ( 4 ) ) ( F i g u r e 1.) a s new p o l y m e r i c a n t i - c o r r o s i o n agents f o r copper i n e l e v a t e d temperature 0097-6156/86/0322-0268506.00/ 0 © 1986 American Chemical Society
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
24.
ENG AND IS H IDA
Corrosion Protection on Copper by Polyvinylimidazole
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environments. P o l y v i n y l i m i d a z o l e s (PVIs) a r e p r e f e r e d because of the following reasons. PVIs have t h e i m i d a z o l e r i n g as t h e i r pendant group which would l e a d t o complex f o r m a t i o n with copper. F u r t h e r m o r e , t h e polymers c a n e a s i l y form t h i n f i l m s o f r e l a t i v e l y h i g h e r d u c t i l i t y t h a n s m a l l m o l e c u l e s on c o p p e r s u r f a c e s . It is known t h a t t h e h i g h e r d u c t i l i t y would enhance t h e a d h e s i o n o f t h e f i l m t o the s u b s t r a t e . L a s t l y , amorphous polymer/copper complex is expected t o have less defects w h i c h may be i m p o r t a n t i n i n f l u e n c i n g the the r a t e o f o x i d a t i o n o f copper. In t h i s elevated temperature study, commonly used copper corrosion inhibitors for copper, benzotriazole and u n d e c y l i m i d a z o l e w i l l be used f o r c o m p a r i s o n s . Benzotriazole is one o f t h e most e f f e c t i v e and w i d e l y used c o r r o s i o n i n h i b i t o r s specifically f o r copper i n both atmospheric and immersed environments for over 35 years. At the same time, undecylimidazole also exhibits superior anti-corrosion property. The r e a c t i v i t y of i m i d a z o l e w i t h copper i s very h i g h , forming a t h i c k i m i d a z o l e / c o p p e r complex f i l m w h i c h makes undecylimidazole an a t t r a c t i v e corrosion inhibitor. F o u r i e r transform i n f r a r e d r e f l e c t i o n - a b s o r p t i o n s p e c t r o s c o p y (FT-IRRAS) i s u t i l i z e d i n the experiment. FT-IRRAS i s an e x t e r n a l r e f l e c t i o n t e c h n i q u e w h i c h i s u s e f u l f o r s t u d y i n g t h i n f i l m s on m e t a l surfaces by reflecting infrared r a d i a t i o n from the metal surfaces at high,[A nearly grazing angles o f i n c i d e n c e . The t h e o r y of t h e t e c h n i q u e was developed by F r a n c i s and E l l i s o n [38] and G r e e n l e r [ 3 9 ] . Cuprous o x i d e f o r m a t i o n i s used t o f o l l o w t h e c o r r o s i o n k i n e t i c s . Experimental B o t h b e n z o t r i a z o l e and u r o c a n i c a c i d were purchased from Aldrich Chemical Co. and a z o b i s ( i s o b u t y r o n i t r i l e ) was from Eastman Kodak C o . undecylimidazole and N - v i n y l i m i d a z o l e were supplied by S h i k o k o C h e m i c a l C o . and BASF C o . , r e s p e c t i v e l y . Copper p l a t e s ( 2 . 5 x 5 . 0 x 0 . 2 cm, ASTM Β 125, type ETP) were m e c h a n i c a l l y p o l i s h e d w i t h No.5 c h r o m e o x i d e , u l t r a s o n i c a l l y washed with acetone, rinsed with d i l u t e h y d r o c h l o r i c a c i d and d i s t i l l e d water, and d r i e d w i t h a stream of nitrogen gas. Corrosion i n h i b i t o r s were d i s s o l v e d i n e i t h e r e t h a n o l o r m e t h a n o l , solution cast onto copper substrates and a i r d r i e d . F i l m t h i c k n e s s was c a l c u l a t e d based on t h e c o n c e n t r a t i o n o f t h e s o l u t i o n , d e n s i t y of t h e sample and t h e a r e a o f t h e c o p p e r s u r f a c e . I n t h i s s t u d y , 150 nm t h i c k films were used. The r e f l e c t i o n - a b s o r p t i o n (R-A) attachment (Harrick S c i e n t i f i c ) along with a gold wire g r i d p o l a r i z e r ( P e r k i n - E l m e r ) were mounted i n a D i g i l a b F T S - 1 4 F o u r i e r transform i n f r a r e d spectrometer equipped w i t h a t r i g l y c i n e s u l f a t e d e t e c t o r and purged w i t h d r y a i r . Spectra collected were the average of 200 scans a t 4 cm" resolution u s i n g an o p t i c a l v e l o c i t y o f 0.3 c m / s . The a n g l e o f i n c i d e n c e used was 75 . hxrlfi-Ga&lon oL A z o b i s ( i s o b u t y r o n i t r i l e ) Crude AIBN was first dissolved i n warm methanol ( 3 5 ° rystallized in i c e b a t h and f i n a l l y d r i e d i n a vacuum oven a t room temperature f o r two d a y s . c )
f
t
n
e
n
r e C
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
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Purification o£ N-Vinyl imidazole Crude brownish N-vinylimidazole was d i s t i l l e d i n vacuo ( 5 1 ° C / 2 . 5 mm Hg) t o y i e l d a pure and c o l o r l e s s l i q u i d .
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S y n t h e s i s q £ P o l y - N - V i n y U m J - d a z o j l e [40] A solution of N-vinylimidazole (30 g , 0.32 mol) and a z o b i s ( i s o b u t y r o n i t r i l e ) ( 0 . 2 6 g , 0.0016 mol) i n benzene (200 ml) was heated a t 68°C w i t h stirring under n i t r o g e n f o r two d a y s . The w h i t e p r e c i p i t a t e d polymer was c o l l e c t e d by f i l t r a t i o n , washed four times with benzene (20 ml) and d r i e d i n a vacuum oven (30 mm Hg) a t 40°C f o r three days. The y i e l d was 30 g (100$ conversion). The weightjjaverage molecular weights o f t h e polymer ranged from 5.5x10 t o 1.3x10 [40]. The p o l y m e r , as suggested by NMR s t u d i e s , was a t a c t i c [ 4 1 ] . D e n s i t y measured was 1.246 g / m l . S y n t h e s i s p £ 4 ( 5 ) - V i n y l i m i d a z o l e [42] - U r o c a n i c a c i d ( 7 . 6 g , 0.055 mol) was d e c a r b o x y l a t e d a t t h e m e l t i n g p o i n t i n vacuo i n a d i s t i l l i n g apparatus with a s i l i c o n e o i l bath of temperature 280°C. A h e a t i n g t a p e w i t h t e m p e r a t u r e s e t a t 140°C was wrapped around t h e c o n d e n s e r t o p r e v e n t t h e d i s t i l l a t e from solidifying before reaching the r e c e i v e r . A v i s c o u s and c o l o r l e s s l i q u i d was c o l l e c t e d ; t h e y i e l d was 2.0 g ( 2 6 $ ) . The p r o d u c t s o l i d i f i e d upon c o o l i n g t o room t e m p e r a t u r e . SyjxJ&eiOs p £ P o l y - 4 ( 5 ) - V i n y l i m i d a z o l e [42] A solution of 4(5)-vinylimidazole (1.50 g, 0.016 mol) and a z o b i s ( i s o b u t y r o n i t r i l e ) (5 mg, 0.030 mmol) i n benzene (200 ml) was heated a t r e f l u x w i t h s t i r r i n g under n i t r o g e n f o r t h r e e d a y s . A f t e r w a r d , t h e w h i t e polymer was c o l l e c t e d by f i l t r a t i o n , washed with benzene (20 ml) f o u r t i m e s and d r i e d i n vacuum oven (30 mm Hg) a t 40°C f o r t h r e e d a y s . The y i e l d was 0 . 9 g (60$ c o n v e r s i o n ) . D e n s i t y measured was 1.246 g / m l . S y n t h e s i s q£ Es>lx^rVlDyI3jRXte2S>lelCepi>$rSlI) Complex - To PVI(1) ( 1 . 7 mg)/methanol (5 ml) s o l u t i o n was added c u p r i c c h l o r i d e ( 0 . 7 mg, 0.0041 mmol). A f t e r t h e m i x t u r e s o l u t i o n was a l l o w e d to stand a t room t e m p e r a t u r e o v e r n i g h t , b l u e c r s t a l s appeared a t t h e bottom o f t h e r e a c t i o n f l a s k . Blue c r y s t a l s o f PVI(1)/copper(II) complex were t h e n c o l l e c t e d and washed r e p e a t e d l y w i t h m e t h a n o l . &a&he£Jtè p X P p l v ^ ( l ) - y ^ ^ Gqm&SL - To a PVI(4) ( 2 . 0 mg)/methanol (5 ml) s o l u t i o n was added c u p r i c c h l o r i d e ( 1 . 0 mg, 0.0059 mmol). A f t e r the mixture s o l u t i o n was allowed t o stand a t room t e m p e r a t u r e o v e r n i g h t , g r e e n c r y s t a l s appeared a t t h e bottom o f the beaker. Green c r y s t a l s of PVI(4)/copper(II) complex were then collected and washed repeatedly with methanol. RejLul^s a n d Pi£pu£&ipji M o l e c u l a r S l x ^ t u j - e p f PVJ7 CppperiII)
Cpmpjex^
F i g u r e 2 shows t h e r e f l e c t i o n s p e c t r a o f P V I ^ D and PVI(4) coated on c o p p e r mirrors. The peak a t 3140 cm~ i s a s s i g n e d t o t h e NH s t r e t c h i n g mode. Peaks a t 3115, 2950, 2940 and 2850 cm
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
a
24.
Corrosion Protection on Copper by Polyvinylimidazole
ENG AND ISHIDA
( CHo - CH ) l η
( CHo - CH )
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POLY-N-VINYLIMIDAZOLE
POLY-'KSÎ VINYLIMIDAZOLE
PVI(l)
PVIW) Fig.
1.
Polyvinylimidazoles.
1500 1110 0.0545
WRVENUMBERS Fig.
2.
R-A S p e c t r a o f PVI(1)
and P V I ( 4 ) .
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
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are t h e CH s t r e t c h i n g modes o f t h e i m i d a z o l e ring and t h e aliphatic chain. Peaks a t 1585, 1500 and 1485 c m " a r e due t o t h e ring stretching. Finally, peaks at 1115 and 1110 cm" a r e a s s i g n e d t o t h e CH i n - p l a n e b e n d i n g o f t h e i m i d a z o l e r i n g . From t h e s t u d y o f the synthesized model compounds of PVI(1)/copper(II) and P V I ( 4 ) / c o p p e r ( I I ) , i t was found t h a t b o t h polymers were c a p a b l e o f f o r m i n g complex w i t h c o p p e r . Solubility tests indicated that t h e complexes were n o t s o l u b l e i n w a t e r , m e t h a n o l , o r any o t h e r common o r g a n i c s o l v e n t s . Then t h e complex formation between t h e PVI t h i n f i l m and c o p p e r m i r r o r s u r f a c e was s t u d i e d b o t h a t room and e l e v a t e d t e m p e r a t u r e s . F i r s t , 150 nm PVI films were deposited on t h e c o p p e r m i r r o r s and t h e r e f l e c t i o n s p e c t r a were t a k e n . After various temperature treatments, the c o p p e r m i r r o r s were washed w i t h m e t h a n o l , d r i e d and t h e r e f l e c t i o n s p e c t r a were t a k e n a g a i n . A r e a o f peaks a t 1115 and 1110 cm" was used to follow the k i n e t i c s o f t h e complex f o r m a t i o n . The assumption of this experiment was t h a t since PVI/copper(II) complexes were n o t s o l u b l e i n m e t h a n o l , t h e r e f o r e t h e amount o f m a t e r i a l remained on t h e c o p p e r surface would be due t o t h e complex formed. A t room t e m p e r a t u r e , PVI(1) formed complex i n s t a n t l y w i t h c o p p e r once t h e p o l y m e r i c f i l m was s o l u t i o n cast onto the copper surface and d r i e d . However, PVI(4) d i d n o t i m m e d i a t e l y complex w i t h t h e c o p p e r . F i g u r e 3 shows t h a t after h e a t i n g a t 6 0 ° C f o r 15 m i n , o n l y 7 % o f t h e PVI(4) f i l m complexed with the copper. I t was n o t u n t i l t h e t e m p e r a t u r e r e a c h e d 1 2 0 ° C before 92 % o f t h e PVI(4) complexed w i t h c o p p e r . T h i s phenomenon i s l i k e l y caused by t h e c o n f o r m a t i o n a l e f f e c t s o f t h e p o l y m e r . In each o f the imidazole rings, there i s a NH group c a u s i n g t h e imidazole rings to i n t e r a c t w i t h one a n o t h e r through hydrogen bonding intraand i n t e r m o l e c u l a r l y . Such i n t e r a c t i o n s cause a s h r i n k a g e , r e s u l t i n g i n t h e exposure o f a l i p h a t i c c h a i n s and t h e burying o f the imidazole groups. As a consequence, steric hindrance prevents nitrogen atom from c o m p l e x i n g w i t h copper. Thus, t h e r a t e o f complex f o r m a t i o n w i t h c o p p e r i o n s i s s t r o n g l y i n f l u e n c e d by t h e s t r e n g t h o f hydrogen b o n d i n g . i ^ A ^ j A f i P A 9f BBD&ïri&zs&SLt. Vntiecyliiniitezplé âDd 300°C)
pyjs
(150
£o_
F i g u r e 4 shows t h e r e f l e c t i o n s p e c t r a o f u n d e c y l i m i d a z o l e on copper heated at 150° C f o r various lengths o f time. Complex f o r m a t i o n was o b s e r v e d w i t h o u t any heat t r e a t m e n t (spectrum at 0 min) [433· Degradation o f u n d e c y l i m i d a z o l e was o b s e r v e d a s t h e i n t e n s i t y o f t h e peaks i n t h e 2900 cm" r e g i o n d e c r e a s e d g r a d u a l l y with prolonged^ h e a t i n g . A t t h e same t i m e , new bands appeared around 1600 cm" . Further degradation also resulted in nitrile formation as i n d i c a t e d by t h e peak a t 2183 c m " . Increase_of c o p p e r o x i d e f o r m a t i o n w i t h h e a t i n g time was o b s e r v e d a t 650 cm" . At 1 5 0 ° b e n z o t r i a z o l e showed complete d e g r a d a t i o n a f t e r o n l y 15 min o f h e a t i n g ( F i g u r e 5 . ) . Degraded p r o d u c t showed an i n t e n s e peak a t 740 c m " . Copper o x i d e f o r m a t i o n a l s o o c c u r r e d a f t e r 15 min and was even more prominent a f t e r 2 h o u r s . As f o r PVI(1) and PVI(4) (Figures 6 and 7 . ) , no d e g r a d a t i o n was d e t e c t e d a f t e r 1 c
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In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
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TEMP (C) F i g . 3. P V I ( 4 ) / C U ( I I ) F o r m a t i o n v e r s u s Heated f o r 15 M i n u t e s .
UNDECYLIMIDAZOLE
Various
Temperatures
i58o
ON COPPER
1423
655 1162
22
H
3
H
1
H
5
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0.0425
MIN
λ 0 MIN
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3000
2000
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R-A S p e c t r a o f u n d e c y l i m i d a z o l e
w i t h Heat Treatment a t
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
POLYMERIC MATERIALS FOR CORROSION CONTROL
BENZOTRIRZOLE (BTR) ON CU ητ
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1.5 Η
0.0301
0.25 Η 0.0712
WRVENUMBERS Fig.
5·
R-A S p e c t r a o f BTA w i t h Heat Treatment
a t 150° C.
PVI(l) ON CU RT 150 C o.owi
0.0519
WRVENUMBERS Fig.
6.
R-A S p e c t r a o f P V I ( 1 ) w i t h Heat Treatment
a t 150° C.
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
24.
ENG AND IS H IDA
Corrosion Protection on Copper by Polyvinylimidazole
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hour o f h e a t i n g . Even a f t e r 27 o r 30 h o u r s , little degradation was seen a s t h e emergence o f t h e n i t r i l e peak a t 2200 cm" and c a r b o n y l peaks a t 1600 cm" r e g i o n was r e l a t i v e l y small. No c o p p e r o x i d e was o b s e r v e d a t any t i m e f o r e i t h e r p o l y m e r . When t h e t e m p e r a t u r e was r a i s e d t o 2 1 0 ° C , u n d e c y l i m i d a z o l e was c o m p l e t e l y d e g r a d a t e d a f t e r 15 min ( F i g u r e 8 . ) . No i m i d a z o l e r i n g s t r u c t u r e was o b s e r v e d . The n i t r i l e peak a t 2190 cm" was pronounced, and t h e c o p p e r o x i d e f o r m a t i o n was i n t e n s e . On t h e o t h e r h a n d , P V I ( 1 ) and PVI(4) d e g r a d a t i o n was r e l a t i v e l y m i l d a t 210°C a f t e r 15 min ( F i g u r e s 9 and 1 0 . ) . I t was n o t u n t i l t h e t e m p e r a t u r e was r a i s e d t o 2 5 0 ° C and h i g h e r t h a t major d e g r a d a t i o n of t h e polymers was o b s e r v e d . Even i n s u c h d e g r a d i n g c o n d i t i o n s , no c o p p e r o x i d e was d e t e c t e d a t 210 o r 2 5 0 ° C . A t 3 0 0 ° C , where the polymers s u f f e r e d r e l a t i v e l y s e v e r e d e g r a d a t i o n , o x i d a t i o n o f c o p p e r was s t i l l s u p p r e s s e d .
Sigh
TweiatottS. S£uHy QL PIIs 1338 to U50°CJ
F i g u r e 11 shows t h e r e f l e c t i o n s p e c t r a o f b a r e c o p p e r m i r r o r s heated a t h i g h t e m p e r a t u r e s f o r 15 m i n . A1| 330 C , cuprous o x i d e was d e t e c t e d by t h e band absorbed a t 655 cm" . However, at 3^0 and 400 C , two bands were observed near 611 and 655 c m " . According to the theory of reflection-absorption infrared s p e c t r o s c o p y d e v e l o p e d by G r e e n l e r e t a l . [ 4 4 ] , bands 611 and 655 cm" are assigned to the transverse optical and l o n g i t u d i n a ^ o p t i c a l modes o f t h e h i g h f r e q u e n c y phonon o b s e r v e d nearC 609 c m " i n j j i e l e c t r i c s p e c t r a o f cuprous oxide [ 4 5 ] . The band around 611 cm" was o b s e r v e d by B o e r i o and Armogan [46] w i t h o x i d e s h a v i n g a t h i c k n e s s o f about 200 nm o r t h i c k e r . F i g u r e 12 shows t h e r e s u l t s o f P V I ( 1 ) a f t e r b e i n g heated at v a r i o u s h i g h t e m p e r a t u r e s f o r 15 m i n . The bands o f c u p r o u s o x i d e s formed on b a r e c o p p e r m i r r o r s a t c o r r e s p o n d i n g t e m p e r a t u r e s a r e superimposed on t h e P V I ( 1 ) s p e c t r a f o r d i r e c t c o m p a r i s o n s . The s c a l e o f t h e two t y p e s o f s p e c t r a is shown by t h e difference between t h e maximum and minimum a b s o r b a n c e , A . Note t h a t no c u p r o u s o x i d e f o r m a t i o n was o b s e r v e d a t 330 o r 4 0 0 ° C . In f a c t , at 400 C t h e polymer c o a t e d s u r f a c e o f t h e c o p p e r m i r r o r s remained m o s t l y s h i n y whereas t h e b a r e r e f e r e n c e c o p p e r s u r f a c e t u r n e d d u l l with a layer o f r e d d i s h - b l a c k s c a l e on i t . A t 410°C o r h i g h e r , t h e polymer was no l o n g e r p r o t e c t i n g t h e c o p p e r s u r f a c e . The two c u p r o u s bands n e a r 611 and 655 c m " began t o emerge. Even s o , a t 450 C , t h e amount o f o x i d e s formed was much l e s s t h a n t h a t o f b a r e copper. Similar results were obtained f o r PVI(4) ( F i g u r e 1g.) where no s i g n i f i c a n t c u p r o u s o x i d e was o b s e r v e d a t o r below 400 C . Figure 14 summarizes the h i g h temperature study w i t h a p l o t o f r e l a t i v e cuprous oxide formation versus temperatures. As t h e t e m p e r a t u r e went u p , t h e amount o f c u p r o u s o x i d e formed on b a r e copper a l s o i n c r e a s e d . However, f o r t h e polymer samples, it is interesting t o note that t h e t r a n s i t i o n from no o x i d e t o o x i d e formation a t 410°C i s r e l a t i v e l y s h a r p .
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
275
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POLYMERIC MATERIALS FOR CORROSION CONTROL
PVI Î4) ON CU ΔA n T 1 5 0c
V \ 0.0499
JT
fA
j vv
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0.0369
A
θθί|37
**/^ rs.
0.0586
I
^
/
ι
4000
3500
Λ
1
1
1
3000
2500
2000
1
1
I
1500
1000
500
WRVENUMBERS Fig.
7.
R-A S p e c t r a o f PVI(4) w i t h Heat Treatment a t 1 5 0 ° C .
UNDECYLIMIDAZOLE ON COPPER ( 2 1 0 C FOR 1 5 M I N )
3000 ι F i g . 8. 210° C.
.
.
.
2000 . ι .
.
550 I
.
1000 . I .
cm*' .
R-A S p e c t r a o f U n d e c y l i m i d a z o l e w i t h Heat Treatment a t
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
ENG AND IS HI DA
Corrosion Protection on Copper by Polyvinylimidazole 277
PVI(1) ON CU
300 C FOR 15 MIN
JLA-
250 C FOR 15 MIN
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210 C FOR 15 MIN
150 C FOR 15 MIN
PRIOR HERT TREATMENT
4000
3500
3000
2500
2000
1500
1000
500
F i g . 9 . R-A S p e c t r a o f PVI(1) w i t h Heat Treatment a t V a r i o u s Temperatures.
Δ
PVI(4) ON CU
A
0.0450
300 C FOR 15 MIN
0.0510
PRU
4000
RERTMENT
I
I
3500
3000
2500 2000 WRVENUMBERS
0.0424
1500
1000
500
F i g . 10. R-A S p e c t r a o f PVI(4) w i t h Heat Treatment a t V a r i o u s Temperatures.
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
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POLYMERIC MATERIALS FOR CORROSION CONTROL
WRVENUMBERS F i g . 11. R-A S p e c t r a o f B a r e Copper w i t h H i g h Temperature Treatments.
I 750
.
1
1
1
1
700
650
600
550
WRVENUMBERS
12. R-A S p e c t r a o f P V I ( 1 ) w i t h H i g h Temperature
1 500
Treatments.
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
Corrosion Protection on Copper by Polyvinylimidazole 279
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ENG AND ISHIDA
F i g . 14. R e l a t i v e Amount o f Oxides Formed on B a r e , P V I ( 1 ) and P V I ( 4 ) Copper v e r s u s V a r i o u s H i g h T e m p e r a t u r e s .
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
280
POLYMERIC MATERIALS FOR CORROSION CONTROL
Summary P o l y v i n y l i m i d a z o l e s a r e e f f e c t i v e a n t i - o x i d a n t s f o r copper a t elevated temperatures. Below 250° C, there i s no major degradation o f t h e coated polyvinylimidazole films on c o p p e r . Furthermore, degraded polyvinylimidazole films can suppress o x i d a t i o n even a t 4 0 0 ° C . Finally, p o l y v i n y l i m i d a z o l e s a r e more effective anti-oxidants than b e n z o t r i a z o l e and i m i d a z o l e s a t elevated temperatures. I t i s a l s o demonstrated t h a t FT-IRRAS i s a useful technique t o s t u d y d e g r a d a t i o n o f p o l y m e r i c c o a t i n g s and c o r r o s i o n o f metal simultaneously.
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Acknowledgment, The a u t h o r s g r a t e f u l l y acknowledge t h e f i n a n c i a l s u p p o r t o f the International Copper R e s e a r c h A s s o c i a t i o n , Inc. and t h e I n t e r n a t i o n a l B u s i n e s s Machines C o r p o r a t i o n .
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RECEIVED March 14, 1986
In Polymeric Materials for Corrosion Control; Dickie, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.