Spectroscopic Analysis of Southern Pine Treated with Chromated Copper Arsenate. II. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFT)

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Spectroscopic Analysis ofSouthern Pine Treated withChromated Copper Arsenate.II. Diffuse ReflectanceFourier Transform InfraredSpectroscopy (DRIFT)Jeffrey G. Ostmeyer a , Thomas J. Elder b & JerroldE. Winandy ca Kerr-McGee Technical Center , Oklahoma City,Oklahoma, 73125b School of Forestry and Alabama AgriculturalExperiment Station Auburn University , Alabama ,36849c USDA Forest Service, Forest Products Laboratory ,Madison, Wisconsin, 53705Published online: 23 Oct 2006.

To cite this article: Jeffrey G. Ostmeyer , Thomas J. Elder & Jerrold E. Winandy(1989) Spectroscopic Analysis of Southern Pine Treated with Chromated CopperArsenate. II. Diffuse Reflectance Fourier Transform Infrared Spectroscopy(DRIFT), Journal of Wood Chemistry and Technology, 9:1, 105-122, DOI:10.1080/02773818908050288

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JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY, 9(1), 105-122 (1989)

SPECTROSCOPIC ANALYSIS OF SOUTHERN PINE TREATED WITH CHROMATED COPPER ARSENATE. 11. DIFFUSE REFLECTANCE F O U R I E R TRANSFORM

I N F R A R E D SPECTROSCOPY ( D R I F T )

Je f f rey G. Ostmeyer Kerr-McGee Technical Center

Oklahoma C i t y , Oklahoma 73125

Thomas J . Elder School of Forestry and Alabama Agricul tural Experiment S ta t ion

Auburn University, Alabama 36849

Jer ro ld E . Winandy USDA Forest Service, Forest Products Laboratory

Madison, Wisconsin 53705

ABSTRACT

Although chromated copper arsenate ( C C A ) is one of the most important treatment methods fo r the prevention of decay i n wood, the nature of wood/CCA react ions a r e not c l ea r . The current s t u d y was undertaken t o e luc ida te the nature of chemical react ions occurring between the components of the t r ea t ing solut ion and the cons t i tuents of wood. Small, c l ea r Southern pine samples were t rea ted with s i x d i f f e ren t preservat ive solu i o n s ( C r ; Cr/Cu; C r / A s ; CCA-A; CCA-B; CCA-C) , a t 6 . 4 and 40 Kg/m (0 .4 and 2.5 pcf) re ten t ions , and compared t o water t rea ted and untreated controls . Samples were dr ied following treatment and analyzed by d i f fuse re f lec tance Fourier transform infrared spectroscopy (DRIFT) . Evaluation of DRIFT data indicated tha t the preservat ive components reacted with the aromatic and carbonyl groups i n wood.

5'

105

Copyright 0 1989 by Marcel Dekker, Inc.

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106 OSTMEYER, ELDER AND WINANDY

INTRODUCTION

One of the most important preservative treatments for the

prevention of decay in lumber is chromated copper arsenate (CCA).

Between 33% and 41% of all the southern pine lumber produced

annually is treated with CCA to prevent decay. ’-* Although the advantages of CCA treated lumber (such as superior decay

resistance, minimal environmental leaching, and relatively low

cost) are k n o ~ n , ~ - ~ the influence of CCA treatment on the

mechanical properties of wood are not yet ~ l e a r . ~ - ~ Because any

differences in mechanical properties may be a result of chemical

changes that occur during treatment, a fundamental understanding

of the wood/CCA reactions could lead to treatments that do not

have a negative impact on mechanical properties. Studies led by

Dahlgren8-’ and Pizzi14-17 investigated the kinetics of CCA

fixation and suggested possible metal complexes, but the nature

of wood/CCA bonding was not determined.

In the current study, several nondestructive, solid-state,

spectroscopic techniques were utilized to elucidate the nature of

wood/CCA complexes in situ in an attempt to understand the

influence of CCA treatment on the mechanical properties of

southern pine. These methods do not require an extraction or

isolation step, and should, therefore, be more representative of

the actual condition of the wood. Diffuse reflectance Fourier

transform infrared spectroscopy (DRIFT) is one of these

techniques, and Schultz et al. 18-19 and Schultz and Classer 20

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SOUTHERN P I N E WITH CHROMATED COPPER ARSENATE. I1 10 7

have demonstrated that DRIFT can be applied to wood, cellulose,

and lignin. Consequently, the functional groups in treated and

untreated wood could be evaluated without altering the nature of

the sample during preparation, such that the reactions between

preservative components and the constituents of wood might be

detected. This paper, the second in a series, presents results

from the DRIFT analysis of treated and untreated wood, and

provides supporting evidence for the nature of wood/CCA

complexes.

that the components of the treating solutions reacted with

non-oxygenated carbon atoms (predominately found i n the aromatic

ring of lignin) of wood, probably through some type of chromate

ester. Future papers will present additional chemical data and

will correlate the chemical information with matched mechanical

data.

In the first paper of this series,21 it was found

EXPERIMENTAL

The experimental design for this project consisted of six

treatments, each at two levels and two sets of controls, one

water-treated and one untreated (Table 1). Target retentions for

single (Cr) and double (Cr/Cu and Cr/As) component treating

solutions were based on individual component retentions of a

comparable CCA type C solution, not on total combined retention.

In this way, the amount of any particular preservative element in

the single and double component formulations was comparable to

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108 OSTMEYER, ELDER AND WZNANDY

TABLE 1 .

Trea tment R e t e n t i o n s .

R e t e n t i o n Kg/m3 ( p c f ) Low High

Treatment T a r g e t A c t u a l Target A c t u a l CCA t y p e A 6.4 ( 0 . 4 ) 6.2 (0 .39) 40 (2 .5 ) 42 (2 .63) CCA t y p e B 6.4 (0 .4) 4.8 ( 0 . 3 0 ) 40 (2.5) 24 (1.52) CCA t y p e C 6.4 ( 0 . 4 ) 5.6 (0 .35) 40 (2 .5 ) 39 (2 .42) Chromium 3.0 (0 .19) 2.7 (0.17) 19 (1 .19) 23 (1 .41) Chromium + Copper 4.2 (0 .26 ) 3.8 ( 0 . 2 4 ) 26 (1 .65) 25 (1 .53 ) Chromium + A r s e n i c 5.3 (0.33) 4.8 (0 .30) 33 ( 2 . 0 4 ) 38 (2.36) C o n t r o l s -Water -- -- -- -- -- -- -_ --

-- -- -- -- -- -- - U n t r e a t e d -- --

t h e amount o f t h a t e lement i n CCA t y p e C a t t h e same t a r g e t

r e t e n t i o n l e v e l . T h u s , when o n l y one o r two components were

c o n t a i n e d i n t h e t r e a t i n g s o l u t i o n , t h e t a r g e t r e t e n t i o n was l e s s

than t h e t a r g e t r e t e n t i o n of the three component CCA s o l u t i o n s .

The v a r i o u s t r e a t i n g f o r m u l a t i o n s were employed i n a n a t t e m p t t o

better u n d e r s t a n d the r e a c t i o n s between t h e p r e s e r v a t i v e

components and the c o n s t i t u e n t s of wood.

Sample P r e p a r a t i o n

For t h i s e x p e r i m e n t , o n l y c lear s o u t h e r n p i n e sapwood,

measur ing 2.54 cm x 6.35 cm x 76.2 cm (1.0 i n c h x 2.5 i n c h e s x 30

i n c h e s ) , was t reated. To r e d u c e v a r i a b i l i t y , t h e sample material

f o r t h e chemica l a n a l y s e s was c u t from a s i n g l e s o u t h e r n p i n e

f l i t c h . P r i o r t o t r e a t i n g , the samples were c o n d i t i o n e d t o a n

e q u i l i b r i u m m o i s t u r e c o n t e n t of 12% by s t o r i n g for two months i n

a n envi ronment chamber m a i n t a i n e d a t 23.3'C (74'F) and 65%

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SOUTHERN P I N E WITH CHROMATED COPPER ARSENATE. I1 109

relative humidity. Treating was performed at the United States

Department of Agriculture Forest Service, Forest Products

Laboratory in Madison, Wisconsin, in an experimental pressure

cylinder at ambient temperature with an initial vacuum of 74 kPa

(22 inches of mercury) maintained for 15 minutes, followed by 60

minutes of pressure at 1034 kPa (150 psig). Following treatment,

samples were stickered and conditioned for three months in a

controlled environment maintained at 23.3'C (74'F) and 6 5 %

relative humidity. After conditioning, 12.7 cm ( 5 inches) was cut

off one end of each specimen for chemical analysis. Sample blocks

were cut from this 12.7 em (5 inch) specimen for chemical

analysis. Except for samples analyzed for preservative retention

(which included the entire cross section), all chemically analyzed

material originated from within the ffbulkff of the original sample

(which excluded the original sample surfaces). Specimens for

DRIFT analysis were prepared from sample blocks, measuring 1.0 cm

(0.4 inch) radially, 1.0 em (0.4 inch) tangentially, and 2.0 cm

(0.8 inch) longitudinally, by cutting a clean, smooth transverse

surface using a sliding microtome. The specimen for analysis was

then sawn off the sample block at 0.2 cm (0.08 inch) below the

microtome prepared surface.

Sample Analysis

Diffuse reflectance Fourier transform infrared spectroscopic

(DRIFT) analysis was performed during February 1986 at the

Anglo-American Clays subsidiary of ECC America Inc., in

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S a n d e r s v i l l e , Georgia, u s ing a Perkin-Elmer 1710 FTIR equipped

wi th a Har r i ck S c i e n t i f i c d i f f u s e r e f l e c t a n c e a t tachment . A l l

s p e c t r a were t h e r e s u l t of 250 scans being s i g n a l averaged , wi th a

r e s o l u t i o n of 2 cm-’ . A s i n g l e spectrum was ob ta ined f o r each

t r ea tmen t , The specimens were placed d i r e c t l y i n t o t h e d i f f u s e

r e f l e c t a n c e sample ho lde r , such t h a t t h e i n f r a r e d beam impinged on

the microtomed t r a n s v e r s e su r face . I t should be noted t h a t DRIFT

is cons idered t o be a “bulkg1 a n a l y s i s t echn ique , w i t h a sampling

d e p t h f o r wood g r e a t e r than 1.0 micron. 22

RESULTS AND DISCUSSION

Peak assignments f o r DRIFT s p e c t r a were made accord ing t o

24 those of Liang and M a r c h e ~ s a u l t , ~ ~ Higgins e t a l . ,

Marchessault ,25 Szymanski,26 Sarkanen e t a l . ,27 Marton and

Sparks ,28 and Pretsch e t a12’ (F igu re 1 ) . While DRIFT

( r e f l e c t a n c e ) s p e c t r a are n o t i d e n t i c a l t o t r ansmiss ion

(absorbance) s p e c t r a ob ta ined v i a a KBr d i s k , i t was found t h a t

t h e r eg ions of i n t e r e s t a r e c o n s i s t e n t between t h e two methods.

I t should be noted t h a t t h e s p e c t r a could be smoothed t o reduce

n o i s e , however, t h i s Smoothing masked changes between the

t r ea tmen t s . The s p e c t r a were t h e r e f o r e , analyzed wi thout

smoothing. For between sample comparisons, the peak a r e a s of

i n t e r e s t were taken as their r a t i o a g a i n s t t h e carbon-hydrogen

(C-H) s t r e t c h i n g peak area (3020 - 2775 em-’), t o reduce the

in f luence of sample he t e rogene i ty due t o v a r i a t i o n s i n s i g n a l

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SOUTHERN P I N E WITH CHROMATED COPPER ARSENATE. I1 111

OH

c-0 w C-0-C

4,000 3,000 2,000 1,600 1,200 800 400

(cm-'1

F I G U R E 1 . Major P e a k a s s i g n m e n t s f o r DRIFT S p e c t r a (C02 peak is from t h e a i r n o t t h e s a m p l e ) .

e n e r g y and b a s e l i n e errors. Peak b a s e l i n e s were drawn from the

p o i n t o f t r a n s m i t t a n c e on o n e s ide of t h e peak t o t h e p o i n t o f

t r a n s m i t t a n c e on the other side of t h e peak. Past s t u d i e s have

o f t e n used the a r o m a t i c peak c e n t e r e d a t 1510 cm-l as a n i n t e r n a l

s t a n d a r d . 2 6 S i n c e t h e aromatic peak a t 1510 cm-l was t o be

a n a l y z e d i n t h i s s t u d y , t h e C-H peak was c h o s e n as t h e i n t e r n a l

s t a n d a r d because o f its between sample s t a b i l i t y . I t s h o u l d be

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noted tha t when the peaks of i n t e re s t were taken as t h e i r r a t i o

against the oxygen-hydrogen ( 0 - H ) s t re tch ing peak (3700 - 3020

cm 1, which was used a s an in te rna l standard by St-Germain and

Gray3', the same general r e s u l t s were obtained a s when the C-H

peak was used.

-1

DRIFT analysis of earlywood specimens gave consis tent

r e s u l t s , b u t the latewood results were incons is ten t , with a

low-signal-to noise r a t i o . T h i s was because the higher density

latewood portion of the sample resu l ted i n extensive specular

ref lectance. While latewood spectra could have been obtained by

grinding the sample and d i l u t i n g i n potassium bromide ( K B r ) , the

reason the neat DRIFT technique was used i n t h i s study was t o

analyze the wood i n the so l id s t a t e without a l t e r i n g i ts chemical

s t ruc ture . Because the react ion of K B r w i t h the t r ea t ing

chemicals and t rea ted wood a r e unknown, mixing KBr with the wood

samples might result i n uncertainty i n in te rpre ta t ion and was

unacceptable. Therefore, DRIFT ana lys i s was r e s t r i c t e d to the

earlywood samples. While the earlywood DRIFT spec t ra could have

been smoothed t o yield very c lear spectra with a high

signal-to-noise r a t i o , it was found i n t h i s s t u d y t h a t t he

smoothing procedure masked treatment e f f ec t s . For t h i s reason,

the or ig ina l unsmoothed spectra were evaluated.

Aromatic Peak

In general , the aromatic region (1549 - 1483 em-' ) of the

Spectra is la rger fo r t h e controls than f o r the CCA treatments,

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SOUTHERN PINE WITH CHROMATED COPPER ARSENATE. I1 113

TABLE 2.

DRIFT Peak Ratios.

CH : Aromat i c CH : Carbonyl Treat men t Low Ret. High Ret. Low Ret. High R e t . CCA type A 4 .O 5.8 4.5 5.5 CCA type B 6 - 3 6.5 5.4 5.9 CCA type C 6.1 12.1 5.9 8.1 Chromium 4.3 3.5 4 .2 4 .O Chromium + Copper 3.6 2.8 4.2 3.7 Chromium + Arsenic 3.6 3.8 4 .O 4.1

Controls -Water 4.4 4.6 -Untreated 3.7 3.9

CH:Aromat i c CH:Carbonyl

w i t h CCA-C having the smallest aromatic peak (Table 2 and F i g u r e

2 ) . The s ingle and double component t r ea t ing so lu t ions ind ica te

no differences i n aromatic content r e l a t i v e t o the cont ro ls ,

suggesting tha t the s ing le and double component treatments cannot

be used a s model systems to understand the CCA treatments.

CH:aromatic r a t i o was 3.7 fo r the untreated control and 12.1 f o r

high re ten t ion CCA-C t reated wood. With almost a 7 0 % reduction i n

the aromatic peak, t h i s suggests t h a t some of the preservat ive

components i n CCA treatments reac t with the l ign in cons t i tuents of

the wood. I t is a l so in te res t ing tha t f o r each of the three CCA

formulations the h igh re ten t ions resul ted i n greater reductions in

the aromatic peak than the comparable low re t en t ions , indicat ing

tha t both formulation and re ten t ion a re important. Further , i t

should be noted t h a t the water t rea ted control has a smaller

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l3 c

Treatment

FIGURE 2. CH:Aromatic Peak Ratios from DRIFT Spectra for Earlywood Samples.

aromatic peak t h a n the untreated Control, suggesting t h a t water

treatment alone may cause changes i n the l i gn in cons t i tuent of

wood,

The aromatic r i n g of l i g n i n contains non-oxygenated carbon

atoms, and X-ray photoelectron spectroscopy indicated tha t some of

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SOUTHERN P I N E WITH CHROMATED COPPER ARSENATE. I1 11 5

CH2 OH

C I C

OH

-c-o\ I / C \ I / 1 /Cr\ ll + Pr\ -c-0

\ / I

I

d

I I ?\ FIGURE 3 . Proposed Wood Chromate Esters.

t h e components of t h e t r e a t i n g s o l u t i o n s reacted wi th t h e

non-oxygenated carbon atoms i n wood.21 T h e r e f o r e , t h e decrease in

a romat i c c o n t e n t observed h e r e s u p p o r t s p r e v i o u s f i n d i n g s from t h e

a n a l y s i s of CCA t r e a t e d s o u t h e r n p ine by X-ray p h o t o e l e c t r o n

SpeCtrOSCOpy,21 t h a t CCA forms bonds wi th l i g n i n .

i n f r a r e d bands a r e s e n s i t i v e t o v a r i a t i o n s i n s u b s t i t u t i o n , 2 6 t h e

wood/CCA bonding proposed by Ostmeyer e t a1.21 (see F i g u r e 3 ) may

Because

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e x p l a i n t h e decrease i n t h e a romat i c peak detected v i a DRIFT. I t

must be noted t h a t the decrease i n the a romat i c peak e v a l u a t e d

h e r e does n o t i n f e r t h a t t h e a romat i c r i n g is be ing d e s t r o y e d , b u t

on ly t h a t t h e bonding about the a romat i c r i n g is changing .

I t is impor tan t t o no te t h a t f i v e o f t h e s i x CH:Aromatic

r a t i o s f o r the CCA t r e a t m e n t s are a l l grouped t o g e t h e r , and t h o s e

f o r the two c o n t r o l s and a l l of the s i n g l e and double component

t r e a t m e n t s are a l s o grouped t o g e t h e r . Of the s i x CCA t r e a t m e n t s ,

f o u r had CH:aromatic r a t i o s between 5.8 and 6.5. The CH:aromatic

r a t i o f o r h igh r e t e n t i o n CCA-C was 12.1, i n d i c a t i n g t h a t i t

reacted wi th the l i g n i n t o a g r e a t e r e x t e n t t han t h e o t h e r

fo rmula t ions . Converse ly , t h e low r e t e n t i o n CCA-A t r e a t m e n t had a

CH:aromatic r a t i o o f on ly 4 .0 , i n d i c a t i n g t h a t t h i s fo rmula t ion

d i d no t react wi th l i g n i n t o t h e e x t e n t o f t h e other CCA

fo rmula t ions . The s i n g l e and double component t r e a t m e n t s i n d i c a t e

l i t t l e o r no d i f f e r e n c e i n a r o m a t i c c o n t e n t a s compared t o the

u n t r e a t e d c o n t r o l . T h i s t h e n , demons t r a t e s t h e s y n e r g i s t i c n a t u r e

of CCA f o r m u l a t i o n s , and i n d i c a t e s t h a t a l l three o f t h e

p r e s e r v a t i v e components are r e q u i r e d t o e v a l u a t e CCA/wood

r e a c t i o n s . T h i s is i n good agreement wi th X-ray p h o t o e l e c t r o n

spec t roscopy results.

Carbonyl Peak

21

The ca rbony l ( C = O ) s t r e t c h i n g r e g i o n (1767 - 1690 cm-1) of

t h e s p e c t r a i n d i c a t e s t h e same t r e n d as found i n the a romat i c

r e g i o n , such t h a t t r ea tmen t w i th CCA decreases ca rbony l c o n t e n t

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9 i-

Treatment

FIGURE 4 . CH:Carbonyl Peak Ratios from DRIFT Spectra.

(Table 2 and Figure 4 ) .

most of the CCA treatments were grouped together , and the two

cont ro ls and a l l of the s ing le and double component treatments

were grouped together. The CH:carbonyl r a t i o was 3.9 fo r the

untreated control and 8.1 f o r h i g h re ten t ion CCA-C t r ea t ed wood

which had the highest CH:carbonyl r a t i o . Four of the s i x CCA

A s was the case wi th the aromatic region,

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treatments had CH:carbonyl r a t i o s between 5.4 and 5.9, w i t h low

retent ion CCA-A having a CH:carbonyl r a t i o of only 4.5. T h i s

again indicates t ha t the most and l e a s t reac t ive CCA formulations

a re high retent ion CCA-C and low re ten t ion CCA-A, respect ively.

A s was the case wi th the aromatic peak, increasing re ten t ions f o r

the CCA formulations resul ted i n greater reductions i n carbonyl

content. Water treatment a l so appears t o r e s u l t i n a decrease in

carbonyl content a s compared t o untreated controls .

I t is s u r p r i s i n g , however, tha t none of the treatments

indicated a marked increase i n carbonyl func t iona l i ty over the

untreated control . Based on c l a s s i ca l organic chemistry, it might

be expected tha t the la rge number of a lcohol ic -OH groups present ,

par t icu lar ly i n ce l lu lose , would be oxidized to carbonyl compounds

(aldehydes, ac ids , and ketones) , 31-35 and suggests t h a t the

react ions between the cons t i tuents of wood and the components of

CCA preservat ives a re qui te complex. I t has been reported,

however, tha t t h e ra te - l imi t ing s t ep i n chromic acid oxidation of

alcohols and aldehydes is the decomposition of the intermediate

chromate e s t e r t o form the carbonyl .32 I t is possible , therefore ,

tha t the wood/chromate intermediates, formed by alcohol and

aldehyde oxidations, do not decompose t o form carbonyls, b u t

ra ther remain a s s t ab le complexes. This would explain why the

carbonyl peak decreased w i t h treatment ra ther than increased.

Thus, i t appears tha t wood/CCA complexes a l so form a t carbonyl

func t iona l i t i e s i n wood.

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There was no ev idence i n t h e i n f r a r e d s p e c t r a i n d i c a t i n g a

r e a c t i o n of ca rbohydra t e s w i th t h e components o f t h e t r e a t i n g

s o l u t i o n . However, t h i s does n o t mean t h a t the c a r b o h y d r a t e s

cou ld n o t have reacted with the t r e a t i n g s o l u t i o n s . Due t o the

complexi ty and width o f t he C-0 band o f t h e i n f r a r e d s p e c t r a , peak

s h i f t s r e s u l t i n g from some wood/preserva t ive bonds may n o t have

been detectable . For example, i f c e l l u l o s e reacted wi th CuO, t h e

r e s u l t i n g C-0 v i b r a t i o n from a C-0-Cu bond might n o t be

d i s c e r n a b l e from o t h e r C-0 v i b r a t i o n s such as C-0-C and C-0-H

bonds. The C-0 band a l s o o v e r l a p s the a romat i c C-H in -p lane

deformat ion band.36

and r e l i a b i l i t y , the C-0 band was n o t e v a l u a t e d .

T h e r e f o r e , due t o q u e s t i o n a b l e i n t e r p r e t a t i o n

SUMMARY AND CONCLUSIONS

DRIFT a n a l y s i s of earlywood samples r e s u l t e d i n c o n s i s t e n t

s p e c t r a t h a t were similar t o t r a n s m i s s i o n ( abso rbance ) s p e c t r a .

Latewood samples , however, r e s u l t e d i n i n c o n s i s t e n t s p e c t r a , w i th

a low s i g n a l - t o - n o i s e r a t i o , t h a t could n o t be ana lyzed . A s such ,

o n l y t h e ear lywood r e s u l t s were d i s c u s s e d .

Treatment o f sou the rn p ine wi th CCA p r e s e r v a t i v e s r e s u l t e d i n

a decrease i n both t h e a romat i c and ca rbony l peaks o f t h e i n f r a r e d

s p e c t r a . T h i s s u p p o r t s t he r e s u l t s o b t a i n e d u s i n g X-ray

p h o t o e l e c t r o n spec t roscopy2’ and s u g g e s t s t h a t t h e components o f

the v a r i o u s t r e a t i n g s o l u t i o n s s t u d i e d form bonds wi th the

a romat i c r i n g of l i g n i n and the ca rbony l groups p r e s e n t i n wood.

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O f the CCA fo rmula t ions , i t appea r s t h a t CCA-C and CCA-A may be

s l i g h t l y more and l e s s r e a c t i v e wi th t h e wood, r e s p e c t i v e l y .

While the CCA t r e a t m e n t s r e s u l t e d i n decreased aromatic and

carbonyl f u n c t i o n a l g roups , none of t h e s i n g l e or double component

t r e a t m e n t s had a marked e f f e c t on the a romat i c or carbonyl groups

a s compared t o wa te r - t r ea t ed or u n t r e a t e d c o n t r o l s . I t appea r s

t h a t a l l t h r e e of t h e CCA components a r e r e q u i r e d i n t h e t r e a t i n g

s o l u t i o n f o r wood/CCA r e a c t i o n s t o occur .

ACKNOWLEDGMENTS

T h i s r e s e a r c h was suppor t ed , i n pa r t , by t h e USDA F o r e s t

Products Labora tory , is publ i shed a s Alabama A g r i c u l t u r a l

Experiment S t a t i o n J o u r n a l S e r i e s No. 9-881812P, and is based on

t h e s e n i o r a u t h o r ' s doctoral d i s s e r t a t i o n . The a u t h o r s are

g r a t e f u l t o Anglo-American Clays and p a r t i c u l a r l y Dr. C . Arlyn

Rice f o r t h e i r coope ra t ion and a s s i s t a n c e i n performing t h e DRIFT

a n a l y s i s . Mention of manufac turers and p roduc t s i n t h i s paper is

p resen ted for t h e b e n e f i t o f the r e a d e r and does no t c o n s t i t u t e

endorsement by Auburn U n i v e r s i t y , t h e Alabama A g r i c u l t u r a l

Experiment S t a t i o n , o r t h e USDA F o r e s t S e r v i c e , F o r e s t P roduc t s

Labora tory .

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Spectroscopic Analysis of Southern Pine Treated with Chromated Copper Arsenate. II. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFT)