989
NOTES
Sept., 1955
evaporated into a 400-ml. flask equipped with a mercury cut-off valve. It was freed of residual nitrogen by successive freezing and melting under CHI-CDZ + DSC-CH3 +CHaCDzCD2CHa vacuum. The pumped material had a pressure of As long as the temperature is kept low the D and H GO mm. a t room temperature. This butane gave on an ethyl radical should not exchange and the in- the mass spectral pattern shown in Table I. dicated butane should be formed. At room temIt is not possible with our present knowledge to perature the ethylene and ethane should be formed assess the exact isotopic purity of the butane we almost exclusively by the disproportionation reac- have made. For this reason we have presented the tion via a head-to-tail mechanism. spectrum in its entirety. Certain features of the CHZCDZ f HCHZCD2 +CHsCD?;H + CHz=CDz spectrum do, however, allow us to place some limits The ethane, ethylene and butane were separated on the purity. The fact that mass 63 is present in quantitatively by means of fractional desorption almost the exact amount to be expected from the from silica gel using nitrogen as the elutant. The natural abundance of C l 3 isotopic butane-& indiseparation was monitored by means of a matched cates that no butane-& is present. This is further pair of thermal conductivity cells, one of which had confirmed by the observation of the (mass 48)/ pure nitrogen flowing through it a t about 40 cc./ (mass 47) ratio. The fact that mass 47 is the base min., while the other contained the desorbed gas as peak shows that we undoubtedly are dealing mainly well as nitrogen. When the recorder indicated that with CH3CD2CD2CH3. The remaining question is, a gas was being desorbed, the gas stream was di- how much of the butane is CH3CD2CDHCH3? If rected to a refrigerated trap. In this way the ma- an appreciable percentage were present we wouId terial was fractionated into its component parts, expect a peak a t mass 61 and again at mass 46. each of which was contaminated only with nitro- However, these masses are also to be expected from gen. The samples were then analyzed on the mass CH3CD2CD2CHz+ and CDzCDzCHz+, respecspectrometer. The ethane was 96.5y0 CH3CDzH tively. While there is no reliable method of preand 3.4% CH3CD3,while the ethylene was princi- dicting the size of the mass 61 and mass 46 peaks in from the corresponding mass pally CH2=CD2, 0.5% CHD=CDz being found pure CH3CD2CDzCH3 in the products. It was not possible to assess the 57 and mass 42 peaks in normal butane, it is eviamount of CHZ=CHD since the mass spectrum of dent from a comparison of the normal butane spectrum with the heavy butane spectrum at these CH2=CDz is not known unequivocally. After pumping off most of the nitrogen from the peaks that a very small percent,age of the butane refrigerated butane trap, the butane fraction was is butane-&. From the purity of the DzO, we would calculate that there is a minimum impurity TABLE I of 1-2y0butane-d3.
butane formation is probably recombination of ethyl radicals formed in the primary step
M A s s SPECTRA OF CH3CH2CH2CH3 and CHsCDzCD2CHa These spectra were measured on a Consolidated Engineering mass spectrometer, Model 21-103, ionizing current, 10.5 pa.; magnet current, 0.540 amp.; ion source T = 250'. For n-butane mass 58 appears at 780 v. and mass 2 appears at 3480 v. Standard sensitivity of the mass 47 peak in butane-d4 is 48.63 compared with 50.0 for the mass 43 peak in butane. Butane-dd,
B u t ane , %
Butane-dr,
%
n-Butane,
Mle
0.2
0.1
...
...
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 81 G2 63
6.4 4.5 10.2 17.3 14.4 9.6 100.0 3.4 0.1 0.3 0.4 0.4 0.3 0.3 0.3 0.2 0.3 0.8 0.4 1.3 0.5 11.0 0.5
30.6 12.6 100.0 3.4
M/e
%
2 3 4 12 13 14 15 16 17 18 26 27 28 29 30 31 32 33 37 38 39 40
... ...
0.1
0.8 3.3 0.9 0.8 0.3 1.1 6.7 20.8 23.8 30.7 34.9 4.4 0.3 0.2 0.5 1.6 4.9
B-
... ... 0.1 0.7 5.0 0.1
...
... 5.5 37.5 30.7 40.9 0.9
... ,..
... 0.7 1.8 14.0 1.o
%
...
... ...
...
0.2 1.1 1.1 0.3 0.9 0.2 1.1 0.8 2.6 12.1 0.5
...
... ... ...
VISCOELASTIC PROPERTIES
OF- CRYSTALLINEPOLYMERS: POLYTRIFLUOROCHLOROETHYLENE BY A. V. TOBOLSKY AND J. R. MCLOUGHLIN Contriblltionfrom the Frick Chemicat Laboratories, Princeton University, Princeton, N . J . Received A p r i l Id, 1866
I n previous studies of the viscoelastic properties of linear amorphous polymers it was shown that certain features are common to the behavior of all of these polymers. In particular it was shown that there are four characteristic regions of viscoelastic behavior: a glassy region, a transition region, a rubbery plateau region and a flow region.' The existence of these regions is demonstrated in Fig. 1, showing the stress relaxation behavior of polyisobutylene. The data are plotted in the form log E,(().versus log ( t ) where E,(t) is the stress per unit strain as a function of time in a sample maintained a t constant extension. The behavior in the transition region is particularly to be noted. In the time scale of the stress relaxation experiments (0.01 to 10 hr.), the transition region occurs in the temperature interval between -80 and -40". In this interval the modulus changes very rapidly with time and temperature as can be seen in Fig. 1. The values of E,(t) range between a "glassy modulus" value of 1010.5 dynes/ (1) A. V. Tobolsky and J. R . McLouglilin, J . Polymer Sei., 8 , 543 (1952).
990
NOTES I
VOl. 59
I
I
10'0
- 74. I'C. 10s
L
N*
$ c
x
I
a
6c:
0"c.
108
2 5°C.
\
SO"C,
104
0.001
1.0 Time, hr. Fig. 1.-N.B.S. polyisobutylene. 0.01
100
to the rubbery modulus value of 106.88dynes/ Stress relaxation curves a t different temperatures can be superposed by a horizontal translation along the log time axis, and this principle of superposition permits the construction of a master curve that covers the complete time scale. Polytrifluorochloroethylene is a polycrystalline polymer whose melting temperature T m is 212'. Its glass transition temperature has not been accurately determined but should be somewhere in the neighborhood of room temperature if the approximate relation Tg = 2/3Tmis valid. Figure 2 shows stress relaxation data for polytrifluorochloroethylene in the temperature range between 30 and 193". I n this interval the modulus varies from 10'O.l dynes/cm.2 to dynes/cm.2. It is particularly interesting to contrast Figs. 1 and 2. I n Fig. 2 the log E r ( t ) versus log ( t ) curves between 30 and 144" are relatively flat; ie., the modulus change with time in the "transition region" is much less marked for the polycrystalline polymer as compared to the amorphous polymer. Also in Fig. 2 the modulus value of log Er(t) at t = 0.01 hr. changes from a value of 10'O.l dynes/ cm.2 at 30" to a value of a t 144", a very gradual change. The '(transition region," if such it can be called, for a polycrystalline polymer obviously extends over a much wider temperature range than for an amorphous polymer. The "transition region" blends into a high modulus "rubbery region," the crystallites playing the same role that entanglements or cross links do in the amorphous polymers. The relatively rapid decay of stress a t 193" is no doubt associated with a change of microcrystalline
0.1 1 10 100 1000 Time hours. relaxation of polytrifluorochloroethylene.
0.01
Fig. 2.-Stress
structure or texture, i e . , an orientation of crystalline material. Because there are changes with temperature in the microcrystalline structure and in the stress bearing mechanisms, it is certain that the simple time-temperature superposition that is valid for amorphous polymers in the transition region is not valid for polycrystalline polymers. There is not only a horizon displacement along the log time axis due to changing rate of molecular motions with temperature, but also an even more important vertical shift along the log Er(t) axis due to the changing structure and other factors.
METAL-POLYELECTROLYTE COMPLEXES. IV. COMPLEXES OF POLYACRYLIC ACID WITH MAGNESIUM, CALCIUM, MANGANESE, COBALT AND ZINC BY HARRYP. GREGOR, LIONELB. LUTTINGER' AND ERNST M. LOEBL
Contributionfromthe Department of Chemistry of the PoEytechnicInstitute of Brooklyn, New York Received March IO, 1966
I n the first paper in this series2 the formation of complexes of polyncrylic acid (PAA) and copper(11) was reported. In this paper the analogous complexes with magnesium, calcium, manganese(11) cobalt(I1) and zinc are described. The experimental procedure and the mathematical tech(1) A portion of this work is abstracted from the Dissertation of Lionel B. Luttinger, submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry, Polytechnic Institute of Brooklyn, June, 1954. (2) H. P. Gregor, L. R . Luttinger and E. h i . Loebl, T H I B JOURNAL, 69, 34 (1955).
I
a
