Hvdrocellulose Water Flow Number J
RELATIONSHIP TO FINE STRUCTURES OF FIBERS, PARTICULARLY FIBER ORIENTATION 0. A. BATTISTA, J. A. HOWSMON, AND SYDNEY COPPICK American Viscose Corp., Marcus Hook, P a .
D
1
1
'
4
.
URING work on the measurement of the per cent hydrocellulose residue and the leveling-off basic degree of polymerization (1)of cellulose fibers, (originally defined as the basic degree of polymerization of the hydrocellulose residue recovered after a sample has been subjected to 2.50 N hydrochloric acid for 15 minutes at 105" C.), i t was observed qualitatively that the ease with which a hydrocellulose residue could be purified appeared to be related to the history of the original fibers prior to hydrolysis. Hydrocellulose residues prepared from cotton linters could be washed free of the hydrolyzing acid more rapidly than equivalent weights of hydrocellulose residues prepared in an identical manner from wood pulps. With regenerated fibers, for example, godet stretch which affects the x-ray orientation parameter sharply was found to have an unusually pronounced influence on the time required to filter water through equivalent weights of hydrocellulose residues prepared by a uniform hydrolysis procedure. I n attempts to put the foregoing observations on a quantitative basis, the hydrocellulose water flow number has been developed. The present work primarily concerns evaluation of this property of hydrocelluloses as a new parameter of fiber orientation, although several other variables that affect fine structure are considered. The hydrocellulose water flow number is correlated quantitatively with two other well established orientation parameters-linear swelling and x-ray diffraction.
.PREPARATION OF SAMPLE AND ITS HYDROCELLULOSE RESIDUE. The apparatus and procedure for reducing cellulose to its leveloff basic degree of polymerization in a uniform manner have been described (1). Rayon samples that are free of finishes are cut i n approximately 0.5-inch lengths with a sharp scissors. Pulp samples are handled in flock form and are prepared in the following manner: The pulp in the form of cut squares or as flock is gently dispersed in distilled water at room temperature (25' (10 grams of pulp per liter) by means of a Waring Blendor or Osterizer for about 5 minutes, so as to mix all the fibers together in a homogeneous manner. The fibers are collected on a coaree fritted-glass filter, soaked for 15 minutes in redistilled methanol, and recollected on the filter. The resulting loose mat is airdried and then broken up by hand into small pieces. All samples are conditioned for a minimum of 24 hours in a conditioning room (58% relative humidity, 74" F.). Moisture is determined on an aliquot of the conditioned sample. On the basis of this moisture content, a weight of the conditioned sample equivalent to 2.000 grams of cellulose on an oven-dry basis is weighed out. The actual equilibration conditions are not critical, inasmuch as the sample is wet out with 2.50 N hydrochloric acid at room temperature (25' C.) just prior t o being hydrolyzed t o its level-off basic degree of polymerization. The important information is the per cent of water in the sample, so that the oven-dry weight used may be accurately determined.
c.)
HYDROCELLULOSE WATER
FLOW NUMBER
-
*
DEFINITION.The hydrocellulose water flow number is defined as the time in seconds required t o draw 100 ml. of distilled water (25"C.) through B hydrocellulose residue collected on a calibrated sinteredglass thimble. The vacuum under which the measurement is carried out is 60-mm. reduced pressure. The hydrocellulose residue is prepared in a uniform manner by hydrolyzing 2.000 grams of sample (equivalent oven-dry weight) in 2.50 N hydrochloric acid a t 105' C. for 15 minutes. This hydrolysis treatment reduces the cellulose to its leveling-off degree of polymerization (1). The hydrocellulose water flow number as defined is abbreviated in use as the HF number.
Figure 1. Apparatus for Measuring Hydrolysis-Resistant Cellulose and Reducing Cellulose to Its Leveling-Off Basic Degree of Polymerization 2107
2108
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol, 45, No, 9
Figure 2. Apparatus for Measuring FIF Xumber of Hydrocellulose Residue Fifteen to 20 nll. of 2.50 A' hydrochloric acid a t 25" C. are added t o the mrnple t o wet it out completely and t o make it easier t o transfer it quantitatively t o the 2.50 N hydrochloric. acid a t 105' 6. It is important t o effect a uniform saturation of the cellulose fibers with water (hydrochloric acid solution), just prior t o their addition t o the hot hydrochloric acid.
A study of the effect of the actual water content in cellulose fibers (conditioned to equilibi ium from both the wet and ovendry sides in a range of relative humidities from 1 to 1007,) on the hydiocellulose mater f l o number ~ will comprise a separate publication. I n general, the hjdiocellulose water flow number of a sample that is ovendi y upon addition to 2.50 S hydrochloric acid a t 105" C. is lower than the hj-drocellulose mater flow number of the same sample added to the 2.50 S hydrochloiic acid a t 105' C. in a water saturated state-i.e., normal test conditions. This behavior may be related to the predisposition of the chains in the amorphous regions of the fibeip to crystallize on hydrolysis, such predisposition being influenced by the water content of the fibers. *
Vsing stainless steel tweezers, the sample is transferred as quantitatively as possible t o 300 ml. of 2.50 S hydrochloric acid previously brought t o 105" C., and is hydrolyzed for exactly 15 minutes from the time of addition t o the 2.50 A- hydrochloric acid, Apparatus for carrying out this step is shown in Figure 1. The temperature of the 2.50 N hydrochloric acid drops temporarily 2' to 3" upon the addition of the sample, but may be re-established quickly by controlling the rheostat and the rate of nitrogen inflow. The hydrocellulose residue resulting from the treatment is collected on a tared and calibrated sinteredglass filter, The filters on which the hvdrocellulose residues are collected are a special type designed and calibrated for the measurement of the hydrocellulose water flow number. Although the filters are calibrated by the manufacturer, it is best t o check their calibration prior to each use, using the e uipment shown in Figure 2. These filters are made by Ace d a s s Co., Vineland, S . J., and are identified as "Battista HF number thimbles." The porosity of the filter is such that 100 ml. of a 259" aqueous sodium chloiide solution will pass through it i n not more than 7 seconds whcn an initial reduced pressure of 60 mm. is applied. It
is recommended that the hydrocellulose water flow number of a standard sample of celluIose be determined on each new filter before it is put into service, to double-check its conformity with the porosity of other filters in previous use. MEASUREMENT OF HYDROCELLULOSE KATER FLOWSUMBIOR. The apparatus shown in Figure 2 is M adjusted that when t h e stopcock leading to the filtering flask is closed, a reduced pressure of 60 mm. is maintained, using a Cenco Hyvac pump. Immediately after the sample has been hydrolyzed for 15 minutes a t 105" C., it is collected on a tared HF thimble. After the contents of the 3-necked flask have been transferred, 50 ml. of distilled water are used to rinse the flask out and remove any hydrocellulose particles adhering to the flask; the rinse water is added to the tared filter. The residue is collected on the filter in the form of a level cake or pad. As soon as the 50 ml. of rinse water have passed through t h e filter, the stopcock leading to the filtering flask is closed until the 60 mm. of reduced pressure is re-established; the cake is not allowed t o suck dry. portion of a 100-ml. aliquot of distilled water (at 25" C.) is added t o the filter, the stopcock t o the filtering flask is opened, and the time in seconds for a total of 100 ml. of distilled water t o pass through the wet residue on the filter is determined. The manometer serves as a very sensitive indicator t o tell when the 100 ml. of distilled water have passed through the residue; the clock is stopped the instant a loss of vacuum is noticed on the manometer. The 100-ml. flow time is recorded as the hydrocellulose v,-ater flow number of the sample. Further purification of the residuc may be carried out on soparate equipment using a laboratory bench vacuum line ( 1 ) . The basic degree of polynierization of the original sample as well as of its residue is measured using the Battista equation ( 2 ) . The basic degree of polymerization term iq used to specify a degree of polymerization value calculated from cuprammonium viscosity measurements a t a single concentration. The experimental bases of the Battista viscosity-basic degree of polymerization correlation equation and similar formulas utilizing one viscosity measurement have been elaborated upon in recent years by Calvert and Clibbens (3)and substantiated by the work of X'altasaari (10).
September 1953
INDUSTRIAL AND ENGINEERING CHEMISTRY
2109
tial blocking of pores in the sintered-glaas filter by very small hydrocellulose particles. TABLEI. EFFECTOF RESIDUEWEIGHTON HYDROCELLULOSE WATERFLOW NUMBER In Table 11, the effect of constant residue weight Oven-Dry Wt. of Original Sample,
G.
Time for 100 MI. of Water t o Pass through Filter (under a Vacuuin of 60-Mm. Pressure), Sec. With After After Filter hydroscraping flushing residue prior to cellulose residue off from use residue on filter (no (control) filter flushing) filter I
TABLE 11. COMPARISON OF CONSTANT us. VARIABLE RESIDUE J17E:IGHT ON IIYDROCELLULOSE WATER FLOW NUMBER H F Number, Sec. Constant .4s residue defineda weight
Sample
Absorbent cotton linters Cotton lintere pulp Sulfite pulp Sulfate pulp Fortisan Special tire yarn Tire yarn Textile yarn I Textile yarn I1 a Original weight of sample constant at 2.000 grams, oven-dry. Residue weight of sample constant a t 2.000 grams, oven-dry.
*
MEASUREMENT O F ORIENTATION
d
"
BY LINEARSWELLING.The method used is essentially a modification of that described by Preston and Bhat (8). Yarns are hung in a vertical tube with a nickel weight corresponding to 0.001 gram per denier, and conditioned to 75' F. in a room having the relative humidity controlled a t 40%. Water is drawn into the tube a t 75" F. and the yarn is wetted out and dried through a number of cycles. Dimensional changes are followed during each cycle using a cathetometer. The average extension on wetting, neglecting the first cycle which is influenced by yarn strain, is taken as the linear swelling. All linear swelling- data were measured on the original samples prior to hydrolysis. BY X-RAY DIFFRbCTION. The methods of measuring fiber orientation by x-ray diffraction are reviewed and discussed by Howsrnon ( 5 ) . In the present work, x-ray results are expressed in terms of the maximum angle, as has been done by Hermans et al. ( 4 ) and Ingersoll (6). The orientation of the crystallite components increases with decreasing values for the 1 / ~ maximum angle. All x-ray orientation measurements were made on the original samples prior to hydrolysis.
us. variable residue weight-i.e., constant sample w e i g h t o n the hydrocellulose water flow number for a range of samples is shown. Inasmuch as the hydrocellulose water flow number normally is measured as part of the per cent hydrocellulose residue and leveling-off basic degree of polymerization methods ( 1 ), it is customary to keep the original weight of the sample constant a t 2.000 grams (oven-dry basis). All data are 90 obtained unless otherwise indicated. Where i t is desired to measure the hydrocellulose water flow number on the basis of a constant residue weight, per cent hydrocellulose residue must be determined first to find the necessary factor whereby the initial weight of the sample required to give 2.000 grams of residue (oven-dry) after hydrolysis may be calculated. For some research purposes, where small differences in hydrocellulose water flow number are significant, it is preferable to measure the hydrocellulose water flow number on the basis of constant residue weight in lieu of constant oven-dry sample weight. When this is done, it is suggested that the data be so qualified by being quoted as hydrocellulose water flow number (constant residue weight). However, for most practical studies, a single measurement made in conjunction with hydrolytic characterizations in terms of per cent hydrocellulose residue and the level-off degree of polymerization has been found satisfactory; such a measurement is made on the basis of constant oven-dry sample weight in accordance with the original definition of the hydrocellulose water flow number. REPRODUCIBILITY OF HYDROCELLULOSE WATERFLOW NUMBER. The reproducibility of the hydrocellulose water flow number (using constant original oven-dry sample weight) is better in the low ranges than in the high ranges. I n Table 111,repeat tests on a sample of high-tenacity regenerated cellulose yarn having a relatively low hydrocellulose water flow number are compared with repeat tests on a sample of lower-tenacity regenerated cellulose yarn having a considerably higher hydrocellulose water flow number. The coefficient of variation of the hydrocellulose water flow number in the 200-second range is about 1.5%. I n the 1300-second range, it is about 5%.
TABLE , 1 11. REPRODUCIBILITY OF HYDROCELLULOSE WATER FLOW NUMBER
Experimental tire yarn (high-tenacity regenerated cellulose yarn)
Test NO. 1 2 3 4
Avisco staple regenerated oelluloee yarn
1 2 3 4
Hydrooellulaqe Hydrocellulose Residue, Flow Number, % Seo. 81.2 210 81,O 205 81.5 209 81.1 202 79.6 79.7 79.3 79.9
1320 1395 1268 1251
RESULTS
EFFECTO F SAMPLE WEIGHT ON HYDROCELLULOSE WATER FLOWSUMBER. Inasmuch as the per cent hydrocellulose residue from 2.000 grams (oven-dry basis) of various samples differs within relatively narrow limits, depending on the history and fine structure of the original sample, the effect of the weight of the hydrocellulose residue on the hydrocellulose water flow number was determined (Tables I and 11). As might be expected, sample weight has a significant effect on the hydrocellulose water flow number. However, the variations in per cent hydrocellulose residue found within families of native and regenerated celluloses are always relatively small in comparison with the large differences in the hydrocellulose water flow number values. The data in Table I also show that the hydrocellulose water flow number is a measure of the porosity of the hydrocellulose residue on the filter, and not a reflection of filter plugging due to preferen-
EFFECT O F VARIOUS FACTORS ON HYDROCELLULOSE WATER FLOW NUMBER
EFFECT OF WILEY MILLING. To test the advisability of standardizing the physical form of the cellulose prior t o hydrolysis and measurement of the hydrocellulose water flow number, Wiley milling, using a 20-mesh screen, was chosen for the experiments described i n Table IV. The hydrocellulose water flow number increases when the original sample is ground in a Wiley mill prior to hydrolysis. This demonstrates the great sensitivity of the supermolecular structure of cellulose t o mechanical manipulations and the undesirability of reducing samples t o a uniform physical form by mechanical treatment when fine structure studies are involved. The results focus attention on the importance of a n accurate knowledge of sample history if data on fine structure characteri-
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 45, No. 9
hydrolysis timea have been progressively increased. Results are given in Table V. The effect of time of hydrolysis on the hydrocellulose water flow number seems t o be a characteristic property of each sample. EFFECT OF MILD PREHYDROLYSIS. When freshly spun rayon yarns are given a mild prehydrolysis treatment] before being subjected to the swelling and hydrolysis that accompany the normal processing and purification of viscose rayons, a crystallization of chains in t h e more accessible regions is believed to occur without a significant loss in weight (1). Commercial rayons may not exhibit as marked a recrystallization behavior on being given a prehydrolysis treatment, inasmuch as such recrystallization already may have been effected by the desulfiding, bleaching, and other purification steps. The effect of this crystallization on the hydrocellulose water Aow number is shown by the data in Table VI. The hydrocellulose water flow number is reduced by the mild prehydrolysis treatment] and the per cent hydrocellulose residue on subsequent drastic hydrolysis is increased ( 1 ) in the case of these regenerated celluloses.
TABLE VI. EFFECT OF h k L D PREHYDROLYSIS TRE.4TMENT HYDROCELLULOSE ~ $ r A T E RFLOW h-UMBER
LINEAR SWELLING, %
Yarns I , V, and VI from three different godet stretch runs
zation are to be reliably interpreted. Furthermore, they confirm t h e work reported by Nelson and Conrad (7), who studied the effects of Wiley mill grinding on the fine structure of cellulose. Although the hydrocelluEFFEGT OF TIMEOF HYDROLYSIS. lose water flow number is arbitrarily determined on a sample after 15 minutes of hydrolysis i n 2.50 N hydrochloric acid at 105' C., i t is interesting to study changes in the observed hydrocellulose water flow number of the hydrocellulose residue after
TABLE IV.
Kever-dried control sample. Placed directly as spun in 2.50 N HC1 a t 18' C. for 10 days, purified, dried
84.11
165
Control sample. Freshly spun, washed, and dried, placed in 2.50 A' HC1 a t 18' C. for 10 days, purified, dried
83.47
94
TABLEVII. EFFECT OF VISCOSE AGE lv.4TER
EFFECT OF WILEYMILLINGON HYDROCELLCLOSE WATERFLOW NUMBEROF CELLULOSES
Level-Off HF HydroBasic Number, cellulose D.P. Sec. Residue, % D.P. Sample Before After Before After Before After Before After 237 200 14 23 Special raw cot- 3960 3380 9 2 . 4 91.2 ton 260 242 18 22 2260 2130 9 5 . 6 9 4 . 4 Absorbent sotton linters 232 208 32 82 1325 1280 9 5 . 8 9 3 . 6 Acetate grade linters 230 148 360 390 1425 1360 95.2 9 1 . 5 Acetate grade wood pulp 220 110 334 1030 1000 9 2 . 2 8 8 . 8 , 270 Viscose grade wood pulp 65 61 20 93 467 449 8 9 . 6 8 7 . 8 Fortisan rayon 42 40 183 305 420 397 8 1 . 9 7 8 . 7 Avisco textile yarn
80 7 6 a
HF Number, Sec. 315
Sample (Experimental Tire Yarn) Control sample. No prehydrolysis b y 2.50 .V HC1 a t 18' C., processed and dried in commercial manner
Figure 3. Relationship between Hydrocellulose Water Flow Number and Per Cent Linear Swelling of Rayons
Hydrocellulose Residue,
ON
ON
%
HYDROCELLULOSE
FLo\i- XUMBER
Sample Godet stretch constant, bath 1
Salt Test Old viscose Young viscose
Godet stretch constant, bath 2
Old vlscose Young viscose
HF Number, Seo.
106 435 269 753
Original Basic
TABLEV.
EFFECTOF TIMEOF HYDROLYSIS ox OBSERVED HYDROCELLULOSE WATERFLOW NUMBER
Sample Sulfite wood pulp Sulfate wood pplp Acetate grade linters Textile yarn Tire yarn Fortisan
H F Number, Seconds, after Hydrolysis 2P 5 1.5 min. min. mI?n . min. 136 297. 365 425 823 165 448 616 48 42 78 144 1098 15 236 783 43 412 110 l5 19 15 18 18
EFFECTOF VISCOSE AGE. The hydrocellulose water flow number of two series of yarns spun from viscoses of different ages (as indicated by the sodium chloride salt test index) were measured (Table VII). All samples were prepared using the same godet stretch, so t h a t the orientation variable was kept reasonably constant. HYDROCELLULOSE WATER FLOW NUMBER AND FIBER ORIENTATION
The distribution of intensity in the x-ray diffraation pattern of fibers has, for many years, been the most notable parameter of fiber orientation. Two other parameters that have been used are the swelling anisotropy and the double refraction of fibers, both of which are the results of preferred axial orientation of t h e macromolecules and crystallites. Unfortunately, the three foregoing parameters do not necessarily give rreults that are directly comparable for the evaluation of fiber orientation. This is understandable because each parameter is dependent upon the crystalline and amorphous components of the fiber in different ways. For example, the x-ray
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
September 1953
%
and refraction parameters agree best in the case of highly oriented fibers in which both the crystalline and the amorphous parts are well oriented. On the other hand, if the orientation in the amorphous parts is low while the orientation of the crystallites is high, then the x-ray and the refraction parameters diverge; the x-ray results are relatively unaffected by poor orientation i n the amorphous regions, whereas the optical values refiect the combined orientation of the amorphous and the crystalline regions. Agreement between the refraction and swelling parameters, however, is likely to be better over wide variations in gross fiber orientation because both of these properties depend more or less completely on the orientations of both the crystalline and amorphous regions. The above-described parameters of fiber orientation are discussed in greater detail in a n excellent paper by Preston and Bhat (8).
2111
OF THREE DIFFERENT PARAMETERS TABLEVIII. COMPARISON OF FIBER ORIENTATION Godet
Linear Swelling,
%
Maximum Angle
45
2.16 1.98
14.1
stretch
50
'/e
...
HF Number, 8%.
227 64
On the basis of these data, it appears that the hydrocellulose flow number may provide a sensitive and new parameter for following changes in fiber orientation.
COMPARISON AT RELATIVELY CONSTANT ORIENTATIONS MEASX-RAYDIFFRACTION AND LINEARSWELLING PARAM-
URED BY
Although the hydrocellulose water flow number is shown t o be sensitive t o progressive changes in fiber orientation for several distinct families of samples of known and controlled histories, other variables of fiber structure also affect it. For example, in Table IX, samples having relatively constant orientations, as measured by linear swelling and x-ray diffraction methods, are shown to have wide variations i n their hydrocellulose water flow numbers. The variations are larger in the case of samples with low orientations (high hydrocellulose water flow numbers). This is as expected, inasmuch as it is with samples of low orientation t h a t the hydrocellulose water flow number exhibits the greatest sensitivity. It is not unexpected that fine structure variables other than orientation should affect a property such as the hydrocellulose water flow number. Ingersoll (6), for example, found t h a t yarns of essentially the same orientation and lateral order may have difETERS,
-
O
'S
I
2
3
4
5
6
LINEAR SWELLING, % Figure 4. Relationship between Hydrocellulose Water Flow Number and Per Cent Linear Swelling of Rayons Yarns 11, 111, IV, and VI1 form four different godet stretch runs
I
Inasmuch as the hydrocellulose water flow number was found t o be more sensitive to variations in godet stretch than to other variables of sample history, considerable attention was focused on the evaluation of this property of hydrocelluloses as a new parameter of fiber orientation. The approach was to measure the hydrocellulose water flow numbers of yarns of accurately known histories in which godet stretch was a uniform variable. At the same time, the orientation of the corresponding original samples was characterized by means of two already established parameters of fiber orientationnamely, x-ray diffraction ('/* maximum angle method) and linear swelling. Results that are typical of the high sensitivity of the hydrocellulose water flow number to fiber orientation are given for one godet stretch run in Table V I I I . Correlations between the various parameters of fiber orientation for yarns from several different godet stretch series of known and controlled histories are illustrated in Figures 3 to ti. The relationships between the hydrocellulose water flow number and the per cent linear swelling are plotted in Figures 3 and 4. The same data are plotted in Figures 5 and 6 against the corresponding x-ray '/2 maximum angle data.
X-RAY DATA
l/!2 MAX. ANGLE-
Figure 5. Relationship between Hydrocellulose Water Flow Number and X-Ray Orientation Data (I/* Maximum Angle) of Rayons Yaras I, V, and VI from three different godet stretch runa
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
2112
TABLEIx.
.
I’ARIATIONS I N HYDROCELLULOSE Jv.4TER NUMBER .4T REL.4TIVELY CONSTANT ORIEXTATIOX
FLOW
Orientation Parameter I/, /
I
Sa nip le
hIaximiiin angle
Linear swelling
L o w orientations No. 2 yarn No. 6 yarn No. 7 yarn
21.6 20.3 20.5
2.90
High orientations h-0. 1 yarn No. 2 yarn S o . 6 yarn S o . 7 yarn
14.1 12.5 12 2 12.4
1.98 1.22 2.33 1.65
TABLE X.
HF Nukber , Sec.
Vol. .45, No. 9
the hydrocellulose water flow number. The existence of thi? relationship has been established, using samples of accurately known histories, by a direct comparison of hydrocellulose water flow number data with data obtained using two well recognized methods for characterizing fiber orientation-linear swelling and x-ray diffraction.
414 1239 132
...
3.43
64
21 166
88
HYDROCELLULOSE WATERFLOW NLXBERSFOR SOME NATIVECELLUUISES Original Basic D.P. 3950 2200
Sample R a w cotton J & J absorbent cotton linters Acetate grade linters Viscose grade sulfite pulp Viscose grade sulfate pulp
HydroHE’ cellulose Level-off Basic Suinber, Residue, D.P. Sec. % 92.4 240 14 95.6 260 18
1300 1030 680
95.8
92.2 91.9
232 270 184
78 110 620
ferent properties, indicating that other structural variables also have a n important effect on physical properties, At a given orientation yarns may exhibit a relatively wide range of tenacities and elongations. This fact emphasizes once again the importance of a n accurate knowledge of sample history for the interpretation of data on cellulose fine structure.
X-RAY DATA FLOW NUMBERDATA TABLE XI. HYDROCELLULOSE
FOR
RAYONS
(Regenerated cclluloses) HydroLevelOriginal cellulose . Off Basic Residue, Basic Sample
rayon Avisco viscose staple fiber rayon Deacetylated commercial cellulose acetate
HF Number, Sec. 16 18 22 311 183 65
D.P.
70
D.P.
467 550 476 410 430 660
89.1 87.0 78.7 81.3 83.7 86.4
65 55 45 42 40 42
420
79 8
36
1475
340
81.5
36
2200
- lh MAX.ANGLE
Figure 6. Relationship between Ily-drocellulose Water Flow Number and X-Ray Orientation Data (% Maximum Angle) of Rayons Y a r n s 11,111, IV, and VI1 from four different godet stretoh runs
Several variables that are known to affect cellulose fine structure (mechanical treatment, prehydrolysis, salt test, etc.), other than orientation, also have been studied in terms of changes in the hydrocellulose water flow number. However, further work is required to understand more fully and measure more quantitatively how these variables are related to the hydrocellulose water flow number. ACKNOWLEDGMENT
CHARACTERIZATION O F NATIVE AND REGENERATED CELLULOSES
The hydrocellulose water flow numbers of several native fibers are shown in Table X. Hydrocellulose residues from cotton fibers usually are more readily purified than theresiduesfromm-ood pulps, as reflected by the much lower hydrocellulose water flow numbers for the samples of cotton fibers and linters. REGENERATED CELLULOSES.The hydrocellulose water flow numbers of several rayons having widely different properties are compared in Table XI. The results show wide variations depending on the type of rayon; orientation history stands out as a major factor. CONCLUSIONS
Hydrocelluloses that are prepared in a uniform manner show marked variations i n the rate a t which water may be filtered through them. This property has been characterized in terms of the hydrocellulose water flow number using a method having good reproducibility and ease of operation. A relationship has been found for regenerated celluloses, a t least, between the orientation in a fiber before acid hydrolysis and
The authors wish to acknowledge the assistance of Elizabeth L. Derrick and Marian B. Bruce, who made some of the measurements that were required in the course of this work. REFERENCES
(1) B a t t i s t a , 0. A., Iiw. EYG.CHEX, 42, 502-7 (1950). (2) B a t t i s t a , 0. A , , IND.ENG.C H E Y . ,ANAL.ED.,1 6 , 3 5 1 4 (1944). (3) Calvert, A l . A., a n d Clibbens, D. A , J . Fertile Inst., 42, T-215 (1950). (4) H e r m a n s , P. H., Kratky, O., a n d T r e e r , R., Kolloid-Z., 96, 30 (1941). (5) H o w s m o n , J. A., “Physical X e t h o d s in Chemical Analysis,” Vol. I, pp, 139-41, New York, Academic P r e s s , 1950. (6) Ingersoll, H. G., J . A p p l . Phus., 17, 924 (1946). (7) Nelson, M. L., and C o n r a d , C. RI., Teztile Research J . , 18, 155 (1948). ( 8 ) Preston, J. M., a n d Bhat, R. V., J . Testile I n s t . , 39, T211-16 (1948). (9) P r e s t o n , J. M., and D a s Gupta, S., Ibid., 38, T60-4 (1947). (10) Valtasaari, L., Paperz j a Puu, 33B, No. 12, 391-8 (1951).
RECEIVED for review December 26, 1952
ACCEPTEDMay 4, 1953. Presented before the Division of Cellulose Chemistry at the 122nd Meeting of t h e AMERICANCHEMICAL SOCIETY,Atlantic City, 5 . J.
