The structure and properties of linear and branched polychelatetitanodimethylsiloxanes

Linear and branched polyehelatetitanosiloxilanes

1755

CONCLUSIONS

(1) P o l y m e r s of a new t y p e h a v e b e e n s y n t h e s i z e d for the first time, n a m e l y poly-fl-hydroxyvinyl-N-alkylcarbamates: --CH-- - CH-Oil CONHR where R = C H ~ , C2H5, n-C4Hg, n-C6HI~, n-C10H21, f l - h y d r o x y e t h y l a n d eyelohexyl, a n d also p o l y - f l - h y d r o x y v i n y l - N - N - d i m e t h y l e a r b a m a t e . (2) T h e s t r u e t u r e of t h e p o l y m e r s was p r o v e d b y c o m p a r i s o n of their i n f r a r e d s p e c t r a w i t h t h e s p e c t r a of corresponding m o d e l f l - h y d r o x y e t h y l - N - a l k y l e a r b a m a t e s . (3) Some t h e r m o m e e h a n i e a l a n d p h y s i e o m e e h a n i e a l p r o p e r t i e s of the p o l y m e r s were d e t e r m i n e d (glass t e m p e r a t u r e , film s t r e n g t h , s e d i m e n t a t i o n , solubility a n d v i s c o s i t y of solutions). (4) I t was s h o w n t h a t t h e p o l y m e r s possess film f o r m i n g properties. Translated by E. O. PHILLIPS REFERENCES

I. N. D. FIELD and Y. R. SCHAEFGEN, J. Polymer Sci. 58: 539, 1962 2. S. S. SKOROKHODOV, S. E. LEVIN and A. L. SHAPIRO, Khimich. volokna, 4: 1, 1963 3. R. DELABY et al., Compt. rend. 234: 2374, 1952; B.P. 689705, 1953; Chem. Abs. 48: 7055, 1954 4. I. TABUSHI and R. ODA, :Nippon Kagaku Zash. 84: 162, 1963 5. U.S.P. 2930779, 1960; RZhKhim., 4P234, 1962; U.S.P. 3063391, 1962; Chem. Abs. 58: 8112, 1963 6. E. A. GLAZUNOV et al., X nauchn, konf. IVS An SSSR. Tezisy dokl. (Tenth Scientific Conference of the Institute of Macromoleeular Compounds, U.S.S.R. Academy of Sciences. Report summaries.) p. 14, 1963 7. A. SIMON and G. HEINTZ, Chem. Ber. 95: 2333, 1962 8. A. B. THOMAS and E. G. ROCHOW, J. Amer. Chem. Soc. 79: 1843, 1957

T H E S T R U C T U R E A N D P R O P E R T I E S OF L I N E A R A N D B R A N C H E D POLYCHELATETITANODIMETHYLSILOXANES* K . A. ANDRIANOV a n d I . A. LAVYGIN Institute of Heteroorganic Compounds of the U.S.S.R. Academy of Sciences (Received 19 October 1964)

T H E increased i n t e r e s t s h o w n a t p r e s e n t in seeking new m e t h o d s of s y n t h e s i s a n d s t u d y of p r o p e r t i e s of p o l y e l e m e n t - o r g a n o s i l o x a n e s is due to t h e f a c t t h a t b y introd u c t i o n in t h e molecular chain of p o l y o r g a n o s i l o x a n e s of a t o m s of v a r i o u s e l e m e n t s * Vysokomol. soyed. 7, No. 9, 1585-1591, 1965.

1756

K. A. ANDRIANOVand I. A. LAVYGIN

such as aluminium, titanium, boron, tin, etc., the properties of the polymers obtained can be varied within a wide range. This paper describes the physico-chemical properties of liquid polychelatetitanosiloxanes of linear and branched structure in comparison with linear polydimethylsiloxanes (PMS), the properties of which are described in the literature with sufficient detail. The study of the dependence of viscosity on temperature aroused particular interest since the attention of scientists was drawn to the low temperature coefficient of viscosity of polyorganosiloxanes, a property of great theoretical and practical interest. H u r d [1] has studied the physico-chemical properties of low-molecular weight linear and cyclic PMS. Hunter et al. [2] investigated several liquid PMS with trimethylsilyl end groups a molecular weight of up to 26,000. Gordon [3] in his paper considered the dependence of PMS viscosity on the rate of shear. Studies by Wilcock [4] and Barry [5] in which the physico-chemical properties, including viscosity, of PMS are investigated and a review of this problem by Warrick, H u n t e r and Barry [6] should be mentioned. All scientists note the direct relationship between viscosity and molecular weight, whereas specific gravity, refractive index, activation energy of viscous flow increase up to certain molecular weights, after which they remain constant in practice. In the paper proposed two polymeric homologous series of polychelatetitanosiloxane oligomers were investigated: a) linear structure of general formula

CH3 \.2 CHs I (CH3)~SiO(SiO)n Ti CHa /,.,% (OSi).OSi(CI-Is)a,

where n = 15, 60, 98, 170, 350; b) branched structure V% !1 / CH3 ~O N

I

\/

CH3

I

(CHs)3SiO(SiO)n Ti (OSi)nOSi(CH3)~, CIH8 I CH3 [OS}(CH,h]~ OSi(CH3)a where n = 1 0 , 15, 98, 136, 170.

1757

Linear and branched polyehelatetitanosiloxilanes

To substitute "unnecessary" valencies for titanium, 8-hydroxyquinoline was selected which, as pointed out b y the authors of papers [7, 8], forms a thermally and hydrolytically stable intramoleeular complex compound with titanium. For comparison, we studied the properties of five linear PMS specimens with trimethylsilyl end groups and molecular weights of 1410, 2800, 12 130, 13 900, 53 950. Molecular weights were determined by a viscometric method in toluene solution using constant K = 2 . 1 5 x 10 -4 and ~=0.65 [9]. We found that for polychelatetitanosiloxanes, as also for PMS, an inverse linear relationship between specific gravity and temperature is typical (Fig. la and b). Specific gravity was measured in 0.5-2 ml pyknometers over a temperature range of 20--70 ° . Temperature variations in this case did not exceed 0.05 ° .

a

~

b

32

3"98

i)94

990

i

20

I

!

4O

i

E

80

i

T, oc

030

~

k

20

r

L

40

I

l

60

k

T,°C

8O

FIG. 1. Dependence of specific gravity on temperature: a--for branched, b--for linear oligomers, a: 1--n=15, 2--n=98, 3 - - ~ = 1 3 6 , 4 - - n ~ 1 7 0 ; b : l - - n = 1 5 , 2--n=60, 3--n=98, 4--n=170, 5--n=350.

In Figure 2, where the dependence of specific gravity at 20 ° on molecular weight is illustrated, it can be seen that for PMS specific gravity increases in the range of low molecular weights. For polychelatetitanosiloxane oligomers an inverse relation is typical. In the range of molecular weights above 20,000 the specific gravities of all compounds studied asymptotically approximate to the same constant value. The increase of specific gravity with the reduction of molecular weight of the polychelatetitanosiloxanes is probably due to the effect of polar 8-hydroxyquinolinetitanooxane groups. With increased concentration of the latter, the molecular interaction and density of molecular packing increases. The considerable associative forces in this case overcome the loosening effect of braching on packing density. The temperature coefficient of specific gravity in all the series of polymeric homologues studied has a tendency to decrease with increased molecular weight.

1758

K.A. ANDRIANOVand I. A. LAVYGIN

We h a v e s t u d i e d the d e p e n d e n c e of viscosity on t e m p e r a t u r e for the above c o m p o u n d s a n d calculated the a c t i v a t i o n energy of viscous flow, one of the import a n t c o n s t a n t s which characterizes molecular interaction, on which d e p e n d such properties of liquids as viscosity, t h e r m a l c o n d u c t i v i t y , diffusion coefficient, vapour pressure, evaporation, etc.

1.g2 ~

$g8

1

x

o

ggq' I

3

5 Mol.~C..xlO-4

F~G. 2. Dependence of specific gravity (d~o) on molecular weight: /--linear oligomers, 2--branched oligomers, 3--PMS.

z¢O,

2egg a

b

/800~

¢800

6gO

g

qO

80

~20

,°c t5g

~/0

80

/zg

~°C t50

FIO. 3. Dependence of kinematic viscosity orL temperature: a--for linear, b--for branched oligomers, a: 1 - - n ~ 15, 2 - - n = 60, 3 - - n = 98, d - - n = 170; b: 1--n~-- 15, 2--n=30, 3--n=98, 4--n-~136, 5--n=170. Figure 3a a n d b presents curves showing the d e p e n d e n c e of viscosity on t e m p e r a t u r e for linear a n d b r a n c h e d oligomers in t h e t e m p e r a t u r e range of 0-160 °. I t can be seen in the figure t h a t , with increased molecular weight the viscosities o f b o t h

Linear and branched polychelatetitanosiloxilanes

1759

types of oligomers increase. The effect of structure of the compounds studied on viscosity can be seen in Fig. 4 where the dependence of dynamic viscosity on molecular weight is shown. In the range of low molecular weights (to 15,000) PMS is the least viscous. The viscosity of linear po]ychelatetitanosiloxanes is higher and t h a t of branched polychelatetitanosiloxanes even higher. The high viscosity which is abnormal in this case is apparently due to the molecular interaction which has increased because of the effect of 8-hydroxyquinolinetitanooxane groups. I t can also be added t h a t an oligomer of branched structure with a polymerization coefficient n== 10 (molecular weight 2700) does not flow at room temperature. q, cp Z q00

1800

f200

# / 800

!

fO

20

F/o/.wt. x/O-3

30

FIG. 4. Dependence of dynamic viscosity on molecular weight: 1--branched oligomers, 2-- lirLear oligomers, 3 -- PMS. In t h e range of high molecular weights (over 16,000) the effect of 8-hydroxyquinolinetitanooxane groups decreases and the effect of the structure of the compounds studied on their viscosity becomes apparent. In fact, of equal molecular weight, the viscosity of branched oligomers is lower t han t h a t of linear ones, whereas the viscosities of linear oligomers and PMS are approximately the same. I t was found t h a t the logarithm of viscosity has a linear relation to the reciprocal of absolute temperature both for branched and for linear oligomers in the temperature range of 0-160 °. A linear oligomer with n = 15 is an exception for which this relation is disturbed at temperatures below 70 ° . At temperatures ranging from 70 to 160 ° all the oligomers studied are thus " n o r m a l " liquids. I t appeared to be possible to calculate for t he m their activation energy of viscous flow according to the formula ~/-~ A e Q/RT

1760

K.A. ANDRIANOVand I. A. LAVYGIN

where q is viscosity, A is a constant in the temperature range studied, Q is the activation energy of viscous flow, R is the universal gas constant, T - - a b s o l u t e temperature. The character of the dependence of activation energy of viscous flow on molecular weight (Fig. 5) is reminiscent of the dependence of specific gravity on this parameter. In the range of low molecular weights the activation energy of viscous flow for PMS increases and for polychelatetitanosiloxane oligomers decreases; for branched oligomers it is somewhat higher than for linear ones. With increased molecular weight the activation energy asymptotically approximates to a constant value.

~,kc~l/mole Z3 q'8 ~ _ _ J'8 /0 I

~o

Ja

/v/O/.v~. xyO"'~

FIG. 5. D e p e n d e n c e of t h e a c t i v a t i o n energy of viscous flow oi1 molecular weight: 1 - - P M S , 2 - - l i n e a r oligomers, 3 - - b r a n c h e d oligomers.

It can also be seen in Fig. 5 that the apparent flow value of a segment for PMS is in the molecular weight region of the order 6-7000, whilst for polychelatetitanosiloxanes it is displaced to higher molecular weights (of the order of 10-12,000). This indicates that the 8-hydroxyquinoline group increases rigidity on being incorporated into the siloxane chain. The relation between viscosity and specific volume was first expressed b y Batschinski [10] in the well known equation C V--o) where ~/is viscosity, C and ~o are constant values, V is specific volume. The value of co is also termed the critical or fixed volume and represents a certain intermediate value between the specific volume of the liquid V1 and of the solid substance, Vso •

V=o~C~,

I t follows from Batschinski's equation that where ~ is flow. For all the oligomers and PMS investigated the dependence of specific volume on flow is linear in the temperature range of 20-70 ° . I t can be seen in the Table that the constant increases regularly with increased molecular weight in each polymeric homologous series and m decreases (the latter relation is only disturbed in two

Linear and branched polychelatetitanosiloxilanes

1761

PHYSICO-MECHANICAL CONSTANT OF POLYCHELATETITAI~'OSILOXANES AND POLYDIMETHYLSILOXANES i

I

M(~an ,, eoeffi(:ient of i polvnaerization

Molecular weight

d~ °

Temperature coefficient of sp. g r a v i t y , b x 103

20 ~t D

10 15 98 136 170

2 3 22 30 38

680 800 050 700 240

Branched polychelatetitanosiloxancs 1.015 1.4287 0.9832 1.2400 1.4204 0.9801 1.2250 1.4084 0.9793 1.2016 1.4070 0.9790 1-4052

15 60 98 170 350

2 9 15 25 52

740 400 030 700 370

Linear polychelatetitanosiloxanes 1.0179 1.256 1.4408 0.9837 1.266 1.4091 0-9831 1.240 1.4089 0.9799 1-206 1.4077 1-4050

1 410

2 12 13 53

810 130 900 950

P o l y m e t h y l s i l o x a n e s (PMS) 0.9601 1.2840 0.9681 1-2466 0.9733 1-2616 ~1 0.9762 1.2540 I 0.9780 1.1880 I

C

9'996

28"392 48-810 103'504

1.4011 1.4025 1.4032 1-4035 1-4038

(9

0.995 0.985 0.982 0-980

4.0986 13'6753 18.7759 68.9762

0.965 0.980 0.978 0.974

1.2243 2.I653 13.8681 19.4505 4392.2706

0'993 0.988 0.982 0.980 0.966

cases: for a linear oligomer with n = 15 and PMS with molecular weight of 53,950). A similar relationship between these values was observed by Hurd [1] for low molecular weight PMS. The dependence of free volume (V-m) on molecular weight (Fig. 6) proves the marked effect of polar 8-hydroxyquinolinetitanooxane groups on the density of molecular packing. Actually for branched oligomers the free volume is much lower

5gk

3t

z~

1 /0

20

30

4'0

Mo/.wt. x13-3

FIG. 6. D e p e n d e n c e o f free v o l u m e o n m o l e c u l a r weight: 1 - - b r a n c h e d oligomers, 2 - - l i n e a r oligomers, 3 - - P M S .

1762

K.A. ANDRIANOVand I A. LAVYGIN

than for PMS. For linear oligomers the free volume is somewhat higher t han tbr branched oligomers, but lower t han for PMS. The variation of free volume according to molecular weight is i n satisfactory agreement with the variation of activation energy of viscous flow. CONCLUSIONS

(1) The physico-chemical properties of two polymeric homologous series of polychelatetitanosiloxanes of linear and branched structure have been investigated and their properties compared with those of linear polydimethylsiloxanes. I t was shown t h a t the introduction into the siloxane chain of titanium atoms surrounded b y the 8-hydroxyquinoline group considerably increases molecular interaction which influence the physico-chemical properties of the compounds investigated. (2) I t has been found t h a t t h e the specific gravity, the activation energy v a r y with t e m p e r a t u r e in the range of 20-70 ° . (3) I t has been shown t h a t specific gravity and activation energy of viscous flow and the refractive index of polychelatetitanosiloxanes decrease with increased molecular weight unlike PMS, for which a reverse relation is observed. The free volume of polychelatetitanosiloxanes in the range of low molecular weights is lower t h a n t h a t for PMS. With rise of molecular weight the variations of the properties mentioned decrease. (4) The viscosities of polychelatetitanosiloxanes and PMS increase with rise of molecular weight. I n the range of molecular weights of up to 16,000, the viscosities of polychelatetitanosiloxanes are higher than for PMS. With rise of molecular weight the viscosity of branched polychelatetitanosiloxanes becomes lower t han t h a t of the linear polymer and PMS. Tranolated by E. SEMEll.E REFERENCES 1. C. B. HURD, J. A~mer. Chem. Soe. 68: 364, 1964 2. M. J. HUNTER, E. L. W~LI~RIGK, J. F. HYDE, and C. C. CI.TRRIE, J. Amer. Chem. Soo. 68: 2284, 1946

3. 4. 5. 6. 7. 8.

F. D. A. E. K. H.

GORDON, J. Chem. Engng. Data 6: 275, 1961 WILCOCK, J. Amer. Chem. Soc. 68: 691, 1946 J. BARRY, J. Appl. Phys. 17: 1020, 1946 L. WARRICK, M. J. HUNTER and A. F. BARRY, Industr. and Engng. 44: 2196, 1952 A. ANDRIANOV and Sh. V. PICIIKtIADZE, Vysokomol. soyed. 4: 1011, 1962 H. TAKIMOTO and J. B. RUST, J. Organ. Chem. 26: 2467, 1961 9. A. Ya. KOROLEV, K. A. ANDRIANOV, L. S. UTESHEVSKAYA, T. Ye. VVEDENSKAYA, Dokl. Akad. Nauk SSSR 89: 65, 1953 1O. A. BATSCHINSKII, Z. phys. Chem. 84: 643, 1913