Hydrogen Bonding Ring Containing Polymers: Poly(enamineâKetones)

31 Hydrogen Bonding Ring Containing Polymers: Poly(enamine-Ketones)

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on January 6, 2017 | http://pubs.acs.org Publication Date: August 12, 1982 | doi: 10.1021/bk-1982-0195.ch031

SAMUEL J. HUANG, BRIAN BENICEWICZ, and JOSEPH A. PAVLISKO University of Connecticut, Department of Chemistry and Institute of Materials Science, Storrs, CT 06268 Monomeric and polymeric enamine-ketones were synthesized by the condensation reaction of 1,3-diketones with amines. These compounds exhibit liquid crystalline properties when heated to appropriate temperatures. The transition temperatures of these compounds are much lower than those of the aromatic hydrocarbon analogs. High solubilities in organic solvents of these compounds together with the low transition temperatures suggest possible processability for the poly(enamine-ketones) as high strength materials.

Hydrogen bonds a r e o f t e n r e s p o n s i b l e f o r h o l d i n g n a t u r a l p r o t e i n s i n s p e c i f i c conformations. Segments o f the p r o t e i n c h a i n and hydrogen bonds form r i n g systems that a r e the main p a r t of the p r o t e i n h e l i x . The hydrogen bonding r i n g s formed between the base p a i r s a r e r e s p o n s i b l e f o r the unique double h e l i c a l s t r u c t u r e o f the DNA molecules. However, i n t r a m o l e c u l a r hydrogen bonds i n s y n t h e t i c polymers remain as a r e l a t i v e l y unexplored area o f research. We have r e c e n t l y synthesized s e v e r a l polymers c o n t a i n i n g hydrogen bonding r i n g s i n the polymer backbone w i t h very i n t e r e s t i n g p r o p e r t i e s . We r e p o r t here our recent f i n d i n g s on poly(enamine-ketones) (1-J3). R e g u l a r i t y and r i g i d i t y i n a polymer chain enhance the a b i l i t y f o r the polymer to c r y s t a l l i z e . High c r y s t a l l i n i t y and o r i e n t a t i o n order o f the c r y s t a l l i n e regions r e s u l t i n high strength/modulus and thermal s t a b i l i t y o f polymeric m a t e r i a l s . Recent s t u d i e s on r i g i d c h a i n polymers have r e s u l t e d i n a few u s e f u l high strength/modulus m a t e r i a l s (4-9). Traditionally aromatic hydrocarbon r i n g s a r e incorporated i n t o a polymer chain backbone to provide r i g i d i t y f o r the polymer c h a i n . As the number o f aromatic hydrocarbon r i n g s i n c r e a s e s i n the polymer chain the melting p o i n t of the polymeric m a t e r i a l i n c r e a s e s and the s o l u b i l i t y o f the m a t e r i a l decreases. Many 0097-6156/82/0195-0403$06.00/0 © 1982 American Chemical Society

Butler and Kresta; Cyclopolymerization and Polymers with Chain-Ring Structures ACS Symposium Series; American Chemical Society: Washington, DC, 1982.


404

POLYMERS WITH CHAIN-RING

STRUCTURES

high temperature s t a b l e r i g i d polymers c o n t a i n i n g aromatic hydrocarbon r i n g s are i n f u s i b l e and i n s o l u b l e i n common s o l v e n t s . These p r o p e r t i e s l i m i t e d the u s e f u l n e s s of the polymers because of the l a c k of e f f e c t i v e ways to process them i n t o u s e f u l end products. We have been i n t e r e s t e d i n the p o s s i b i l i t y of r e p l a c ing aromatic hydrocarbon r i n g s with other r i g i d s t r u c t u r a l u n i t s to o b t a i n processable m a t e r i a l s with h i g h strength/modulus and thermal s t a b i l i t y . Six-membered hydrogen bonding r i n g s such as carbonyl-enamines and carbonyl-hydrazones are of s p e c i a l i n t e r e s t s to us s i n c e the conjugated double bonds and the hydrogen bonding system make up the near planar six-membered r i n g s . We expect these systems to be reasonably r i g i d and thermally s t a b l e . ^

Carbonyl-enamines

Carbonyl-hydrazones

A polymer c o n t a i n i n g one or more of these r i n g systems i n the backbone can be expected to be r i g i d and yet having lower thermal t r a n s i t i o n temperatures than that of the analogous polymers cont a i n i n g only aromatic hydrocarbon r i n g s . The presence of hetero atoms and the low symmetry of the hydrogen bonding r i n g s should a l s o provide the polymer with higher s o l u b i l i t y than those of the analogous polymers c o n t a i n i n g only hydrocarbon r i n g s . Low thermal t r a n s i t i o n temperatures and high s o l u b i l i t y should prov i d e p r o c e s s a b i l i t y f o r the hydrogen-bonding r i n g c o n t a i n i n g polymers. We approach the research by f i r s t l y studying the synthesis and p r o p e r t i e s of monomeric model components. EXPERIMENTAL General. Thermal a n a l y s i s was c a r r i e d out w i t h a DuPont 990 Thermal Analyzer with a DTA/DSC c e l l and a DuPont 950 DTA u n i t . The thermal o p t i c a l a n a l y s i s (70A) u n i t used was constructed i n our l a b o r a t o r i e s and c o n s i s t s of a L e i t z D i a l u x P o l p o l a r i z i n g microscope f i t t e d with a hot stage. I n f r a r e d s p e c t r a were recorded w i t h a P e r k i n Elmer 283 g r a f t i n g spectrophotometer. NMR were recorded w i t h a Brucker WH90FT NMR spectrophotometer and a V a r i a n EM360 NMR spectrophotometer w i t h a V a r i a n EM3630 lock/ decoupler. Inherent v i s c o s i t y measurements were made with a Ubbelohde viscometer i n a constant temperature bath. M i c r o a n a l y s i s were performed by Baron C o n s u l t i n g Co. of Orange, Conn. A l l s o l v e n t s and reagents were p u r i f i e d b e f o r e used. 1

4 , 4 - D i a c e t y l b i p h e n y l . Anhydrous aluminum c h l o r i d e 26.7 g (200 mmoles) was covered w i t h a mixture of 100 mL C S and 15.4 g (100 mmoles) b i p h e n y l . A c e t y l c h l o r i d e 15.7 g (200 mmoles) was slowly added and e v o l u t i o n or HC1 allowed to become complete by 2


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Poly(enamine-Ketones)

405

subsequent heating f o r 12 hours on a water bath. The C S was evaporated, the mixture decomposed on i c e - H C l and the r e s u l t i n g white s o l i d c o l l e c t e d and d r i e d . F r a c t i o n a l c r y s t a l l i z a t i o n from a l c o h o l gave phenyl acetophenone and 4 , 4 - d i a c e t y l b i p h e n y l . The l a t t e r was p u r i f i e d by r e c r y s t a l l i z a t i o n from CCI, to give 9.95 g (41.5%) o f c o l o r l e s s l e a f l e t s , mp 193-194°C. The i n f r a r e d s p e c t r a (KBr) showed absorptions a t 1685 (vnC=0), 1600 (vnC=C) and 815 (vSC-H). The proton NMR showed peaks a t 2.656 s i n g l e t (3) and 7.86 m u l t i p l e t (4). A n a l : Calcd C, 80.61, H, 6.00. Found: C, 80.67; H, 5.88. 2


f

Acetylacetophenone (Benzoylacetone). To an i c e cooled s o l u t i o n o f 352 g (4 moles) e t h y l a c e t a t e and 100 g sodium ethoxide (1.47 mole) was added dropwise 240 mL of acetophenone (2 moles) extended over a p e r i o d o f one hour. A f t e r a d d i t i o n was completed the r e a c t i o n mixture was allowed to warm to room temperature and l e t stand 20 hours. The r e a c t i o n mixture was poured i n t o 1.5 of water and s t i r r e d u n t i l s o l u t i o n . The aqueous s o l u t i o n was washed with two 250 mL p o r t i o n s of e t h y l ether, and a c i d i f i e d with 100 mL o f g l a c i a l a c e t i c a c i d to p r e c i p i t a t e a yellow s o l i d which was c o l l e c t e d and d r i e d overnight. The yellow s o l i d was c r y s t a l l i z e d from a l c o h o l to a f f o r d 175.6 g (72.2%) of pale yellow needles, mp 54-55°C. The i n f r a r e d s p e c t r a showed absorp t i o n s a t 3450 (vO-H), 1615 (vC=0), and 3005 (vC-H). The proton NMR showed peaks a t 2.56 s i n g l e t (3), 6.26 s i n g l e t (1), and 7.66 m u l t i p l e t (5). Anal: Calcd C, 74.07; H, 6.17. Found: C, 73.86; H, 6.40. (lyl'-p-Phenylene d i ) l , 3 - B u t a n e d i o n e ( T e r e p h t h a l o y l d i a c e t o n e ) . Sodium ethoxide 6.8 g (100 mmoles) was covered with a mixture o f 30.8 g (350 mmoles) of e t h y l acetate and 8.1 g (50 mmoles) of jD-diacetylbenzene. The r e a c t i o n mixture was allowed to stand f o r 18.5 hours and then poured i n t o 750 mL of water and e x t r a c t e d with two 100 mL p o r t i o n s of e t h y l ether. The aqueous dark brown s o l u t i o n was then a c i d i f i e d with 20 mL of g l a c i a l a c e t i c a c i d to p r e c i p i t a t e a y e l l o w s o l i d which was c o l l e c t e d and d r i e d . The yellow m a t e r i a l was r e c r y s t a l l i z e d s e v e r a l times from chloroform to give 6.5 g (52.9%) o f white prisms, mp 183.5-184.5°C. The i n f r a r e d spectrum (KBr) showed absorptions a t 3425 (vO-H), and 1620 (vC=0). The proton NMR showed peaks a t 2.56 s i n g l e t (3), 6.186 s i n g l e t (1), and 7.96 s i n g l e t (2). Anal: Calcd C, 68.29; H, 5.69. Found: C, 68.24; H, 5.81. 1

(1,1*-p-Biphenylene di)1,3-Butanedione(ρ,ρ -Dibenzoyldiacetone). Sodium ethoxide 8 g (220 mmoles) was covered w i t h a mixture o f 20.7 g (235 mmoles) o f e t h y l acetate and 14 g (59 mmoles) o f d i a c e t y l b i p h e n y l . The r e a c t i o n mixture was allowed t o stand f o r 23 hours and then poured i n t o 2.5 L o f water. S o l u t i o n d i d not occur and upon subsequent heating appeared as a f i n e l y suspended orange s o l i d . T h i s suspension was a c i d i f i e d



406

POLYMERS WITH CHAIN-RING STRUCTURES

with 75 mL of g l a c i a l a c e t i c a c i d and s t i r r e d f o r a one-hour p e r i o d with m i l d h e a t i n g . The p r e v i o u s l y orange s o l i d now appeared as a yellow m a t e r i a l which was f i l t e r e d and d r i e d . The yellow s o l i d was c r y s t a l l i z e d from choloroform followed by r e c r y s t a l l i z a t i o n from a chloroform-CCl, mixture to give 8.5 g (44.9%) of white p l a t e l e t s , mp 221.5-223°C. The i n f r a red spectrum (KBr) showed absorptions at 3425 (vN-H), 1620 (vC=0). The proton NMR showed peaks at 2.36 s i n g l e t s (3), 6.186 s i n g l e t (1), 7.96, 7.46-8.16 m u l t i p l e t (4). A n a l : Calcd C, 74.53; H, 5.59. Found: C, 74.37; H, 5.48. l,4-Bis(2-benzoyl-l-methyl-vinylamino)benzene. A typical s y n t h e s i s of a model compound f o l l o w s : To a s o l u t i o n of 5 mL N-methylpyrolidene (NMP) and 1 mL t r i f l u o r o a c e t i c a c i d (TFA) (10 M i n NMP) was added 0.5 g (3.1 mmoles) of acetylacetophenone and 0.154 g (1.5 mmoles) of £-phenylenediamine. The s o l u t i o n was heated to 125°C f o r a one-hour p e r i o d and then poured i n t o 50 mL of water p r e c i p i t a t i n g a yellow s o l i d . The yellow m a t e r i a l was c o l l e c t e d , d r i e d , and c r y s t a l l i z e d from a c h l o r o f o r m - a l c o h o l mixture to give 0.53 g (86%) of yellow p l a t e l e t s , mp 224-225°C. The i n f r a r e d s p e c t r a (KBr) showed absorp t i o n s at 3400 (vN-H), 3005 (vC-H), 1600 (vC=0), 1580 (vC=C). The proton NMR showed peaks at 2.26 s i n g l e t (3), 5.86 s i n g l e t (1), 7.36, 7.86 m u l t i p l e t (7), and 13.56 s i n g l e t (1). Anal: Calcd C, 78.79; H, 6.99; N, 7.07. Found: C, 77.56; H, 6.72; N, 6.82. Poly[1,4-Bis(3-m-xylylamino-2-butenoyl)benzene]. A typical polymer s y n t h e s i s i s given below. To a s o l u t i o n of 5 mL NMP and 1 mL TFA (10 M i n NMP) was added 0.25 g (1 mmole) of t e r e p h t h a l o y l d i a c e t o n e and 0.12 g (1 mmole) of xylyenediamine. The r e a c t i o n mixture was s t i r r e d , kept under n i t r o g e n , and heated to 135°C f o r a p e r i o d of 8 hours. The r e a c t i o n mixture was then poured i n t o 75 mL of water to p r e c i p i t a t e a yellow s o l i d which was c o l l e c t e d and d r i e d to give 0.32 g (92%) of a yellow powder. The i n f r a r e d spectrum (KBr) showed absorptions at 3400 (vN-H), 1600 (vC=0), 1580 (vC=C), and 3002 (vC-H). Anal. Calcd. f o r r e p e a t i n g u n i t C 2 2 H 2 2 N 2 O 2 : C, 76.27; H, 6.40; N, 8.09. Found: C, 75.63; H, 6.10; N, 8.47. RESULTS AND

DISCUSSION

Monomeric Models Although o r d i n a r y enamines are e a s i l y subjected to h y d r o l y s i s and o x i d a t i o n carbonyl-enamines such as methyl 3-aminocrotonate and 3-aminocrotonamide are s t a b l e m a t e r i a l s . In s o l u t i o n s of i n e r t s o l v e n t s the cis-carbonyl-enamine form i s g e n e r a l l y the most important d e t e c t a b l e form presence by proton and carbon13 nmr spectroscopy. The 4 - e l e c t r o n π system and bonding e l e c t r o n of the N-H 0 system together make up a six-membered s i x - e l e c t r o n


31.

HUANG E T A L .


407

" a r o m a t i c - l i k e " system. T h i s apparently provides s u f f i c i e n t s t a b i l i z a t i o n to make the cis-carbonyl-enamine the most s t a b l e form among the p o s s i b l e tautomeric forms (others i n c l u d e carbonyl-imine, trans-carbonyl-enamine, and emine-enol).


Me

emine-enol

trans-carbonyl-enamine

carbonyl-imine

The proton nmr o f a monomeric enamine-ketone prepared from benzoylacetone and m-xylylenediamine._l, shows a i n t e r n a l hydrogen bonding s i g n a l a t 11.5-13.5. I t s C ^"nmr s i g n a l s are l i s t e d i n Table I. The nmr s i g n a l s a r e i n agreement with an enamineketone s t r u c t u r e . 1

Table I Carbon-13 NMR Assignment of Enamine-Ketone, 1

β c

A. B. C. D. E. F. G.

128.34 ppm 127.14 130.71 140.55 188.36 92.84 165.91

H. I. J. K. L. M.

19.38 46.93 138.81 125.61 126.27 129.69

We f i r s t i n v e s t i g a t e d the f e a s i b i l i t y of using c a r b o n y l enamine r i n g s as r i g i d mesogenic u n i t s by studying monomeric compounds c o n t a i n i n g enamine-ketone u n i t s . Recently, the m e l t i n g behavior o f some o l i g o m e r i c polyphenyIs was i n v e s t i g a t e d and




408

the nature of t h e i r mesophases was v e r i f i e d (10-11). The f i r s t compound i n the s e r i e s to d i s p l a y a nematic mesophase was p-quinque-phenyl. In general, these compounds e x h i b i t very high t r a n s i t i o n temperatures, i n the case of p-sexiphenyl, i t decom posed at 500°C i n the nematic mesophase before forming an i s o tropic liquid. They are a l s o p r a c t i c a l l y i n s o l u b l e . We reasoned that the replacement of one or more of the phenyl r i n g s with an enamine-ketone hydrogen bonding r i n g should lower the t r a n s i t i o n s of the compounds and increase t h e i r s o l u b i l i t y i n common s o l v e n t s . A s e r i e s of enamine-ketones were prepared by the condensation of 3-diketones with arylamines and arylene diamines (2, 12). The

CH

R

3

- Q -

R

'

enamine-ketones

Table I I M e l t i n g Behavior of Some O l i g l o m e r i c Polyphenyls and Enamine-Ketones Aromatic Hydrocarbons Enamine-Ketone H

N

u

3

H

H Oη

K 229i

H

y

A

CH

3

' Λ O Hυ

Κ 386 η 415 i

K 434 s 464 n 5 0 0 d

CH

—'

CH

CH

3

OH

3

H

HO

K 239n

244i

melting behavior of the enamine-ketones was compared with that of the polyphenyls, Table I I . Compared with the polyphenyls, the enamine-ketones have much lower t r a n s i t i o n temperatures, w i t h the



31.

HUANG E T AL.

409


six-membered system being the f i r s t one i n the s e r i e s that d i s played a nematic mesophase. A l s o , as expected, a l l the enamineketones were found to be s o l u b l e i n common organic s o l v e n t s . In order to o b t a i n more proof that the enamine-ketone r i n g system i s s u f f i c i e n t l y r i g i d to be used as mesogenic s t r u c t u r a l u n i t we prepared three s e r i e s o f enamine-ketones with a l k y l , alkoxy, and carbalkoxy f l e x i b l e end groups. A l l three s e r i e s were found to e x h i b i t nematic mesomorphic phases. Some of the higher alkoxy members s t u d i e d a l s o d i s p l a y sematic phases. The thermal data of the a l k y l s e r i e s are shown i n Table I I I and F i g . 1. The thermal behavior o f the enamine-ketones are s i m i l a r to that of the monomeric l i q u i d c r y s t a l s c o n t a i n i n g only hydrocarbon r i n g s . With the knowledge that enamine-ketone r i n g i s s u f f i c i e n t l y r i g i d to a c t as mesogenic u n i t we proceeded to prepare polymeric enamine-ketones. Poly(enamine-ketones) Several polymers w i t h v a r i o u s combinations of enamine-ketone and phenyl r i n g s as the r i g i d case connected with a l k y l e n e and m-xylylene groups were prepared by condensation r e a c t i o n of diamines with b i s - ( 3 - d i k e t o n e s ) . High y i e l d s of poly(enamineketones) I-VIII w i t h moderate molecular weight were obtained, Table IV. Polymers with C , a l k y l e n e and m-xylylene connecting

» •-©-

« • «H I„

• -Or©-

2

groups between the r i n g s were found to e x h i b i t thermotropic nematic mesophases whereas those with short a l k y l e n e connecting groups only e x h i b i t i s o t r o p i c melt on heating, Table V. Although poly(carbonyl-enamines) have been p r e v i o u s l y reported (14-19), t o our knowledge we were the f i r s t to detect the thermotropic l i q u i d c r y s t a l l i n e p r o p e r t i e s of p o l y ( c a r b o n y l enamines) (3). Since 1975 s e v e r a l thermotropic l i q u i d c r y s t a l l i n e polymers c o n t a i n i n g aromatic r i n g s as the main mesogenic u n i t have been reported. These i n c l u d e polyalkenoates o f 4,4'dihydroxy-ajCt'-dimethylbenzalazine (20), polyalkanoates of biphenols (21), polycarbonates of 4 , 4 - d i h y d r o x y - a , a - d i methylbenzaTa~zine (22), copolymers c o n t a i n i n g 4-hydroxybenzoate and ethylene t e r e p h t h a l a t e segments (23, 24, 27), p o l y ,

?


410

POLYMERS WITH CHAIN-RING

STRUCTURES


Table I I I Thermodynamic Data f o r the b i s [ 3 - ( p - n - a l k y l a n i l i n o ) - 2 - b u t e n o y l ] benzenes

Compound C

l

Transition

T,°C

ΔΗχΙΟ ,cal/mole

AS,cal/mole/°K

K->n n+i

C

2

Κ

Λ ΐ

K

I I ^ n+i C

3

S

C

6

C

7

8

.211

4.73

184

.628

13.7

222

.039

.788

K->n

173

1.12

25.2

n+i

224

.050

1.01

K-*n

150

.767

18.1

n+i

225

.035

.703

R+n

150

.826

19.5

220

.040

.811

I I ^ n+i

134 138

.274 .510

6.72 12.4

198

.038

.807

K+n

145

1.22

29.2

n+i

188

.044

.954

K->n

157

1.38

32.1

n->i

175

.042

.937

K+K K

C

173


HUANG

ET

AL.


411


31.

Figure 1. Transition temperatures versus the number of carbon atoms in the alkyl chain of the C series. n


412


Table IV Poly(l,4-bis(3-hydrocarbylamino-2-butanoyl)benzene)


CH

C H

3

3

m

R

h h

1

MXD

HMPA/TFA /4 h r s .

97

0.18

1

MXD

DMAc/TFA/4 h r s .

88

0.16

1

h h II

Conditions solvent/catalyst/time b

C

Yield(%)

a

Polymer

n inh dL/g

MXD

NMP/TFA/4 h r s .

97

0.16

1

MXD

NMP/TFA/8 h r s .

97

0.21

1

MXD

NMP/TFA/16 h r s .

89

0.18

1

MXD

NMP/TFA/24 h r s .

82

0.18

1

NMP/TFA/8 h r s .

76

0.18

1

V l O (CH )

NMP/TFA/8 h r s .

75

0.39

IV

1

(CH )

NMP/TFA/8 hrs.

87

0.45

ν

2

MXD

VI

2

(CH )

VII

2

VIII

2

III

(

C

2

6

4

NMP/TFA/8 h r s . 2

(CH

1 2

2>10 (CH ) 2

6

83

0.22

NMP/TFA/4 h r s .

d

75

0.26

NMP/TFA/6 h r s .

d

89

0.76

83

0.17

NMP/TFA/8 h r s .

a.

Concentration of 0.5g/dl measured i n m-cresol at 35°C.

b.

MXD = m-xylylene.

c.

TFA c o n c e n t r a t i o n o f 1.6·10

d.

P r e c i p i t a t e d from r e a c t i o n s o l u t i o n .

M.



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HUANG

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E T AL.

Table V Thermal T r a n s i t i o n o f Poly(enamine-ketones)

CH3

- f Q Polymer

f

MXD

OK> ^^(165),

b

χ

1 ^ - ^ ( 9 5 ) , K ^ m i U O ) , n-*i(185), d235

1

( C H

III

1

( C H

)

6

R>i(170), d245

IV

1

(CH )

4

K-KL(185), d235

V

2 2

VII

2

VIII

2

2

2

)

Κ - η (175), n+i(235), d250

II

VI

2

1

0

^ ^ ( 2 2 0 ) , 1^(240),

MXD ( C H

2

)

1

2

n+i(290), d295

1^+1^(225), Κ ->η(260), n - i ( 2 9 0 ) , d295 χ

1^-^(230), (CH

3

T r a n s i t i o n Temperature (°C)

R

m

1

C H

a

1^(240),

n->i(295), d300

2>10

(CH ) 2

6

R>i(285), d 330

a.

DSC and Thermal O p t i c a l Microscopy

b.

MXD « m-xylylene.

y

h e a t i n g r a t e 5°C/min.



414

POLYMERS WITH CHAIN-RING STRUCTURE:

Table VI TGA of Poly(enamine-ketones)

10% Wt. Loss

u f

Polymer

m

R

I

1

IWP

1

< VlO

D

II

1

III

T

QÏL

V

2

MXD

VI

2

( C H

2

( c

2

(CI

MXD

O Q

Wt. a

t

5 0 0

Residue c ( % )

59 3 0

360

4

)

39

360

47

3

Vio

3 7 0

V6

9

0

3 8 5

2

28

340

2 12

S e a t i n g r a t e at 15°C/min i n N

b.

p

2 5 0

( 2h (CH )

2

m

c

1

VIII

e

380

IV

VII

a

3 3

3 2

3 0

atmosphere,

» m-xylylene.


31.

HUANG E T A L .

415


azomethines (25), copolyescer with p o l y ( e t h y l e n e t e r e p h t h a l a t e ) and terphenylene segments (26), poly ( S c h i f f bases) (27, 28) , p o l y e s t e r analogs o f 4-alkoxyphenyl-4'-alkoxybenzoates (29), and p o l y e s t e r s derived from t e r e p h t h a l i c a c i d and 4,4 dihydroxy-a,w-diphenoxyalkanes (30). These polymers c o n t a i n f l e x i b l e connecting groups between r i g i d aromatic mesogenic u n i t s , s u b s t i t u t e d aromatic mesogenic u n i t s , or mesogenic u n i t s of d i f f e r e n t s i z e s and shapes f o r the purpose of d e c r e a s i n g the symmetry of the polymer backbone so that the packing order of the c h a i n w i l l be somewhat reduced. Otherwise the t r a n s i t i o n temperatures of the polymers would have been too h i g h f o r the polymers to be thermally p r o c e s s a b l e . Compared w i t h those reported polymers our poly(enamine-ketones) have r e l a t i v e l y low t r a n s i t i o n temperatures and much higher s o l u b i l i t i e s i n commonly used s o l v e n t s (m-cresol, NMP, DMA, e t c . ) . These polymers were a l s o found to have reasonable thermal s t a b i l i t y as i n d i c a t e d by the TGA a n a l y s i s , Table V I . We are now studying both the l y o t r o p i c and thermotropic l i q u i d c r y s t a l l i n e p r o p e r t i e s of poly(enamine-ketones). A l s o i n progress i s the s y n t h e s i s o f poly(enamine-ketones) d e r i v e d from diaminoarenes, polymers c o n t a i n i n g a l l r i n g systems. We hope to o b t a i n r o d - l i k e polymers w i t h both l y o t r o p i c and thermotropic l i q u i d c r y s t a l l i n e p r o p e r t i e s that permit t h e i r p r o c e s s i n g i n t o u s e f u l end products.


f

Acknowledgement P a r t i a l f i n a n c i a l support from the N a t i o n a l Science Foundation (DMR8013689) i s g r a t e f u l l y acknowledged.

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8.

Huang, S. J.; Benicewicz, B. C.; Pavlisko, J. Α.; Quinga, E. Polym. Preprints 1981, 22, No. 1, 56. Benicewicz, B. C.; Huang, S. J.; Johnson, J. F. Polymer Preprints 1980, 21, No. 2, 268. Huang, S. J . ; Pavlisko, J. Α.; Hong, E. Polym. Preprints 1978, 19, No. 2, 57. Benicewicz, B. C. Ph.D. Dissertation, University of Connecticut, 1981, pp. 20-31. Blumstein, A. Polymer News 1979, 5, 254. Samulski, E. T.; Dupre, D. B. in "Advance in Liquid Crystals" Vol. 4, Brown, G. H., Ed.; Academic Press, New York, Ν. Υ., 1979; p. 121-145. Blumstein, Α., Ed.; "Liquid Crystalline Order in Polymers"; Academic Press, New York, Ν. Υ., 1978. Cifferi, Α.; Wards, I. Μ., Eds.; "Ultrahigh Modulus Polymers"; Applied Science, Barking, Essex, U. Κ., 1979.


416



9.

Black, W. B.; Preston, J.; "High Modulus Aromatic Polymers"; Dekker, New York, Ν. Υ., 1970. 10. Smith, G. W. Mol. Cryst. Liq. Cryst. 1979, 49, 207. 11. Lewis, I. C.; Kovac, C. A. Mol. Cryst. Liq. Cryst. 1979, 51, 173. 12. Benicewicz, B. C.; Huang, S. J.; Johnson, J. F. Mol. Cryst. Liq. Cryst., in press. 13. Gray, G. W. "Molecular Structure and Properties of Liquid Crystals"; Academic Press, New York, Ν. Y., 1962. 14. Moore, J. Α.; Kochanowski, J. E. Macromolecules 1975, 8, 121. 15. Moore, J. Α.; Mitchell, T. D. Polymer Preprints 1978, 19, No. 2, 13. 16. Ueda, M.; Sakai, N.; Imai, Y. Makromol. Chem. 1979, 180, 2813. 17. Ueda, M.; Otaira, K.; Imai, Y. J. Polym. Sci.: Polym. Chem. Ed. 1978, 16, 2809. 18. Ueda, M.; Kino, K.; Hirono, T.; Imai, Y. J. Polym. Sci.: Polym. Chem. Ed. 1976, 14, 931. 19. Imai, Y.; Ueda, M.; Otaira, K. J. Polym. Sci.: Polym. Chem. Ed. 1977, 15, 145-7. 20. Roviello, Α.; Sirigu, A. J. Polym. Sci.: Polym. Lett. Ed. 1975, 13, 455. 21. Blumstein, Α.; Sivaramakrisknan, K. N.; Clough, S. B.; Blumstein, R. B. Mol. Cryst. Liq. Cryst. Lett. 1978, 49, 119. 22. Roviello, Α.; Sirigu, A. Europ. Polym. J. 1979, 15, 423. 23. MacFarlane, F. E.; Nicely, V. Α.; Davis, T. G. Contemp. Top. Polym. Sci. 1977, 2, 109. 24. Jackson, W. J . , Jr.; Kuhfuss, H. F. J. Appl. Polym. Sci. 1980, 25, 1685. 25. Morgan, P. German Patent 2, 620, 351 (Nov. 18, 1976). 26. Fayolle, B.; Noel, C.; Billard, J. J. Phys. (Paris), Colloq., 1979. C3, 485. 27. Guillim, D.; Skoulious, A. Mol. Cryst. Liq. Cryst. Lett. 1978, 49, 119. 28. Samulski, E. T.; Wiercinski, R. W. Bull. Am. Phys. Soc. 1978, 23, 296. 29. Griffin, A. C.; Havens, S. J. Mol. Cryst. Liq. Cryst. Lett., 1979, 49, 239. 30. Antoun, J.-I. S.; Ober, C.; Lenz, R. Brit. Polym. J. 1980, 132. RECEIVED December 7, 1981.


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