INDUSTRIAL AND ENGINEERING CHEMISTRY
1634
Vol. 44, No. 7
compounding ingredienh in Type V latex lowered slightly the film tensile strength. For the X-370 1at.e.u the situation is similar. Table I1 shoms that the ultimate tensiles of compounded films are greater than Sample Tu& Eu those of uncompounded films by a factor of about two. However, 321 139 930 280 290 2 . 0 2 1425 1100 0 . 7 7 322 130 740 241 305 1 . 8 6 1090 970 0 . 8 8 the actual tensiles show no such reinforcement, the ratio of 600 242 320 1 . 8 1 323 134 935 1015 S,/Su having an average value of 1.04 =k 0.11. 324 121 590 251 305 2 . 0 8 830 990 11 .. 10 99 325 117 955 270 380 2 . 3 1 1225 1300 1 . 0 6 Natural latex films, on the other hand, were found to behave 327 127 880 326 335 2 . 5 7 1250 1480 1 . 1 8 very differently and to give considerably higher values for both 328 116 795 259 300 2 . 2 3 1030 1030 1 . 0 0 330 127 740 267 365 2 . 1 0 1070 1225 1 . 1 4 the ultimate and actual tensiles of the compounded films. The Averages 126 779 267 328 2 . 1 2 i 0 . 1 9 1107 1139 1 . 0 4 & 0 . 1 1 data in Table I11 show the average value of T J T , to be 3.50 a See Table I for definitim of symbols. i. 0.29, and of S J S , t.0 be 2.94 f 0.26. This factor of t,hree in the actual tensiles of compounded TABLE 111. ULTIMATE AXD ACTVAL TEXSILES O F SATURAL I,.&~ex F J I , ~ ~ and uncompounded films of natural latex indicates that compounding and curing leads in essence to TC SC Sample Tya Eu Tc E,: Tu SU SC S U a threefold increase in the intrinsic strength of the 4630 920 3.39 20 1365 1175 17,400 47,200 2.71 films. In contrast’, no such reinforcement as a 24 1640 1125 5320 855 3.24 20,100 50,700 2.52 26 1390 1080 5110 945 3.68 16,350 53,500 3.27 result of compounding and curing has been ob27 1520 1090 5280 915 3.47 18,100 53,600 2.96 served with Type 111, Type V, and X-370 latices, 31 1540 1050 4720 955 3.06 17,700 49 800 2.81 4760 900 4.10 33 1160 1125 14,200 47:600 3.35 all of which show a value of S,/Suequal essentially 35 1530 1055 5460 880 3.57 17,700 53,300 3.01 41 1510 1130 5000 910 3.31 18,600 50,300 2.70 to unity. 1110 4490 925 46 1440 3.12 17,300 46,000 2.66 Whether this failure of synthetic latices to be 5930 870 4.10 56 1445 1075 17,000 57,500 3.38 Averages 1445 1102 5070 908 3 . 5 0 It 0 . 2 9 17,245 50,980 2.94 + 0.26 reinforced by and is an herent weakness of the systems, or whether it is Bee Table I for definition of symbols. due to use of an inappropriate compounding formula, cannot be decided a t present. In this work the same compounding formula was employed R E S U L T S AND D I S C U S S I O N for a11 ’tatices,one which was developed primarily for natural latex. It may well be that this formula, while satisfactory for natural The tensile obtained in this study are given in Tables I latex, is unsuitable for the synthetic latices. If such be the case, to 111. The and actual tensile strengths, as well as then more attention may have to be devoted to formulas and elongations, are given for both the compounded and techniques employed in the compounding of synthetic latices in pounded samples. Symbols used a t the c o l u headings ~ signify: S = actual tensile strength as calculated from the cross-aeotiona] order to bring out more uniquely their optimum properties. area a t break, T = ultimate tensile strength as calculated on the ACKNOWLEDGMEhT basis of the original cross-sectional area, E = elongation of test strips between bench marks in per cent, and the subscripts u and This study was sponsored by the Reconstruction Finalee Corp., c refer to uncompounded or compounded films, respectively. Synthetic Rubber Division, as part, of the government, synthetic Upon examination of Table I iti may be seen that for Type V rubber program, latex ultimate tensiles of the compounded films are greater than LITERATURE CITED those for the uncompounded films, the ratio of T,/T, averaging 1.60 0.12. However, the data recalculated on the basis of cross(1) M ~s. E.,~and ~~ ~ ~B. p., ~ Ad ~, ~chmn., z~ . 20,~,545 (1948). , sectional area a t break reveal no such increasein tensilestrength (2) Maron, S . H., Madow, B. P., and Trinastic, J. C., IND. ENO. CHEM..40, 2220 (1948). as a result of compounding. The ratio of S,/S, averages in fact only 0.86 f 0.12, indicating that, if anyt’hing, the presence of ‘ R E C E I V E D f o r review December a, 19.51. .&ccEpTsoMarch 6 , 1952.
TABLE11.
ACTUAL TESSILES O F x-370 LATEX FILMS TC SC To Ec Tz su Sc su
L ~ L T I M A T E AND
*
Turpentine from Ponderosa Pine L. A. GOLDBLATT AKD A. C. BURGDAHLl , V a d Stores Station, Bureau of Agricultural and Industrial C h e m i s t r y , United States Depurtment oJ Agriculture, Olustee. F l a .
S
TEAM-distilled wood turpentine, one of the four kinds of turpentine recognized by the Federal Kava1 Stores Act (the three others are gum spirits of turpentine, destructively distilled wood turpentine, and sulfate wood turpentine), is classified officially as that kind .‘obtained by steam distillation from the oleoresinous component of wood whether in the presence of the wood or after extraction from the wood” ( 3 ) . This class of turpentine, which furnishes more than a third of the country’s present supply, is derived from aged stumps of old southern pines felled 20 or more years ago. But this supply 1
Present address,
Xew Orleans, La.
U. S. Food
& Drug Ad~ninistration,Customs House,
of raw material is declining, as trees cut more recently have generally come from younger second-growth stands, and such stumps, which consist largely of sapwood, are not suitable for the wood naval stores industry. ilccordingly, there has recently been revived interest in western pines as a source of naval stores. The United States is the world’s leading producer of naval stores and, according to Homer, currently accounts for approximately 7070 of the world output of turpentine ( 5 ) . Production of turpentine of all kinds in the United States in the crop year 1950-51 (i2prill-March 31) was 708,550 barrels (8). Gum turpentine comes almost entirely from the southeastern states-chiefly from longleaf pine (Pinus Palustris Miller) and
INDUSTRIAL AND ENGINEERING CHEMISTRY
July 1952
slash pine (Pinus Caribaea Morelet). Sporadically, however, turpentine has also been produced in the western states. For example, during the Civil War, when the supply of naval stores from the South was cut off, the northern states were supplied with turpentine from the pines of the Sierra Nevada range of California ($). Also the crude distillate of the gum from two species of western pines, Jeffrey pine (Pinus Je$reyi Oreg.) and Digger pine ( P . sabiniana Douglas), which contain n-heptane in their oleoresinous exudate, was used locally in California during the latter part of the 19th century, chiefly as a cleaning agent. During the 1920's commerical production of oleoresin from these pines was revived to supply a demand for n-heptane for use as a standard reference fuel for the measurement of detonation in internal-combustion engines. However this turpentine is not produced commercially today.
TABLU I. APPROXIMATECOMPOSITION OF TURPENTINES FROM PONDEROSA STUMPWOOD AND LTJMBER Component
Per Cent by Weight Stumpwood Lumber
