Hydrodynamic and conformation characteristics of polyimidoamide macromolecules in solution

0032-3950/79/0301-0593507.50]0

Polymer Science U.S.S.R. Vol. 21, pp. 593-600. (~) Pergamon Press Ltd. 1979. Printed in Poland

HYDRODYNAMIC AND CONFORMATION CHARACTERISTICS OF POLYIMIDOAMIDE MACROMOLECULES IN SOLUTION* G. V. TARASOVA, A. YE. POLOTSKII, T. I. GAI~MO~OVA, V. S. GALEI~KO, A. N. CHERKASOV, ~¢[. ~¢[. KOTO:N, V. A. GUSIASTSKAYA, T. V. BATRAKOVA a n d

K. A. ]:~OMASItKOVA High Polymers Institute, U.S.S.R. Academy of Sciences ( R e c e i v e d 14 _February 1978)

Diffusion, sedimentation, viscosity, and birefringence in solution have been used to study polyimidoamides (PIA) produced from imido acid dichlorides. These were shown to possess a narrow MWD ( M ~ / , l l ~ = 1.1-1-3). The Kutm segment consists of 2.5 monomer units and the anisotropy of the latter (a,i--a±)=250× 10-25 em 8. THE a r o m a t i c p o l y i m i d o a m i d e s (PIA) are of considerable interest as t h e r m o s t a b l e polymers. This is m a i n l y due to their g o o d physical a n d m e c h a n i c a l properties, high t h e r m a l stability (400°C) a n d their solubility in amide solvents which facilit a t e s their processing. P I A are widely used in various b r a n c h e s o f i n d u s t r y as electrical insulations in t h e shape of p r o t e c t i v e paints, films, coatings, c o m p o u n d i n g materials, adhesives, laminates; t h e y c o m p e t e well w i t h the p o l y a m i d e s a n d polyimides. Our aim was to investigate the properties of P I A p r o d u c e d b y a single stage m e t h o d f r o m imido m o n o m e r s . EXPERIMENTAL

The PAI samples had the following chemical formula

Their reduced viscosity t/red ranged from 0.8 to 4.5 when synthesized by the method described in [1]. The samples as 15% solutions in methyl pyrollidone (MP) were studied by diffusion, sedimentation and viscosity methods (in MP and DMF) at 25°C. The solution viscosities were determined in an Ubbelode type, "Veskan" automatic viscometer at a g~ 1000 sec -1 velocity gradient (this work was carried out by V. V. Alekseyeva). The intrinsic viscosity and the Huggins constants k' are listed in the Table. The latter were determined from the equation: t]sp

---- = [ O ] + k ' c . ~ . . . . c

in which c is the concentration. * Vysokomol. soyed. A21: No. 3, 541-547, 1979. 593

(1)

G. V.

594

et al.

TARASOVA

The diffusion coefficiehts D of the solutions were determined in the Tsvetkov [2] polaat 0.02-0.03% concentrations. TL _ interference curves were processed

rizing diffusometer

by the surface area and maximal The D values for the PIA the 15%

were determined

on those prepared from

solutions in MP. The diffusion therefore consisted also of that of a small amount

FIG. 1. The concentration diffusion

ordinates method.

solutions in DMF

gradient

distribution

curves

over cell height

got

during the

of PIA solutions in DMF at various time intervals after the start of the test, min: I-45; Z-465; 3-1185.

Polyimidoamide of residual

MP

molecules.

Typical

macromolecules

diffusion

curves

using 0.03%

contained in Fig. 1 which shows them to have typical “wings” of the low mol.wt.

admixture

595 solutions

in DMF

am

(Fig. la) due to the diffusion

[3]. The D values were calculabed after the passage of the MP

(Figs. lb,c) when no further error could be due to it. The D for the sample with the largest mol.wt. the independence

of D so that the D detormined

tllet of critical dilution

THE

as a function

of concentration

at ~=0-02%0.03~~

showed

could bc taken t,o be

(Do in the Table).

MAIN

CHARACTERISTICS

OF

THE

STUDIED

PIA

SAMPLES

c: ;y 2

b

2,

3

x P;

-

X

X

Ez

-I

A

d

1

2.5

0.72

3.0

0.60

1.5

3.1

181

1.11

3.4

2

2.2

0.68

2.5

0.88

1.6

142

1 .O3

3.2

3 4 5

1.9 1.8 -

0.69

2.2

0.60

2.2

2.6 2.3

91

1.33

0.57

1.9

0.66

1.7

2.0

103

1.30

3.6 2.9

1 .5

0.89

0.9

0.89

6

~-

-

I.0

0.73

1.2

0.64

2.9

1.7

51

1.15

3.3

8

0.7

0.02

1.1

O.GG

3.0

1.6

45

1.33

2.8

9

) 0.5

I.60

0.7

1.23

3.5

1.3

31

1.11

2 .;j

The scdinxxntatiol> coefficients U.S.A.)

S mere determined

at (52-68)

peaks on the sediment,ation

curves.

x IO3 rpm.

~

-

, 68

-

7

Spinco E (Beckman,

An nr x 1°-‘0

:.

%

he

G8

I

-

on an analJ-tic:?1 ultraccntrifuge

The S vllucs

wp:‘e calculated

from tho

The saml)les with thr Ial‘Pest mOl.T\-t. (X = 1 s1 x 103

ant1 142 x 10”) lvere used to find the concentration

dependence

of AS,and tllp parurxtcr

7

~4~s fourrd from the fxyuation

in x-hi&

S, is the sedimentation

into account the concentration

constant dependence

at critical dilution.

The above u-as used to take

of X in the cases of other PIA

samples; tllr: S,

values a,re listed in the Table. The polydispersity 5‘ cluves,

of the polymer

fractions was determined

from the disp(%ion

A. The latter is known to be described as a function of sedimentation

(3)

A== 2DtT ~4xziF2tZ s 3 in which 0) is the angular velocity

of the

time t by:

of the rotor; x, distance from the rotation

ccntre to the

peak on the curve; cS, scatter due to the polydispersity. The AS/t as a function oft is shown in Fig. 2. The slopes of the plots were used to find (TV. One gathers from formula 20.

(3) that the intersection of AZ/t with the ordinate must equal

Figure 2 contains the values of 20 for samples after determination

fusometer;

in the polarizing dif-

one can see good agreement of the values got by the two independent

methods,

596

TAm~sovA et al.

G.V.

w h i c h m e a n s t h a t t h e r e is n o Shape d i s t o r t i o n o f t h e S c u r v e s d u e t o c o n c e n t r a t i o n effects [4]. T h e r a t i o .Mz/Mw~ w h i c h is l i n k e d w i t h ~, b y t h e e q u a t i o n [4]:

.M-7

--

'

(4

w a s u s e d t o c h a r a c t e r i z e t h e p o l y d i s p e r s i t y o f t h e s a m p l e s . . M ~ , Mw are t h e n u m b e r a n d w e i g h t a v e r a g e m o l . w t , r e s p e c t i v e l y ; b e x p o n e n t i n eqn. (6). T h e e x p e r i m e n t a l r a t i o s , .Mz/.Mw, (see T a b l e ) are w i t h i n t h e r a n g e 1.1-1.3 w h i c h is a p o l y d i s p e r s i t y o f e x t r e m e l y n a r r o w p o l y m e r f r a c t i o n s . S u c h a n a r r o w M W D is d u e t o t h e

! Z

•

/0

,y

5 I

I

ZOO0

#000 ]-/me,sec

F I e . 2. T h e s c a t t e r o f t h e s e d i m e n t a t i o n c u r v e s as a f u n c t i o n o f s e d i m e n t a t i o n t i m e f o r t h e s a m p l e s : •--7; 2 - - 8 ; 3 - - 4 ; 4 - - 2 .

logSo

Iog.Po

~G

2

.

//. I

4"5

I

5"0

I

f2.5 log Ms~v

4.5

I

I-

E

5-5

logMs~ Fro. 4

FIG. 3

F I e . 3. T h e d e p e n d e n c e s of: 1--Do; 2--So, o n t h e MSD o f t h e P I A s o l u t i o n s i n D M F . a

F~o. 4. T h e i n t r i n s i c v i s c o s i t i e s o f t h e P I A s o l u t i o n s in: 1 - - D M F ; 2--MP, as f u n c t i o n s o f .Ms/)

•

Polyimidoamide naaeromolocules

597

use of the imido-containing monomer in the PIA synthesis which eliminates any secondary reactions. The mol.wt, of tim investigated samples were determined from the Svedberg formula [2]: RT So

in which R is the universal gas constant; T absolute temperature; p, solvent density, ~, partial specific volume equalling 0.76 cm3/g. The found MSD are contained in the Table. The optical anisotropy of the polymer melccules was determined by dynamic birefringence in an instrument having a rotor length l = 30 mm and a 0.3 mm slit [2]. Samples having mol.wt, of 51-3 × l03 and 103 × l02 had a reduced birefringence An/A~ = 68 × 10~° (see Table; Av is the shear stress at finite solution concentration; An, birefringence). RESULTS

T h e t a b u l a t e d results show t h a t the P I A s a m p l e s h~ving mol.wt, in t h e r a n g e (30-180) X 103 h a v e u n u s u a l l y n a r r o w M W D . W e e x a m i n e d t h e r e f o r e s a m p l e s as f r a c t i o n s of a series of p o l y m e r homologues. T h e correctness of this a p p r o a c h was confirmed b y t h e f a c t t h a t a M a r k - K u h n - H o u w i n k t y p e correlation e x i s t s b e t w e e n t h e Do, So, [~] a n d MSD values. T h e D a n d S values are p l o t t e d a g a i n s t the mol.wt, in double l o g a r i t h m i c c o o r d i n a t e s in Fig. 3; these p l o t s are described by: 7lAr--0.55

Do---- 1"12 X 10 -a ~v~ s ~ So:

1.78 X 10 -15 ~vlTIAr-°'45SD

(6)

T h e intrinsic viscosities o f t h e P I A in D M F a n d M P as a f u n c t i o n of t h e MSD a r e i l l u s t r a t e d b y Fig. 4 (double l o g a r i t h m i c scale); it shows t h e M a r k - K u h n - H o u w i n k correlations to a p p l y again, a n d one can t h e r e f o r e write: ~0.86 [ q ] = 0 . S 1 4 × 10 -~ ~v~ so (in D M F )

(7)

~,0.86

[ t / ] = l . 0 6 × 10 -2 ,/11 SD (in MP) T h e large e x p o n e n t s in eqn. (6) a n d (7) could in principle reflect either a higher rigidity of t h e P I A m a c r o m o l e c u l e s , or t h e r m o d y n a m i c n o n - i d e a l i t y o f t h e i r solutions in D M F or MP. T h e equilibrial r i g i d i t y was t h e r e f o r e w o r k e d o u t a c c o r d i n g to t h e t h e o r y for p e r s i s t e n t p o l y m e r chains which considers t h e p e r m e a bility of t h e molecules [6] as well as according to t h a t p e r m i t t i n g a d e t e r m i n a t i o n o f chain size w h i c h considers b u l k effects [7]. T h e d e p e n d e n c e of DoMsD/RT on MtsD is s h o w n for t h e D M F solutions of P I A in Fig. 5. According to t h e progressive friction t h e o r y for semi-rigid m a c r o m o l e c u l e s [6] this d e p e n d e n c e is described b y the equation:

RT

-- 3 ~ o N A \ 2 A : ]

M÷+(3n"°NA)-I

In -d--

'

in which M o is t h e mol.wt, of the m o n o m e r unit, 2, p r o j e c t i o n of t h e m o n o m e r

598

TARASOVA et al.

G.V.

unit length in main-chain direction; d, effective chain diameter; ~/0, solvent viscosity; NA, Avogadro number, and Am, Kuhn's statistical segment. The equilibrial rigidity of the polymer chains characterized by the length of the K u h n segment can be determined from eqn. (8). The K u h n segment length which ig/

1o

8

1

F~G. 5. ~_e

r

dependencesof: 1--DoMso/RT; 2--kT]D~M~D, on

M~o for D M F solutions o f

PIA.

considers the non-ideality of the solutions can be found according to the CowieBywater theory [7] from the distance cut off the ordinate by the response line when plotting kT /Am 2\ Do~D=PYlo~--~-o ) +0"201rloPB (Am)-2 MiD, (9) in which k is the Boltzmaan constant; P, hydrodynamic constant=5.2; and B, effective occluded volume. The plot of kT/DoM~D against M~D is reproduced in Fig. 5. One gathers from eqn. (8) and (9) that it is essential to know the projection of the monomer unit in the direction o f the fully stretched chain, 4, in order to determine the length of the K u h n segment. The determination of ~ was made on the basis of the model shown in Fig. 6. The molecular chain is found to consist of two alternating, rigid and linear segments (ll and 12) which are joined to each other at angles 01----120° and 02----150° when the difference between the valence angles on the C and N atoms in the amide groups is neglected. One gets on the basis of the known X-ray data for the phthalimide and phthalamide groups and also from the known length of the C--O bond t h a t 11~ 15.46 and/~----9.24 A.

( 01 ~) =22.15 A. T h e

The value of ~ calculated from A----½(/1-~-/2) sin ~ - + s i n

length of the K u h n segment determined from eqn. (8) was found to be 50 A and f r o m eqn. (9) 43 A which agrees with the Am values typical of semi-rigid macromolecules. There is relatively good agreement between the K u h n segment length

rolyimidoamide macromolecules

599

-obtained by various theories and this is evidently due to the small sensitivity of constant P to bulk effects. Constant P depends however to some extent on chain r~gidity and P < P 0 = 5 . 2 in the case of semi-rigid molecules [8]. This condition causes the value of A to be too low when the Cowie-Bywater theory is used. More reliable is therefore a A ~ = 5 0 -~ which was got by using the progressive friction theory with the semi-rigid chains. 0

.o

/(_.)J

\x/

D

1

FIG. 6. Schematic illustration of the, molecular chain of tZlA. For this length of the segmeIlt in semi-rigid molecules one gets a number of monomers S = A m l I ~ 2, which is normally the case for chain of critical flexibility. Such a large flexibility is evidently associated with the independent and only slightly hindered rotations of the long bonds around the O atoms, which agrees with the theoretical calculations [9] and other experimental results [10, 11]. The specific birefringence is however substantially larger than t h a t found for the usual flaxible polymers. The Gaussian coil model was used to calculate the optical anisotropy because the reduced birefringence was the same for samples having mol.wt, of 51-3 and 103× 103 (see Table). The optieaA anisotropy ~--a,, was determiued from the K n h n formula [2]; it is the sum of the specific anisotropy of the segment plus t h a t of the micro-shape (the refractive index of the polymer differs from t h a t of the solvent). The consideration of the latter yield on the basis of the existing theories the specific segmental anisotropy ( ~ - - ~ ) ~ = 630 × 10 -t~ cm ~ (all--a±):

(~1--~2)e . . . s

.

630× 10 -25 . . 2.5

250 × 10 -25

The monomer unit contains 4 benzene rings (or 4 phthalamide groups); the average anisotropy attributable to the ring is therefore 60 × 10 -25 cm 3. This value agrees with t h a t found for the monomer unit of polybenzamide [10]. The authors wish to t h a n k S. Ya. Frenkel' for his participation in the criticism o f the results. Translated by K. A. ALL~

600

N . V . AULOVA et al. REFERENCES

1. V. A. G U S I N S K A Y A , 1VI. M. KOTON, T. V. BATRAKOVA and K. A. R O M A S H K O V A ,

2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Yysokomo1. soyed. A18: 2681, 1976 (Translated in Polymer Sci. U.S.S.R. 18: 12, 3062, 1976) V. N. TSVETKOV, V. Ye. ESKIN and S. Ya. FRENKEL, V kn.: Struktura makromolekul v rastvorakh (In book: Macromolecular Structure in Solutions). "Nauka", 1964 S. I. KLENIN, V. N. TSVETKOV and A. N. CHERKASOV, Vysokomol. soyed. A9: 1433, 1967 (Translated in Polymer Sci. U.S.S.R. 9: 7, 1604, 1967) P. N. LAVRENKO, A. A. GORBUNOV and E. U. URINOV, Vysokomol. soyed. A18:: 244, 1976 (Translated in Polymer Sci. U.S.S.R. 18: 1, 285, 1976) G. SCHULZ and F. BLASCHKE, J. prakt. Chem. 158: 130, 1941 J. HEARST and W. STOCKMAYER, J. Chem. Phys. 37: 1425, 1962 G. COWIE and A. BYWATER, Polymer 6: 197, 1965 O. B. PTITSYN and Yu. E. EIZNER, Vysokomol. soyed. 3: 1863, 1961 (Not translated in Polymer Sci. U.S.S.R.) T. M. BIRSHTEIN, Vysokomol. soyed. A19: 54, 1977 (Translated in Polymer Sci. U.S.S.R. 19: 1, 63, 1977) V. N. TSVETKOV, G. I. KUDRYAVTSEV, Ye. I. RYUMTSEV, V. Ya. NIKOLAYEV et al., Dokl. Akad. Nauk SSSR 224: 398, 1975 N. A. GLUKHOV, T. I. GARMONOVA, V. S. SKAZKA, S. V. BUSHIN, et al., Vysokomol. soyed. B17: 579, 1975 (Not translated in Polymer Sci. U.S.S.R.)

Polymer Science U.S.S.R. Vol. 21, pp. 600-605. (~) Pergamon Press Ltd. 1979.Printed in Poland

0032-3950/79/0301-0600507.50101

THE REACTIVITIES OF OLIGOMERS BASED ON AROMATIC HYDROCARBONS AND FORMALDEHYDE* N.

V. AULOVA, E . D. ARSEN'EVA, N . P . GASHNIKOVA a n d T. I. KRUPENINA. All-Union Research a n d P]anning I n s t i t u t e for Electrical Insulations and Non-conducting Foils (Received 15 February 1978)

The results are presented of the study of the composition, structure and of some of the properties of reactive oligomers based on aromatic hydrocarbons of formula P h - - X - - P h ( X : O , S, CHp, CHp--Cttp) and formaldehyde. The chemical reactivity of these substanccs in a n acid medium in the presence of an active diluent has shown the aromatic hydrocarbons to be arranged in the following sequence of descending chemical activity: diphenyl e t h e r - - d i p h e n y l s u l p h i d c - - d i t o l u y l m e t h a n e - - d i b e n z y l - diphenyl. The most reactive amongst the ditoluylmethane isomers were the o- and /)-isomers. Branched oligomers formed in addition to linear ones and most branched * Vysokomol. soyed. A21: No. 3, 548-552, 1979.