Lt.
.., &j
Department of Agriculture, Forest Service
FOREST PRODUCTS LABORATOR Y
In cooperation with the University of Wisconsin
MADISON, WISCONSIN
DECAY OF WOOD AND GROUNDWOOD PUL P
Relation of Loss in Weight to Chemical Properties
By MARK W. BRAY
Chemist in Forest Products
Published in
PAPER TRADE JOURNAL
June 5, 1924
DECAY01'WOOD AND GROUNDWOOD PULP
Ireatn
6f !JO -et '1 n -T'g T
Chemical Propertie s
k .' °
In a recent article entitled "Chemical Changes o f
Groundwood During Decay" 2 the writer and a collaborato r
reported the more important chemical changes, together wit h
the losses in weight, which took place in groundwood as a
result of infection with four different fungi in pur e
culture .
The data indicated that the hymenomycetes causin g
brown rots, with which the pulp samples were inoculated ,
acted to a greater extent on the cellulose of groundwoo d
than on the lignin . It was pointed out that the cellulos e
lost, in the case of one sample of extremely decayed pulp ,
was 54 .0 per cent on the basis of the original sound materia l
with an accompanying loss of but 3 per cent of the lignin .
This lignin loss was practically accounted for in ■ on e
typical case by the loss in the methoxyl content of th e
decayed material .
Although the loss in weight and the chemica l
changes which the groundwood underwent varied with the natur e
of the organisms, further study of these and other dat a
similarly obtained indicate that for the species of woo d
and the types of decay considered there exists certai n
-constant relationships between the loss in weight, th e
solubility of the material in a 1 per cent solution o f
caustic soda, solubility in hot water, and amount of cellulose and of lignin in the decayed material . A study o f
these relationsh i p s' forms the subject of the present paper .
1 Chemist in Forest Product ' t_
Laboratory, Madison, 'r ig .
2 Bray and A'nirewe, J . Ind . & Eng . C!
Forest Product s
►, . ,
16, 137 (1924) .
reported in bile where the val u
weight of the sample analyzed, and i
same values are bayed on the weight o
material .
Fig . 1, ou ve 1, shows the r,ALat ,O g @
ism' th e
solubility of the- decayed material in 1 per cent caustic
soda solution and the loss in weight during decay, whic h
loss is due to the production of gaseous material and wil l
be referred, to as the "volatile loss ." For the particula r
woods anc organisms used, a fairly smooth curve may be drawrw
through the points obtained from the data reported i n
Table 1 . With sound grdundwood the sb
i ' h'7tkali i s
approximately 10 per cent, and the curve is drawn so tha t
this point represents zero volatile loss .- The indicatio n
is clear that a definite loss in weight corresponfs to a
definite solubility in 1 per cent caustic soda solution .
,
The solubility of the pul p s in hot water, as shown
in Tables 1 and 2, increased as decay progressed . Therefore ,
when the groundwood pulp decayed ; it not only suffered a
volatile loss, but became subject to a further loss b y
solution in water . In Fig . 1, curve 2 the sum of thes e
losses, designated "total loss", is plotted agains t
solubility in 1 per cent alkali .
Relationship between cellulose content and solubility i n
alkal i
Just as there exist definite relationships betwee n
the alkali solubility of the infected groundwood pulps and "
the volatile and total losses respectively, so also there
bill
3 The r
l lerrtal data reported in Tables 1 and 2, upog) .whichi
discussion in this paper is based and the c
constructed, were presented in a manuscript 'r hi .ch
submitted for publication as a bulletin of the
._
Department of Agriculture, entitled "Control or Decay in
nd
kAood", by Kress, Humphr
ards, Bray and
A.
. Chi
Rich ds, =WI* ' '~olog -'
Offi c
Bureau bf
Tf
on, Wi s
R836
-2-
}
'
exists a definite relationship between the alkali solubilit y
and the cellulose content . The data sho w ing this relationshi p
are also given in Tables 1 and 2 . During incipient decay th e
organisms examined attacked the cellulose, but exerte d
apparently little action on the lignin . However, in on e
case previously alluded to_ in which the stage of decay wa s
well advanced, there was a small lignin loss which (based o n
the original sound,material) was, within experimental error ,
equal to the loss in the methoxyl content .
In plotting the values for cellulose against th e
solubility in alkali, curves 1 and 2 of Fig . 2 are obtained .
Curve 1 represents the cellulose content as referred to th e
sample analyzed ; curve 2 to the original sound, material . Al l
the values
very close to the respective curves, and th e
small divergencies are within the limits of experimenta l
error . It is possible, therefore, by determining the alkal i
solubility of a groundwood pulp . infected by any of th e
organisms listed in Table 1 and then by referring to th e
curves in Fig . 2, to determine the amount of cellulose i n
the affected sample per 100 parts of the sound pulp from *whic h
the affected pulp was obtained . Comparison of this value wit h
the cellulose content of sound pulp will reveal the proportio n
of the original cellulose that has been destroyed through th e
action of the decay organisms .
lie
In comparing curve 1 of Fig . 1 with curve 1 o f
Fig . 2, it will be noted that the observed loss in weigh t
of the groundwood as a, result of decay is less than th e
loss in the cellulose, up to the point "there the "volatil e
loss" is approximately 50 per cent . This is because th e
cellulose is attacked by the organisms to such an exten t
that a part of it is rendered soluble in the process o f
cellulose determination, but not decomposed into volatile :
substances . This deterioration of the cellulose
indicate d
by the increase in the reducing power of the decayed sample s
as shown by an increase in the copper number 4 and also by a
decrease in the alpha- and gamma-cellulose content of th e
Cross and Bevan cellulose . 5
is
Relation of the alkali solubility to the lignin content .
In plotting the alkali solubility of the decaye d
samples against their lignin content based on the sampl e
as analyzed, curve 1, Fig . 3 was obtained . This curv e
shows an apparent increase in lignin with increase in alkali :
solubility . If, ho wever, the data in Table 2, in which the .
values for lignin are based . on the original sound material ,
4 Bray and Staidl, J . Ind . & Eng . Chem ., 14, 35 (1922) .
5 Bray and Andrews, (loc . cit . )
R836
-3-
•
are examined it will be observed that a slight loss i n
lignin is sustained owing to decay .
Assuming, then that only a small percentage o f
lignin is decomposed by these types of organisms, th e
percentage of lignin to be expected in the decayed sampl e
as analyzed may be calculated approximately by the followin g
formula :
Percentage lignin in sound material x 100
100 -- "volatile loss "
= calculate d
percentage of lignin in sample as analyzed .
Possible Application of the Curve s
Calculation of losses in yiel d
of ground~r~ood pulp due to T deca y
By determining the solubility of a sample of woo d
decayed by any of the organisms listed in Table 1 and then
applying the relation expressed graphically by curve 1 ,
Fig . 1, it is possible to estimate the loss, which the origina l
sound wood has undergone in reaching the given state of decay .
By reference also to curve 2, Fig . 1, it is possible t o
estimate the further loss the decayed wood, during it s
manufacture into groundwood pulp, may suffer on account o f
its solubility in water .
Prediction of chemical properties of 'decaye d
wood by determining solubility in alkal i
In applying the curves derived from these experiment s
on groundwood to pulpwood itself, account must be taken o f
the removal of water-soluble material during grinding, whic h
tends to make the cellulose and lignin content of groundwoo d
pulp greater than that of the wood from which it is made .
In correcting for this removal, groundwood is taken a s
containing 60 per cent cellulose and spruce wood 58,6 per cent ,
and the abscissa of each point found on curve 1, Fig . 2 ,
is multiplied by the ratio 58 .6 for tabulation or plotting .
60
Similarly, the ratio for balsam is 56 .75 .
60
R836
-4-
By means of a determination of the solubilit y
in alkali it is thus possible to estimate without actua l
analysis the cellulose and lignin content of wood decaye d
by the organisms listed in Table 1 . It should be possibl e
to make similar estimations for wood decayed by any organis m
which acts upon the wood by attacking chiefly the cellulose .
In Table 3 are shown the solubility in alkali and th e
cellulose and lignin contents, determined experimentally ,
of 4 samples of spruce wood decayed by organisms whos e
identity has not been determined ; also for a sample of balsa m
in various stages of decay caused by Fomes pinicola . Al l
these samples show a lower cellulose content and a highe r
lignin content than sound wood, which indicates that th e
causative organisms have acted upon the wood in a manne r
similar to those listed in Table 1 . In columns 5 and 7 ,
Table 3, are shown the corres ponding values for cellulos e
and lignin calculated from the alkali solubilities by mean s
of the relations shown in Fig . 2 and the lignin formula ,
respectively . In calculating the lignin values a conten t
of 28 .3 per cent and of 31 .5 per cent were used for soun d
spruce and balsam respectively . The close agreement with th e
values experimentally determined tends to confirm th e
predicted character of the action of the organisms . It i s
reasonable to conclude that under these circumstances the `
relation between solubility and "volatile'loss" is equall y
applicable . The calculated values for the "volatile loss "
are shown in column 8 .
That the relationships as plotted in Figs . 1 and 2
are applicable only to conditions of decay in which th e
cellulose is attacked and the lignin practically unattacke d
is evidenced by lack of agreement between the calculate d
values and those determined experimentally for samples o f
spruce decayed by Trametes pini, a fungus which apparentl y
removes a greater proportion of the original lignin than o f
the original cellulose . It is possible, however, that an
analogous set of relationships may, by further investigation ,
be established for the properties of wood decayed by thi s
general type of organism .
Summary
With the data obtained from the chemical analyse s
of samples of groundwood pul p s inoculated with certai n
wood-destroying fungi, interrelationships have bee n
established between the following chemical constants :
Solubility in hot water, solubility in 1 per cent causti c
R836
-5-
soda solution, cellulose content, and lignin content ; and
a relationship of these values to the "volatile" and "total "
losses suffered during decay has been demonstrate d
f
From a knowledge of the solubility in l per cen t
sodium hydroxide solution of a sample of g roundwood infecte d
with the types of fungi herein studied, the above Values an d
losses may be calculated with a fair degree of accuracy .
R836
_g-
Table 1 .--Chemical properties of decayed groundwood pulps .
Data based on weight of samples as analyzed .
Sam- :Incuba :0_rganism :'Volatile :Cold :Hot : 1% :Lig-• :Cellu :"Total
pie :-tion :
or
: loss" :water : wa- :al- : nisi :-lose : loss "
:"VolaNo . :period : culture :
: sol- :ter :kali :
.
:sol:
: til e
:
No
: uble :sol:uble :uble :
: loss "
:+ ho t
:wate r
solubl e
:Months :
2544 : 0
26 : 6
25 : 9
24 ; 12
100 : 6
102 : 12
182 :3 yrs
106 : 6
107 : 9
108 : 12
130 : 6
131 :
9
148 :
6
149 :
9
152 :
157 :
6
6
158 :
9
27 :
28 :
32 :
6
9
6
30 :
9
31 : 12
49 :
50 :
133 : '
136 :
137 :
142 :
6
9
6
6
9
6
145 :
160 :
172 :
6
6
6
:Sound pulp :
:82219-15 :
:82219-15 :
:82219-15 :
: 4620-2
: 4620-2
. : 4620-2
: 4620-1
: 4620-1
4620-1 _
:Fomes
roseus
:Fome s
roseus
:Peniophor a
tabacina
:Peniophor a
tabacina
: 61420-7 :
: Lentinus :
lepideus
: Lentinus :
lepideus
:102019-la :
:102019-la :
:Paxillus :
panuoides
:Paxillus :
panuoides
:Paxillus :
panuoides
:10918-10 :
:10918-10 :
:_61520-1 :
: 61420-3 :
: 61420-3 :
:Corticium :
galactinum
: 62220-1 :
: 61420-4 :
: 6920-1
P
0
18 .13
21 .13
26 .39
27 .13
49 .45
62 .40
22 .20
33 .11
38 .63
10 .30
r
e
: 0 .0
: 6 .1
: 7 .6
: 8 .8
:11 .0
:14 .8
: -:12 .3
:16 .6
:14 .9_
. 3 .2
c
e
:1 .00 :10 .1 :
:11 .1 :46 .3 :
:13 .3 :47 .7 ;
:15 .5 :52 .1 :
:18 .0 :54 .9 :
:22 .2 :66 .8 :
:15 .4 :70 .0 :
:17 .7 :52 .4 :
:22 .8 :62 .2 :
:21 .2 :62 .0 :
: 6 .4 :33 .0 :
n
t
29 .7 :
35 .3 :
36 .0 :
39 .1 :
38 .0 :
53 .4 :
71 .0 :
39 .5 :
43 .1 :
46 .5 :
34 .1 :
60 .0 : 1 . 0
43 .5 :29 .2 3
42 .5 :33 .4 3
37 .8 :41 .89
36 .7 :45 .1 3
21 .8 :71 .65
16 .1 :77 . 8
37 .3 :39 . 9
27 .2 :55 .91
27 .6 :59 .83
49 .4 :16 . 7
12 .94 : 3 .7 : 5 .9 :33 .6 : 34 .9 : 50 .7 :18 .8 4
13 .51 : 5 .6 :10 .4 :40 .4 : 32 .1 : 46 .8 :23 .91
19 .48 :
-- : 9 .8 :46 .2 : 39 .8 : 43 .6 :29 .28
7 .94 : 4 .6 : 7 .7 :27 .8 : 31 .5 : 53 .0 :15 .64
21 .54 : 9 .6 :15 .1 :52 .3 : 36 .7 : 40 .9 ;36 .6 4
30 .31 :13 .9 :22 .6 :58 .2 : 41 .1 :*34 .7 :52 .9 1
1 .48 : 2 .4 : 4 .6 :14 .4 : 29 .1 : 57 .5 : 6 .0 8
2 .33 : 2 .0 : 3 .6 :14 .2 : 29 .8 : 59 .4 : 5 .9 3
1 .94 : 0 .0 : 1 .7 :13 .9 : 29 .3 : 56 .8 : 3 .64
2 .83 : 0 .7 : 5 .2 :14 .9 : 29 .2 : 57 .5 : 8 .0 3
3 .55 : 1 .5 : 4 .8 :18 .5 : a8 .8 : 58 .0 : 8 .3 5
1 .00
1 .77
2 .09
8 .-66
13 .94
2 .17
:
:
:
:
:
:
0 .0
2 .0
1 .6
5 .5
8 .1
1 .7
: 0 .6 :13 .2 :
: 2 .5 :12 .3 :
: 3 .3 :14 .3 :
: 8 .7 :33 .6 :
:11 .6 :43 .3 :
. 3 .1 :16 .2 :
29 .0 :
30 .1 :
30 .1 :
32 .1 :
33 .9 :
29 .1 :
58 .3 : 1 . 6
58 .0 : 4 .2 7
58 .7 : 5 .69
49 .4 :17 .36
44 .5 :25 .5 4
58 .5 : 5 .2 7
3 .19 : 1 .2 : 2 .4 :15 .1 : 29 .4 : 59 .6 : 5 .59
2 .77 : 1 .8 : 3 .2 :17 .7 : 29 .7 : 57 .4 : 3 .9 7
3 .31 : 2 .5 : 3 .8 :16 .3 : 29 .8 : 58 .3 : 7 .1
*This value appearing in Table 1, Bray and Andrews, loc . cit ., i s
in error .
Table 2 .--Chemical properties of decayed groundwood pulps .
Data based on weight of original sound pul p
Sam- :Incuba- : Organism :"Volatile : Cold : Hot
ple : tion :
or
loss" :water :water
.
culture
:sol- : solNo :period :
:
No .
:uble :uble
. Months :
2544 :
0
26 :
6
25 :
9
24 : 12
100 :
6
102 : 12
182 : 3 yrs
106 :
6
107 :
9
108 : 12
130 :
6
131 :
9
148 :
6
•
149 :
9
152 :
157 :
6
6
158 :
9
27 :
28 ;
32 :
6
9
6
30 :
9
31 :
12
49 :
50 :
133 :
136 :
137 :
142 :
6
9
6
6
9
6
145 :
160 :
172 :
6
6
6
:Sound pulp :
: 82219-15 :
: 82219-15 :
82219-15
46 04620-2
. : 4620-2
4620-1
: 4620-1
4620-1
Fomes
roseus
:Peniophora :
tabacina
:Peniophora :
tabacina
61420-7 .
Lentinu s
lepideus
Lentinu s
1epideus
102019-la :
102019-la :
Paxillu s
panuoides
Paxillus
panuoides
Paxillus
Danuoides
10918-10
10918-10
61520-1 .
61420-3 .
61420-3 .
:Corticium
galactinum
6222:0-1 .
. 01420-4 .
6920-1
e
0 .0
5 .0
6 .0
6 .4
8 .0
7 .4
-: 9 .5
:11 .1
: 9 .1
: 2 .8
: 3 .2
: 4 .8
r
: 1%
: al:kali
: sol:uble
c
e
: 1 .00 :
: 9 .1 :
:10 .5 :
:11 .4 :
:13 .1 :
:11 .1 :
: 6 .2 :
:13 .7 :
:15 .3 :
:13 .0 :
: 5 .7 :
: 5 .1 :
: 9 .0 :
,Lig- :Cellu: nin : los e
.
:
.
n
10 .1 :
37 .9 :
37 .6 :
38 .4 :
40 .0 :
33 .4 :
26 .3 ;
40 .8 :
41 .6 :
38 .0 :
29 .6 :
29 .3 :
34 .9 :
t
29 .7 ;
28 .9 :
28 .4 :
28 .0 :
27 .7 :
26 .7 :
26 .7 :
30 .7 :
28 .8 :
' 28 .5 :
30 .6 :
30 .7 :
27 .7 :
60 . 0
35 . 6
33 . 5
27 . 8
26 . 8
10 . 9
6 .1
29 . 0
18 . 2
16 . 9
44 . 3
44 . 2
40 . 5
0
18 .13
21.13
26 .39
?7 .13
49 .45
62 .40
22 .20
33 .11
38 .63
10 .30
12 .94
13 .51
:
:
:
:
;
19 .48
: 4 .9 : 7 .9 : 37 .2 : 32 .1 : 35 . 1
7 .94
21 .54
: 4 .3 : 7 .1 : 25 .5 : 29 .0 : 48 . 8
: 7 .5 :11 .8 : 41 .0 : 28 .8 : 32 . 1
30 .31
: 9 .6 :15 .7 : 40 .6 : 28 .6 : 24 .2*
1 .48
2 .33
1 .94
: 2 .4 : 4 .5 : 14 .2 : 29 .4 : 56 . 7
1 .9 : 3 .5 : 13 .9 : 29 .1 : 58 . 0
: 0 .0 : 1 .7 : 13 .7 : 28 .7 : ' 55 . 6
2 .83
: 0 :7 : 5 .1 : 14 .4 : ' 28 .4 : 55 . 9
3 .55
: 1 .4 : 4 .6 : 17 .8 : ' 27 .7 : 55 . 9
1 .00
1 .77
2 .09
8 .66
13 .94
2 .17
3 .19
2 .77
3 .31
:
:
:
.
:
:
0 .0
0 .2
1 .6
5 .0
6 .0
1 .7
: 0 .6
: 2 .4
: 3 .3
: 7 .8
:10 .0
: 3 .0
:
:
:
:
:
:
13 . 0 ,:
12 .1 :
14 .0 :
30 .7 :
37 .3 :
15 .9 :
28 .7 :
29 .6 :
29 .5 :
29 .4 :
29 .2 :
28 .4 :
57 . 7'57 . 0
57 . 4
45 . 2
38 . 3
57 . 2
: 1 .1 : 2 .4 : 14 .6 : 28 .5 : 57 . 7
: 1 .7 : 3 .1 : 17 .2 : 28 .9 : 55 . 8
: 2 .4 : 3 .7 : 15 .8 : 28 .8 : 56 .4
*This value appearing i n Table 2, Bray and Andrews, loc . cit . ,
is in error .
R
Table 3 .--A comparison of analytical and .
calculated data of the chemical propertie s
of certain decayed wood s
Sam- :
pie : Wood and organism
No . :
:"Vola:Alka- : Cellulose: Lignin
:
By
:
By
li : By
: By : til e
:
cal:expert
cal- : loss "
sol- :experuble :iment : cu- :iment : cu- : By
. la- :
: la- :calcu. tion :
: tion :lation
P
2549 :Spruce :organism unknown
e
r
c
e
n
t
15 .1 : 54 .6 : 56 .6 : 30 .6 : 29 .0 : 2 . 5
2545 :Spruce :
do .
: 20 .6 : 54 .2 : 54 .3 : 30 .5 : 29 .8 : 5 . 0
2546 :Spruce :
do .
: 39 .9 : 46 .9 : 46 .3 : 35 .2 : 33 .2 :14 . 8
2541 :Spruce :
do .
: 50 .2 : 42 .0 : 39 .5 : 38 .2 : 36 .2 :21 . 8
-- :Sound balsam
: 10 .1 : 56 .75 : -- : 31,5 :
-- .
208 :Balsam :Fomes pinicola : 29 .4 : 49 .7 : 49 .2 : 34 .5 : 34 .7 : 9 . 2
248 :Balsam :Fomes pinicola : 34 .8 : 45 .3 : 46 .9 : 36 .4 : 35 .8 :12 . 0
249 :Balsam :Fomes pinicola : 52 .5 : 35 .7 : 36 .6 : 44 .1 : 41 .2 :23 . 5
250 :Balsam :Fomes pinicola : 65 .5 : 25 .2 : 23 .6 : 52 .8 : 56 .3 :44 . 0
253 :Spruce :Trametes pini : 17 .5 : 57 .7 : 55 .9 : 29 .6 : 29 .3 : 3 . 5
254 :Spruce :Trametes pint : 20 .3 : 58 .5 : 54 .4 : 27 .5 : 29 .8 : 4 . 8
223 :Spruce :Trametes pini : 22 .9 : 59 .8 : 53 .6 : 25 .8 : 30 .1 : 6 .0
90
R6- L4T/0Y OF ~lLk9I/ Soh.014/kITr
-To
aROv/va Wooa PU~s
.Oec4rfb
CONTENT --l
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t
5n '
3a
CE'h
R83G
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R836
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