The structure of phenoxy- and phenylacetylene polymers

THE STRUCTURE OF PHENOXY- AND PHENYLACETYLENE POLYMERS * fl-. A. BERLIN, M. I. CHERKASHIN, I. P. CHERNYSHEVA, YU. G. ASEYEV,

u

I. BARKAX and P. P. KISlLITSA

Chemical Physics Institute, U.S.S.R. Academy of Sciences

(Received 19 April 1966) IN Rv.C~,NTyears several papers have appeared regarding the synthesis of polymers based on acetylene and its derivatives [1-4]. It has been established that oligomeric products are formed in all cases, and that these have paramagnetism detectable by E P R and increased electrical conductivity and heat resistance. However the structure of the polymers (structural regularity, arrangement of the substituents in space, and so on) has not yet been elucidated. In this paper an attempt has been made to examine the structure of acetylene polymers using data obtained by thermal and catalytic polymerization of phenoxy- and phenylacetylene, as well as the results of infrared and X-ray analysis. DISCUSSION OF RESULTS

In the phenylacetylene polymers (PPA) obtained thermally and with Ziegler:Natta catalysts in previous investigations [2, 3] the valency vibration of the C = C bond was inactive in the IR spectrum (Fig. 1) owing to high symmetry (with the 60 @r

2O

I

f

800

f

t

I

I

1200

I

k

I

[

i600

t

[

f

[

2000

I r l l l ] r

2000

f If

~ ill

r lift

3000

FIG. 1. Infrared spectrum of PPAZ (NaC1, LiF). * Vysokomol. soyed. A9: No. 9, 1840-1846, 1967. 2075

i]]Jfl

4000

Ill

it

P,cm-~

2076

A.A. BERLIN et al.

trans-configuration of the phenyl groups). I n view of this it was not possible

to make a confident assignment of

I

0 structure for the polymers. However as the I R spectra were completely identical with those of polystyrene (except for the absorption bands due to the vibrations of UI-I~ groups [3]) it could be assumed that P P A is a linear polymer with conjugated double bonds and side phenyl groups. In this paper a study is made of the I g spectra of phenoxyacetylcne polymers (PP03_) obtained with a (C~I-Is)~kl-TiC14 catalyst and also thermally (Fig. 2, 3). It was to be expected that the II~ spectra of these polymers would be mainly 50 z+O

d

30 2O

~0 8O

0 8O 8O

c,o

4O 8O GO

5O

~0 2O GO

El

-

~0 2O fSO0

1400

1000

2000

8000

~000 ~,crn-1

FIG. 2. Infrared spectra of polymers: a--PPOA-I; b--PPOA-S; c--PPOA-v; d--PPOA-v (200~ 6 hr, air). the same as those previously obtained in the polymerization of phenylacetylene, and that the spectra should contain absorption bands due to the vibration of the C - - O - - C bonds. It was also assumed t h a t there would be bands due to the vibrations of the C----C bond caused by the deformation of its electron cloud b y the nearby oxygen atom.

2077

Structure of phenoxy- and phenylacetylene polymers

Figure 2 shows that all the polymers have a polystyrene type of structure. Moreover in all the spectra there are bands at 1220 and 1170 em -1 related to the asymmetrical and symmetrical vibrations of the C--O--C bond (respectively). In the region of the vibration of double bonds there is a band at 1660 cm -1 with an inflexion at about 1650 cm -x (trans-configuration) related to the valency vibration of the C = C bond. The insoluble polymer in contrast to the soluble one is characterized by a considerable background of absorption (~50%). In the region of CH valency vibrations (LiF prism) of the low molecular weight polymer (Fig. 2c) there are the valency vibrations of aromatic CH (3040 cm -x) and = C I t (3065 cm -1) groups and also weak bands apparently due to the vibrations of end methylene groups. In the more high molecular weight products (Fig. 2a and b) there is practically no sign of these bands.

~o ~-

_

d

c

40~ -~'20

b 7O El

0 ~0

1800

1~00

I000

2500

3500

#500 ~,cy1-1

FrG. 3. Infrared spectra of polymers: a--PPOAT-I; b--PPOAT-S; c--PPOAT-v; d--PI~OAT-v (200 ~ 6 hr, air).

The phenoxyacetylene polymers produced thermally (see Fig. 3) have a similar type of structure. The valency vibrations of C = C bonds (though less welldefined) were found in their IR spectra also. The trans-configuration in the polymers was confirmed also by the results of a study of the I1% spectra of cis- and trans-stilbenes. In the cis-stilbene spectrum there is a band at 1620 cm -1 characteristic of the valency vibrations of C = C bonds, while in the spectrum of the trans-stilbene the valency vibration of the C = C bond is inactive (owing to high symmetry). For polyacetylene a trans-configuration of the polyene chain [1, 5] is also characteristic. During the thermal processing of PPOA (Fig. 4) up to 200 ~ both under an argon atmosphere and in air, up to 30% of the phenol splits off and insoluble polymers are formed.

2078

A . A . BERLIN et al.

In the IR spectrum of samples of catalytic I~I)OA heated up to 200 ~ ((Figs. 5-9) there is a considerable absorption background (~70%). With samples of thermal :P1)OA heated up to 200 ~ in argon the absorption background is greater than with the samples heated in air. ~Iowever both types of polymer have absorp-

40

2O 10 0

i

I

2

I

r

0

]

I

t

6'

I

8

77me,hp

FIO. 4. Heat resistance of polymers: 1 - - P P O A - v (250 ~ air), 2 - - P P O A - S (200 ~ air), 3 - - P P O A T - I (200 ~ air), 4 - - P P O A T - S (200 ~ air), 5 - - P P O A T - S (200 ~ argon), 6 - - P P O A T - I (200 ~ argon), 7--PPOA-S (200 ~ argon). e

80

h

2O ~0 2O 1

2000

t

]

7800

1

T

/200

I

i

800 ~,cm-r

FIG. 5. Infrared spectra of polymers hetated in air: a - - P P O A - S (300~ b - PPOAT-S (300~ c--PPOAT-S (200~ d - - P P O A - S (200~ e - - P P O A T - I (400~

tion bands (although they are more diffuse) like those of the initial polymers. In the case of polymers heated up to 200 ~ the main absorption bands are retained in the IR spectrum; it may therefore be assumed that under these conditions there is intermolecular crosslinking of the polyene chains through a Dielsen-Alders reaction in separate places in the macromolecules, accompanied by the detachment of phenol and the formation of network polymers.

Structure of phenoxy- and phenylacetylene polymers

2079

On h e a t i n g t h e p o l y m e r s u p to 300-400 ~ t h e r e is f u r t h e r crosslinking of t h e m a c r o m o l c c u l e s a c c o m p a n i e d b y the f o r m a t i o n of w h a t a p p e a r to be condensed a r o m a t i c s t r u c t u r e s . A u n i f o r m b a c k g r o u n d of a b s o r p t i o n o v e r t h e whole region of t h e s p e c t r u m is c h a r a c t e r i s t i c of t h e I R s p e c t r a of these p o l y m e r s . T h e d a t a

80 6O .{ 60

Z;

"~ 40

# 20

20 I

2000

I

I

1800

I

~

1200

r

I

800 ~cm -1

(200 ~ argon): a--PPOAT-S; b--PPOA-S; c-- PPOAT-I.

FIo. 6. Infrared spectra of heated polymers

60 ~50 "~

40

~" 30 r r Er 9 I n e s a I Ln r I I I I I IIr r n I i I I I 2000 3000 4000 v, cm-;' FIo. 7. Infrared spectra of polymers heated in air: a--PPOAT-S b--PPOAT-I (400~

(300~

o b t a i n e d r e g a r d i n g the s t r u c t u r e of the :PPA a n d :PI~OA are f u r t h e r s u b s t a n t i a t e d b y e x a m i n a t i o n of t h e X - r a y spectra. I n t h e X - r a y p h o t o g r a p h s of I~PA a n d P P O A o b t a i n e d w i t h t h e Z i e g l c r I ~ a t t a c a t a l y s t t h e r e are diffuse rings t o g e t h e r w i t h lines c h a r a c t e r i s t i c of c r y s t a l line p o l y m e r s . On h e a t i n g :PPOA u p t o 200 ~ p r a c t i c a l l y no a p p r e c i a b l e change

2080

A . A . BERLIN et. al.

P O L Y M E R I Z A T I O N CONDITIONS AND C E R T A I N P R O P E R T I E S OF PHEI~OXY- AND P H E N Y L A C E T Y L E N E POLYMERS

T y p e of polymer PPOAT-I PPOAT-S

Polymerization conditions T h e r m . , 50 ~ Ditto

PPOAT-v

PPOA-I PPOA-S PPOA-v PPAZ PPA

(C2Hs)sA1-TiC14 _ _ 35 ~ Ditto

(C2Hs)3AI'TiCI~ -4- 70 ~ (C2Hs)3AI'TiC13 9N C s H 5 + 70 ~

M e t h o d of s e p a r a t i n g polymers

2~n

Softening point, ~

EPR, spin/g

I n s o l u b l e in o r g a n i c solvents Precipitated with petroleum ether Low molecular wt. I n s o l u b l e i n o r g a n i c solvents Precipitated with petroleum ether L o w m o l e c u l a r wt. Precipitated with methanol

--

>550

0.7 • 101~

2700 840

125-128 85-88

Ditto

1"1 • 1014 4100 710

138-140

8"3 • 1017 7"5 • 10 le

5000

190-200

1"0 • 1017

8OO

142-145

7"1 • 101~

70

10 ),,,

2000

I],E~ffJ,[l[r,t~lrll~l*tTll

3000

4000

5000~,em-I

Fio. 8. Infrared spectra of polymers heated in air.. a--PPOA-S (300~ b - - P P O A T - S (200~

1 " 4 • 10 iv 0'9 • 101~

c - - P P O A - S (200~

Structure of phenoxy- and phenylaeetylene polymers

2081

occurs in the structure of the polymers (Fig. 10). The intermolecular crosslinking in the polymer increases the magnitude and the number of ordered segments, only at temperatures exceeding 300 ~, and this is accompanied by the appearance of new bands in the X-ray photograph.

80 80

\

70 60 50 ~0

+f 50

40 30

6O 50 4O 30

l+rr

2000

~Ttrlft+IIi+Jllrill]Ii~l

3000

+000

V, cm -I

Fro. 9. Infrared spectra of polymers heated in argon: a--PPOAT-S (200~ b--PPOA-S (200~ c--PPOAT-I (200~

All the data obtained favour the assumption t h a t in the polymerization of phenoxy- and phenylacetylene linear polymers are formed having a transconfiguration of the main polyene chain and side substituents arranged in the trans-position (trans-trans-configuration). EXPERIMENTAL

For the investigation we used samples of PPA and PPOA obtained both with a eatalys~ (C~I-I6)sA1.TiC14 (PPOA), (C2tIs)aA1.TiC13 (PPAZ) and also thermally (PPOAT). The polymerizing conditions, yield of polymers, methods of separation and purification and the physieochemicM properties of the polymers were described by the authors in [3, 6]. The main properties of the products investigated t~re given in the Table.

A.A. ]3ERLI~r et al.

2082

The I R spectra of the polymers were recorded on an IKS-14 spectrophotometer (NaC1 and LiF prisms) in the region from 5000 to 670 cm -1. The samples were press moulded into pellets containing KBr following the normal procedure. The X-ray photographs of the polymers were recorded on an URS-55 device with K~Cr radiation and a vanadium

filter for fl-radiation using the Debye

la

method.

]c

| I

I

i

5 6

I I] i fill I l l , I

f

5 0

l

1

3

I

1

, I

2

I

I

15

I

125 d,A"

Fie. 10. Schematic representations of X-ray photographs of polymers: 1--PPA, 2--PPAZ, 3--PPOA-S, 4--PPOAT-I (200 ~ air), 5--PPOA-S (200 ~ argon), 6--PPOAT-S (300 ~ air), 7--PPOA-I (200 ~ 350 ~ air); a--diffraction line; b--diffuse ring; c--indistinct line. CONCLUSIONS A s t u d y has b e e n m a d e of the I R s p e c t r a of p h e n o x y - a n d p h e n y l a c e t y l e n e p o l y m e r s , a n d of p r o d u c t s of t h e i r t h e r m a l processing, which t o g e t h e r w i t h t h e d a t a of X - r a y s t r u c t u r a l analysis p r o v i d e g r o u n d s for t h e suggestion t h a t p o l y a r y l a e e t y l e n e s h a v e a linear s t r u c t u r e (trans-configuration of t h e p o l y e n e chain) w i t h side s u b s t i t u e n t s in t h e trans-position. Translated by R. g. A. ]-IENDRY

REFERENCES 1. G. NATTA, G. MAZZANTI and P. CORADINI, Atti Aead naz. Lincei. Rend. Classe sci fis. mat. e naz. 25: 3, 1958 2. A. A. BERLIN, M. I. CttERKASHIN, O. G. SEL'SKAYA and V. Ye. LIMA_NOV, Vysokoreel. soyed. 1: 1817, 1959 (Not translated in Polymer Sci. U.S.S.R.) 3. A. A. BERLIN, M. I. CHERKASHIN, Yu. G. ASEYEV and I. M. SHCHERBAKOVA,

Vysokomol. soycd. 6: 1773, 1964 (Translated in Polymer Sci. U.S.S.R. 6: 10, 1965, 1964)

l~r

characteristics of cellulose acetates

2083

4. A. F. DONDA, E, CERVONE and M. A. BIANCIFLORI, Recuell trav. chim. 81: 585, 1962 5. F. M. NASIROV, B. A. KRENTSEL' and B. E. DAVYDOV, Izv. AN SSSR, chem. series, 1009, 1965 6. A. A. BERLIN, M. I. CHERKASHIN and I. P. CHERNYSHEVA, Izv. AN SSSR, chem. series, 55, 1967

STUDY OF SOME OF THE MACROMOLECULAR CHARACTERISTICS OF CELLULOSE ACETATES USING SPEED SEDIMENTATION IN ACETONE* V. M. GOLU~EV and S. YA. F~E~KEL' Synthetic Resin Research Institute, Vladimirovo

(Receiveg 29 June 1966)

TO CALCULATEthe molecular weights of polymers relations such as [t/]=KnM a are sometimes used where [~/] is the intrinsic viscosity, M~ is the number average molecular weight, and Kn and a are parameters depending upon the polymersolvent system. Strictly speaking, these formulae are only applicable under certain conditions, i.e. when the polymers are homodisperse, or when their molecular weight distribution (MWD) is known beforehand. Otherwise as one of us has shown [1], the formulae in question are theoretically incorrect, as the ratio of the viscosity average molecular weight M, to M n is strongly dependent upon parameter a and upon the M U D of the samples. At the same time the existing formulae for converting the viscosity of cellulose acetates to molecular weight are generally based on osmotic pressure measurements without taking the polydispersity of the fractions into account [2-3]. Great care is therefore needed in using these formulae; in any case careful checking by methods such as ultracentrifuging, free dispersion or light scattering will be necessary. However, very few such studies have been undertaken with cellulose acetates [3] and their limited scope makes them of little practical use in calculating the parameters in Mark-Kuhn-Houwink (MKH) equations for intrinsic viscosity and sedimentation constant So [~l]-~K,rM, a, (1) so=K

M2

,

(2)

where M s is the sedimentation average molecular weight [1]. To the best of our knowledge there is only one paper [4] where the parameters in formulae (1) and (2) were found using independent measurements of the * Vysokomol. soyed. A9: :No. 9, 1847-1859, 1967.