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Analysis of the 19F NMR spectra of copolymers of vinylidene fluoride with tetrafluoroethylene, and of vinylidene fluoride with tetrafluoroethylene and hexafluoropropylene. The use of an empirical additive scheme and of the principle of alternation
10F ~
spectra of copolymers of VF with TFE
711
12. L S. ~ t ~ E M , N. I. CHISTOVAL0VA, Ye. L "MYSOVand M. Ye. V0LPIN, I~sshche. pleniye svyazi Si--C soyedin~aiyami platinovoi gruppy (Si--C Bond Splitting by Platinum Group Compounds). Izv. AN 8SSR, seriya khimich,, No. 9, 2069, 1976 13. M. R. STOBER, M. ¢. MUSOLE and J. L. S p ~ z l t , The Addition of Silicon H~ydrides to Olefinic Double Bonds. Exchange of Methyl and Trimethylsiloxy Groups in bis-trimethyisiloxymethylsilane, J. Org. Chem. Soc. 80: No. 5, 1651, 1965 14. A. F. B ~ , V. 8. PAPKOV, A. A. ZHDANOV and K. A. ANDRIANOV, Osobennosti okisleniya polimetilfenilsiloksilovykh zhidkostei (Features of the Oxidation of Polymethylphenylsiloxane Liquids). Vysokomol. soyed. B2O: 70, 1978 (Not translated in Polymer Sci. U.S.S.R.)
l~olymer 8c/ence U.S.S.R. Vol. 23, No. $, PI~. 711-720, 1981 PHnted in Poland
0032--3950/81/0307U-10507.50[0 ~) 1982 Pergamon P r e ~ Ltd.
ANALYSIS OF THE 19¥ NMR SPECTRA OF COPOLYMERS OF VINYLIDENE FLUORIDE WITH TETRAFLUOROETHYLENE, AND OF VINYLIDENE FLUORIDE WITH TETRAFLUOROETHYLENE AND HE.XAFLUOROPROPYLENE. THE USE OF AN EMPIRICAL ADDITIVE SCHE.ME AND OF THE. PRINCIPLE OF ALTERNATION* YE. M. MU~ASHEVA,A. S. S~SHKOV and A. A. Do~rrsov Research Institute of the Rubber Industry (R~/ved 11 January 1980) An additive scheme is proposed for determining chemical shifts of fluorine atoms
,I
included in --CF--, --CFn-- and --CFs groups in fluorine-containing polymers. The spectra of the copolymers of vinylidene fluoride and tetrafluoroethylene and of vinylidene fluoride and tetrafluoroethylcne and hexafluoropropylene are interpreted in accordance with this additive scheme. Application of the principle of alternation in changes in chemical shifts of I'F nuclei on varying the electronegativity of nearest polymer chain fragments allowed interpretation of the fine structure of spectrum lines and enabled these to be assigned in terms of tetrads and pentads. TH~ m e t h o d o f I°F N M R spectroscopy provides t h e simplest a n d m o s t reliable m e a n s o f q u a n t i t a t i v e analysis o f t h e chain s t r u c t u r e s o f fluorinated polymers. Reliable i n t e r p r e t a t i o n of t h e / l t F N M R spectra is a necessary condition for this t y p e o f analysis. Various empirical relations a n d a d d i t i v e schemes reflecting t h e influence o f i n d u c t i v e a n d o t h e r factors on chemical shifts of l°F nuclei [1-7] h a v e * Vysokomol: soyed. A28: No. 3, 632-639, 1981.
712
YE. M. MURASHEVA e~ a/.
appeared in numerous papers aimed at simplifying interpretation of the spectra. In earlier work [8] we considered a fruitful application of the principle of alternation of changes in 19F chemical shifts relative to the number of bonds between a resonating nucleus and substituents of differing electronegativity. In the present instance we generalized data on increments in the previously proposed additive schemes and extended the latter in the light of published data and our own data on chemical shifts for 19F in polymers and in some low molecular substances, and on the basis of these data an additive scheme was developed for determining chemical shifts of 19F nuclei in the most widely used polymers, allowin~ for the principle of alternation referred to above. The application of this additive scheme is illustrated by interpretation of the 19F NMR spectra of a vinylidene fluoride (VF)-tetrafluoroethylene (TFE) binary copolymer and a VF-TFE-hexafluoropropylene (HFP) ternary copolymer. The influence of surroundings on chemical shifts of fluorinated groups has been discussed repeatedly in special papers and monographs. Saika and Slichter [1] showed that the main contribution to changes in the degree of screening of fluorine nuclei is made by the paramagnetic term of the screening constant. The latter depends on the extent of the ionic character of the bond -- as its ionic character decreases (as the e!ectronegativity of attached atoms increases) the paramagnetie contribution to the screening is increased (the chemical shift of 19F nuclei is reduced on the 4 " scale). However, it was noted in [9] that the rule of electronegativity of substituents is not satisfied in the case of fluorochloromethanes. This was accounted for in terms of ideas regarding ionic structures containing double bonds where fluorine atoms, it was thought, are most prone to double bondedness [9, 10]. Finally, it was shown in [11] that simple inductive effects do not determine the screening of fluorine nuclei for more extensive range of polyatomic fluoroalkanes. According to Evans [2] a simple electronegativity principle m a y break down on account of the action of intramolecular dispersion forces operating between 1~ atoms and the nearest groups, arkd the role of such forces will be growing as the size of substituents increases. These general premises will no doubt hold for polymers a s well. However a feature in the case of the latter is the feasibility of an induction effect being transferred along the polymer chain and leading to regular changes in the chemical shifts of F atoms depending on the immediate and'remote (at a distlance of 3-5 bonds) surroundings. Comparing the chemical shift data f o r 19F NMR lines for PVF and model low molecular compounds~ Wilson and Santee [3] found that in the ease of mutual substitution of --CH2-- and --CFz-- in a position Adjacent or preadjacent to --CF2-- the chemical shift of the latter changes in an approximately additive fashion, and irrespective of other groups in the quintet. The cited authors felt that the same property might well be possessed by linear quintets with another make-up that include groups --CHF--, --CHCI--, --CFCI--, CC12-- etc. Another empirical relation was found by Ciampelli and coworkers [4] while investigating a number of fluorinated compounds, includifig polymers. On
19F NMR spectra of copolymers of VF with TFE
713
e x a m i n i n g fragments containing only carbon, fluorine and ether oxTgen o n e finds t h a t a chemical shift for a given fluorocarbon group is a linear function of tha~ for its nearest neighbours. In addition, a change of x p.p.m, in the chemical shift for one of two adjacent fluorinated groups will on average cause of a change of 0.12 x p.p.m, in the opposite direction for the nearest neighbours. The effect is reduced b y one-half if the fluorinated groups are separated b y an 0 atom. The relationship breaks down when fragments comprise multiple bonds or protonated groups (CHF--, CH~-- etc.). Sass and coworkers [6, 7] found t h a t oxygen and perfluorinated ethers had a similar effect on the chemical shifts of fluorine. It appears difficult to extend t h e relations found b y those authors so as to cover a wide range of compounds. Meanwhile on analysing published information one m a y conclude t h a t additivity in changes in chemical shifts found [3] for linear pentada has a more general character and is not restricted to the fluoromcthylene group. It seems that chemical shifts of fluorinated compounds could in general b e found b y using an empirical method of determining the magnitude of the shifts in the manner proposed b y Primas and coworkers [12] for proton resonance. An additive scheme on which the empirical analysis is based would appear more complex and 'laborious if one considers the above-described features of change in the chemical shifts of 19F nuclei as a function of the surroundings. Nevertheless on the basis of material already available an attempt m a y be made to use an additive scheme to predict chemical shifts of fluorinated groups in various compounds. In the present instance we limit ourselves to the construction of an additive scheme for calculating chemical shifts for three most common groups in polymers,
J
viz. CFs-- , - - C F 2 - and - - C F - - . Polymers are convenient materials for creating an additive scheme for the following reasons: 1) in polymers one m a y more readily trace induction effects of substituents via several bonds; in most cases the latter effect is not masked b y the effect of endgroups; 2) when analyzing the spectra of fluorinated polymers one need not take t o o wide a range of increments for an additive scheme; 3) an empirical means of deter.miuing chemical shifts is particularly valuable in the case of high molecular compounds, since chemical shifts are the main and frequently the sole parameter in the 19F N M R spectrum of a polymer. An increment table (see above) was compiled when analyzing chemical shifts of ~* and the extent to which the latter are influenced b y adjacent and penultimate groups of a large number of fluorinated high- and low molecular compounds. The magnitude of the chemical shift (from CFC13, ~*-scale) for the three groups referred to above was found as follows. In the case of CF 3 - we took as the initial group the fragment CF3CF2CF2-- , where the value of ~* is p u t at 81 p.p.m. [13, 14]. I f instead of --CF~-- we have in the adjacent position one of the groups appearing iri the top colum n of Table 1, the value of ~* for CT 8 in this fragment is found b y adding increment A, allowing for the sign.
714
Y~. M, Mu~zAs~vA ~ a/.
In the case of --CF~-- the initial fragment was --CF2CFzCF~CFICFs--, in which the value of ~* for the --CF~-- group in heavy print was 121 p.p.m. (our data, and those in [3]). On replacing an adjacent --CF,-- group by groups indicated in the top column of Table 1, we have a consequent change, amounting to the value of increment ,4, in the chemical shift. As was pointed out in [3] the addition of a second --CH~-- group adjacent to --CF~-- causes a disproportionately large change in the chemical shift of the latter. Accordingly the increments for some groups are given individually for one (1) or two (2) single,type substituents in the adjacent position. Some asymmetrical substituents have ~he bond nearest to the group of interest marked with heavy type.
I
In the case of --CFCFs we took as the initial fragment group (CFsCFs)~CFCF2CFs--, where --CF-- has a chemical shift of 184 p.p.m. [15]. Here the procedure for determining the chemical shift is similar to that described above'(the case of simultaneous substitution of adjacent --CF~-- groups by three monotype substituents is not considered). It should be noted that the scheme does not cover
I
i
the --CF-- group linked directly to --CFs (i.e. fragment --CFCFs), since the
I
influence of adjacent protonated groups on the chemical shift of --CF-- in the fragment is abnormal, judging by our data and by the data in [16]. The B increments provide a correction that is called for on replacing preadjaoent groups in the above fragments by groups appearing in the top column of Table 1; the procedure is the same as that described above. According to the idea of the additive scheme B increments are added irrespective of which A increment has already been taken into account. T~BLE I.
ADDITIVE
SCHEME I N C R E M E N T S F O R DET1~.~MTtVIlq'G
Adjacent and preadjacent groups Resonant group p.p.n~
-..-C~ 8
Increment
81
A
.21
~B A
--11
A
.84
(1)
--22 +4 _ 10,, +2.~
B --CFIn
---CH,~
B • The Inc~ztent8 are ~
1. Inconvot
for
I
--CR'I~
(2)
--18
+7 ~29" +5 +9
c(F)
~CH~ CI(H)
--9
0 --5
i
c(F) --22 0 --9 --3.5
--10 --2 --8.5 - - 1.5 --9
--1.5
correct for determining chemical ,dflfts o f - C K F - g r o u . ~ .
-OFCF. (L~eetext).
--~H¥(1)
----CFB
--22 0 --!2
+1.5 --5
1IF NMR spectra of copolymers of VF with TFE
715
For instance, let us say that we have to find the chemical shifts for all the groups in the copolymer of T F E with perfluoronitrozomethane ("head to t a i l " addition), i.e. in a fragment of the type of
--NOCFICFjNO--CFs For CFs ~*=81--25nu9-=65 p.p.m., where --25 is the A increment for an
I
adjacent - - N - - , and + 9 is the B increment for a preadjaeent --O--. For CF2 ~* = 121 -- 3 0 + 7 nt- 1 -=--99 p.p.m., where -- 30 is the A increment for an
I
adjacent - - N - - , + 7 is the B increment for two preadjacent - - 0 - - and + 1 is the B increment for a preadjacent --CFs. For CF~ ~ * ~ 121--37~-2~2-~88 p.p.m., where --37 is the .4 increment for an
I
adjacent - - O - - and -{-2 is the E increment for each preadjacent - - N - - . The found chemical shifts are in good agreement with the experimental d a t a in [17]. Chemical shifts calculated in the same w a y for all the CF8--, --CF2-- a n d
I
--OF-- groups for the copolymers stated below give a maximum deviation (from experimental values) amounting to 1.5 p.p.m. It is, of course, to be expected t h a t as the N M R analysis of novel fluorinated polymers (and low molecular compounds) proceeds the present increments will be refined, and their number increased. The scheme in its present form cannot reflect effects of steric isomerism, or the influence of ring currents of aromatic substituents, or the role of solvents and other subtle effects. Obviously we are in this instance dealing only with features of the induction effect and the effect of dispersion forces. However, the existing material may be used not only for calculating magnitudes of chemical shifts relating to. CHEMICAL
--CHF-(2)
SHIFTS
OF
19F I N F L U O R I N A T E D
POLYMERS
Adjacent and preadjacent groups C(H,F) --CFCI-- --CFCI-- --OCF---O----0--(1)
(2)
~(H.F)
--OC-]
i
(1)
(2)
1
--N--
---CF,
C(H,F)
--25
--25
+9 --6
--6
--2-5
--15
--41 +4"5
--48 +5'5
--37 +5 --47 4
--65
+7
--30 +2
+3
+1 +5
716
YE.
M. MURASHEVA e~ al.
single- a n d multi-type groups (still more successfully) for p r e d i c t i n g the relative placement of their resonance lines. T h e use of an empirical schema also facilitates t h e search or assignment of low i n t e n s i t y lines pertaining to fluorinated groups in t h e vicinity of " h e a d to h e a d " a n d "tail to t a i l " additions in homo- a n d copolymers. TABLE 2. CALCULATEDAND EXPERIMENTALVALUES OF CHEMICAL SHIFTS
OF I N T E N S E
LINES
IN
'l,f l ~
VF-TFE SPECTRUM Fragments CF,CH,CFsCH,CF, CF,CF,CF,CH,CF, CH,CF,CF,CF,CH,
(h*, p.p:m. calculated I experimental I • 92.0 [ 91-5 II1.0 [ 110.5-111-3 126.0 124.5-125.8
I n other words, the additive scheme described above facilitates to a first order of c o m p l ~ i t y interpretation of the spectra of fluorinated polymers. H o w e v e r it will be shown below t h a t the spectra of polymers often have a complex t y p e of line structure pertaining to single-type fluorinated groups w i t h similar i m m e d i a t e surroundings (adjacent a n d p r e ~ l j a c e n t groups) a n d resulting from the purely inductive influence of remote groups. On analyzing this fine line structure we o b t a i n the n u m b e r of triad, t e t r a d a n d p e n t a d sequences in the polymer chain. TABLE 3. CHEMICALSHLW~SOF CF, Gz~ouPs IN THE VF-TFE COPOLYM~R FragLines ment,
¢~, p.p.m.* Sequences expericalculated mental
Fragments
No.
/
g h i k 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-- C H , C F , C H z C F , C H , C F ,CF, --- C F , C F , C H I C F , C H , C F , C F , - -- C H , C F , C F , C F I C H , C F , C H ,-- C H , C F , C H , 6 ' F , C F , C F , C H , - -- C H , C F , C F , C F , C H , C F , C F , - -
i I
-- CF,CF,CH,CF,CF,CF,CH,--- CF,CF,CH,CF,CF,CH,CF,--
-- CF,CF.CH,CF,CF
,CH,CF,CI?,
--
}
-- CF,CH,CF,CFCH,CH,CF,--- C F , C H , C F , C F , C F , C F , C F , C H , C F , - -- C F , C F , C H , C F , C F , C F a C F , C F , C H , - -- CHzCFzCHaCF,CF,CFaCFaCFsCH,--
-- CF,CF2CHzCF,CF,CF,CH,CF ,CF 2--- C F , C F , C H , C F Z C F , C F I C H z C F z C H , - - - CH,CFzCH,CF,CF,CF,CH,CF,CH,--
91 '5 92.8
92.0 92.0
VVVT T~T
110.5
111.0
111.3
III.0
VT~ VVTV VT~
113"4
113.5
TVTV
115.9 120"8 122.5 123.2 124.5 ] 125.2 ~ 125.8 )
116.0 121-0 123.5 123.5 126.0
WTTV TVTTV VVTTV TVTVT TVTW W T W
* In the imper by Wilson and I~ntee [3] with a reference ~o a prlvace communication o f Boikelman one finds the ~hemical t h i f ~ of CF, groups o f low molecular co.mpounds, fragments of which are similar to same fragments in the Table.
717
t0F NMR spectra of copolymers of VF with TFE
! m
a
•
c
d
a
k
b h~ ~
e
,,,
I 100
I
90
I 110
1 120
I 130
b C
Q
d m
j
r
f
q
n
¢.
I
90
I10
130
I I
1
t
180 .
180
x'F NMR spectra of the V F - T F E (a) and V F - T F E - H F P (b) copolymers.
7i8
~
Y z . M. M ~ V A
~g ~ .
"
This analysis may be done using the alternation principle described in some detail in [8]. The Figure shows the 19F NMR spectra of the VF-TFE and V F - T F E - H F P copolymers. In the Figure, a, we have the spectrum of the VF-TFE copolymer wherein there are three intense line groups in the 91, 116-111 and 124-126 p.p.m, regions. All the lines pertain to --CF~-- groups, as there are no other fluorinated groups in the copolymer, and so this collection of chemical shifts can only be attributable to differing surroundings of resonating groups. Table 2 gives the chemical shifts calculated in accordance with the above scheme. This line assignment is in good agreement with data published in [3]. Let us now turn to the fine structure of the lines in question. Peak b is displaced by 1.3 p.p.m, towards the stronger field compared with peak a, and so the difference in surroundings of the resonating atoms will be not closer than at a distance of five simple.bonds, since a difference at a distance of four simple bonds will give a chemical shift change of ~2.5 p.p.m. Examining the first two fragments in Table 3 it can be seen that chemica! shifts of marked F atoms must differ by a value of the order of ~ 1 p.p.m, on account of the replacement of F atoms by protons through five simple bonds on going from fragment 1 to fragment 2. The direction of change in chemical shift in the case of such a transition is predicted by the alternation principle -- replacement of fluorine b y hydrogen through five simple bonds ought to result is a resonance line displacement towards weak field. Since there is a predominant amount of VF there is but littl'e probability of formation of a TBBT type tetrad, where B is the VF unit, and T is TFE, and so the integral lin~ intensity of a will clearly exceed that of line b. One may similarly account for a splitting of the peak in the region of ~ 111 p.p.m. (comparing fragments 3 and 4 with 5 and 6). A three line group in the region of ~125 p.p.m, is assigned to fragment --CH2CF~CF~CF2CH~--, and so a difference in the chemical shifts of the latter lines ( ~ 1 p.p.m.) is attributable to a change in the still more remote surroundings, i.e. at a distance of six simple bonds. Comparing fragments 13-15 in Table 3 we are of the opinion that the most weakly polar line must relate to resonance of the CF2 --group in pentad TVTVT, and the most strongly polar line to pentad VVTVV. Turning now to the less intense lines we see that lines e and f have shifts typical for thermodynamically unfavourable ("incorrect") additions [3], although peak e is considerably larger than peak f. This is attributable to the fact that resonant groups in this region (113 p.p.m.) are not only CF2 groups with an "incorrect" addition of VF units, but also --CF2 groups of TFE units (see Table 3, fragment 8). Line g pertains to fragment --CF~CFzCFzCF2CFz--, which accords with published data [18, 19]. The next line h is displaced approximately 2 p.p.m, towards stronger field, and so one may say that there is a difference in the surroundings of resonant atoms at a distance of four simple bonds. Line i is displaced towards
"F
NMR spectra of oopolymers of VF with TFE
71~
T~LW 4. Cmm~CALS~DCTSOF 7LUORn~A~1) OROU~S IN ~ m VF-TFE-HEP c m ~ o L ~ a Lines n o
q (3 ?. 8
t' U V
~, p.p.m.* ' Sequences experiment calculated
Fragments -- C H , C F , C F ( C F , ) C F , C H ,OF, --- C H , C F , C F , C F ( C F , ) C H , C F , - -- CH,CF,CHaCF,CF(CF,)CF ,--- CF2CF(CFs)CH.CF,CF,CF(CFs)--- C H , C F , C H I C F 2 C F , C F ( G F s ) --- C H , C F I C F z C F ( C F , ) C H , C F , - -- C F , C F ( C F s)C H , C F 2 C F , C F , C H , C F , C F , - -- CF,CF(CFs) C H 2 C F s C F , C F , C H , C F s C H , - -- C H I C F , C F ( C F s ) C F I C H , C F 2--- C H , C F , C F ~ C F ( C F 3 ) C H I C F , - -
70.3 75-2 103.1 108.6 110.4 117.9 124.1 } 124.8 189.4 184.1
71-0 75-0 103.5 108.0 109.5 117.5 126-0
VHV HVH VVH VHV HVTVT HVTVV YHV
•strong field compared h by less t h a n l'p.p.m, and so here there will be a difference in the surroundings at a distance of six simple bonds. Thus on 'examining fragments 10, 11 and 12 in Table 3 it is seen t h a t the lines in question pertain to T F E micro-blocks. On comparing the spectra in the Figure, b, showing the spectrum of the V F - T F E - H F P copolymer~ with Figure a it is seen t h a t all the lines for the V F T F E copolymer are in the spectrum of V F - T F E - H F P , and their assignment m a y be found in Table 3. Table 4 gives the assignment of lines not appearing in the. spectrum of the V F - T F E copolymer of lines absent from the spectrum oi' the V F - T F E copolymer is given in Table 4. There is no need to give a detailed description of all the lines in Table 4 as the chemical shifts of the latter are almost identical to those o f the lines for t h e V F - H F P eopolymer interpreted by Ferguson [20]. However two lines with shifts of 124.1 and 124.8 p.p.m, were absent from the other spectra. As was noted above this is the resonance region for --CF 2 - in T F E with surrounding VF units. Changes in the remote environment of " C F - - gave three lines in the spectrum of VF~TFE. The appearance of two new lines in the region in question is attri-
I
butable solely to the fact t h a t the --CF(CF3) group is in the preadjacent position to the resonating group, i.e. new pentads of type HVTVT with a shift of 124-1 p,p.m, have appeared, where H is the H F P unit, and HVTVV is 124.8 p.p.m. The spectra of solutions of the copolymers in acetone (cone. 2-4 wt.°/o) were recorded at 84'68 MHz using a Bruker HX-90E type spectrometer with an accumulator; the internal standard was trichlorofluoromethane. Translated by R. J. 'A. H~.ND~Y REFERENCES 1. A. SAIKA and C. P. SLI~2rrER, J. Chem. Phys. 22: 26, 1954 2. D. F. EVANS, J. Chem. Soc., 877, 1960
3. C. W. WILSON and E. R. SANTEE, J. Polymer Sei. C8: 97, 1965
720
N. A. PLATE e~ a/.
4" F. CIAMPELLI, M. T. VENTURI and D. SIANESI, Organ. Magnet. Resonance 1: 281, 1969 5. R . E. NAYLOR and S. W. LASOSKI, J. Polymer Sei. 44: 1, 1960 6. V. P. SASS, V. A. SHCHERBAKOV and S. V. SOKOLOV, D. I. Mendeleyev J. All-Union Chem. Soc. (ZhVKhO) 17: 6, 471, 1972 7. V. P. SASS, V. A. SHCHERBAKOV and S. V. SOKOLOV, D. I. Mendeleyev J. All-Union Chem. Soc. (ZhVKhO) 17z.6, 689, 1972 8. Ye. M. MURASHEVA, A. S. SHASHKOV and F. A. G~,LIL-OGLY, Vyso~omol. soyed. A21: 882, 1979 (Translated in Polymer Sci. U.S.S.R. 21: 4, 968, 1979) 9. L. H. MEYER and H. S. GUTOWSKY, J. Phys. Chem. 57: 481, 1953 10. G. V. D. TIERS, J. Amer. Chem. Soc. 78: 2914, 1956 11. T. S. SMITH and E. A. SMITH, J. Phys, Chem. 63: 1701, 1959 12. J. EMSLEY, J. FINNEY and L. SUTCLIFFE, High Resolution NMR Spectroscopy, vol. 2, p. 161, Izd. "Mir", 1969 13. S. BROWNSTEIN~, Chem. Revs. 59: 463, 1959 14. D. D. ELLEMAN, L. C. BROWN and D. WTLIJ~,MS, J. Molec. Spectrosc. 7: 307, 1961 15. J. W. EMSLEY and L. PI~ILIJPS, Progress in NMR Spectroscopy 7: 1, 1971 16. F. J. WEIGERT, Organ. Magnet. Resonance 3: 373, 1971 17. D. D. LOWSON and J. D. INGHAM, J. Polymer Sci. B6: 181, 1968. 18. V. A. LOVCHIKOV, V. P. SASS, A. I. KONSHIN, I. M. DOLOOPOLSKH and S. V. SOKOLOV, Vysokomol. soyed. B17: 662, 1975 (Not translated in Polymer Sci. U.S.S.R.) 19. G. KOFIMA, H. WACHI, K. ICHIGYRE and Y. TABATO, J. Polymer Sci., Polymer Chem. Ed. 14: 1317, 1976 20, R. C. FERGUSON, J. Amer. Chem. Soc. 82: 2416, 1960
Polymer Science U.S.S.R. Vol. 23, ~ o . 3, pp. 720--732, 1981 Printed in Poland
0032-3950/81/030720-13507.50/0 © 1982 Pergamon Press Ltd.
HYDROPHILIZATION OF POLYMER SURFACES BY SYNTHETIC POLYELECTROLYTES AND ~ I R COMPLEXES* N. A. P ~ T ~ . , Y~.. D. ALIY~.VA a n d A. A. KAY~CHEV •. V . Topchiyev Institute of Petrochemical Synthesis, U.S.S.R. Academy of Sciences
(Received 14 Jan~ry 1980) Methods were developed for the hydrophilization of the surfaces of hydrophobic polymers--polyolefins, polyesters, polymers containing silicon--using synthetic polyelectrolytes and their complexes. Chemical modification was effected by radiation -chemical grafting of ionogenic polymers (polyacrylic and polymethacrylie acids, poly-4vinylpyridine), followed by the formation on the surface of polymeric products of polyelectrolyte complex type coatings or polyelectrolyte complexes with ionogenic surface* Vysokomol. soyed. A2S: No. 3, 640--650, 1981.~
spectra of copolymers of VF with TFE
711
12. L S. ~ t ~ E M , N. I. CHISTOVAL0VA, Ye. L "MYSOVand M. Ye. V0LPIN, I~sshche. pleniye svyazi Si--C soyedin~aiyami platinovoi gruppy (Si--C Bond Splitting by Platinum Group Compounds). Izv. AN 8SSR, seriya khimich,, No. 9, 2069, 1976 13. M. R. STOBER, M. ¢. MUSOLE and J. L. S p ~ z l t , The Addition of Silicon H~ydrides to Olefinic Double Bonds. Exchange of Methyl and Trimethylsiloxy Groups in bis-trimethyisiloxymethylsilane, J. Org. Chem. Soc. 80: No. 5, 1651, 1965 14. A. F. B ~ , V. 8. PAPKOV, A. A. ZHDANOV and K. A. ANDRIANOV, Osobennosti okisleniya polimetilfenilsiloksilovykh zhidkostei (Features of the Oxidation of Polymethylphenylsiloxane Liquids). Vysokomol. soyed. B2O: 70, 1978 (Not translated in Polymer Sci. U.S.S.R.)
l~olymer 8c/ence U.S.S.R. Vol. 23, No. $, PI~. 711-720, 1981 PHnted in Poland
0032--3950/81/0307U-10507.50[0 ~) 1982 Pergamon P r e ~ Ltd.
ANALYSIS OF THE 19¥ NMR SPECTRA OF COPOLYMERS OF VINYLIDENE FLUORIDE WITH TETRAFLUOROETHYLENE, AND OF VINYLIDENE FLUORIDE WITH TETRAFLUOROETHYLENE AND HE.XAFLUOROPROPYLENE. THE USE OF AN EMPIRICAL ADDITIVE SCHE.ME AND OF THE. PRINCIPLE OF ALTERNATION* YE. M. MU~ASHEVA,A. S. S~SHKOV and A. A. Do~rrsov Research Institute of the Rubber Industry (R~/ved 11 January 1980) An additive scheme is proposed for determining chemical shifts of fluorine atoms
,I
included in --CF--, --CFn-- and --CFs groups in fluorine-containing polymers. The spectra of the copolymers of vinylidene fluoride and tetrafluoroethylene and of vinylidene fluoride and tetrafluoroethylcne and hexafluoropropylene are interpreted in accordance with this additive scheme. Application of the principle of alternation in changes in chemical shifts of I'F nuclei on varying the electronegativity of nearest polymer chain fragments allowed interpretation of the fine structure of spectrum lines and enabled these to be assigned in terms of tetrads and pentads. TH~ m e t h o d o f I°F N M R spectroscopy provides t h e simplest a n d m o s t reliable m e a n s o f q u a n t i t a t i v e analysis o f t h e chain s t r u c t u r e s o f fluorinated polymers. Reliable i n t e r p r e t a t i o n of t h e / l t F N M R spectra is a necessary condition for this t y p e o f analysis. Various empirical relations a n d a d d i t i v e schemes reflecting t h e influence o f i n d u c t i v e a n d o t h e r factors on chemical shifts of l°F nuclei [1-7] h a v e * Vysokomol: soyed. A28: No. 3, 632-639, 1981.
712
YE. M. MURASHEVA e~ a/.
appeared in numerous papers aimed at simplifying interpretation of the spectra. In earlier work [8] we considered a fruitful application of the principle of alternation of changes in 19F chemical shifts relative to the number of bonds between a resonating nucleus and substituents of differing electronegativity. In the present instance we generalized data on increments in the previously proposed additive schemes and extended the latter in the light of published data and our own data on chemical shifts for 19F in polymers and in some low molecular substances, and on the basis of these data an additive scheme was developed for determining chemical shifts of 19F nuclei in the most widely used polymers, allowin~ for the principle of alternation referred to above. The application of this additive scheme is illustrated by interpretation of the 19F NMR spectra of a vinylidene fluoride (VF)-tetrafluoroethylene (TFE) binary copolymer and a VF-TFE-hexafluoropropylene (HFP) ternary copolymer. The influence of surroundings on chemical shifts of fluorinated groups has been discussed repeatedly in special papers and monographs. Saika and Slichter [1] showed that the main contribution to changes in the degree of screening of fluorine nuclei is made by the paramagnetic term of the screening constant. The latter depends on the extent of the ionic character of the bond -- as its ionic character decreases (as the e!ectronegativity of attached atoms increases) the paramagnetie contribution to the screening is increased (the chemical shift of 19F nuclei is reduced on the 4 " scale). However, it was noted in [9] that the rule of electronegativity of substituents is not satisfied in the case of fluorochloromethanes. This was accounted for in terms of ideas regarding ionic structures containing double bonds where fluorine atoms, it was thought, are most prone to double bondedness [9, 10]. Finally, it was shown in [11] that simple inductive effects do not determine the screening of fluorine nuclei for more extensive range of polyatomic fluoroalkanes. According to Evans [2] a simple electronegativity principle m a y break down on account of the action of intramolecular dispersion forces operating between 1~ atoms and the nearest groups, arkd the role of such forces will be growing as the size of substituents increases. These general premises will no doubt hold for polymers a s well. However a feature in the case of the latter is the feasibility of an induction effect being transferred along the polymer chain and leading to regular changes in the chemical shifts of F atoms depending on the immediate and'remote (at a distlance of 3-5 bonds) surroundings. Comparing the chemical shift data f o r 19F NMR lines for PVF and model low molecular compounds~ Wilson and Santee [3] found that in the ease of mutual substitution of --CH2-- and --CFz-- in a position Adjacent or preadjacent to --CF2-- the chemical shift of the latter changes in an approximately additive fashion, and irrespective of other groups in the quintet. The cited authors felt that the same property might well be possessed by linear quintets with another make-up that include groups --CHF--, --CHCI--, --CFCI--, CC12-- etc. Another empirical relation was found by Ciampelli and coworkers [4] while investigating a number of fluorinated compounds, includifig polymers. On
19F NMR spectra of copolymers of VF with TFE
713
e x a m i n i n g fragments containing only carbon, fluorine and ether oxTgen o n e finds t h a t a chemical shift for a given fluorocarbon group is a linear function of tha~ for its nearest neighbours. In addition, a change of x p.p.m, in the chemical shift for one of two adjacent fluorinated groups will on average cause of a change of 0.12 x p.p.m, in the opposite direction for the nearest neighbours. The effect is reduced b y one-half if the fluorinated groups are separated b y an 0 atom. The relationship breaks down when fragments comprise multiple bonds or protonated groups (CHF--, CH~-- etc.). Sass and coworkers [6, 7] found t h a t oxygen and perfluorinated ethers had a similar effect on the chemical shifts of fluorine. It appears difficult to extend t h e relations found b y those authors so as to cover a wide range of compounds. Meanwhile on analysing published information one m a y conclude t h a t additivity in changes in chemical shifts found [3] for linear pentada has a more general character and is not restricted to the fluoromcthylene group. It seems that chemical shifts of fluorinated compounds could in general b e found b y using an empirical method of determining the magnitude of the shifts in the manner proposed b y Primas and coworkers [12] for proton resonance. An additive scheme on which the empirical analysis is based would appear more complex and 'laborious if one considers the above-described features of change in the chemical shifts of 19F nuclei as a function of the surroundings. Nevertheless on the basis of material already available an attempt m a y be made to use an additive scheme to predict chemical shifts of fluorinated groups in various compounds. In the present instance we limit ourselves to the construction of an additive scheme for calculating chemical shifts for three most common groups in polymers,
J
viz. CFs-- , - - C F 2 - and - - C F - - . Polymers are convenient materials for creating an additive scheme for the following reasons: 1) in polymers one m a y more readily trace induction effects of substituents via several bonds; in most cases the latter effect is not masked b y the effect of endgroups; 2) when analyzing the spectra of fluorinated polymers one need not take t o o wide a range of increments for an additive scheme; 3) an empirical means of deter.miuing chemical shifts is particularly valuable in the case of high molecular compounds, since chemical shifts are the main and frequently the sole parameter in the 19F N M R spectrum of a polymer. An increment table (see above) was compiled when analyzing chemical shifts of ~* and the extent to which the latter are influenced b y adjacent and penultimate groups of a large number of fluorinated high- and low molecular compounds. The magnitude of the chemical shift (from CFC13, ~*-scale) for the three groups referred to above was found as follows. In the case of CF 3 - we took as the initial group the fragment CF3CF2CF2-- , where the value of ~* is p u t at 81 p.p.m. [13, 14]. I f instead of --CF~-- we have in the adjacent position one of the groups appearing iri the top colum n of Table 1, the value of ~* for CT 8 in this fragment is found b y adding increment A, allowing for the sign.
714
Y~. M, Mu~zAs~vA ~ a/.
In the case of --CF~-- the initial fragment was --CF2CFzCF~CFICFs--, in which the value of ~* for the --CF~-- group in heavy print was 121 p.p.m. (our data, and those in [3]). On replacing an adjacent --CF,-- group by groups indicated in the top column of Table 1, we have a consequent change, amounting to the value of increment ,4, in the chemical shift. As was pointed out in [3] the addition of a second --CH~-- group adjacent to --CF~-- causes a disproportionately large change in the chemical shift of the latter. Accordingly the increments for some groups are given individually for one (1) or two (2) single,type substituents in the adjacent position. Some asymmetrical substituents have ~he bond nearest to the group of interest marked with heavy type.
I
In the case of --CFCFs we took as the initial fragment group (CFsCFs)~CFCF2CFs--, where --CF-- has a chemical shift of 184 p.p.m. [15]. Here the procedure for determining the chemical shift is similar to that described above'(the case of simultaneous substitution of adjacent --CF~-- groups by three monotype substituents is not considered). It should be noted that the scheme does not cover
I
i
the --CF-- group linked directly to --CFs (i.e. fragment --CFCFs), since the
I
influence of adjacent protonated groups on the chemical shift of --CF-- in the fragment is abnormal, judging by our data and by the data in [16]. The B increments provide a correction that is called for on replacing preadjaoent groups in the above fragments by groups appearing in the top column of Table 1; the procedure is the same as that described above. According to the idea of the additive scheme B increments are added irrespective of which A increment has already been taken into account. T~BLE I.
ADDITIVE
SCHEME I N C R E M E N T S F O R DET1~.~MTtVIlq'G
Adjacent and preadjacent groups Resonant group p.p.n~
-..-C~ 8
Increment
81
A
.21
~B A
--11
A
.84
(1)
--22 +4 _ 10,, +2.~
B --CFIn
---CH,~
B • The Inc~ztent8 are ~
1. Inconvot
for
I
--CR'I~
(2)
--18
+7 ~29" +5 +9
c(F)
~CH~ CI(H)
--9
0 --5
i
c(F) --22 0 --9 --3.5
--10 --2 --8.5 - - 1.5 --9
--1.5
correct for determining chemical ,dflfts o f - C K F - g r o u . ~ .
-OFCF. (L~eetext).
--~H¥(1)
----CFB
--22 0 --!2
+1.5 --5
1IF NMR spectra of copolymers of VF with TFE
715
For instance, let us say that we have to find the chemical shifts for all the groups in the copolymer of T F E with perfluoronitrozomethane ("head to t a i l " addition), i.e. in a fragment of the type of
--NOCFICFjNO--CFs For CFs ~*=81--25nu9-=65 p.p.m., where --25 is the A increment for an
I
adjacent - - N - - , and + 9 is the B increment for a preadjaeent --O--. For CF2 ~* = 121 -- 3 0 + 7 nt- 1 -=--99 p.p.m., where -- 30 is the A increment for an
I
adjacent - - N - - , + 7 is the B increment for two preadjacent - - 0 - - and + 1 is the B increment for a preadjacent --CFs. For CF~ ~ * ~ 121--37~-2~2-~88 p.p.m., where --37 is the .4 increment for an
I
adjacent - - O - - and -{-2 is the E increment for each preadjacent - - N - - . The found chemical shifts are in good agreement with the experimental d a t a in [17]. Chemical shifts calculated in the same w a y for all the CF8--, --CF2-- a n d
I
--OF-- groups for the copolymers stated below give a maximum deviation (from experimental values) amounting to 1.5 p.p.m. It is, of course, to be expected t h a t as the N M R analysis of novel fluorinated polymers (and low molecular compounds) proceeds the present increments will be refined, and their number increased. The scheme in its present form cannot reflect effects of steric isomerism, or the influence of ring currents of aromatic substituents, or the role of solvents and other subtle effects. Obviously we are in this instance dealing only with features of the induction effect and the effect of dispersion forces. However, the existing material may be used not only for calculating magnitudes of chemical shifts relating to. CHEMICAL
--CHF-(2)
SHIFTS
OF
19F I N F L U O R I N A T E D
POLYMERS
Adjacent and preadjacent groups C(H,F) --CFCI-- --CFCI-- --OCF---O----0--(1)
(2)
~(H.F)
--OC-]
i
(1)
(2)
1
--N--
---CF,
C(H,F)
--25
--25
+9 --6
--6
--2-5
--15
--41 +4"5
--48 +5'5
--37 +5 --47 4
--65
+7
--30 +2
+3
+1 +5
716
YE.
M. MURASHEVA e~ al.
single- a n d multi-type groups (still more successfully) for p r e d i c t i n g the relative placement of their resonance lines. T h e use of an empirical schema also facilitates t h e search or assignment of low i n t e n s i t y lines pertaining to fluorinated groups in t h e vicinity of " h e a d to h e a d " a n d "tail to t a i l " additions in homo- a n d copolymers. TABLE 2. CALCULATEDAND EXPERIMENTALVALUES OF CHEMICAL SHIFTS
OF I N T E N S E
LINES
IN
'l,f l ~
VF-TFE SPECTRUM Fragments CF,CH,CFsCH,CF, CF,CF,CF,CH,CF, CH,CF,CF,CF,CH,
(h*, p.p:m. calculated I experimental I • 92.0 [ 91-5 II1.0 [ 110.5-111-3 126.0 124.5-125.8
I n other words, the additive scheme described above facilitates to a first order of c o m p l ~ i t y interpretation of the spectra of fluorinated polymers. H o w e v e r it will be shown below t h a t the spectra of polymers often have a complex t y p e of line structure pertaining to single-type fluorinated groups w i t h similar i m m e d i a t e surroundings (adjacent a n d p r e ~ l j a c e n t groups) a n d resulting from the purely inductive influence of remote groups. On analyzing this fine line structure we o b t a i n the n u m b e r of triad, t e t r a d a n d p e n t a d sequences in the polymer chain. TABLE 3. CHEMICALSHLW~SOF CF, Gz~ouPs IN THE VF-TFE COPOLYM~R FragLines ment,
¢~, p.p.m.* Sequences expericalculated mental
Fragments
No.
/
g h i k 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-- C H , C F , C H z C F , C H , C F ,CF, --- C F , C F , C H I C F , C H , C F , C F , - -- C H , C F , C F , C F I C H , C F , C H ,-- C H , C F , C H , 6 ' F , C F , C F , C H , - -- C H , C F , C F , C F , C H , C F , C F , - -
i I
-- CF,CF,CH,CF,CF,CF,CH,--- CF,CF,CH,CF,CF,CH,CF,--
-- CF,CF.CH,CF,CF
,CH,CF,CI?,
--
}
-- CF,CH,CF,CFCH,CH,CF,--- C F , C H , C F , C F , C F , C F , C F , C H , C F , - -- C F , C F , C H , C F , C F , C F a C F , C F , C H , - -- CHzCFzCHaCF,CF,CFaCFaCFsCH,--
-- CF,CF2CHzCF,CF,CF,CH,CF ,CF 2--- C F , C F , C H , C F Z C F , C F I C H z C F z C H , - - - CH,CFzCH,CF,CF,CF,CH,CF,CH,--
91 '5 92.8
92.0 92.0
VVVT T~T
110.5
111.0
111.3
III.0
VT~ VVTV VT~
113"4
113.5
TVTV
115.9 120"8 122.5 123.2 124.5 ] 125.2 ~ 125.8 )
116.0 121-0 123.5 123.5 126.0
WTTV TVTTV VVTTV TVTVT TVTW W T W
* In the imper by Wilson and I~ntee [3] with a reference ~o a prlvace communication o f Boikelman one finds the ~hemical t h i f ~ of CF, groups o f low molecular co.mpounds, fragments of which are similar to same fragments in the Table.
717
t0F NMR spectra of copolymers of VF with TFE
! m
a
•
c
d
a
k
b h~ ~
e
,,,
I 100
I
90
I 110
1 120
I 130
b C
Q
d m
j
r
f
q
n
¢.
I
90
I10
130
I I
1
t
180 .
180
x'F NMR spectra of the V F - T F E (a) and V F - T F E - H F P (b) copolymers.
7i8
~
Y z . M. M ~ V A
~g ~ .
"
This analysis may be done using the alternation principle described in some detail in [8]. The Figure shows the 19F NMR spectra of the VF-TFE and V F - T F E - H F P copolymers. In the Figure, a, we have the spectrum of the VF-TFE copolymer wherein there are three intense line groups in the 91, 116-111 and 124-126 p.p.m, regions. All the lines pertain to --CF~-- groups, as there are no other fluorinated groups in the copolymer, and so this collection of chemical shifts can only be attributable to differing surroundings of resonating groups. Table 2 gives the chemical shifts calculated in accordance with the above scheme. This line assignment is in good agreement with data published in [3]. Let us now turn to the fine structure of the lines in question. Peak b is displaced by 1.3 p.p.m, towards the stronger field compared with peak a, and so the difference in surroundings of the resonating atoms will be not closer than at a distance of five simple.bonds, since a difference at a distance of four simple bonds will give a chemical shift change of ~2.5 p.p.m. Examining the first two fragments in Table 3 it can be seen that chemica! shifts of marked F atoms must differ by a value of the order of ~ 1 p.p.m, on account of the replacement of F atoms by protons through five simple bonds on going from fragment 1 to fragment 2. The direction of change in chemical shift in the case of such a transition is predicted by the alternation principle -- replacement of fluorine b y hydrogen through five simple bonds ought to result is a resonance line displacement towards weak field. Since there is a predominant amount of VF there is but littl'e probability of formation of a TBBT type tetrad, where B is the VF unit, and T is TFE, and so the integral lin~ intensity of a will clearly exceed that of line b. One may similarly account for a splitting of the peak in the region of ~ 111 p.p.m. (comparing fragments 3 and 4 with 5 and 6). A three line group in the region of ~125 p.p.m, is assigned to fragment --CH2CF~CF~CF2CH~--, and so a difference in the chemical shifts of the latter lines ( ~ 1 p.p.m.) is attributable to a change in the still more remote surroundings, i.e. at a distance of six simple bonds. Comparing fragments 13-15 in Table 3 we are of the opinion that the most weakly polar line must relate to resonance of the CF2 --group in pentad TVTVT, and the most strongly polar line to pentad VVTVV. Turning now to the less intense lines we see that lines e and f have shifts typical for thermodynamically unfavourable ("incorrect") additions [3], although peak e is considerably larger than peak f. This is attributable to the fact that resonant groups in this region (113 p.p.m.) are not only CF2 groups with an "incorrect" addition of VF units, but also --CF2 groups of TFE units (see Table 3, fragment 8). Line g pertains to fragment --CF~CFzCFzCF2CFz--, which accords with published data [18, 19]. The next line h is displaced approximately 2 p.p.m, towards stronger field, and so one may say that there is a difference in the surroundings of resonant atoms at a distance of four simple bonds. Line i is displaced towards
"F
NMR spectra of oopolymers of VF with TFE
71~
T~LW 4. Cmm~CALS~DCTSOF 7LUORn~A~1) OROU~S IN ~ m VF-TFE-HEP c m ~ o L ~ a Lines n o
q (3 ?. 8
t' U V
~, p.p.m.* ' Sequences experiment calculated
Fragments -- C H , C F , C F ( C F , ) C F , C H ,OF, --- C H , C F , C F , C F ( C F , ) C H , C F , - -- CH,CF,CHaCF,CF(CF,)CF ,--- CF2CF(CFs)CH.CF,CF,CF(CFs)--- C H , C F , C H I C F 2 C F , C F ( G F s ) --- C H , C F I C F z C F ( C F , ) C H , C F , - -- C F , C F ( C F s)C H , C F 2 C F , C F , C H , C F , C F , - -- CF,CF(CFs) C H 2 C F s C F , C F , C H , C F s C H , - -- C H I C F , C F ( C F s ) C F I C H , C F 2--- C H , C F , C F ~ C F ( C F 3 ) C H I C F , - -
70.3 75-2 103.1 108.6 110.4 117.9 124.1 } 124.8 189.4 184.1
71-0 75-0 103.5 108.0 109.5 117.5 126-0
VHV HVH VVH VHV HVTVT HVTVV YHV
•strong field compared h by less t h a n l'p.p.m, and so here there will be a difference in the surroundings at a distance of six simple bonds. Thus on 'examining fragments 10, 11 and 12 in Table 3 it is seen t h a t the lines in question pertain to T F E micro-blocks. On comparing the spectra in the Figure, b, showing the spectrum of the V F - T F E - H F P copolymer~ with Figure a it is seen t h a t all the lines for the V F T F E copolymer are in the spectrum of V F - T F E - H F P , and their assignment m a y be found in Table 3. Table 4 gives the assignment of lines not appearing in the. spectrum of the V F - T F E copolymer of lines absent from the spectrum oi' the V F - T F E copolymer is given in Table 4. There is no need to give a detailed description of all the lines in Table 4 as the chemical shifts of the latter are almost identical to those o f the lines for t h e V F - H F P eopolymer interpreted by Ferguson [20]. However two lines with shifts of 124.1 and 124.8 p.p.m, were absent from the other spectra. As was noted above this is the resonance region for --CF 2 - in T F E with surrounding VF units. Changes in the remote environment of " C F - - gave three lines in the spectrum of VF~TFE. The appearance of two new lines in the region in question is attri-
I
butable solely to the fact t h a t the --CF(CF3) group is in the preadjacent position to the resonating group, i.e. new pentads of type HVTVT with a shift of 124-1 p,p.m, have appeared, where H is the H F P unit, and HVTVV is 124.8 p.p.m. The spectra of solutions of the copolymers in acetone (cone. 2-4 wt.°/o) were recorded at 84'68 MHz using a Bruker HX-90E type spectrometer with an accumulator; the internal standard was trichlorofluoromethane. Translated by R. J. 'A. H~.ND~Y REFERENCES 1. A. SAIKA and C. P. SLI~2rrER, J. Chem. Phys. 22: 26, 1954 2. D. F. EVANS, J. Chem. Soc., 877, 1960
3. C. W. WILSON and E. R. SANTEE, J. Polymer Sei. C8: 97, 1965
720
N. A. PLATE e~ a/.
4" F. CIAMPELLI, M. T. VENTURI and D. SIANESI, Organ. Magnet. Resonance 1: 281, 1969 5. R . E. NAYLOR and S. W. LASOSKI, J. Polymer Sei. 44: 1, 1960 6. V. P. SASS, V. A. SHCHERBAKOV and S. V. SOKOLOV, D. I. Mendeleyev J. All-Union Chem. Soc. (ZhVKhO) 17: 6, 471, 1972 7. V. P. SASS, V. A. SHCHERBAKOV and S. V. SOKOLOV, D. I. Mendeleyev J. All-Union Chem. Soc. (ZhVKhO) 17z.6, 689, 1972 8. Ye. M. MURASHEVA, A. S. SHASHKOV and F. A. G~,LIL-OGLY, Vyso~omol. soyed. A21: 882, 1979 (Translated in Polymer Sci. U.S.S.R. 21: 4, 968, 1979) 9. L. H. MEYER and H. S. GUTOWSKY, J. Phys. Chem. 57: 481, 1953 10. G. V. D. TIERS, J. Amer. Chem. Soc. 78: 2914, 1956 11. T. S. SMITH and E. A. SMITH, J. Phys, Chem. 63: 1701, 1959 12. J. EMSLEY, J. FINNEY and L. SUTCLIFFE, High Resolution NMR Spectroscopy, vol. 2, p. 161, Izd. "Mir", 1969 13. S. BROWNSTEIN~, Chem. Revs. 59: 463, 1959 14. D. D. ELLEMAN, L. C. BROWN and D. WTLIJ~,MS, J. Molec. Spectrosc. 7: 307, 1961 15. J. W. EMSLEY and L. PI~ILIJPS, Progress in NMR Spectroscopy 7: 1, 1971 16. F. J. WEIGERT, Organ. Magnet. Resonance 3: 373, 1971 17. D. D. LOWSON and J. D. INGHAM, J. Polymer Sci. B6: 181, 1968. 18. V. A. LOVCHIKOV, V. P. SASS, A. I. KONSHIN, I. M. DOLOOPOLSKH and S. V. SOKOLOV, Vysokomol. soyed. B17: 662, 1975 (Not translated in Polymer Sci. U.S.S.R.) 19. G. KOFIMA, H. WACHI, K. ICHIGYRE and Y. TABATO, J. Polymer Sci., Polymer Chem. Ed. 14: 1317, 1976 20, R. C. FERGUSON, J. Amer. Chem. Soc. 82: 2416, 1960
Polymer Science U.S.S.R. Vol. 23, ~ o . 3, pp. 720--732, 1981 Printed in Poland
0032-3950/81/030720-13507.50/0 © 1982 Pergamon Press Ltd.
HYDROPHILIZATION OF POLYMER SURFACES BY SYNTHETIC POLYELECTROLYTES AND ~ I R COMPLEXES* N. A. P ~ T ~ . , Y~.. D. ALIY~.VA a n d A. A. KAY~CHEV •. V . Topchiyev Institute of Petrochemical Synthesis, U.S.S.R. Academy of Sciences
(Received 14 Jan~ry 1980) Methods were developed for the hydrophilization of the surfaces of hydrophobic polymers--polyolefins, polyesters, polymers containing silicon--using synthetic polyelectrolytes and their complexes. Chemical modification was effected by radiation -chemical grafting of ionogenic polymers (polyacrylic and polymethacrylie acids, poly-4vinylpyridine), followed by the formation on the surface of polymeric products of polyelectrolyte complex type coatings or polyelectrolyte complexes with ionogenic surface* Vysokomol. soyed. A2S: No. 3, 640--650, 1981.~