Synthesis and properties of sulphonated polypyromellitimides

160

~'. V. VASIL'NVA et ~ .

14. M. JONAS(IN, J. Appl. Polymer ScL 4: 129, 1961 15. L. M. PIS'MEN and S. I. KUCHANOV, Vysokomol. soyed. AIS: 791, 1971 (Translated in Polymer Sol. U.S.S.R. 18" 4, 890, 1971) 16. E. KA1WKE, Spravochmk po uravnemyam v chastnykh promvodnykh (Manual for Equations m Partial Derivations). Izd. "Nauka", 1966 17 R. H: KIENLE, P. A. Van Der MEULEN arid F. E. PETKE, J. Am. Chem. Soc. 61: 2258, 2268, 1939

SYNTHESIS AND PROPERTIES OF SULPHONATED POLYPYROMELLITIMIDES* I. V.

VASIL'EVA,

E N.

TELESHOV,

T. N. K ~ i N x m x and A. N. PRAVEDNIKOV

L. Ya. Karpov Physmochemmal Research Institute (Received 26 June 1970) SOME of the recently synthesized heterocychc polymers (polybenznmdazoles, polylm,des, polybenzoxazoles, etc.) have good thermal and chemmal stability and good mechanical properties. I t is therefore nnportant to investigate the posmbfl,ty of using these polymers as a barns for the preparation of materials possessing not only the good properties referred to above but also certain specific propertms such as 1on- or electron-exchange propertms, ere Reports have already been pubhshed [1, 2] relating to the synthesls and the thermal transformations of hydroxyl- or ammo-contahumg polypyromelhtnmdes, and Information is also available as to methods of introducing the functional carboxyl, hydroxyl or sulpho acid groups into polybenznnidazoles [3]. O u r a i m in t h e p r e s e n t i n v e s t i g a t i o n w a s to e x a m i n e t h e t h e o r e t i c a l possibility of m o & f y i n g heteroeyclic p o l y m e r s , p a r t i c u l a r l y p y r o m e l l i t i m i d e s , using as s t a r t i n g m a t e r i a l s m o n o m e r i c c o m p o u n d s containing f u n c t i o n a l groups. This p a p e r describes t h e synthesis of s u l p h o n a t e d p o l y p y r o m e l l i t i m i d e s b y t h e m e t h o d of t w o - s t a g e p o l y c o n d e n s a t i o n o f p y r o m e l l i t i c d i a n h y d r i d e ( P D A ) a n d sulphoh a t e d a r o m a t i c diamines O 0 O O -

\0+H,N--R---NH,-, -\C/N//\C/

o/

/

YY

-

N/t/ I

\

N--R--

\cA//l,,,c /

so, where

M=L1, K, NHd, N(CHs). H, N(C,Hs)s H, N(CdHt), H.

* Vysokomol. soyed A14: No. 1, 143-149, 1972.

Synthes:s of sulphonat~d polypyromelhbnmdes

161

T h e f a c t o r s g o v e r n i n g t h e s e l e c t i o n o f p o l y i m i d e s as t h e p o l y m e r s t o b e i n v e s t i g a t e d w e r e p r i m a r i l y t h e g o o d t h e r m a l ancl m e c h a n i c a l p r o p e r t i e s o f p o l y m e r s o f t h i s t y p e , as well as t h e f a c t t h a t m o r e d e t a i l e d s t u d i e s o f p o l y i m i d e s , as c o m p a r e d w i t h o t h e r he~erooyclio p o l y m e r s , h a v e b e e n m a d e [4].

EXPERIMENTAL

Starting compounds. The sulphonated dlammes investigated were commercial benz:dme2,2'-dlsulpho amd (BSA), 4,4'-dlammostllbene-2,2'-chsulpho ac:d (SSA) a n d 4,4'-d, am,nodlphenyloxade-2-sulpho acid (DPOSA) The last was synthesized m the course of this investigation. DPOSA was synthesized b y the sulphonatlon of 4,4'-dmltrod~phenyloxlde with subsequent reduction of the sulphonated product b y t m hydrochlorlde. To 45 ml of 20~o oleum were added at 3-4 ° m small batches 62.4 g of 4,4'-dm:trodlphenyl ether, a n d the mixture was st:rred for 10 hr at 4-6 °. The reaction m:xture was then decanted rote 75 ml of cold water, and cooled to 2-3 °. The crystals wlnch separated out were filtered and dissolved m 900 ml of hot water, and neutrahzed with bamtun hydrox,de to pH-~ 5. The n n x t u r e was filtered m the hot state, a n d after the solution had cooled 31 g of yellow crystals of 4,4'-dmltrod~phonylox:de-2-sulpho acid were separated, and then recrystalhzed from water containing :llummat:ve activated carbon. The I R spectrum of the resulting compound has bands at 1250 and 1030 cm -1 charactemstlc for the sulpho group. To a solution of 7 4 g of t m chchlorlde m 80 ml concentrated hydrochloric ae:d were added 7 5 g of 4,4'-damtrodlphenyloxlde-2-sulpho acid, a n d the mixture was st:rred for 3 hr at 80-90 °. After cooling 10-7 g prempltate was obtained a n d recrystalhzed from dilute hydrochloric acid; 5 g of DPOSA hydrochlorlde were obtained. To obtain a n analytically pure compound the DPOSA hydrochlorlde was treated with hydrogen sulphide to remove any tin-containing compounds. Found, %: C 45 14; H 4.35; N 8.68; C1 11.53. Calculated, ~/o: C 45.50; H 4-12; N 8 85; C1 11-12.

CIzHIaNaO~C1S.

The structure of the product compound was confirmed b y infrared spectrum a n d b y potentlometrlc t~trat~on Sulphonated chamme salts were obtained b y treatment w~th aqueous solutions of the appropriate bases The resulting salts were purified b y recrystalhzat:on, and vacuum-dried. The TGA data show that the salts form crystal hydrates containing from 1 to 4 molecules of water. For example, the h t l n u m salt of SSA contains 4 molecules of H I e , the a m m o m u m BSA 1 molecule of H~O, the potassmm salt of BSA. 1.5 mole H~O, etc. The water of crystal1,zat~on is released from the salts at 150-200 °. P D A were recrystalhzod from acetic anhydride and vaeuum-sublLmed, m.p. 286.5-287 °. Dlmethylaeetarmde (DMA) was d~rod w:th P~O~, d~st~lled first on a rectifying column and then over molecular s:eves munedlately prior to use. Phthahc anhydride was reerystalhzod from acetic anhydr:de, m.p. 129-130 °. L:thlum salt of sulphan~hc acid was obtained m quantltat:ve amounts by treating sulphamhc acid w:th an aqueous solut:on of h t t u u m hydrox,de

The model compound (hthmm salt of phthalamlsulpho acid) was synthesized by condonsat~ol~ of 0 3 g h t h l u m salt of sulphanlhc acid w:th 7 4 g phthahe anhydride m 100 ml DMA at 140-150 ° for 2 hr. The excess solvent was vacuum-d~st:lled and the prec~p:tated crystals ~ ~rc~ ~eparated, washed and recrystalhzod from ethanol Y:eld 7.5 g (45 7 ~o). Found, ~o C 52 0, Calculated, %: C 51 4;

H 3 80; N 4 49; L: 2 31 H306, N428; L:214

CI~HsL:NO~S'I-I~O

I . V . VASIL'EVAet al.

162

The I R spectrum of the model compound has bands of the sulpho group (1250 and 1030 cm -1) and bands chaxactenstm for the ~nlde ring (1780, 1720, 1380 and 720 cm-1). Synthes@ of ~ulphonated poly~m~des To a solution of 0-559 g L1 salt of DPOSA m 9 ml I)MA were added 0.427 g PI)A at room temperature. After the addition of an equLmolecular amount of PDA the solution was stirred for 30 ram, after which a further 1-2% PDA was added. Water-soluble, strong, fiexlble, bright-yellow films were made from the reaction solution and were transformed rote polym]lde films by vacuum-heating for 1 hr at 250 °, or by treatment with a bmlmg pyrldme-benzene-acotm anhydride maxturo [5]. A sn~mlar procedure was followed m the polycondensatlon of other salts of sulphonated dlarmnes m PDA, as well as m the copolycondensatlon of L1 salt of DPOSA and 2,5-DAH* wlth PDA. The formatlon of the imlde ring and the preservatlon of the sulpho groups during the eyehzatmn process was verffied by infrared analysis. To convert the sulphonated polyn~ldes from the salt form to the H form the films were kept m hydroehlorm acid for several days, and were then washed with &stilled water and drmd. The thermal stability of the product polymers and of the model compound was deterrnmed from the TGA data, and the hydrolytm stability of the model was estimated on the barns of elementary and infrared analys~s A UR-10 spectrometer was used to record the I R spectra DISCUSSION OF RESULTS

A r o m a t i c a m i n o s u l p h o acids f o r m i n t e r n a l salts in which t h e a m i n o g r o u p h a s b e e n n e u t r a l i z e d b y t h e sulpho acid residue. This explains, for e x a m p l e , w h y s u l p h a m l i c acid fails t o f o r m salts w i t h m i n e r a l acids a n d does n o t u n d e r g o a c y l a t i o n H o w e v e r t h e sulpho acid g r o u p in a m i r m s u l p h o acid is readily n e u t r a l ized b y alkalis, a n d in this case t h e a m i n o g r o u p b e h a v e s in t h e n o r m a l m a n n e r . T h u s we k n o w f r o m [7] t h a t t h e presence of S O s as a s u b s t l t u e n t in a r o m a t m a m i n e s h a s v i r t u a l l y no effect on t h e b a s i c i t y of t h e a m i n o group. T a k i n g this into a c c o u n t it was o b v i o u s t h a t s u l p h o n a t e d d i a m i n e salts would h a v e t o be u s e d for t h e p o l y c o n d e n s a t i o n w i t h P D A . A c c o r d i n g l y we s y n t h e s i z e d salts o f B S A , SSA a n d I ) P O S A w i t h different cations, a n d s t u d i e d t h e i r p r o p e r t i e s and their interaction with PDA. I t was f o u n d t h a t t h e solubility of salts o f these s u l p h o n a t e d d i a m i n e s in t h e solv e n t s u s e d for t h e e x p e r i m e n t s . (DMA, dimethylsulphoxide (DI~ISO) etc.) was largely d e p e n d e n t on t h e n a t u r e of t h e cation: in t h e ease o f B S A o n l y a salt containing t r i b u t y l a m i n e dissolved in DMA, w h e r e a s t h e salts w i t h t h e o t h e r cations (Li+, K +, N a +, N H ~ , N ( C H s ) s H + a n d N(C2H~)sH+ ) dissolved o n l y in DMSO. T h e s a m e b e h a v i o u r was o b s e r v e d v ~ t h t h e SSA salts. T h e D P O S A salts, on t h e o t h e r h a n d , dissolved in all t h e solvents used for t h e p o l y e o n d e n s a t i o n T h e results of a T G A s t u d y of t h e t h e r m a l b e h a v i o u r of t h e s u l p h o n a t e d d i a m i n e salts (Fig. 1) s h o w e d t h a t all these salts stuched c o n t a i n w a t e r of crystallization w h i c h t h e y lose a t 150-200 °. T h e h t h i u m a n d p o t a s s i u m salts r e m a i n stable on f u r t h e r h e a t i n g r i g h t u p to 300 °, while in t h e case of the a m m o n i u m * 2,5-B~s-(p-ammophenyl)hydroqumone; the synthesis of th~s compound was described m [6].

Synthesis of sulphonated polypyromelhtnmdes

163

salts major changes take place at around 200 ° I n the latter case the salt apparently decomposes, accompanied b y the liberation of ammonia, and no sulphonamide is formed Thus the I R spectrum of the ammonium salt of SSA heated in vacuo at 200 ° does not contain bands of the sulphonamlde group, and differs from that of the original diamine solely on account of the bands at 1430 and 3200 em -z which are characteristic for N H +. The nitrogen content of the sample after heating was 8.07 instead of 13.85 and 15.20% calculated for the ammonium salt of SSA_ and the sulphonamlde respectively. One would therefore expect, in view of the TGA data, that the sulpho group would remain stable during the thermal cyclization of poIyamidoacids. A study was made of the properties of a model compound prepared b y the condensation of phthalic anhydride and lithium salt of sulphanilic acid 0

C

It was found that this compound remains stable right up to 500 ° m an inert atmosphere (Fig. 2). To determine the hyd.rolytie stability of the model compound the latter was treated with water or with 1 g hydrochloric acid at different ~ m -

tO0

,001 I

100

I

2oo FIG. 1

~IG.

I

3oo

~00 T,°C

200

~00

~ °0 600

FIG. 2

1. TGA curves of salts of sulphonated dlammes m air. Rate of heating 6 deg/mm: 1--K-salt of BSA, 2---htlmun salt of SSA, 3--K-salt of SSA, 4---NH4 salt of BSA.

F~a. 2. TGA curves of htlnum salt of phthalanLl-p-sulpho acid m argon Rate of heating 6 deg/mm. peratures. The solution was then evaporated and the I R spectrum and the elementar~ composition of the residue were examined. As is seen from the d a t a in Tables 1 and 2, no hydrolysis takes place except when the model compound is treated with hydrochloric acid.

164

I . V . VASrr/~-VA~ aL

On investigating the two-stage polycondensation of PDA with the sulphonated diamines it was found that the salts of BSA, SSA and DPOSA enter into reactions with PDA under the same conditions as unsulphonated aromatic diamines and form polyamidoacids of fairly high molecular weight*. The introduction of powderTABLE 1.

HYDROLYTIC

STABILITY

OF L I T ~

SALT OF

P H T R f A IJA N I L - ~ - S U L P H O A C I D

Agent o f hydrolysm

Tune of treatment, hr

Temperature, °C

Water 1 ~ HCI 1 ~ HC1

10O 20 1OO

40 48 5

Results of treatment No hydrolysis Partial hydrolysis Hydrolyzes

* According to e l e m e n t a r y a n d i n f r a r e d analysis data.

form PDA into a solution of the salt of diaminosulpho acid resulted in the appearance of a yellow colouring and in a rise in the viscosity of the solution which reached a maximum after the addition of a stoichiometric amount (or 1 ~ excess) TABI~ 2. PROPERTIES OF SULPHOI~ATEDPOLYPYROMELLITIMIDES Dmmme

Swelling m water*, %

Strengtht, kg/em I

Relative elongationt, ~/o

L l t t n u m salt of DPOSA BSA salt contaimug trflutyl-

12

1200

5

4

ll0O

4

10

1600

10

8/nine

L i t l n u m salt of D P O S A + + 2.5DAH (33%)

* Linear swellh~ of the films of size 5 × 50 mm. t In dry state.

of PDA (Fig. 4). Strong, flexible, bright-yellow films were obtained from polyamidoacid solutions based on lithium salt of DPOSA and BSA salt with tributylamine. The films based on SSA prepared from DMSO solution were vmT brittle which prevented further work with this diaminosulpho acid. The polyamide structure of the films was confirmed by infrared (Fig. 5a). The polyamidoacid films were water-soluble but after the cyclization only limited swelling of the films took place in water. To control the degree of swelling of the film~ in water and to improve their mechanical strength we synthesized mixed * P r e l n n m a r y tests showed t h a t the catlon nature has no appreciable effect on the polycondensatlon, and so the selection of cations was from now on determined b y the solubility of the salt m the reaction medmm.

Synthesis of sulphonated polypyromelh~lmldes

165

polymers, replacing some of the sulphonated 4iamine with unsulphonated diamines (4,4'-dlaminodll0henyloxide or 2,5-DAH). The cyclization of the ratermediate polyamidoacids likewise proceeds under conditions similar to those for the eyclizatmn of unsulphonated polyamidoacids. The results of IR analysis show that with the polyamidoacld film based on the hthium salt of DPOSA I00 80 60 z/O 20 I

0

I

P

I

I

L

I

l

I00

b

2O I

0

I

I

100

I

l

I

J

I

I

0

6O *0 20 0

J

I

18

I

I

14

I

I

I

I

fO

8

6

p x fO"2, Cm-7

Fro. 3. I R spectra: ~ - - h t l n u m salt of phthalaml-p-sulpho acid; b, c---dztto, after treatment with boiling water for 40 hr, a n d with 1 N hydrochloric amd at room temperature for 48 hr, respectively.

166

I. V. VASIL'~.VAet ~.

a n d P D A h e a t i n g for 1 h o u r a t 250 ° results in p r a c t i c a l l y c o m p l e t e conversion o f t h e film to p o l y p y r o m e l l i t i m i d e (Fig. 5b). Chemical cyclization leads to similar results. 88C

JO0

200

a

h

ioo

05 0.7 o8 PDA: dlamine , mole/mole

FIG. 4. Viscosity of reactmn solutmns versus ratm of PDA and salts of dlammosulpho acids: a--htlnum salt of DPOSA; b---BSA salt with tnbutylamme; w--tnne of outflow of solution, see.

8O

a

6O 4O

h 70 5O 80 10 16

•/I

12

I

8

I

6 w l O ' f em"1

FIG. 5. I R spectra of films of polyamzdoacld (a) and poly~mde (b) based on PD/k and hthmm salt of DPOSA.

Synthems of sulphonat~d polypyromelhtlm~des

167

Table 2 gives some of the properties of the sulphonated polypyromellitimides (in the salt form). I t is seen that the sulphonated polyim]de films have fairly high mechanical strength in the dry state, and that they swell in water. The introduction of hydroquinone units into the polymer considerably increases the strength of the films. However, conversion of the films from the salt form to the acid form b y treatment with 1 ~ hydrochlorm acid greatly impairs their strength, and in some cases this made it difficult to measure their electrical conductivity. The reason for this marked loss of strength has not yet been found. In the wet state the most satisfactory mechamcal propertms were possessed 1oo

?eo 000

600

T,°g Fm 6 TG/k curve of polypyromollltlmldo based or~ PDA and hthmm salt of PDOSA. Heating m air at the rate of 6 dog/ram by the copolymer film based on the lithmm salt of DPOSA and 2,5-DAH (33%). The resistivity of this film amounted to 20 ohm. em, and its ion-exchange capacity measured b y t]tration was 1.15 mg-equiv./g (calculated value 1.43 rag-equiv./g). The thermal stabfltty of the sulphonated polypyromelhtinndes is faLrly high in a~r: according to the TGA data the polyp)romelhtimide based on the hthium salt of DPOSA suffers no loss of weight below 300 ° (see Fig. 6)* CONCLUSIONS

(1) I t is shown that sulphonated aromatm dlammes (m the form of salts) m a y be used for the synthems of polypyromelhtimldes by two-stage polycondensatlon under conditions mmdar to those of the synthesis of unsulphonated poly]mides (2) A number of different sulphonated polypyromelhtlmides have been synthemzed and some of their properties have been investigated. Translated by R. J .4.. ]-IEI~DRY REFERENCES

1. I. E. KARDASH and A. N. PRAVEDNIKOV, Vysokomol soyed. B9: 873, 1967 (bTot translated m Polyraer Sc]. U S S 1~.) 2. N. D. MALEGINA, B. V. KOTOV, V. V. KOPYLOV and A. N PRAVEDNIKOV, Vysokomol. soyed. A13: 2800, 1971

3 F. D. TRISCHLER and H. H. LEVINE, J Appl. Polymer ScL 13" 101, 1969 * Weight losses at temperatures arotmd 100° are probably due to the ol~nmatmn of water from the sample

E. N. ~ o v

168

e~a/.

4. N. A. ADROVA, M. I. BESSONOV, L. A. LAIUS and A. P. RUDAKOV, Pohm~dy--no~yl klass termostolktkh polnnerov (Polylmxdes,a l~ovel Class of Thermally Stable Polymers) Izd. "Nauka", 1968 5. U K. Pat. 903271, 1960 6. E. N. TELESHOV, I. V. VASIL'EVA and A. N. PRAVEDNIKOV, Vysokomol soyed. AI4: 150, 1972 7. J. CLARK and D. D. PERREN, Uspekhl khlmn 36: 288, 1967

SYNTHESIS AND PROPERTIES OF HYDROQUINONE- AND QUINONE-CONTAINING POLYPYROMELLITIMIDES* E. N. TELESHOY, I. V. VASIL'EVA and A. N. PRAVEDNIKOV L. Ya. Karpov Physlcochemlcal Research Instatute (Received 26 June 1970)

IN an earlier paper [1] we reported on the synthesis of sulphonated polyimides by the two-stage polycondensation of sulphonated diamines with pyromelhtlc dianhydride (PDA). The present investigation relates to the synthesis of polypyromellitimides having hydroquinone or quinone functional groups in the chain and consequently capable of electron exchange. The combination of good thermal stability and redox properties in these polymers could tend to accentuate various processes involving the participation of electron-exchange resins. This paper describes the methods of synthesis and some of the properties of polypyromellitimldes of the following structure -

-

O

-,2,ao

O

~

~

o~

~

~

.

I -

O

O

~ _

~

v v

o

~

,~,

H

* Vysokomo]. soyed. A14: No. 1, 150-155, 1972.

k

, ~