Polyorganosiloxanes with linear and cyclic segments

POLYORGANOSILOXANES WITH LINEAR SEGMENTS *

AND

CYCLIC

K. A. ANDRIANOV, V. S. TIKHOI~OV, I. YI~. KLEMENT'EV and M. N. ROZHNOVA M. V. Lomonosov I n s t i t u t e of Fine Chemical Technology, Moscow

(Received 2 February 1976) H y d r i d e transfer to the trieyclic siloxane compound, i.e. 1,7-dimethyl-l,7-divinyl-3,5,9,11-tetraphenyltricyclohexamethylsiloxane, from the a,co-mothylphonylsiloxano dihydrido and the ~,to-dimethylsiloxane hydride oligomers yielded polymers with linear-structure polydiorgano- and polycyelosiloxano segments. H y d r i d e transfer reaction between diallyl isophthalato and the ~,co-dimethylsiloxane dihydrido oligomers yielded polymers containing molecules with linear siloxano and aromatic segments. The glass temperatures (Tg) were determined for all the produced polymers. The larger the contents of tricyclic siloxano a n d also of aromatic segments in the linear siloxano chains, the larger were the Tg. The TGA of the polymers showed their resistance to thermal-oxidative degradation to increase with the content of tricyclic siloxane segments and to decrease as the content of aromatic segments increased in the linear siloxane chain.

THE hydride addition reaction is a method suitable for the production of polymers with a specific macromolecular chain structure [1]. It yielded new polymers containing polycyclic and linear organosiloxane segments in the structure. One of the starting reagent was the crystalline 1,7-dimethyl-l,7-divi~ayl-3,5,9,11tetraphenyltricyclosiloxane (TS), i.e. a tricyclic compound which had been produced earlier [2]. The presence of two vinyl groups in it made possible its use in hydride poly-addition reactions with ~,o~-diorganosiloxane dihydrides C6H5

C6H5

L

Si CHa

\

/

-Si

0

0

5i C H2=C H

I

G

0 0

O

\ "0

/

/

I

~

0

\

CH=CH2

C8H5

CHs \

CHs

I

~

I

I

/

I

-4- H - - S i O - - [ - - S i O - - ] - - S i - - H CHs

+

l

C6Hs

I

CH8

Si

I

CHs

/ Si

/ Si

\

R

/ n CHs

* Vysekomol. soyed. A18: lifo. 10, 2288-2292, 1976. 2618

HzPtCl ~ -

Polyorganosiloxanes with linear and cyclic segments ,

~c.~ OH= @

[

~Ha /

261~

(~H3 ~ ~ H3

'CH~--,~--|--.~iO--t--SiO-L CIHa \

R

/n]--~i--(CH')'--CH,

(CH2)2--/--SiO--(--SiO-- I--Si--H / I ~, I / I AmCHa \ B / n Clta in which R = C s H s - - p o l y m e r I (with chain unit numbers n = 6 , 23, 40, and 74); R----CHa--polymer I I (n----0, 10, 19, 49, and 86). The reaction was carried out at 70°C in toluene (60~/o reagents concentration); the catalyst was a 0.04 M platinum hydrochloric acid solution in T H F at 0.01% w/w of reagents. The reactive hydrogen content present in the reaction mixture was used to check the reaction progress. The process and conversion rates were found to depend greatly on the length of the original e,e)-diorganosiloxane dihydride, as Fig. 1 shows. 5d

I 1

0

I Z

Time, M

FIG. 1. Hydride addition reaction as a function of time for: 1, 2--a,eo-methylphenylsiloxano dihydrides; 3, 4--a,co-dimethylsiloxane dihydrides, with TS. n values: 1--40; 2--23 3--86; 4--0. The temperature was gradually raised to 170°0 as soon as the reaction rate dropped to attain the highest possible conversion (85-95~o). The specific viscosity of 1% toluene solutions increased as a result. The process conditions and theexperimental yields of polymers I and I I are listed in Table 1. *

C,HI

=_;\/

Cdls

CHs 0

ell3

0

o

°l\

i I C6H5

si

o

,

Io/'/

s~ I C6Hb

2620

K.A.

A2cmtL~ov et a/.

The I R spectra of the polymers were free from the 2140 cm -1 absorption line characterizing the S i - - H group, but also of the 720, 750 and 980 cm -1 lines which are typical for the original TS and belong to the deformation oscillations ~)f the C - - H valence bonds of the vinyl group. T h e r e remained however the 1000-1100 cm -I absorption lines which are typical for the siloxane bonds of the original compounds. TABLE 1. THE S ~ E S I S

CONDITIONS AI~'D SPECIFIC VISCOSITIES OF POLYM'~.R8

IAZ~D I I The n value of the original siloxane dihydride

Hreact,

% w/~

0.077 0.028 0.019 0.011

6

23

40 74

0.147 0.075 0.054 0.027 0.017

0

10 19 49 86

H,PtCIe Xl0 s, mole/mole

lr-/react

% Conversion

T y p e I polymers 0.35 0-76 1.2 2.1

96 91 98 92

Type I I polymers 0.16 95 0.30 82 0-43 93 0-86 78 1.39

90

Spee. viscosity of a 1% solution initial I final 0.012 0.030 0.038 0.041

0.079 0.088 0.090 0.099

0.005 0.015 0.076 0.116 0.120

0.047 0.147 0.162 0.209 0.222

All the polymers were viscous fluids (with the exception of that based on ¢etramethyldisfloxane, which was a solid). We also investigated the hydride addition reaction between a,co-dimethylsiloxane dihydride oligomers and diallyl isophthalate in the absence of solvent but otherwise under identical conditions. Table 2 gives the process conditions a n d the spec. viscosities of this group of polymers produced; t h e y are incorporated in group III. Some of the physico-chemical characteristics of all 3 polymer groups were determined. TABLE

2. T H E

SYI~THESIS CONDITIONS AND SPECIFIC VISCOSITIES OF TYPE

III

POLYMERS

The n value of [ the original silo- Hreaet' xano dihydride % w/w

0 I0

]

0.530 0-173

19 49 86

I

0-112 0"050 0"029

H2PtC18 × 103, mole/mole

% Conversim

Hreact

0.38I 0.224 0.034 0.039 0.065

97 97 87 93 86

Spec. viscosity of a 1% solution initial final 0-005 0.015 0.076 0-116 0-120

0.041 0"096 0"170 0"208 0-223

Polyorganosiloxanes with linear and cyclic segments

2621

Figure 2 shows the temperature dependence of the Tg on the length of diorganosiloxane chain segments. One can see that shorter linear segments, i.e. a larger proportion of tricyclie ones in the linear chain, raised the Tg of polymers I and II. This seems to be associated with the rigid segments reducing the molecular mobility. A similar effect was also detected in the case of polymers III. I t should be noted that the Tg of all 3 types only altered visibly in the range of smaller n values. An increase of n from 0 to 6 in polymers I for example caused the Tg to drop from 47 to --7°C, while a further increase in n to 74 caused it to drop only to -- 18°C.

50

~-~/0

JO

500 ~'60 4ZO 380 J~o JO0

0 fo

JO

50

70

,90

r

I

i

i

I

0/0

JO

50

"10

90 n

n

FIG. 2

FIG. 3

FIO. 2. The Tg depenctonco for polymers I-III as a function of polycUorganosiloxano segment length (n values). F~G. 3. The temperature at which a 15% weight loss is roached (Tls) for polymers I-III as a function of the polydiorganosiloxane segraent length (n values). An increase of the length of the di-organosfloxane segment, i.e. a reduction in the number of tricyclic segments present in polymer s I and II, greatly reduced their resistance to thermal-oxidative degradation, as Fig. 3 shows. For example, a polymer containing alternating tetramethyldisiloxane and tricyclic segments (n~-0) showed a 15% weight loss at 540°C, while an increase of the first segments in polymer I to 74 and in I I to 86 caused such a weight loss even at 380 and 420°C respectively. This dependence is the reverse in type I I I polymers (Fig. 3), i.e. the resistance to thermal-oxidative degradation increases when the number of aromatic segments b y weight increased in the polymer structure. The polymer containing

2622

ANDRIANOV et al.

K.A.

tetramethyl disiloxane segments showed a 15% weight loss at 290°C while one with dimethylsiloxane chain units and n = 8 6 only showed it at 410°C. TABLE 3. SOME

OF THE CHARACTERISTICS

OF DIORGAlqOSILOXAI~E

DIHYDRIDES

n~°

i I

Mol. w t found from reactive H

calculated

~, ~-Methylphenylsiloxane dihydrides 6 23 40 74

1.5038 1.5431 1-5469 1.5471

930 3260 5650 10,180

952 3274 5584 10,124

~-Dimethylsiloxane dihydrides I0 19 49 86

1.4018 1.4037 1.4060 1.4060

910 1560 3790 6550

876 1544 3764 6506

EXPERIMENTAL Tg were determined on a Kargin balance at a constant 50 g stress and a 7°C/min temperature gradient. The accepted value was t h a t point at which the projection of the peak on the deformation curve on to the abscissa intersected t h e latter. i torsion balance at an average 5.6°C/rain temperature gradient was used in the TGA. 1,7 -Dimethyl - 1,7 -divinyl- 3,5, 9,11 -tetraphenyltricyclohexasiloxano was produced by a published m e t h o d [2], a,~o-methylpbenylsiloxane dihydrido oligomers by reacting the respective sodium hydroxide derivatives [3] with dimethylehlorosilano in benzene at 20-60°C. Th e sodium chloride precipitate was removed by filtration and the filtrate washed with w a t e r t o neutral reaction, after which the washed benzene layer was filtered through a paper filter. Th e solvent was then evaporated and the residue dried under v a c u u m to constant weight. T h e ~,¢o-dimethylsiloxane 4ihydrides were produced by the same method. Some of t h e oligomer characteristics are contained in Table 3. The hydride poly-addition reaction was as follows: I n t o a three necked flask fitted with a stirrer, reflux condenser, calcium chloride tube and thermometer were added 4.60 g o f the methylphenylsiloxane dihydride having n = 6, under intense stirring; this was followed by the addition of 3.40 TS in 6.15 ml dry toluene. The reaction mixture was heated to 70°0 a n d 0.008 g H,PtC1, in 40 ml T H F were added. The reaction progress was checked b y tracing the spec. viscosity of 1 ~o toluene solutions of the product, but also determining t h e H r e a c t . conten*5 (in a Tserevitin apparatus using alcoholic :bTaOH). As soon as the reaction rate showed a distinct drop, the temperature was raised stepwise to 110 and t h e n to 170°C. The final conversion, assessed from the Hreac t content, was 96~o. The [q] of t h e polymer was 0.089 dl/g. The same m e t h o d was used to react the TS and the diallyl isophthalate with other siloxane dihydrides. The diallyl isophthalate was freshly distilled before use; its b . p . = 153155°C/10 m m Hg .

Translated by K. h..~T,T,I~,I/~

Molecular mobility and free volume changes in e p o x y polymers

2623

REFERENCES 1. A. A. ZHDANOV, K. A. ANDRIANOV and A. P. MALYKHIN, Dokl. Akad. N a u k SSSR 211: 1104, 1973 2. K. A. ANDRIANOV, I. Yu. KLEMENT'EV, B. D. LAVRUKHIN and V. S. TIKHONOV, Zh. obsheh, khim. 45: 2658, 1975 3. K. A. ANDRIANOV, M. A. SIPYAGINA, N. P. GASKNIKOVA and Z. M. FROLOVA, Izv. Akad. N a u k SSSR, Neorg. Mat. 1: 1441, 1965

MOLECULAR MOBILITY AND FREE VOLUME CHANGES IN EPOXY POLYMERS IN THE PRESENCE OF PLASTICITY SUPPRESSORS * V. G. K~ozi~, A . G. FARRAKHOV, V. A . CHISTYAKOV, V. P . PROKOP'EV

and V. A. VOfiKRESENSKII Constructional Engineering Institute, K a z a n S. M. K i r o v I n s t i t u t e of Chemical Technology, K a z a n

(Received 6 February 1976) Study of the changes in free volume a n d molecular mobility in poly-epoxido mixtures with diphenyl or its chlorine derivatives has shown that these additives

reduce these properbies more strongly than a molecular plasticizer (dibutyl phthalate). Increasing the chlorine content of the diphenyl chlorides results in a stronger suppression of plasticity. The mechanism of the latter process is being examined here and also the nature.

THE term "antiplasticization" (plasticity suppression) was proposed f o r the increases in strength, and elasticity modulus, and for the simultaneous reduction o f deformational fracture and specific impact viscosity, when some aromatic low molecular weight (mol.wt.) rigid additives are used in rigid chain polar polymers [1]. As antiplastification happens on adding fairly large amounts (30-40% w/w) of miscible low mol.wt, additives, i.e. the antiplasticizers, which reduces the glass temperature Tg and the molecular mobility, these effects cannot be ascribed to the known effect of "small additions" of a plasticizer and the consequent improved orientation of the polymer chains [2]; however, the disappearance of this effect in the highly elastic state [3] and also when large quantities are added (60-70% w/w), as well as the absence of any chemical reactions in the system, make antiplastification appear to be one of the general characteristics of polymer plasticization. * Vysokomol. soyed. A18: No. 10, 2293-2298, 1976.