detergency studies with... sulfated tallow alcohols

Detergency Studies wi th . . Sulfated Tallow Alcohols

LLOTD OSIPOW, DOROTHEA MARRA, CORNELIA T. SNELL, AI\'D FOSTER DEE SNELL

Foster D . Snell, Inc. , JYew York 11, ,V. Y.

L4LLOFV-available as a surplus niateiial becauqe of de- T creasing soap production-can be reduced from the glyceride to mixed fatty alcohols and then sulfated. The sodium salts of the tallow-alcohol sulfates are detergents similar in cheniical composition to the so-called sodium "lauryl" or dodecyl sulfate made from coconut oil. Like the coconut oil-based products, the tallow-based detergents contain a milture of fatty acid radicals, but a higher proportion of CIS and CIS groups-the latter soine- times both saturated and unsaturated.

Two methods of preparing tallow alcohols are used: 1 eduction of tallow by sodium and by hydrogenolysis. Unsaturated groups such as those present in oleic acid are unchanged by sodium re- duction; they are changed to saturated groups by hydrogenation. The object of this study n a s to determine how the t n o types of surfactants produced originally by sodium I eduction and by hydrogenolysis would compare n i th one another in detergent and surface-active properties. Would the presence of unsaturated bonds aid or detract from detergencv? Cornpalison lras also made with commercial spnthetic detei gents based on sodium

SOLUBILITY

Because some syndets axe sold in liquid form or as a solution, the solubility of the tallon--alcohol sulfates was determined quali- tatively alone and mixed with commercial syndets. In this discussion, names of syndets are abbreviated by omitting "sodium salt of," as shown in Table I.

The solutioiiq were then held in a thermostat at the appropiiate temperatuies for 48 hours and observed for clarity, Keither saturated nor unsaturated tallorr sulfates were soluble a t 20" to 60" C., a t a concentration as low as 570. Solubility can be increased eome- what by mixture with other syndets.

Aqueous solutions were prepared by heating.

Anionic 1. Anionic 2 . Anionic 3.

Sonionic 1.

SO^, active dodecylbenzenesulfonate (Sacconol NRSF) 90% active dodecyl sulfate (Duponol LIE) 30% active triethanolamine salt of lauryl sulfate (Ste-

100% active polyoxyethylene condensate of isooctyi- panol WAT)

phenol (Triton X-100)

Table I. Appearance of Solutions Containing Tallow-.llcohol Sulfates after 48 Hours at Indicated Temperatures 5% Solution 10% Solution 20% Solution Tallow-Alcohol Suliate Non-

Saturated Unsaturated Anionic 1 Anionic 2 ionic 1 20' C. 40' C. 60' C. 20' C. 40' C. Coo C. 30° C. 40° C. 60° C , 100

25

50

25

25

. .

. . .

. . .

. . .

. . .

. . . 100

2 5

50

25

25

. . .

. . .

. . .

. . .

0. Clear 1. Sljght turbidity 2 . Slight precipitate 3. Moderate precipitate

. . 75 72 . . . . , . . .

. . 3 0 5 0 - - , J

I J - -

. .

. .

. . 7 3 7;

3 3 3 0 1 3 7

3 3 0

3 3 0 0

3 3 0 0 0 0 0 0 0 0

3 3 3 0 3 3 3 3 3 0

3 3 2

3 3 2 0 0 0 1 0 0 0

3 3

3 3 2 0 2 0 1 3 1 0

dodecyl sulfate and sodiuni dodec)-lbeiieeiiesulfoiiate. The Konionic 2 . 100% active amide condensate of lauric acid and di- latt,er two, particularly the second, are the types of products current,ly most used in industry. The talloir-alcohol sulfates, a This is more often the case with the unsaturated tallow-alcohol term used for brevity but meaning the sodiuni salts, were pre- sulfate product than with the corresponding saturated product- pared by knom-n methods. They were salt-free and contained for example, a 20% solution can be made containing 25 parts of 0.5 to 1.0% of unsulfated tallow alcohol.. unsaturated tallow-alcohol Sulfate and 75 parts of either dodecyl-

benzenesulfonate or the poly-

(xino'

Table 11. Surface Tensions and Interfacial Tensions at Room Temperature Intel iacia

Tension (Suifaces aged 15 seconds)

against Surface Tension, Nu j ol

Tallow-Alcohol S u l f a t e ~$~~~~~ ~ ~ d ~ ~ ~ l sodiull1 Dynes/Cm. Dynes/&. Formula Saturated Unsaturated sulionate Sulfate Sulfate 0.05yo 0 1% 0 05% O.lyo

osyethylene condensate of iso- octylphenol, even at 20" C.

SURFkCE A S D INTERFACIAL TEN SIOS S

In Table 11, the values for surface tension and inteifa- cia1 tension, obtained with the D u A-ouy tensiometer, are seen to be similar for sa tura ted and u n s a t u r a t e d tallow-alcohol sulfates, either alone or with added syndets.

492

March 1955 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 493

- N

lo

Addition of dodecylbenzenesulfonate to the tallow-alcohol sulfates reduces both surface tension and interfacial tension against refined mineral oil. Addition of sodium sulfate does not reduce interfacial tension in the way it does when added to dodecyl sulfate.

FLASH SUDS AND FOAM STABILITY

Values for initial foam capacity and foam stability as measured by the Ross-Miles (1) method are given in Table 111.

Results with unbuilt or light-duty tallow-alcohol sulfates showed the saturated tallow-alcohol sulfate to foam poorly, much less than the unsaturated. However, the unsaturated com- pound did not foam as strongly as dodecyl sulfate. I n built products corresponding to heavy-duty formulations, little difference was found in foaming ability between the built saturated and unsaturated tallow-alcohol sulfates, either as such or mixed with other detergents.

EMULSIFICATION

The results of qualitative tests made under standardized conditions by shaking 2 volumes of a 0.3% detergent solution with 1 volume of Nujol mineral oil containing a trace of dye are shown in Table IV. Little difference in emulsifying power between the saturated and unsaturated tallow-alcohol sulfates appeared. Both were improved by admixture with dodecglbenzenesulfonate.

MANUAL DISHWASHING

The method followed was that developed by the General Aniline & Film Research Laboratory for washing dishes by hand under standardized conditions.

Each flat dinner plate was soiled with a half teaspoonful of 80%'rnelted Crisco, 20% flour, and sufficient Oildag (black) for visibility. The soiled plates were washed one after another in a 0.1% detergent solution until the foam no longer completely covered the wash solution and until grease appeared on the surface of the water in the dishpan. The first end point was a measure of the foam stability in the presence of soil; the second was a measure of the relative effectiveness of a particular detergent solution.

The results, given in Table V, show tha t when admixed with dodccylbenzenesulfonate, with or without further addition of fatty amide, the unsaturated and saturated tallow-alcohol sulfates gave about the same results (formulas A and B). Addi- tion of fatty amide increased both foam stability and detergent ability of the solution (formulas C and D). \\"hen triethanolamine dodecyl sulfate and fatty amide were mixed with the tallow sulfate (formulas E and F), the saturated tallow-alcohol sulfate was superior in foam stability and performance to the unsaturated tallow-alcohol sulfate. This combination with the saturated tallow-alcohol sulfate (formula F) gave the best results in hand dishwashing.

WASHING OF FABRICS

Using commercial soiled cloth swatches (sold as FDS artificially soiled cotton by Foster D. Snell, Inc.) in a Launder-ometer under standardized conditions, the effectiveness of various detergent combinations was determined, both in removing soil and in preventing its redeposition. Both effects are equally important in evaluating a detergent. Soil removal was determined under the test conditions shown herewith

Soil redeposition or antigraying action was measured by washing clean swatches in the detergent solution containing an added 0.025% of carbon black soil. With this amount and under the washing conditions, substantial deposition of carbon black on the cloth occurred.

The higher the number for soil removal, the better the result The smaller the absolute value of the number for soil redeposi-

494 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 47, No. 3

tion-that is, the less the negative figure-the better the result. The latter results are interpreted as indicating the relative effectiveness of a detergent in preventing soil froin redepositing on fabric during an actual washing operation. Both cotton and n-ool were used in soft (2-grain or 34 p.p.m ) and hard (15-grain or 255 p,p.m.) L$-ater. All these variables are of importance in detergent problems.

TEST CONDITIONS

Amount of solution per jai Mechanisal washing assistants

Temperature Speed of rotation of jars Time for nasliing Rinsing procedure

Fabrics per jar

Reflectance reading

per jar IO0 nil. 8 rubber bails

600 c. 40 r.p.m. 15 minutes Rotate 2 minutes r i t h 150 nil. of

mater of same hardness as mash

3/a-inch diameter

water

3 X 2 inches

nesia block

Two swatches of FDS soiled cotton,

Hunter multipurpose reflec- B%n~eter set to read 100 on mag-

Washing Cotton. The detergent effectivenrss of the tallow sulfates on cotton, with and without addition of other surlartants, is ehown in Tables VI, 1'11, and VIII. These are average results obtained in tests run a t different times; the estimate of the standard deviation is 1.45 for soil removal arid 2.10 for soil redeposition.

Results with cotton in Launder-onieter tests, as given in Table VI, show decreasing order of eff ect,ivrness for combinations 4, 1, and 5 in soil removal, and 1, 3, and 5 for soil redeposition. This indicates that a 1 to 1 saturated-unsaturated tallow-alcohol sulfate combination in a heavy-duty 107, active formulation was very effective. Combinations of tallorr--alcohol wlfates with nonionics and other anioiiics gave poorer washing results, and poorer results in soil redeposition, than without added surfactants.

From Table TTI i t is seen that detcrgent samples 5, 6, 9, 11, and 16 gave the better res.uIts for soil removal in 2-grain water; samples 1, 5 , 6, 7, 8, 9, and 13 in I5-grairi vrater. 111 preventing soil redeposition samples 2, 5 , 6, 9, and 11 gave the hetter result,s in 2-grain water; samples 5, 6, 9, 12. arid 16 i n 15-grain wat,er. Comparison of the four sets of figures s h o w that in over-all results for both soil removal and prevention of soil redeposition samples 5 , 6, and 9 gave consistently favorable results. These were mixtures of saturated and unsaturated tallow eulfatcs in proportions varying from 1 part of the first to 3 parts of the second, up to 3 parts oC the first to 1 part of the secorid. The mistures of the two tdloiv-alcohol sulfates appeared to bc more effective than the same amount of either one alone; also more effective than tlodecylbenzenesulfona te ttnd dodecyl sulfate, either alone or coinbiiied with the t:Lllon.-alcohol sulfates. Tallow-alcohol sulfates had better detei.genc>- alone thaii after addition of fatt>y amide.

Table 11'. Emulsification at 25" C. with Rlineral Oil arid Detergent at 0.3% Concentration

Detergent Building A B C D - Emulsion Rating

Active detergent 40 20 100 40 1. Excellent no emulsion break for 30 minutes Sodium tripolyphosphate 32 40 , . . . . 2 . Good, noktnulsion break for 1.5 t o 20 minutes Tetrasodium pyrophosphate 8 10 . . . . . 3 . Fair eiiiulsion break in 3 to 5 minutes Sodium metasilicate, pentahydrate 10 10 4. Poor, emulsion break in less than 2 iiiinutes Sodium sulfate 10 20 : : : 60

Dodecyl- Tallow-Alcohol Sulfate benzene- Dodecyl Detergent

- Building Eitiulsion Rating Saturated Unsaturated sulfonate Sulfate 100

25

50

40

20 20

20

10

. . .

. . .

. . .

. . .

. . .

. . .

. . .

5 (+z 'idnionic 2 ) . . . 5 (

100 , . . 25

5 0

40

20

20

20

10

. . .

. . .

. . .

. . .

. . .

. . .

+.j &;ionic 2) , . .

. . 75 7 5 . . . . . . . . . . 16 20

10 10 10 10 10

. .

. .

c C C C C C D D u .4 A -4 B B B B B B B

2 2 1 1 2

2 2 . 5 1 1 , i 1 1 1 . 5 a 1 . .5 2 1 1 1

>

Table V. Hand Dishwashing Test at 43" C. a i d 0.1% Formulation Concentratioii Basic Ileteigent l'ormulasa

A B C D E 1' Anionic 1 I 5 1 .i 10 10 . . Anionic 3 , . . . 10 I 0 Unsaturated tallow-alcohol

sulfate .5 . . 1 . . 5 . . Saturated tallow-alcohol

sulfate Nonionic 2 Water Appearance

o 1 . . . . 2

> J 5 J

Clear Slight Clear Slight Clear Clear i o sa 80 so 80 so

amber turbidity, amber turbidity, amber amber amber amber

Total Nnmher of Dishes ~~~

Detergent Before foam breakdown Before grease appearance -4 B c D E F

a All proportions on active agent basis

8, 9 9, 9

14, 13 12, 13 13, 14 1B,16

8, 9 9, Q

1 0 , l l 1 2 . 1 3 9, 9

2 4 , 2 4

\Tit11 only 20% of active surfactant plus 80% of builders, as showi in Table YIII, the results for cotton detergency were somewhat different than with the 40% active material. In 2-grxin.water hetter results were ohtained in soil removal n-ith sample.: 1, 2: 5 , arid 8; in 15-grain water with sain- ples 1: 2, 5 , and 10. Samples 5 , 0 ) and 10 were omitted in the soil deposition studies. Of tlio remaining samples, better resiilts were ohtained in 2-grain water with 1, 2, 7 , and 8; in the 15-grain water also with 1, 2, 7 , and 8. For soil removal, the tallon--alcohol sulfate-, alone or conihined, compared favorably with various niixt,ures. They also COIU-

pwed favorably iri preventing soil deposition, but coniliina- tioiis with dodec~lbeneer~esul- fonate plus fatty nmide were also good.

W a s h i n g Wool . Rcsuits with wool detergency are given in Table TX. The technique is similar to that, shown for cotton, escept, for a temperature of 43' C. and the use of FDS artificially soiled wool. -4s tjhe LOOTo active agen- no inorganic salt,s addecl-t,he saturated taliow-alcohol sulfate was the most effcctivc foi washing XI-ool in 2-grain water. The 100% unsaturated tallow- alcohol sulfate was low in de- t ergent eff ectivcness.

Resulte vi th heavy-duty formulations areshorr-n in Table S.

March 1955 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 495

Table VI. Cotton Launder-ometer Test Results (Brightness units gained. Magnesium oxide = 100. 0.2% 2-grain water, 60' C.)

Heavy-Duty Detergent Building

A B I

Active detergent Sodium tripolyphosphate Tetrasodium pyrophosphate Sodium metasilicate, pentahydrate Sodium sulfate

40 20 32 40 8 10

10 10 10 20

Dodecyl- Tallow-Alcohol Sulfate benzene- Detergent soil Removala -

Sample Saturated Unsaturated sulfonate Building 2-grain 15-grain 1 20 20 2 20

4 20 . . 5 . . 20 6 10 . . 7 10

3 . . 20

8 5 j s 5 nonionic 2)

9 . . 5 IY.5 nonionic 2)

10 (10 anionic 1) . . 11 Water

. . 20 20

10 10

10

10 10

. .

. I

A A A B B B B

B

B B

1 3 . 5 1 5 . 0 1 2 . 6 7 . 9 1 2 . 5 6 . 7 1 4 . 0 1 5 . 4 1 3 . 7 1 1 . 6 1 2 . 2 7 . 4 1 2 . 2 6 . 7

- 2 4 . 0 -30 .2 -30 .9 -34 .7 - 2 7 . 4 - 3 1 . 1 - 3 0 . 5 - 3 3 . 4 - 2 8 . 1 - 3 2 . 5 - 3 4 . 7 -37.6 - 3 1 . 5 -36 3

- 2 9 . 8 -33.8 1 2 . 1 9 . 6

12.7 7 . 7 11.5 8 . 1 2 . 5 0 . 0

- 2 8 . 0 -32 .6 - 4 0 . 6 -42 .2 -52 .3 -52 .5

a 2-grain water, 12 replicates. 15-grain water, 4 replicates.

Sample 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18

Table VII. Cumulative Values for Cotton Detergency (Brightness units gained. Magnesium oxide = 100)

Tallow-Alcohol Sulfate ~ ~ i ~ ~ i ~ ~ ~ i ~ ~ i ~ N ~ ~ - Soil Removala Soil Redeposition Saturated Unsaturated 1 2 ionic 2 2-grain 15-grain 2-grain 15-grain

40 . * . . 36 10

20 20

20 10 10 15 15 15

. .

io

. . 40

10 30

20

20 10

10 15 15 15

. .

. .

. . . .

. .

io

.. 40 * . . . . . 30

20 20 10 10 10 20 10

. . . .

.. ..

. . . . . . . . . . , . 10 10 , . . . . . i6 . . . . . . . . 10

1 1 . 2 4)

1 1 . 9 (4) 1 2 . 6 ( 8 ) 1 2 . 7 (8)

10.8 (4)

11.6 14) 10.5 (12)

1 1 . 7 (4)

1 2 . 3 24)

1 2 . 5 (12) 1 2 . 0 LO)

.11 .9 (8 )

1 3 . 4 (4) - 2 5 . 4 (4) 1 2 . 6 (4) - 2 3 . 3 (4) 1 0 . 5 (12) - 3 4 . 7 ( 1 2 ) 1 3 . 2 (4) - 3 7 . 3 (4) 1 4 , s (8) -23 .1 (8) 1 3 . 4 (8) - 2 0 . 6 (8 ) 1 3 . 7 (4) -23 .9 (4) 1 3 . 4 ( 4 ) - 2 8 . 1 ( 4 ) 1 4 . 0 ( 1 6 ) -23 .4(24) 9 . 5 (16) -29 .9 (20) 6 . 7 (4) - 2 6 . 8 112)

1 1 . 0 (8) - 2 7 . 3 (8) 1 3 . 3 (4) 1 1 . 6 (8) -23.'2'(8)

1 0 . 9 9 . 8 ( 1 2 ) (8) - 2 6 . 4 - 2 5 . 5 (8) (8 ) 1 2 . 3 (4) - 2 6 . 9 (4) 1 1 . 7 (4) - 2 4 . 3 (4)

- 3 2 . 3 4) - 3 0 . 8 14) -35.6 (12) -40 .9 (4)

. . 40 . . . . . . 30 . . . . . . . . . . . . . . . . 10

11 : i ' (8) 1 0 , 2 ( 8 ) 12 I 1 (8) 1 1 . 2 (4) 1 1 . 7 (4)

a ( ) indicates number of replicates. Detergency building A, Table 111, with 40% active surfactant.

Table VIII. Cumulative Values for Cotton Detergency (Brightness units gained. Magnesium oxide = 100)

Tallow-Alcohol Sulfate ~ ~ i ~ ~ i ~ ~ ~ i ~ ~ i ~ N ~ ~ - Soil Removala Soil Deposition Sample Saturated Unsaturated 1 2 ionic 2 %grain 15-grain' %grain 15-grain

1 20 2 . . 3 10 4

6 . . 7 5 8 . . 9 8

10 8

5 i0

. . 20

10 io . .

. . . . . . . . . . 1 3 . 6 (18) 1 3 . 4 (18) 12 3 18)

1 2 . 7 (6) 1 1 . 5 (12) 1 2 . 1 (12) 1 2 . 7 12) 9 . 6 i 6 )

1 1 . 8 ( 6 )

12 :2 112)

-30.3 (12) -33 .4 (4) -28 3 (12) - 3 2 . 5 (4) -34 2 (12) -37 .6 (4) -31 4 (12) - 3 6 . 3 (4)

1 4 . 6 10)

8 . 2 (10) 6 . 7 (4)

1 2 . 5 (6)

7 . 7 (4)

1 1 . 4 LO)

8.4 (6) 13.5 (6)

. . 10 10

-40'.6' 12) - 3 0 . 0 {12) - 2 8 . 1 (12)

- 4 i : z (4) - 3 3 . 8 ( 4 ) -32 .6 (4)

. . .

. . .

. . 5 5

. . 5

8 . . 4

4 . . . . . . . .

a ( ) indicates number of replicates. Detergent building B , Table 111, with 20% active surfactant.

Table IX. Wool Launder-ometer Test Results (Brightness units gained. Magnesium oxide = 100)

Soil Redeposition Soil with 0.025570 Tallow-Alcohol Sulfate ~~"n",",~ Dodeoyl Sodium

Sample Saturated Unsaturated sulfonate Sulfate Sulfate Removal Added Carbon Black l a 2 3 4 5 6 7 8 9

10 11 12 Water

100

25

50

40

10

. . .

. . .

. . .

. . .

. . .

. . . . . .

. . . 100

25

50

40

10

. . .

. . .

. . .

. . .

. . .

. . .

. . . . . . . . - 3 0 . 7 -38 .9 - 3 2 . 4 - 3 5 . 7 -36 .2 -36 .9

. . 1 3 . 7 . . 4 . 8 . . 7.8

. . 6.0 . . 8 . 4

. . 75 75

50 50 . . . . 6 . 1

60 6 . 9 60 6 . 3 60 1 2 . 5 60 11.7 60 8.5 60 1 2 . 0

- 4 2 . 7 -38 .0 -43 .3 -37 .9 - 3 9 . 3 - 3 9 . 8 -61,l

46 . . 30 30 40

a 0.2yo-grain water, 43' C. 1 through 9, 8 replicates. 10 through 12, 6 replicates.

496

With formulas -4 coiitaiiiiiig 4OYO of surfactant the beal results for both soil removal and prevention of soil deposition n-ere obtained with mixtures of the saturated and uwat - urated tallow sulfates. Re- p l a c e m e n t i n p a r t h y dodecylbenzenesulfonate mis a deterrent rather than ail im- provement. With the 20% formulation, the best results for soil removal from n-ool n-ere obtained with the saturated tallow-alcohol sulfate. Partial replacement of the saturated tallow-alcohol aulEate with an amide nonionic plus dodecylbenzenesulfonate gave f a i~ ly good soil removal, although not as good as the sat'urated tallow-alcohol sulfate at 207,.

I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 47, No. 3

Table X. Wool Launder-onleter Test Results at 43' C. and 0.2Y0 Concentration (Brightness units gained. l lagnesium oside = 100. 4 replicates)

Detergent Building A B

. i c t i r c detercent Sodiiini tripolyphosphate Tetrasodiuni pyrophosphate Sodium metasilicate, pentahydrate Sodium sulfate

40 20 32 40

8 10 IO 10 I O 20

Soil Deposition with 0.02555

Added Soil Reinoi-al Carbon Black ~ ~ _ _ benzene- Detergent ____~ ~ ___

Saturated Unsaturated sulfonate Building 2-grain 15-grain 2-grain ]%grain

Talloii--.ilcoliol Sulfonate Dodecyl-

. . 70 20 10 30 10 IYater 20

. .

20 10 10 30 . .

40 20

20

i.7 7 3

i.l 1 1 . o 9 . 3

10 8

l L . 0

8 0 0 3

11 0 .5 3

10 0 7 0

7 1 20 R 7 9 d x

io . . 10

. . 3 ( + 3 nonionic 2 ) 10

. . 10 10 10

(10 anionic 2) . . 10

.i (A 3 nonionic 2 )

-30 9 -30 .1 - 1 0 . 4 - 2 8 . 6 - 2 3 3 -24 0 - 6 1 . 1

-31 3 - 3 1 . i -30.0 - 3 0 . 3 - 3 5 e - 3 0 . 3 -61 5

SUMM.4RY AND CONCLUSIONS

Sodium tallow-alcohol sulfates are not sufficiently soluble by t,heiiiselves to he suit,ed for w e in liquid detergentfi. Solubility of the unsaturated tallow-alcohol sulfate is increased somewhat by combination with other syndets.

Saturated talloi\-alcohol sulfate is a low foamer aiid unsaturated tallow-alcohol sulfate is a moderate foamer, in compari- eon with dodecyl sulfate.

Although t,allon--alcohol sulfates are fairly good emulsifier,q of niiiieral oil, they are improved by combinntion with other pyndets.

Saturated tallow-alcohol sulfate appeared to be Poniei~-hat more effective than unsaturated foi iiinnual dishn-ashing, particularly when combined with nonio, ic surfactants.

For both cotton and woo1 detergency, a 1 to 1 coinhination of misaturated and saturated tallon-a,lcohol sulfates in heavy-duty formulations proved very effective in thew tFst.5, and was superior

to coml)ination~ with other syndets. 1Titho:it builders, the saturated tallox--alcohol sulfate as it better ~ o o l detergent than the unsaturated.

The properties of the ti1-o tallow-alcohol sulfates dhow that each may havc special field? of usefulness, while their combinn- tioii should be very effective in heavy-duty proc1uc.t~.

.4CKNOW'LEDG\IEVT

'Phi? 1 ~ 0 1 ~ 1 ~ was carried out uiider a grant, from the Satioriitl Distillei.!: Prodiict,s Cory.

LITERATURE CITED

( I ) Ross. J. , and JIiIes, G . D., Oil & Soap , 5, 99-10? (1941).

RECEII.ED for ieviem June 16, 1934. .~)ICCEPTEI> Octoher 28, 1854. I'sosented before rhe Dirision of Colloid Cliemietry a t the 126th Meetixg of the .IXIERICAS CIIE1IIC.4L SOCIETY, New l-ork. S. Y,, 19.54.

Effect of Milling on Branching Distribution of Hot GR-S

and

W. K. TAFT .4ND JUXE DUKE Gocernntent Laboratories, Unicersity of Akron, iikrort, Ohio

UIlN and Kuhn ( 7 ) point, out that the theory that K branched molecules occupy less space in dilute solution than linear molecules, and therefore give less viscous solutions, is in semiquantitative harmony with experimental data, but in con- rentrated solutions branched eopolymws show inordinately high viscosities ($). Baker and Mullen ( 1 ) state that for branched or netted particles, the slope of the curves of the natural logarithm of the relative viscosity divided by the concentration plotted against the concentration, is zero or positive when in the concentration range of 10 to 15% solids. Or, an increase in the value of the positive slope means more branching. The papeis of Rueche ( 3 ) and Bestul and coworkers (2) substantiate the cori- eepts of Baker and JIuIlen.

Piper and Scott (9) found that, initially, hot milling is lesi. effective than cold in producing a soft material, but after a time the positions reverse and the hot treatment becomes more eflec- tive. The reason for the reversal of eff'ectiveriets was thought to he differences in the manner of breakdoiyn of GR-S, wlirther by inechanical rupture of the chain, occurring in cold milling, or 17)- oxidation ir-hich is accelerated by hot milling. Theories con- tributed by Kauzmann and Eyring ( 6 ) and discussed b. TT-atson (11 ) suggested that, cold mastication ruptures primary chemical bonds of the polymer molecules, aiid the react'ive fragments may recombine or produce oxygenat,ed radicals which stabilize t,heni- selves by side reactions, and that a t temperahres belorr 100" C., oxygen merely intervenes to repress recombination after molecu-

detergency studies with... sulfated tallow alcohols

Documents