2643
Macromolecules 1986, 19, 2643-2644
Table I Dipole Moments ( M ~ (D2) ) and Molar Kerr Constants ,K (X10-'2 cm-' SC2mol-') per Repeat Unit x for E-V Copolymers
---
...-... Ties Left-hand loops that link Right-hand loops linked Total linking number
~~
J
~ t 12 . ' ~ I8. ~ ' 24 . ~M ~ ' Distance Between Planes Figure 4. Density of ties plotted against various linking densities (data from Table 111). o
~
~
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mological linking phenomena that we have observed.
References and Notes (1) Flory, P. J.; Yoon, D. Y.; Dill, K. A. Macromolecules 1984,17,
862. (2) Guttman, C. M.; DiMarzio, E. A,; Hoffman, J. D. Polymer 1981,22, 1466. (3) Guttman, C. M.; DiMarzio, E. A. Macromolecules 1982, 15, 525. (4) Mandelkern, L. Acc. Chem. Res. 1976,9,81. (5) Mansfield, M. L. Macromolecules 1983, 16, 914. (6) Feller, W. An Introduction to Probability Theory and Its Applications, 3rd ed.; Wiley: New York, 1968; Vol. 1. (7) Blackman, D. K.; De Vries, K. L. J. Polym. Sci., Part A-1 1979, 7, 2125. (8) Flory, P. J.; Yoon, D. Y. Nature (London) 1978, 272, 226. (9) Rolfsen, D. Knots and Links; Publish or Perish, Inc.: Berkeley, CA, 1976; Mathematics Lecture Series, Vol. 7. (10) Flory, P. J. Statistical Mechanics of Chain Molecules; Interscience: New York, 1969. (11) Lacher, R. C. The CROSSWALK Simulation: Design, Development, Verification, Analysis, and Data, Technical Report; Florida State University, Tallahassee, FL, 1986. (12) Marsaglia, G. Keynote Address, Computer Science and Statistics, XVI Symposium on the Interface, Atlanta, GA, 1984. (13) Knuth, D. E. The Art of Computer Programming, 2nd ed.; Addison-Wesley: Reading, MA, 1981; Vol. 2. (14) Pohl, W. F. International Symposium in honor of N. H. Kuiper, Utrecht, 1980; Lecture Notes in Mathematics; SpringerVerlag: Berlin, Heidelberg, New York, 1981. (15) des Cloizeaux,J.; Ball, R. Commun. Math. Phys. 1981,80,543.
Kerr Effect and Dielectric Study of Ethylene-Vinyl Chloride Copolymers A. E. TONELLI* and M. VALENCIANO+ AT&T Bell Laboratories, Murray Hill, New Jersey 07974. Received April 11, 1986
A series of ethylene-vinyl chloride (E-V) copolymers were obtained recently1 by reductive dechlorination of poly(viny1 chloride) (PVC) with tri-n-butyltin hydride [(n-Bu),SnH]. Their microstructures (comonomer composition, sequence distribution, and stereosequence) were determined by NMR analysis, and GPC measurements indicated that all E-V copolymers have the same chain length ( x = lo00 repeat units) as the PVC from which they were made. AT&T Bell Laboratories Summer Research Program Participant. Current address: Merck and Co., Inc., Rahway, NJ.
0024-9297/86/2219-2643$01.50/0
"
E-V PVC E-V-85 E-V-71 E-V-61 E-V-50 E-V-46 E-V-35 E-V-21 E-V-14 E-V-2 .PE ~ ~
P, 0.44 0.42 0.40 0.38 0.36 0.34 0.26 0.19 0.15 0.08
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a 2.6 4.2 2.5 2.5 2.2
1.4 1.3
~
b 3.7 3.3 2.8 2.4 2.0 1.9 1.6 0.9 0.6 0.1 0.0
c 3.7 3.5 3.1 2.7 2.6 2.2 1.7 1.0 0.7 0.1 0.0
a -14 9 20 34 23
b
-4 6 15 16 18 16 13 7 4 1.5 1.5
C
-4 5 15 21 30d 27 22 11
6 1.5 1.5
a Measured. *Random with P, = 0.44 calculation. Triad simulation calculation. d , K / x = 31 and 30 when averaged over 10 and 20 chains, respectively. Values of ,K/x ranged from 26 to 42 when calculated for the set of 20 Monte Carlo generated chains.
We are currently studying the physical properties of this well-characterized set of E-V copolymers. To date, we have determined their densities and thermal propertiesz (T, and T,,,), studied the compatibilities of their blend^,^ and completely assigned their IR spectra: all in the solid state. It has been demonstrated both by and by calculations6J0that the molar Kerr constant (,K) as obtained from the electrical birefringence measured on its dilute solutions is one of the properties of a polymer most sensitive to its conformational and configurational characteristics. In this note we describe the results of dielectric (dipole moment) and electrical birefringence (Kerr effect) measurements performed on dilute E-V copolymer solutions. The synthesis and microstructures of the E-V copolymers were presented earlier.' The Kerr effect and dielectric apparatus along with the experimental techniques have been previously described.6 Kerr effect and dipole moment measurements were performed at 25 OC in p-dioxane. E-V copolymers rich in E units are insoluble in p-dioxane, thereby limiting our study to those copolymers with at least 35 mol % V units. Molar Kerr constants and dipole moments were calculated according to the methods detailed in ref 9 and 11. The polarizability tensor and dipole moment for the C-C1 bond are the same as presented in our study of PVC and its model compounds,S and treatment of the polarizability tensors for the E-V copolymers is also described there. Mark's12 conformational model of E-V copolymers was used to perform the appropriate average1' over all conformations. E-V copolymer chains of 200 repeat units ( x ) were generated by Monte Carlo methods in two different ways. In the first method E and V units were randomly added one at a time with adjacent V units (VV diads) incorporated with P,,, = 0.44, i.e., 44% meso (m)and 56% racemic (r) VV diads, correspondingto the P, = 0.44 of the parent PVC.l The second procedure took cognizance of the detailed E-V microstructure as determined by our 13C NMR study.' For each E-V copolymer we have knowledge of the triad comonomer sequence distribution and the VV diad stereosequence. Consequently, we generated each E-V copolymer chain a triad at a time in a way t~ produce an E-V copolymer with the same microstructure (comonomer composition and stereosequence) as observedl by 13C NMR. We generated 20 Monte Carlo chains for each E-V 0 1986 American Chemical Society
Macromolecules 1986, 19, 2644-2647
2644
= 0.073, VEE = EEV = 0.129, VVE = EVV = 0.133, VEV = 0.166, and EVE = 0.192. When K , is calculated for
E-V-50 by triad simulation, which accounts for both P, = 0.36 and the observed triad comonomer distribution, the resulting value is within 10% of the observed molar Kerr constant. It is, therefore, apparent that, unlike ( p 2 ) ,K , is a sensitive indicator of E-V copolymer microstructure, a conclusion reached several times previously by measurement~”~ and calculation^^^^^ performed on other vinyl homo- and copolymers.
3X
\
bz 2 V l-
References and Notes PE
PVC
XV
Figure 1. Comparison of the observed and calculated dipole momenta per repeat unit, ( j ? ) / x , for E-V copolymers,where Xv is the mole fraction of V units. 40
r
i
A
Schilling, F. C.; Tonelli, A. E.; Valenciano, M. Macromolecules 1985, 18, 356. Bowmer. T. N.: Tonelli. A. E. Polvmer 1985.26. 1195. Bowmer; T. N.f Tonelli,’A. E. MaEromolecules 1986,19, 498. Bowmer, T. N.; Tonelli,A. E. J. Polym. Sci., Polym. Phys. Ed., in press. Saiz, E.; Suter, U. W.; Flory, P. J. J . Chem. Soc., Faraday Trans. 2 1977, 73, 538. Khanarian, G.; Tonelli, A. E. J . Chem. Phys. 1981, 75, 5031. Khanarian, G.; Tonelli, A. E. Macromolecules 1982, 15, 145. Khanarian, G.; Cais, R. E.; Kometani, J. M.; Tonelli, A. E. Macromolecules 1982,15, 866. Khanarian, G.; Schilling, F. C.; Cais, R. E.; Tonelli, A. E. Macromolecules 1983, 16, 287. Tonelli, A. E. Macromolecules 1977, 10, 153. Flory, P. J. Statistical Mechanics of Chain Molecules, WileyInterscience: New York, 1969. Mark, J. E. Polymer 1973, 14, 553. The kinetics of (n-Bu)3SnHreduction of PVC have been studied14with the aid of PVC model compounds. Jameison, F. A.; Schilling, F. C.; Tonelli, A. E. Macromolecules, in press.
Compatibility in Chlorinated Poly(viny1 chloride)/Poly(ethylene-co -vinyl acetate) Blends TOMOO SHIOMI,’ FRANK E. KARASZ,* and WILLIAM J. MACKNIGHT
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02
04
06
xv
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Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003. Received May 5, 1986
PVC
Figure 2. Comparison of the observed and calculated molar Kerr constants per repeat unit, m K / x ,for E-V copolymers,where Xv is the mole fraction of V units.
copolymer and averaged K , and ( p 2 ) over this set regardless of whether or not the random or triad simulated method was employed.
Results and Discussion The observed and calculated dipole moments and molar Kerr constants per repeat unit are presented in Table I, where the composition (E-V-85 85 mol % V) and stereoregularity (P,) are also given for each E-V copolymer. In Figure 1the observed and calculated dipole moments are compared. Satisfactory agreement is obtained regardless of the method of calculation employed. On the other hand, the molar Kerr constants compared in Figure 2 make apparent that only the triad simulated ,Ks agree with the observed values. As an example, for copolymer E-V-50, whose P, has been reduced from 0.44 (PVC)to 0.36, assumption of random chlorine removal , nearly a during its production leads to a calculated K factor of 2 smaller than is observed. If chlorine removal were a random process, then we would expect all triad comonomer sequences to be equal to 0.125. Instead, 13C NMR analysis of E-V-50 reveals the following comonomer triad distribution: EEE = 0.045, V W
-
0024-9297/86/2219-2644$01.50/0
Recently, the miscibility and phase separation behavior in blends containing random copolymers have been investigated.’-15 Several homopolymer/copolymer blends were found to be miscible for a certain range of copolymer compositions even though no specific interactions between the component monomer units o ~ c u r r e d . ~ This - l ~ region of miscibility has been termed a “miscibility window” and has been explained by the Flory-Huggins t h e ~ r y l -in~ terms of an unfavorable interaction between the two different monomer units comprising the copolymer. The Flory-Huggins theory for mixtures of homopolymers and copolymers has also been extended to blends of two random copolymer^.^*^ According to ten Brinke et a1.,2 the interaction parameter Xblend between two random copolymers (AXBl& and (CYDl-Jn2can be written as
where the respective x,. are the segmental interaction parameters between the aifferent monomers corresponding to their subscripts and x and y are the copolymer compositions expressed in volume fractions. When the value Permanent address: Department of Materials Science and Technology, Technological University of Nagaoka, Nagaoka, Niigata 949-54, Japan.
1986 American Chemical Society
