INDUSTRIAL A N D ENGINEERING CHEMISTRY
594
Vol. 22, KO.6
a permanently flexible, heat-convertible resin has been made approaching the flexibility of rubber. Conclusion
The postulates that have been developed lead us to a chemical explanation of the formation and properties of synthetic resins and other high polymers. This explanation appears to be broadly substantiated. Further knowledge may warrant its future modification. It has been presented, however, with the belief that it furnishes a better conception of facts in a field full of complexities. Reactivity (2,3) or greater intertwining formation
Reactivity ( 2 , 2 ) chain formation Figure 2
produce synthetic resins from phenolphthalein. glycerol, and formaldehyde: PHENOLPHTHALEIN AND FORMALDEHYDE-The essentials necessary for a very heterogeneous linking of the molecules are present. A resin similar to Bakelite resulted. PHENOLPHTHALEIN AND GLYCEROL-An ester, ether, or both are possible. As the phenolphthalein molecule is relatively large, the interaction should be slow and the product soft A clear viscous liquid resulted. PHENOLPHTHALEIN, GLYCEROL, FORMALDEHYDE-ASthe reactions discussed in the first two cases would both occur, a resin similar to Bakelite, but softer and with less tendency to become infusible, should result. A resin of these characteristics formed.
A second application of these postulates is found in the development of permanently flexible alkyd resins. I t was known, according to Postulate 2, that (2,2) reactions resulted in chain molecules. Furthermore, if both reacting molecules were long as compared with their cross sections, and if the reactive groups were on the ends, flexibility could be expected. Therefore, it was reasoned that glycol and a dibasic acide. g., succinic acid-if added to the glycerol-phthalic anhydride reacting mixture, should enter into the molecular bonding and induce flexibility. Such resins should be heat-convertible and their flexibility should vary according to the mol ratio between the glycol-dibasic acid ester and the glyceryl phthalate. When these resins were prepared, such properties were obtained. By the proper adjustment of the mol ratio,
Acknowledgment
Acknowledgment is made of the assistance given by A. G. Hovey and P. F. Schlingman with the experiment’alwork, and by E. H. Winslow with the manuscript. Literature Cited (1) Auer, Koiloid-Z., 42, 288 (19271. (2) Baekeland and Bender, I N D . ENG.CHEM.,17, 225 (1925). (3) Barry, Drummond, and Morrell, “hTatural and Synthetic Resins,” Van Xostrand. (4) Carothers, J . A m . Chem. Soc., 61, 2548 (1929). ( 5 ) Carothers and Dorough, I b i d . , 62, 711 (1930). (61 Carothers and van Natta, I b i d . , 52, 314 (1929). (71 Clark, “X-Rays and Crystal Structure,” p , 185, McGraw.Hil!. (8) Ellis, “Synthetic Resins and Their Plastics,” Chemical Catalog. (9) Fonrobert and Pollauf, Chem. Cmschau, 33, 4 1 (1926). (10) Hauser, IND.ENG.CHEM.,21, 124 (1929). (11) Hengstenberg, A n n . Physik, 34, 245 (1928). (12) Herzog and Kreidl, Oesterr. Chem.-Ztg., 24, 76 (1921); 2. angew. Chem., 36, 465, 641 (1922). (13) Hovey, Unpublished Thesis for M.Sc. degree, Union College, 1928. (14) Kienle and Ferguson, IND. ENG. CHEM.,21, 349 (1929). (15) Kienle and Hovey, J . A m . Chem. Soc., 61, 509 (1929). (161 Krumbhaar, Chem.-Zlg., 40, 937 (1916). (17) Mark and Meyer, Ber.. 61, 539 11928). (18) Xovak and Cech, IND.ENG.CHEM.,20, 796 (1928). (19) Ostwald, Handbook of Colloid Chemistry, Blakiston. (20) Ott, Helv. Chim. A d a , 11, 300 (1928). (21) Scheiber, Z . angew. Cnem., 40, 1279 (1927). (22) Scheiber and Sandig, “Die kunstlichen Harze,” Wissenschaftliche Verlagsgesellschaft, Stuttgart. (23) Staudinger, Ber., 59, 3019 (1926). (24) Staudinger, Ibid., 62, 2893 (1929). (25) Whitby and Katz, J. A m . Chem. Soc., 60, 1160 (1928). (26) Whitby, McNally, and Gallay, Trans. Roy. SOL.Can., 22, 27 (1928). (27) Wolff, Farben-Ztg., 32, 22 (1926).
Factors during Spinning Which Influence the Physical Properties of Rayon’ Philip C. Scherer, Jr., a n d Robert E. Hussey BLACKSBURG, VA. CHEMISTRY LABORATORY, V I R G I N I A POLYTECHNIC INSTITUTE,
w
HEX a solution of cellulose xanthate, viscose, is extruded into an acid bath, various factors influence the formation of the filament and the physical properties of the regenerated cellulose. Composition of the viscose, its ripeness and viscosity, and composition and temperature of the spinning bath must influence the rapidity of regeneration, since a t the moment of contact between viscose and acid a film of regenerated cellulose must form in the shape of a hollow tube. Such a film will enclose a portion of viscose in its core. Further regeneration of this core of viscose can then occur only by an osmotic passage of the acid liquid through the original membrane. As this penetration proceeds the membrane becomes thicker and it becomes in’
1
Received March 26, 1930.
creasingly more difficult to regenerate the last portions of the core. The rate of such diffusion is probably conditioned by the temperature and the difference in concentrations on the two sides of the membrane. Effect of T i m e of Contact
If all other factors are held constant, it is theoretically possible to attain a time of contact with the acid bath such that the regenerative effect will be complete. Should the time of contact exceed this point, then possibly a hydrolytic effect of the acid bath upon the first-formed film of cellulose can alter the physical properties of the resultant filament. I n actual experiment it is difficult, if not impossible, to realize
INDUSTRIAL AND ENGINEERING CHE.VISTRY
June, 1930
595
this point exactly owing to the time lag introduced by the slowness of penetration of the reagents used. I n a series of experiments to investigate this problem, the authors spun a normal viscose sirup containing 7 per cent cellulose and 6.5 per cent sodium hydroxide through a 24hole spinneret geared to give 150-denier thread into a long trough containing a llueller bath (10 per cent &So4 and 28 per cent r\ra2S04)keeping constant all factors of tension, speed, and temperature and varying the length of time of contact of the filament with the acid bath. The action of the acid was stopped by running the filament into a bath of ammonium hydroxide a t 20" C. After thorough washing,
,
2.0,
I
F m e of C o n r a c t -
Seconds
differing from that of the outer shell. Sear the maximum point the cross sections lacked the core appearance and were homogeneous throughout. For times greater than the maximum point a corelike part again appeared. It is difficult to explain this fact except on the basis of prolonged action of the acid changing the outer portions of the filament. Table 11-Effect
of Ripeness of Viscose on Properties of Rayon ~
EXPERIMEKT
0'
I
5 rime
I I 1.0 /5 of Confasr
-
I 20 Secoods
1
the thread- were twisted and tested in a Schopper tester for tensile strength and elongation. The results are given in Table I and in Curves I and 11, Curve I giving the results for a llueller bath a t 40" C. and Curve I1 for the same bath at 30" C'. In both cases it will be noted that the curves approach a maximum where, apparently, regeneration is complete and further action of the bath reduces the physical propertie.. I t should also be noted that the maximum point for the elongation is not the same as that for tensile strength. Evidently some further factor is involved which is not yet apparent. T a b l e I-Effect
of T i m e of C o n t a c t i n Acid B a t h on Properties of Ravon
TIMEOF
NH4CI
RIPEhINC
RIPENESS
Hours
1 2 2a 3
20 17 13 10 9 7
4 5 6
0 2 7 0 5 2
6 3 5 5
7 8 9 10
3 7 1 5 Gelled
TENSILE STRENGTHELoNCATIoV PER
DEKIER
Kg.,'sq. cm. 1.72 1.78 1.95 1.95 1 84 1.78 1 74 1 66 1.72 Would not spin
Per cenl 24.3 25.0 27.2 24.1 21.9 19.8 19.0 17.6 18.5
Effect of Ripeness of Viscose
I n a set of experiments to determine the effect of ripeness of viscose upon the physical properties of the regenerated filament, a normal viscose sirup containing 7.1 per cent cellulose and 5.8 per cent XaOH was prepared by normal methods and allowed to ripen a t 18" C. Ammonium chloride maturity values were taken each day and a sample was spun I
I
I
I
Seconds K g . sq. cm. P e r cenl KHICI ripeness, 8.7; viscosity, 28 seconds; temperature, 40' C . 1 2 1 39 5.7 2 4 1.51 7.5 3 5 1.40 10.6 4 6 1.43 11.8 7 5 1 59 11.5 6 8 1.60 13.1 7 10 1.70 14.6 11 1 81 13.4 12 1. 5 2 12.7 14 1.68 12.1 16 1.60 11.0 18 1.4s 9.2 21 1.38 8.8
X H L 1 ripeness, 9 0; viscosity, 22 seconds; temperature, 30' C. 1 4 1.17 7.5 2 6 1 1s 7 5 3 1.30 S.9 4 10 1.26 10.7 5 12 1.29 11.5 6 14 1.36 11 8 7 16 1.51 9 8 8 1s 1.4s 9 3 9 20 1.15 8 2 10 28 1.00 7 5
s
Further proof of the coincidence of the maximum of the curve with complete regeneration of the filament was obtained through a series of micro cross sections of the threads obtained by using a bat,h at 30" C. All threads having a contact time of less than the maximum showed a core of material
through a bath containing 10 per cent &So4 and 28 per cent Xa2S04 a t 40" C. a t 48 meters per minute through a 24-hole spinneret geared to deliver 150-denier yarn. The yarn was
INDUSTRIAL A N D ENGIhlEERING CHEMISTRY
596
tested for tensile strength and elongation. Curve I11 and Table I1 give the variation in physical properties with the variation in ammonium chloride number. Conclusion
From the above experiments it can be seen that there are a large number of factors affecting the physical properties of rayon during the spinning process. The time of contact of the newly formed filament apparently is of importance and if carefully controlled should help in obtaining yarns
Vol. 22, KO. 6
of higher grade. Under present methods of spinning actual contact with the spin bath, a t relatively high temperatures, is very short-never more than 0.5 second. Complete regeneration is attained on the spool by the adhering spin liquor a t a relatively low temperature or by the action of heat, during the washing and drying processes. These processes are usually adjusted by experiment to give the maximum physical properties and might well 6e shortened and made more exact by an attainment of complete regeneration through control of time of contact with the spinning bath.
Radiant Heat from Radiant Heaters and Its Measurement’ F. E. Vandaveer .4YERICAS
T
GASA S S O c I A T l O N TESTING L A B O R A T O R Y , 1032 E A 5 r 62ND S T . , CLEVELAND, O H I O
H E value of r a d i a n t The thermopile and its calibration, the method of the “biologic” effect of ultrae n e r a , emitted by the testing radiant heaters for radiant efficiency used at violet rays is widely knomm, sun, for p r o l o n g i n g the American Gas Association Testing Laboratory it is not generally realized h u m a n life and improving have been described in detail. that visible energy and the It has been shown that: (1) the thermopile is capable shorter infra-red rays have a general health conditions is of measuring radiant heat as emitted by a radiant definite stimulative v a l u e , becoming universally recogheater; (2) the method of test is capable of giving an usually a t t r i b u t e d t o t h e nized. Medical science has shown that people who have accuracy within * l per cent of the true reading; and power they possess of penebeen deprived of the benefits 13) the diathermacy constant obtained is consistent trating the outer layers of of exposure to the sun, either and may be accurately obtained. the skin. A higher intensity by reason of adverse climatic Several means of increasing the total radiant heat can be borne of incident enc o n d i t i o n s o r because of have been given, as well as a discussion of possibilities ergy of the visible or short being confined within doors, of future research work along this line. infra-red quality than of the are much more susceptible to long i n f r a - r e d , and this is diseases of various kinds such as tuberculosis, pneumonia, thought to be due to the greater penetrativeness of the neurasthenia, etc. Remarkable relief has been afforded chil- shorter rays. The energy emitted by the sun contains more dren suffering from rickets and malnutrition by giving them visible and short infra-red energy than that emitted by a sun baths and otherwise bringing them into more direct contact domestic fire, and this would appear to explain why it is with the beneficial rays of the sun. The widespread interest possible to bear in comfort more sun energy than of the enin this is reflected by many of the more prominent hospitals ergy produced by an ordinary red-hot body. These conand sanitariums in prescribing sun baths and exposure to siderations indicate a direction of possible improvement in artificial ultra-violet rays in the treatment of certain diseases. the gas radiant heater which should tremendously increase As a knowledge of its medicinal value increases, more and its value for heating and health purposes. more attention will be directed toward duplicating and Considerable research has been conducted along the aboye scientifically controlling this type of radiant energy by arti- lines in this country, but the published scientific information ficial means. The health-giving rays of the sun cannot pene- on the subject is meagre. Possible fields of research are mentrate fog, smoke, dust, ordinary window glass, or solid ob- tioned in two commercial booklets (9, I 6 ) , which, it is believed, jects of such material as are generally used for constructing should be encouraged and developed. houses and factories. In many large cities fog, smoke, or We are interested not only in the spectral quality of the heat dust obstructs the sun’s rays a great proportion of the time, emitted, but also in the quantity, or the efficiency of a heater particularly during the winter months, when the days are for producing radiant heat. It is proposed in this paper t o short and the inclination is to remain inside as much as give a brief review of published literature, to summarize the possible. Statistics show that during the winter months work done a t the Testing Laboratory of the American Gas there are a great many more deaths than during the summer. Association on measuring radiant heat, and to point out how Therefore, if this vital radiant energy is to be obtained, deaths the radiant efficiency of space heaters may be improved. decreased, and general health conditions improved, artificial Published Work radiant energy must be provided. Prior to 1910 few references are made to instruments suitable .i.ery logical Source of supply of such energy is from room heaters of the radiant type. Energy from gas-fired radiant for measuring radiant energy from gas heaters. In 1910 heaters approaches, to Some extent, that emitted by the Callendar (8) described a radiobalance, an ingenious device sun and, by application of the necessary research, could in which the radiometric receiver consisted of a thermoprobably be made to gi\re off a greater percentage of the type junction which could be heated electrically to neutralize the of energy desired. Considerable scientific work has already heat generated in the receiver by absorbing radiant e n e r a . been done in England (IO, IC). It is pointed out that, while Coblentz, of the U. S. Bureau of Standards, wrote several valuable papers ( 3 , 4,,5, ?) in 1913 to 1916, describing his 1 Received March 15, 1930 Presented before the Division of Gas On determining radiant The and Fuel Chemistry at the 70th Meeting of the American Chemical Society, by the iinierican Gas Association Testing Laboratory, and Atlanta, Ga., April 7 to 11, 1930.
