Random copolymerization of acetylenic monomers and 1,3-dienes

Random Copolymerization of Acetylenic Monomers and 1,3-Dienes

JUNJI FURUKAWA, EIICHI KOBAYASHI,* and TAKAHIRO KAWAGOE,? Department of Synthetic Chemistry, Kyoto University, Kyoto

606, Japan

Synopsis

Copolperization of acetylenic monomers and 1,3-dienes was carried out by use of nickel naphthenate-diethylaluminum chloride catalyst. The molecular weight of the copolymers is rather low, and the copolymers are suitable as prepared for direct use as coating vehicles. In the system of acetylene and 1,3-dienes, the order of the copolymerization rate decreases in the following order: butadiene > isoprene > 2,3-dmethylbutadiene > chloroprene. 1,3-Dienes substituted at 1- and/or 4-position were scarcely copolymerized with acetylene. Methylacetylene and dienes tend to form cyclized copolymers. In the system of phenylacetylene and dienes, polyphenylacetylene was the main product; the copolymer was not obtained. The copolymer composition and the sequence distribution of linear copolymers were evaluated by 'H-NMR spectra. Comparison of dyad fractions of copolymers evaluated from NMR spectra and those calculated by assuming random polymerization indicated that the copolymers of acetylene and dienes were random, and that the copolymers of methylacetylene and dienes were somewhat blocky. The coordination of monomers on the catalyst may play an important role in controlling the copolymerizability.

INTRODUCTION

In a preceding paper,l random copolymerization of acetylene and butadiene by use of the nickel naphthenate-diethylaluminum chloride catalyst was described. The catalyst system is suitable for the preparation of soluble linear copolymers in organic solvents such as chloroform, dichloroethane, toluene, and chlorobenzene. The random copolymer possesses an active methylene inserted between two double bonds and shows excellent hardening reactivity like that of a natural drying oil in an air atmosphere. Independently of the authors' work, the research group of Maruzen Petrochemical Co. disclosed in a patent2 the preparation of alternating copolymers of methylacetylene and 1,3-pentadiene or butadiene by use of a VOC13-(i-C4H&Al catalyst. The synthesis of these copolymers belongs to a quite new and interesting research field; so far, only an Italian patent3 claims a method of synthesis an almost insoluble block copolymer from acetylene and butadiene.

This paper deals with the copolymerization of various kinds of acetylenic monomers and 1,3-diene by use of a nickel naphthenate-diethylaluminum chloride catalyst.

* Present address: Department of Industrial Chemistry, Science University of Tokyo, 278 Noda, Japan.

t Present address: Tokyo Research Laboratories, Bridgestone Tire Co. Ltd., Kodaira 187, Tokyo, Japan.

Journal of Polymer Science: Polymer Chemistry Edition, Vol. 16,1609-1625 (1978) 0 1978 John Wiley & Sons, Inc. 0360-6376/78/0016-1609$01.00

1610 FURUKAWA, KOBAYASHI, AND KAWAGOE

EXPERIMENTAL

Materials The procedure for the purification of butadiene (BD) was the same as in the

preceding paper.4 Commercial isoprene (IP), 2,3-dimethylbutadiene (DMB), 1,3-pentadiene (PD), and 2,khexadiene (HD) were distilled over calcium hydride just before use. Chloroprene (CP, TEyE Soda Co.) was distilled from its toluene solution over 3A Molecular Sieves just before use.

Commercially available acetylene (A) compressed in an acetone-containing bomb was purified in the gaseous state by being passed successively through a saturated aqueous solution of sodium bisulfite and then calcium chloride, phosphorus pentoxide, activated charcoal, and 3A Molecular Sieves. Methy- lacetylene (MA, Seitetsu Kagaku Co.) was used without further purification. Commercial phenylacetylene (PhA) was distilled over 3A Molecular Sieves under reduced pressure. Toluene (guaranteed reagent) was dried over 4A Molecular Sieves, followed by bubbling through of oxygen-free dry nitrogen.

Polymerization The procedures for polymerization are the same as those in the preceding

paper.l Since the polymerization activity and the composition of the copolymer obtained were markedly influenced by the conditions of preparation of the catalyst,l nickel naphthenate and diethylaluminum chloride were allowed to react in toluene with stirring at 3OoC for 10 min prior to the monomer charge. The polymerization was carried out by bubbling the gaseous monomer mixture of acetylene and butadiene or methylacetylene and butadiene into the toluene solution of the catalyst with stirring. In the case of the polymerization with isoprene, chloroprene,2,3-dimethylbutadiene,l,3-pentadiene, or 2,4-hexadiene, the gaseous acetylene or methylacetylene was bubbled into the toluene solution of the catalyst and the comonomer. The copolymerization of phenylacetylene with butadiene or isoprene was carried out in a beverage bottle. The catalyst mixture was reacted in the same manner as stated above. After the bottle was cooled to -78"C, liquid butadiene and phenylacetylene were charged. The bottle was sealed with a crown cap and then subjected to polymerization. In the phenylacetylene-isoprene system, the monomers were introduced into the bottle a t room temperature.

After the polymerization, the reaction mixture was poured into a large amount of methyl alcohol containing a small amount of 2,6-di-tert-butyl-p-cresol as a stabilizer. The liquid or waxy polymer in the lower layer was separated from methyl alcohol. The gel portion was filtered off from the chloroform solution of the polymer.

Characterization The microstructure of polymers was determined by infrared5 or NMR meth-

o d ~ . ~ - ~ The copolymer composition and the sequence distribution were evaluated from the 60 MHz lH-NMR spectra of the copolymers (Varian A60), which were measured in CDC13 at room temperature against a TMS standard. The intrinsic viscosity [q] was measured in toluene at 30 f 0.05"C with an Ubbelohde- type viscometer.

COPOLYMERIZATION OF ACETYLENES AND 1,3-DIENES 1611

RESULTS AND DISCUSSION

Preparation of Copolymers

Previously, random copolymerization of acetylene and butadiene was carried out by use of nickel naphthenate-diethylaluminum chloride catalyst.l The same catalyst system can copolymerize various kinds of acetylenic monomers and 1,3-dienes.

Examples of homopolymerization of acetylenic monomers and dienes are summarized in Table I. Acetylene and methylacetylene are scarcely polymerized. The polymerization rate of butadiene is larger than that of the substituted butadiene. Chloroprene does not afford any polymer with this catalyst system.

It was found that the rate of polymerization was markedly accelerated in the copolymerization, as shown in Tables 11-IV. In the case of 1,3-pentadiene or

TABLE I Homopolymerization of Acetylenic Monomer and Dienea

Polymer CHCl3-soluble polymer yield Yield Microstructure (%) hl

Monomer (9) (PI cis- trans- 1,2- 3,4- (dl/g) - - - - - Ab 0.40 0.16

MAb 0.24 0.22 - BDb 6.06 3.75 80.4 14.4 5.2 0.15 IP 3.89 2.67 71.4 0 0 28.6 2.08 CP 0 DMB 0.61 0.35 4 8 1 . 8 C 18.2 0.77 PD 0.39 0.39

- - - -

- - - - -

a Polymerization conditions: diethylaluminum chloride, 15 mmole; nickel naphthenate, 3 mmole; toluene, 70 ml; acetylenic monomer, 0.12 mole; diene, 0.39 mole; polymerization temperature, 3 O O C ; time, 3 hr. Catalyst preparation reaction: 30°C, 10 min.

b Gaseous monomer was polymerized by bubbling the monomer into the catalyst solution. Trace amount of cis-polymer is included.

TABLE I1 Copolymerization of Acetylene and Dienea

Polymer CHCl3-soluble polymer yield Yield Microstructure (%) [d

Diene (%) (g) Ab cis- trans- 1,2- 3,4- (dl/g)

BD 24.11 21.99c 0.218 81.3 11.5 7.2 0.10 IP 11.80 9.54c 0.439 92.9 0 0 7.1d 0.10 CP 1.10 0.85c 0.410 0 -100d 0 0 0.18 DMB 5.33 4.17c 0.623 0 -100d 0 - 0.12

- 0.07 PD 4.26 4.03e HD 2.39 1.40f

- - - - - - - - -

a Polymerization conditions: diethylaluminum chloride, 15 mmole; nickel naphthenate, 3 mmole; toluene, 70 ml; acetylene, 0.12 mole; diene, 0.39 mole; polymerization temperature, 30OC; time, 3 hr. Catalyst preparation reaction: 3OoC, 10 min.

b Molar fraction of acetylene in the copolymer. c NMR spectra of these copolymers are shown in Fig. 1.

e Cyclized polymer. Dime unit.

Homopolymer of HD.


TABLE I11 Copolymerization of Methylacetylene and Butadienea

Feed Catalyst Polymer CHCl3-soluble polymer

(mole) tionb (9) (g) .(dl/g) NMR MA prepara- yield Yield 171

0.064 7.34 6.19 - Polv-BD 0.095 0.120 - } Cyclized copolymer 0.55 0.45

0.45 0.43 - 0.095 BD 14.93 14.93 0.07 Linear copolymep 0.120 BD 0.095 MA

. .

Cyclized copolymer 2.22 2.22 0.47 0.32 -

0.095 MAandBD 13.30 13.30 0.07 Linea: c!polrmef_-

* Polymerization conditions: diethylaluminum chloride, 15 mmole; nickel naphthenate, 3 mmole;

Catalyst was prepared at 30°C for 10 min, in the absence of monomer or in the presence of BD,

MA content, 0.235 molar fraction; microstructure of the BD unit, cis- 62.9%, trans- 30.0%, 1,2-

MA content, 0.278 molar fraction.

tolune, 70 ml; butadiene, 0.39 mole; polymerization temperature, 3OOC; time, 3 hr.

MA, or MA and BD.

7.1%; NMR spectrum of this copolymer is shown in Fig. 2(a).

TABLE IV Copolymerization of Methylacetylene and Dienea

Feed MA

Polymer CHC13-soluble polymer yield Yield [d

(mole) Diene (9) (9) (iiig) NMR

- copolymer 0.120 IP 1.45 1.20 0.095 IP 7.14 6.14 0.076 IP 10.81 9.56 0.09

Partially cyclized

Linear copolymerb - 1

Partially cyclized copolymer

0.120 DMB 1.77 1.77 0.120 CP 0.45 0 45 0.095 CP 0.37 0.37 0.40

* Polymerization conditions: diethylaluminum chloride, 15 mmole; nickel naphthenate, 3 mmole;

Catalyst preparation reaction: 30"C, 10 min, in the presence of the diene monomer. toluene, 70 ml; diene, 0.39 mole; polymerization temperature, 30°C; time, 3 hr.

MA content, 0.289 molar fraction. NMR spectrum of this copolymer is shown in Fig. 2(b).

2,4-hexadiene a cyclized polymer or the homopolymer of hexadiene was produced.

The order of copolymerization rate is as follows: A-BD > A-IP > A-DMB (> A-PD > A-HD) > A-CP

This order coincides with the homopolymerizability of diene monomers. In the copolymer of acetylene and diene, the microstructure of the diene unit is more regular than that of homopolydiene (see Tables I and 11).

The copolymerization of methylacetylene and butadiene yielded a linear copolymer with difficulty, and polybutadiene or a cyclized copolymer was obtained. However, when the preparation of the catalyst was performed in the presence of a small amount of butadiene or methylacetylene and butadiene, linear copolymers were produced in high yield. The preparation of the catalyst in the presence of methylacetylene decreased the catalyst activity and afforded a cyclized copolymer in low yield. These results are summarized in Table 111.

According to the above experimental results, the desirable method for the


TABLE V Copolymerization of Phenylacetylene and Butadienea

Diethyl- Feed Feed aluminum Polymer CHCl3-soluble polymer PhA BD chloride yield Yield

(mmole) (mmole) (mmole) (g) (g) NMR

50 50 5 50 50 10 50 50 20 4.42 3.60 30 70 5 30 70 10 30 70 20 4.11 3.39

or block copolymerb

a Polymerization conditions: nickel naphthenate, 1 mmole; toluene, 30 ml; polymerization tem-

b There are no active methylenes. perature, 30°C; time, 3 hr. Catalyst preparation reaction: 30"C, 10 min.

TABLE VI Copolymerization of Phenylacetylene and Isoprenea

Feed Feed Polymer CHCl3-soluble polymer PhA IP vield Yield

(mmole) (mmole) (g) (d NMR

40 30

60 70

3.38 2.79 2.59 Poly-PhA

10 90 0.95 0.75 Cyclized polymer

a Polymerization conditions: diethylaluminum chloride, 5 mmole; nickel naphthenate, 1 mmole; toluene, 30 ml; polymerization temperature, 30°C; time, 3 hr. Catalyst preparation reaction: 30°C, 10 min.

preparation of catalyst is that the catalyst components are mixed in the presence of the diene monomer. Table IV shows the results of the copolymerization of methylacetylene and 1,3-dienes. MA copolymerized with the 1,3-dienes to form mainly cyclized copolymer; however, a soluble linear copolymer of methylacetylene and isoprene was produced with feed monomers containing excess isoprene.

In the case of phenylacetylene (PhA), the homopolymerization of PhA was predominant and copolymer was not produced (Tables V and VI). However, a mixture of homopolymers or a block copolymer of phenylacetylene and butadiene was obtained from a butadiene-rich monomer mixture, because active methylenes were not seen in the NMR spectra of the polymers.

NMR Spectra of Copolymers The NMR spectra of copolymers of acetylene or methylacetylene and dienes

are shown in Figures 1 and 2, respectively. The assignments for the spectrum of the copolymer of acetylene (A) and butadiene (BD) [Fig. l(a)] were already described in the preceding paper.l The peaks at 2.12,2.82, and 5.40 6 are assigned to the methylene protons of the BD-BD dyad, to the active methylene protons of the A-BD dyad, and to the methyne protons of the BD unit or those of the A unit separated by BD units, respectively. The minor peaks at 6.22-6.37 6 are assigned to the methyne protons of the A-A dyad.

The assignments for the spectra of other copolymers, and the evaluation of

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the copolymer composition and of the dyad fraction of the sequences are described below.

Copolymer of Acetylene and Isoprene The peak at 1.68 6 [Fig. l(b)] is assigned to the methyl protons of the cis-1,4-IP

unit, which is inferred from the chemical shift of methyl protons of cis-1,4- polyisoprene (1.68 6 in CDC13,1.74 6 in benzene: and 1.66 6 in cc147) and that of trans-l,4-polyisoprene (1.59 6 in CDCl,, 1.65 6 in benzene: and 1.56 6 in CC147). The peak at 2.08 6 is assigned to the methylene protons of the IP unit belonging to the IP-IP dyad. The peak at 2.77 6 is assigned to the active methylene protons of the IP unit belonging to the A-IP sequence, because the peak in- tensity increases with increasing content of acetylene units in the copolymers and the chemical shift of the active methylene protons of the A-IP copolymer is thought to be at slightly higher field than that of the A-BD copolymer.

The low field peak at 4.73 6 is assigned to the vinyl protons of the 3,4-IP unit. Peaks of the other protons of the 3,4-IP unit are not observed by overlapping into other large peaks, although the peaks assignable to the methylene protons, methyl protons, and methyne proton of the 3,4-IP unit are expected to be around 1.25,1.63, and 1.98 6, re~pectively.~ The peaks at 5.16-5.33 6 are assigned to the methyne proton of the IP unit (5.16 6) and the methyne protons of the acetylene unit separated by IP units (5.33 6). These main peaks are schematically assigned as shown in structure I.

P -CH,+CH=CH+H,-C=CH-CH,+CH,-

5.33 2.77 1.68 5.16 2.08 6 (cis)

I

The lowest field peaks at 6.22-6.37 6 are assigned to the methyne protons of the acetylene unit in the A-A dyad.

The copolymer composition can be evaluated by the NMR method. Here, A denotes the molar fraction of the A units in the copolymer, and a is the molar fraction of 3,4-bonded IP units in the total IP units. R is the ratio of the sum of areas at 1.68,2.08, and 2.77 6 to that of areas at 4.73,5.16-5.33, and 6.22-6.37 6. Then, the R and R’ are given by eqs. (1) and (21, respectively.

R = (1 - a)( l - A) + 2 a ( l - A) + 2A

2 4 1 - A) (1 - a)(l - A) + 2A

R’ =

From eqs. (1) and (2), A and a can be evaluated. The dyad fractions are also evaluated by the NMR method. Here, FAA, FAI,

and FII denote the dyad fractions of the A-A, A-IP, and IP-IP sequences, respectively. Thus, the ratio of the area at 2.77 6 to the area at 2.08 6 gives the ratio of FAI to FII.

FAI - (area at 2.77)/2 = 2R,, FII (area a t 2.08)/4

(3)


Consequently,

Since the molar fraction of the IP units in the copolymer, I or 1 - A , is expressed by eq. (5), FII is defined by eq. (6).

FAI = 2Rt'F11 (4)

According to the definition of the fraction of each dyad,

Thus, the dyad fractions are determined by eqs. (3), (6), and (7). FAA + FAI + FII = 1 (7)

Copolymer of Acetylene and Chloroprene The peaks at 2.38 and 2.43 6 [Fig. l(c)] are assigned to the methylene protons

of the CP unit belonging to the head-to-tail CP-CP dyad (2.33 and 2.37 6 in CS2,S respectively). The peaks at 2.25 and 2.55 6 may be assigned to the methylene protons of the CP unit due to the tail-to-tail and the head-to-head sequences of the CP-CPdyad, respectively (2.18 and 2.50 6 in CSZ,~ respectively). Similarly to the case of the A-BD copolymer, the peak at 3.06 6 is assigned to the active methylene protons of the CP-unit belonging to the A-CP sequence.

The peak at 5.46 6 is assigned to the methyne proton of the trans- 1,4-CP unit and those of the A unit isolated by the CP units, because the methyne proton of trans- 1,4-polychloroprene obtained by a radical polymerization appears at 5.39 6 in CS2 or at 5.46 6 in CDC13. The methyne proton of trans- 1,4- and cis- 1,4-polychloroprene were reported to appear at 5.35 and 5.51 6 in CSZ,~ respectively.

The infrared spectra of the copolymer show a broad absorption band at 820-790 cm-l, but no absorption around 847 cm-l. This supports the trans- 1,4-structure of the CP unit.8 These main peaks are expressed as shown in structure 11.

c1 I

-CH+CH=CH+CH~-C=CH- CH*-+CH~-

5.46 3.06 5.46 238 6 (trans) 2-43

I1

The lowest field peak at 6.35 6 is assigned to the methyne protons of the A unit in the A-A dyad.

The copolymer composition was evaluated by the NMR method. Here, A means the molar fraction of A units in the copolymer, and R denotes the ratio of the sum of areas at 2.25,2.38,2.43,2.55, and 3.06 6 to that of areas at 5.46 and 6.35 6. Then, the copolymer composition is evaluted by eq. (8).

4(1- A) 2 A + ( l - A )

R =


The dyad fractions are estimated in the same manner as in the case of the A-IP copolymer by substituting the data for the CP unit for those for the IP unit in eqs. (3)-(7); i.e., the sum of areas at 2.25,2.38,2.43, and 2.55 6 and the area a t 3.06 6 instead of the areas at 2.08 and 2.77 6 , respectively.

Copolymer of Acetylene and 2,3-Dimethylbutadiene Poly-2,3-dimethylbutadiene (see Table I) shows a peak at 1.64 6 and very small

one a t 1.77 6 [Fig. l(d)], and the former is assigned to the methyl protons of the trans-1,4-DMB unit and the latter to those of the cis-1,4-DMB unit (1.63 and 1.76 6 in CC14,9 respectively). According to the above information, the sharp peak at 1.67 6 is assigned to the methyl protons of the trans- 1,kDMB unit. The proton signal of the cis-1,4-DMB unit, which is expected to be at 1.77 6 , is not observed in the spectrum of copolymer. The peak at 2.12 6 is assigned to the methylene protons of the DMB-DMB DYAD/ The peaks centered at 2.95 6 are assigned to the active methylene protons of the DMB unit belonging to the A-DMB dyad (structure 111).

PFH, -CH~+CH=CH+CH,-C= c-cH~+cH~--

5.33 295 L67 2.12 6 (trans)

I11

The broad peaks a t 5.33 and 6.38 6 are assigned to the methyne protons due to the A unit separated by DMB units and those of the A unit in the A-A dyad, respectively.

The copolymer composition is evaluated as follows. Here, A denotes the molar fraction of the A units in the copolymer. R is the ratio of the sum of areas at 1.67, 2.12, and 2.95 6 to that of areas at 5.33 and 6.38 6. Then, the eq. (9) is de-

(9) 6(1 - A ) + 4(1- A ) rived

2A The dyad fractions are obtained in the same way as in the case of the A-IP copolymer, i.e., by substituting the areas at 2.12 and 2.95 6 for A-DMB copolymer for the areas at 2.08 and 2.77 6 in eqs. (3)-(7).

Copolymer of Methylacetylene and Butadiene The peak at 1.68 6 [Fig. 2(a)] is assigned to the methyl protons of the MA unit

bonded in the cis form, which is inferred from the chemical shift of methyl protons of cis- 1,4-polyisoprene and that of trans-1,4-polyisoprene (see A-IP copolymer). The peak at 2.08 6 is assigned to the methylene protons of the BD-BD dyad. The peak at 2.73 6 is assigned to the active methylene protons of the BD unit belonging to the MA-BD dyad (structure IV).

R =

'i" -CH, +C=CH+CH~-CH=CH- CH~+CH,--

1.68 5.18 2.73 5.40 2.08 6 (cis)

Iv


The shoulder peak at 5.18 6 is assigned to the methyne proton of the MA unit separated by BD units. The peak at 5.40 6 is assigned to the methyne protons of the BD unit. The minor peaks centered at 5.90 6, which are not evident in this figure, are assigned to the methyne protons of the MA-MA dyad. In fact, copolymers containing a large amount of the MA-unit show the peaks centered at 5.80 and 6.00 6.

The molar fraction of MA units in the copolymer, A, is expressed by eq. (lo), where R is given as the ratio of the sum of areas at 2.08 and 2.73 6 to the area at 1.68 6.

4(1- A) 3A

R =

The dyad fractions are evaluated by the same process as in the case of the A-IP copolymer; i.e., by substituting the areas at 2.08 and 2.73 6 for MA-BD copolymer for the areas at 2.08 and 2.77 6 in eqs. (3)-(7).

Copolymer of Methylacetylene and Isoprene The broad peak at 1.60 6 [Fig. 2(b)] is assigned to the methyl protons of the

1,4-IP unit and those of the MA unit. This peak is not sharp and is split into two peaks at 1.59 6 (trans) and at 1.63 6 (cis) when the MA content in the feed monomer increases. The latter is considered to come from the MA unit. In the A-IP copolymer, the IP unit exists in the cis form [see Fig. l(b)]. On the other hand, in the MA-IP copolymer the IP unit exists to some extent in the trans form. MA monomer disturbs the geometrical regularity of the BD and IP units. Consequently, the microstructure of copolymers is affected by the comonomer.

The peak at 2.04 6 is assigned to the methylene protons of the IP unit belonging to the IP-IP dyad. The peak at 2.73 6 is assigned to the active methylene protons of the Ip unit of the MA-IP dyad. The low field peak at 4.73 6 is assigned to the vinyl protons of the 3,4-IP unit, wheras the other proton signals of this unit are not observed due to overlapping into other large peaks. The peak at 5.13 6 is assigned to the methyne proton of the 1,4-IP unit and those of the MA unit isolated by the IP units.

'i" 'i% -cH~+c=cH+-cu~--c=cH-cH~+cH~- 1.68 5.13 2.73 1.59 5.13 2.04 6 (cis) (trans)

The copolymer composition is evaluated as follows. Here, A denotes the molar fraction of the MA units in the copolymer and a is the molar fraction of the 3,4-bonded IP units in the total IP units. R is defined as the ratio of the sum of areas at 2.04 and 2.73 6 to the area at 1.60 6, and R' is the ratio of area at 4.73 6 to the area at 5.13 6. Then, the R and R' are given by eqs. (11) and (12), respectively.

(11) 4(1 - a)(1 - A) + a(1- A)

3(1 - a)(1 - A) + 5a(l - A) + 3A R =

2a( l - A) (1 - a)(l- A) + A

R' =


TABLE VII Dyad Fraction of the Copolymers

Evaluated from NMRb random structureb Calculated for

Copolymer Aa FAA FAD FDD FAA FAD FDD

A-BD 0.218 0.023 0.389 0.588 0.048 0.341 0.611 A-IP 0.439 0.191 0.495 0.314 0.193 0.49 0.315 A-CP 0.410 0.188 0.444 0.368 0.168 0.484 0.348 A-DMB 0.623 0.405 0.436 0.159 0.388 0.470 0.142 MA-BD 0.232 0.147 0.177 0.676 0.055 0.360 0.585 MA-IP 0.289 0.178 0.221 0.601 0.083 0.411 0.506

a Molar fraction of the acetylenic monomer in the copolymers. b F ~ , FAD, and FDD denote the molar fraction of the acetylenic-acetylenic, acetylenic-diene, and

diene-diene dyads, respectively.

From eqs. (11) and (12), A and a can be evaluated. The dyad fractions are estimated in the same manner as in the case of the

A-IP copolymer by substituting the areas a t 2.04 and 2.73 6 for MA-IP copolymer for the areas at 2.08 and 2.77 6 in eqs. (3)-(7).

DISCUSSION The dyad fractions evaluated from NMR spectra and those calculated from

random structurelo are listed in Table VII. Both values are relatively close to each other for the copolymers of A, wh'ile the copolymers of MA have a larger amount of the homodyad, FAA and FDD, and a smaller amount of the alternating dyad, FAD, than those expected from the random structure. Consequently, the copolymers of MA have rather blocky sequences as compared with those of A.

In this way, this catalyst system was successfully established for the prepar- ative method of the copolymers of acetylenic monomer and 1,3-diene. At present the copolymerization mechanism is not clear, but the coordinative anionic mechanism seems to be most probable. In a cationic polymerization of acetylene and butadiene by ethylaluminum dichloride, the products have a fused ring structure. The coordination of monomers on the catalyst may play an important role in controlling the copolymerizability. The 1,3-diene substituted at the 1 and/or 4 position seems to hinder coordination of acetylenic comonomer on the catalyst. t

The polymerization kineticdl and hardening studies of copolymers12 will be published elsewhere.

References

1. J. Furukawa, E. Kobayashi, and T. Kawagoe, J. Polym. Sci. Polym. Lett. Ed., 11, 573

2. K. Hayashi, A. Kawasaki, and I. Maruyama, Japan Pats. 1972-42 883,1972-43,185. 3. G. Fontana and S. Ferioli, Ital. Pat. 665,277 (1964). 4. J. Furukawa, E. Kobayashi, and T. Kawagoe, Polym. J., 5,231 (1973). 5. D. Morero, A. Santambrogio, L. Porri, and F. Clampelli, Chim. Znd., 41,758 (1959). 6. Y. Tanaka, Y. Takeuchi, M. Kobayashi, and H. Tadokoro, J. Polym. Sci. A-2, 9,43 (1971). 7. J. P. Kistler, G. Friedman, and B. Kaempt, Bull. SOC. Chim. France, 1967,4759. 8. R. C. Ferguson, J. Polym. Sci. A, 2,4735 (1964). 9. F. Assioma, J. Marechal, F. Schue, G. Friedmann, and A. Maillard, in Macromolecular

(1973).


Chemistry, Prague 1965 (J. Polym. Sci. C, 16), 0. Wichterle and B. SedliEek, Eds., Interscience, New York, 1968, p. 3089.

10. F. A. Bovey and G. V. D. Tiers, J. Polym. Sci., 44,173 (1960). 11. J. Furukawa, T. Kawagoe, and E. Kobayashi, J. Polym. Sci. Polym. Chem. Ed., 14,1213

(1976). 12. J. Furukawa, E. Kobayashi, and T. Kawagoe, J. Appl. Polym. Sci., 21,597 (1977).

Received April 18,1977 Revised May 4,1977

Documents

Random copolymerization of acetylenic monomers and 1,3-dienes