Structural peculiarities and properties of poly(isopropenyl ethynyl trimethyl piperidole)

Poly(isopropenyl ethynyl t r i m e t h y l piperidole)

189

Vysokomol. soyed. A9: 1682, 1967 (Tranlated in Polymer Sci. U.S.S.R. 9: 8, 189 3 1967) 29. V. N. TSVETKOV, Ye. I. RYUMTSEV, I. N. SHTENNIKOVA, Ye. V. KORNEYEVA, G. I. OKHRIMENKO, N. A. M:IKHAIL0VA, A. A. BATURIN, Yu. B. A M E R I K a n d B. A. KRENTSEL, Vysokomol. soyed. A15: 2570, 1973 (Translated in Polymer Sei. U.S.S.R. 15: 11, 2915, 1973)

Polymer ScienceU.S.S.R. Vol. 20, pp. 189-196. ( ~ Pergamon Press Ltd. 1978. Printed in Poland

0032-3950178/0101-0189507.50[~

STRUCTURAL PECULIARITIES AND PROPERTIES OF POLY(ISOPROPENYL ETHYNYL TRIMETHYL PIPERIDOLE)* D . K H . KttALIKOV, Z. M. KARIYEVA, G. A . MADZHLISOVA, I. G. SHAI~YAVSKII, I . YA. KALONTAROV, R . MARUPOV

and YE. M. GLAZUZCOVA Chemistry Institute, Tadzh.S.S.R. Academy of Sciences S. U. U m a r o v Physicotechnical Institute

(Received 25 March 1977) A study has been made of the homopolymerization of isopropenyl ethynyl trimethyl piperidole in bulk and in solution under the action of H2SO4, using a radical initiator. The polymer structure has been analyzed b y I R and PMR spectroscopy methods, and the properties of dilute solutions of the polymer determined. Polymerization takes place b y a radical mechanism, and the structure of the macromolecules is represented b y a linear system containing side piperidole rings t h a t are interconnected b y H bonds with participation of water of hydration molecules. The properties of a dilute solution of the iodomethylate of poly(isopropenyl ethynyl t r i m e t h y l piperidole) have been investigated, and the results interpreted in the light of concepts of the behaviour of polyelectrolytes.

II~CREASING interest has recently been shown in polymers containing ionogenic groups that may be either in the main chain (ionenes) or in the side branches [1-4]. Methods commonly used where ionogenic groups are required in the side segments of the polymer chains include reactions of polymerization of ionogeni¢ monomers, and polymer analogue transformations. In this paper we report the results of our study of polymerization processes of isopropenyl ethynyl trimethyl piperidole (IPETP), a novel type of monomer, having in its composition a number of functional (OH) groups, unsaturated * Vysokomol. soyed. A20: No. l, 164-169, 1978.

190

D. KH. KHAI~K0V e~ at.

bonds and tertiary nitrogen atoms CH3

CH3

OH

l

H2C-~C~C~(1-- ~ _ _ _ _ / N - - C H a I

ct-I3 Hitherto the use of I P E T P has been limited to eopolymerization reactions [5, 6], and it appears that praetieMly no information has been published on the homopolymerization of I P E T P . In view of this we included in this investigation a study of the structure and of some physieo-ehemieal properties of I P E T P polymers and of their derivatives. The I P E T P was prepared in accordance w i t h the method outlined in [7]. Aeetylation o f the I P E T P was done in accordance with existing procedures, using acetic anhydride. T h e I P E T P homopolymerization was conducted in bulk at 105 ° in v a c u u m (10 -3 torr). Th e homopolymerization of I P E T P in solution was carried out with a 40-50 wt.~o concentration of monomer, in the presence of DAA. Methanol, ethanol and benzene were used as solvents. The I P E T P polymers were purified by three fold reprecipitation with diethyl ether. T h e spontaneous polymerization was conducted at room temperature in sulphurio acid solutions at concentrations ranging from 0.4 to 1.5 mole/1. The monomer concentration was 1 mole/l, in all cases. The polymer was isolated from solution in HgSO4 by precipitation into acetone. I t was then once again dissolved in water, and the solution was neutralized with NasCO3. I n this ease the polymer separated out as a sediment. TABLE 1. HOMOPOLYMERIZATION OF I P E T P

Solvent

CHsOH CHsOH CeHe C,HsOH C,HbOH Cell6 ~one H2SOI 1"5 M HtSO, 1"0 M

Initiator concentration, w t . % on the monomer 0.5 2.0 2-0 0.2 0.7 1.0 0-2 None

Y~ld,

Conditions and time of polymeriaztion

%

D1, cU/g

I UV-irradiation,I0 hr

Thermal ( P = 10 -a torr 4 hr)

Thermal (P----10 -3 torr, 10 min) Air atmosphere, 7 days

20 20 20 60 60 60 105 20

2.5 3.0 3.0 3.5 4-4 4.0 7.2

0"10 0"10 0"11

7.0

1.40

20

6'3

1.25

0.33

Iodomethylation of the I P E T P monomer and polymer was carried out in alcoholia solution at room temperature. The degree of iodomethylation was determined by the method of Folgard [8]. The intrinsic viscosity of the polymers was determined with the aid of an Ubbelohd~ viscosimeter at 25.04--0.1 °.

Poly(isopropenyl ethynyl t r i m e t h y l piperidole)

191

The I R spectra of the specimens were taken with a UR-20 apectrophotometer. A "Teals'" B487C instrument was treed to record the P M R spectra at a frequency of 80 M ] ~ a t room temperature. Specimens were dissolved either in CCl~ or in CD,OD. Chemical shifts were measured in relation to hexamethyldisiloxane as internal standard, and were reduced t o the 5-scale relative to tetramethylsilane. The following 5 values were obtained for I P E T P in CCl~ : I = l ' 0 ; 6=~:_CH = = 2'0; 6 ~ = 2"3; ~-OI-I = 4"53 and 6_C=CH = = 5"3. --C--CH= N--CHa [ I

p K values of the monomer were obtained by titration; the p H of the I P E T P solution was monitored with a pH-340 lamp potentiometer with a glass electrode as the measuring electrode, pK,pETp = 8.0. Complex thermographic analysis of the P I P E T P after drying for 8 hr under a 10 -a torr vacuum was carried out with a Paulik derivatograph, the sensitivity in respect to D T A and DTG being 1/3 and 1/5 respectively, the temperature rising at the rate of 2.5 deg/min~ exposure time 200 min. Aluminium oxide calcined at 1000 ° was used as the standard. T h e weight of a specimen was 40 mg.

u= I0 ~,mo/e/L .sec

/4

12

~ gO [IJ/z 10 z rno/e/l.

Fro. I. Polymerization rate of I P E T P vs. the P A A concentration at 105 °.

Homopolymerization of I P E T P . T h e r e s u l t s o f a n i n v e s t i g a t i o n o f I P E T P h o m o p o l y m e r i z a t i o n u n d e r d i f f e r e n t c o n d i t i o n s a r e c i t e d in T a b l e 1. I t c a n b e seen from the Table that the highest intrinsic viscosity values appear under c o n d i t i o n s o f b u l k p o l y m e r i z a t i o n a t 105 ° a n d in t h e s p o n t a n e o u s p o l y m e r i z a tion in an H2SO 4 solution. I n t h e b u l k p o l y m e r i z a t i o n o f I P E T P t h e r e a c t i o n r a t e is a p r o p o r t i o n a l t o t h e s q u a r e r o o t o f t h e i n i t i a t o r c o n c e n t r a t i o n , a s is c h a r a c t e r i s t i c o f r a d i c a } p o l y m e r i z a t i o n p r o c e s s e s ( F i g . 1). Structure of I P E T P , P I P E T P and their derivatives. I n a s t u d y o f t h e m a c r o molecular structure of PIPETP the IR spectra of the monomers were recorded a l o n g w i t h t h o s e o f t h e p o l y m e r s a n d o f a n u m b e r o f t h e i r d e r i v a t i v e s ( F i g . 2). I n t h e s p e c t r u m o f I P E T P in t h e c r y s t a l l i n e s t a t e t h e m a x i m u m for t h e b a n d r e l a t i n g t o t h e v a l e n c y v i b r a t i o n s o f O H g r o u p s is d i s p l a c e d i n t h e 3115 c m -1 r e g i o n , a n d i n c r e a s e d a b s o r p t i o n i n t e n s i t y a p p e a r s i n t h e 3 0 0 0 - 2 6 0 0 c m -1 r e g i o n , evidencing feasibility of the formation of associates. A new band appears at

]92

D. K m I~lCfAT,IKOV et al,

3620 cm -~ in the spectrum of the solution of I ~ E T P in CC14, and instead of a broad band at 3115 cm -1 there is the narrow one at 3005 cm -1. Information Cn the interpretation of these bands is given in [9]. 6

100

~0

0

38 0

Jz

z8 .

z4

zo

1~ ~ ~I 0 - z c m -

!

FIG. 2. I R spectra of the crystalline I P E T P (1), XPETP in CCl~ solution (2), acetylated I P E T P (3), the iodomethylate of I P E T P (4), I P E T P homopolymer (5), iodomethylate of the I P E T P homopolymer (6).

The absence of any bands in the 3000-3600 cm -1 region in the acetylation ~ f I P E T P points to OH groups playing a major role in the formation of intermolecular H bonds in the region in question. In the I R spectrum of the I P E T P iodomethylate there are two relatively .clear-cut bands in the 3700-3100 cm -1 region with maxima at 3470 and 3310 cm -1, and a shoulder at 3400 cm -1 relating to the formation of at least two types of energetically nonequivalent H bonds. For P I P E T P and its iodomethylate the absorption in the 3700-3050 cm -1 region is of a specific character, and the maximum of the band of the OH groups is found at 3400 cm -1, pointing to a weakening of H bonds. Bands relating to the valency vibrations of - - C = C double bonds are found a t 1630, 1620 and 1610 cm -~ in I P E T P , in the I P E T P iodomethylate and in the acetylated specimen respectively.

Poly(isopropenyl ethynyl trimethyl piperidole)

193

The spectra of the P I P E T P and of its iodomethylate have no clear cut bands in the 1630 c m - 1 region, b u t relatively diffuse bands appear with maxima at 1600 and 1625 cm -i respectively, the intensity being more makred in the case of the latter specimen. A band that relates to --C---C appears in the 2220 cm -i region, though it is absent form the I P E T P spectrum. The presence of a triple bond in the polymer and the absence of the double bond must rule out polymerization of the t y p e of the 1,4 addition, and corroborates the linear character of the P I P E T P structure.

/c,dl/g

20

1.0

,,o

6O

I00[

I 100

1

I

I

300

500:

O~

:'c

FIG. 3

0-5

f-O c, g/dl

FIG. 4

FIG. 3. D T A (1) and T G A (2) curves of P I P E T P . FIG. 4. R e d u c e d viscosity of P I P E T P vs. P I P E T P c o n c e n t r a t i o n in e t h y l alcohol.

I t is known [10] that the absorption of water adsorbed b y a substance is superposed on frequencies for both the valency and the deformation vibrations of OH groups. In view of this it m a y well be that the diffuse character of the bands relating to the valency (3700-3050 cm -1 region) and deformation (17001 ~ 0 cm -1 region) vibrations of the OH in the I P E T P spectrum could be due to water adsorbed (in the hydrate form) b y the homopolymer. I t should be noted that painstaking drying of the homopolymer in vacuo (10 -3 torr) for 8 hr produces practically no change either in the absorption or in the intensity of the bands in the 3700-3050 and 1700-1550 cm -1 regions. Further evidence of the presence of water in the structure of the P I P E T P and of its iodomethylate appears also in the results of macro analysis for C, H and N (Table 2). First, it should be said that the theoretically calculated amounts of C, H and N for the P I P E T P differ considerably from the experimentally determined amounts. This absence of agreement is practically eliminated if the presence of one molecule of water in each monomer unit is allowed for in

194

the theoretical calculations (Table 2). For the P I P E T P iodomethylate the maximum degree of iodomethylation =<1, whereas in the case of I P E T P under similar conditions =~-1 (Table 2). TABLE 2. RESULTS

oF EL~ME~-T~

ANALYSIS* AND OF T~

MAXIMUM DEGREE

OF Z S O M E T n Y I ~ O ~ = ~OR P I P E T P

~,%

Substance a

b,

6.76 6.76

6.77 6.21

rT,%

0,% e

a

b,

75'36 75.36

75"30 70.55

I

e

~

I I

YPETP PIPETP

-

-

6.22

-

-

69.33

a$

I

b'

75"30 [ 10"14 70.55[ 10.14

1"000 10.22 0.900

* a--Calculated; b--found; c-culculated taking H.O Into account. t Average valu~ of four tests. Average valuel of seven t~ts.

Corroboration of the assumed presence of water in the macromolecular structure was obtained by analysis of DTA and TGA curves (Fig. 3), from which it appears that there is a mild endothermic effect at 105 ° involving a loss of P I P E T P mass amounting to 8-7 ~ , which is consistent with the evolution of water amounting to 1 H=0 molecule per monomer unit of the P I P E T P macromoleeule.

2"0 a

1"5

b

f'O

c/%p,g/dl

~

a

3 0"5 I I

0.2

I

o.0 c,,q/dl

I

0.!

I

I

O~

I

1

0.5

l

[

0.7

~(g/eO '/~ " FxG. 5. P l o t s o f tlap/c vs. e (a) a n d vs. ~/c (5) for t h e i o d o m c t h y l a t e of P I P E T P a t t h e followi n g c o n c e n t r a t i o n s o f K I × 10 a, mole/L: 10 (•); 1 (2); 0-1 (3) a n d 0.01 (4).

Poly(isopropenyl ethynyl trimethyl piperidole)

195

An analysis of an atomic model of part of the P I P E T P chain consisting of four monomer units showed that owing to strong steric hindrance neighbouring piperidole groups are situated as far apart as possible from one another in space. This rules out the formation of intramolecular H bonds between adjacent monomer units, as there is quite a considerable distance between the OH groups. At the same time H bonds between monomer units could appear only if there are H 2 0 molecules situated between the OH groups.

[~],,dl/g 80-,

/

FO-

00-

20

-2

-/-t

I -8

lo~ EKI]

Fro. 6. Intrinsic viscosity [t/] of an aqueons solution of the iodomethylate of P I P E T P vs. the logarithm of the K I concentration.

The structure of the PIPETP macromolecule and of its iodomethylate m a y be represented as a linear system containing side piperidole rings that are interconnected b y H bonds with participation of molecules of water of hydration. Properties of dilute solutions of P I P E T P and its iodomethyIate. The plot in Fig. 4 is characteristic of the dependence of the reduced viscosity tlsp/C on the polymer concentration in ethanol. It can be seen that the curve bears an anomalous character, and brings the behaviour of polyelectrolytes to mind. T o shed further light on the polyelectrolyte effect we prepared P 1 T E T P iodomethylate, and investigated the behaviour of a dilute solution of the latter. Figure 5a shows plots of t/sp/c vs. the polymer concentration when the solutions are diluted with diluents containing different amounts of a neutral electrolyte. The Fuoss formula Ill] was used to determine the intrinsic viscosity from the nonlinear tlsp/c-c plots. Plots of c/11spvs. ~/~ are displayed in Fig. 5b. I t can be

186

D. Km K~AT.T~0V e~ ¢~.

seen t h a t the e x p e r i m e n t a l d a t a plot into satisfactory straight lines. I n the case o f t h e linear c/~Isp-~/c a n d ~/sp/c-c plots, the value o f [~] was f o u n d b y the least s q u a r e s m e t h o d . F i g u r e 6 shows the dependence of on the logarithm.of the electrol y r e c o n c e n t r a t i o n for the P I P E T P iodomethylate. T h e e x p e r i m e n t a l results show t h a t the b e h a v i o u r of a dilute solution of t h e P I P E T P i o d o m e t h y l a t e m a y be a c c o u n t e d for in the light of concepts for polye l e c t r o l y t e solutions. This is c o r r o b o r a t e d b y the m a r k e d rise in the v a l u e s o b t a i n e d for ~sp/C on diluting the solutions. This rise is a t t r i b u t a b l e to swelling o f t h e p o l y m e r coil as a result of the repulsion of like charges. T h e polyelectrolyte effect is reduced, a n d t h e n disappears, when the neutral electrolyte concentrat i o n is increased. This is due to charge screening. T h e a u t h o r s t h a n k V. P. S h i b a y e v for his participation in discussion of t h e results.

Tranalated by R.

J. A. HENDRY

REFERENCES

1. V. A. KABANOV and D. A. TOPCH][YEV, Polimerizatsiya ioniziruyushchikhsya monomercy (Polimerization of Ionizing Monomers), Izd. "Nauka", 1975 2. J. C. SALAMONE and E. J. ELLIS, Water Soluble Polymers, p. 267, New York-London, 1973 3. J. C. SALAMONE, E. J. ET.T.TS,D. F. BARDOLIW2,LL& and C. R. WILSON, Polymer Preprints 14: 773, 1973 4. O.V. KARGINA, P. A. 1KISHUSTINA,V. I. SVERGUN, V. P. YEVDAKOV, G. M. LUKOVKIN and V. A. KABANOV, Vysokomol. soyed. A16: 1755, 1974 (Translated in Polymer Sci. U.S.S.R. 16: 8, 2033, 1974) 5. Ye. M. GLAZUNOVA, V. I. NIKITIN, M. A. NARN1TSKAYA, L. S. YASENKOVA, V. S. KUZIN and T. D. NAGIBINA, Khimiya atsetflena, Trudy I I I Vsesoyuznoi konf. (Acetylene Chemistry, Trans. III All-Union Conf.). Izd. "Nauka", 1972 6. V. I. NIKITIN, Ye. S. ROSKIN, V. V. DARVIN, L Ya. KALONTAROV, M. V. KOZLOVA and Yu. A. KONKHIN, Khimiya atsetilena, Trudy III Vsesoyuznoi konf. (Acetylene Chemistry, Trans. III All-Union Conf.). Izd. "Nauka", 1972 7. V. I. NI~TTIN, Ye. M. GLAZUNOVA, M. A. NARNITSKAYA and I, N. GRIGINA, Dokl. AN Tadzh. SSR l h 33, 1968 8. G. A. LAITINEN, Khimieheskii analiz (Chemical Analysis). Izd. "Khimiya", 1966 9. R. MARUPOV, A. USMANOV, K. MA~[H~AMOV, I. Ya. KALONTATOV and V. L NI~TTIN, Dokl. AN SSSR 187: 100, 1969 10. G. TSUNDEL, Gidratatsiya i mezhmolekulyarnye vzaimodeistviya (Hydration and Intermoleeular Interactions). Izd. "Mir", 1972 11. R. M. FUOS8 and U. P. STRAUSS, J. Polymer SoL 3: 246, 1948