Free radical ring opening for polymerization of cyclic oligomers containing an aromatic sulfide linkage

A polyarylene sulfide free of inorganic contaminants, especially residues of inorganic polymerization catalysts, is produced by the free radical, ring-opening polymerization of a cyclic thioether.

BACKGROUND OF THE INVENTION 
i) Field of the Invention 
This invention relates to a process for producing a polyarylene sulfide, 
more especially an non-ionic process for producing a polyarylene sulfide 
from a cyclic thioether; and to a novel polyarylene sulfide and composites 
containing the polyarylene sulfide, the invention also relates to novel 
cyclic oligomers which are intermediates for manufacture of polyarylene 
sulfides. 
ii) Description of Prior Art 
Aryl thioether polymers such as polyphenylene sulfide (PPS) are known for 
their thermal stability and chemical resistance and as such are of value 
in the manufacture of molded products employed in applications where 
thermal stability and chemical resistance are important. 
U.S. Pat. No. 5,384,391 describes prior processes for producing polyarylene 
sulfides involving a condensation polymerization involving a nucleophilic 
reaction between a dihalo-aromatic compound and an alkali metal compound 
in an organic amide solvent. This process is an ionic process. 
U.S. Pat. No. 5,384,391 describes the problems associated with this prior 
process and proposes a process in which a cyclic arylene sulfide oligomer 
is heated in the presence of a ring-opening polymerization catalyst which 
is cationic or anionic in nature. 
Prior processes for producing polyarylene sulfides result in polymers 
containing inorganic contaminants derived from the inorganic 
polymerization catalysts. These contaminants deleteriously affect the 
properties of the polyarylene sulfide, for example, the electrical 
characteristics. Furthermore, the polyarylene sulfides are frequently 
molded to form articles and the molded polymer is reinforced with 
inorganic fibers, for example, glass fibers. The high melt viscosities of 
the linear high molecular weight polymers make it difficult to fabricate 
fiber filled composites with high loadings of the fiber. 
The use of cyclic oligomer precursors which can be polymerized in situ by 
the addition of a ring opening initiator would allow formation of 
composite structures with high fiber loadings because of their low melt 
viscosity. 
It would also be advantageous to produce polyarylene sulfides free of 
inorganic contaminants resulting from anionic or cationic initiators or 
catalysts. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a non-ionic process for 
producing polyarylene sulfides by the ring opening polymerization of a 
cyclic arylthioether. 
It is a further object of this invention to provide a novel polyarylene 
sulfide free from inorganic contaminants. 
It is another object of this invention to provide a composite comprising 
molded polyarylene sulfide free from inorganic contaminants and reinforced 
with inorganic reinforcing elements. 
It is yet another object of this invention to provide novel cyclic 
(arylether sulfoxide) oligomers novel cyclic arylthioethers and linear 
polymers therefrom. 
In accordance with the invention there is provided a process for producing 
a polyarylene sulfide comprising free-radical, ring-opening polymerization 
of a cyclic thioether. 
In accordance with another aspect of the invention there is provided a 
polyarylene sulfide free of residues of inorganic polymerization 
catalysts. 
In accordance with yet another aspect of the invention there is provided a 
composite comprising a molded polyarylene sulfide free of residues of 
inorganic polymerization catalysts with inorganic reinforcing elements 
throughout said molded polyarylene sulfide.

DESCRIPTION OF PREFERRED EMBODIMENTS 
a) Polymerization 
The ring-opening polymerization of the invention is, in particular, carried 
out at an elevated temperature in the presence of a polymerization 
initiator effective at such elevated temperature to generate 
sulfur-containing free radicals. 
Suitably the elevated temperature is from 250.degree. to 400.degree. C., 
preferably 300.degree. to 360.degree. C. 
Suitably the initiator is elemental sulfur or an organic disulfide, for 
example, 2,2'-dithiobis(benzothiazole), diphenyl disulfide, dinaphthyl 
disulfide or mixtures of sulfur with these disulfides and is employed in 
an amount of 0.5-5.0 (mole) % based on structural units in the cyclic 
arylthioether. 
The cyclic arylthioethers employed in the process of the invention are in 
particular cyclic oligmers containing at least one and preferably 2 to 8 
units of formula (I): 
##STR1## 
in which Ar is an arylene radical of 6 to 24 carbon atoms, unsubstituted 
or substituted by C.sub.1 -C.sub.12 alkyl or C.sub.1 -C.sub.12 alkoxy. 
Such oligomers produce, in accordance with the invention, high molecular 
weight non-cyclic polyarylene sulfides containing said units by a ring 
opening polymerization reaction. 
It will be understood that the cyclic oligomers may contain other units in 
addition to those of formula (I) and such other units will then occur in 
the polyarylene sulfide. Other units which may be linked to the units of 
formula (I) in the cyclic oligmers and the resulting polyarylene sulfides 
include: 
EQU i)--Y.sub.1 --Ar.sub.1 --Y.sub.2 --(II) 
in which Y.sub.1 and Y.sub.2 are the same or different and are --S-- or 
--O--, and Ar.sub.1 is a divalent arylene radical, for example: 
##STR2## 
EQU ii) --Ar.sub.2 --CO-- (III) 
in which Ar.sub.2 is as defined for Ar.sub.1. 
The cyclic oligomers may contain units of type i) or type ii) or both units 
of type i) and type ii). 
b) Cyclic Oligomers 
The cyclic oligomers may, in particular embodiments, be represented by the 
general formula (IV): 
##STR3## 
in which Ar, Ar.sub.1, Y.sub.1 and Y.sub.2 are as defined hereinbefore and 
n is an integer of 2 to 8; or by the general formula (V): 
##STR4## 
in which Ar, Ar.sub.1, Ar.sub.2, Y.sub.1 and Y.sub.2 are as defined 
hereinbefore, m is an integer of 2, to 6 and p is an integer of 1 to 8; or 
by the general formula (VI): 
##STR5## 
in which Ar, Ar.sub.2 and n are as defined hereinbefore. 
The cyclic oligomers of formula (IV), (V) and (VI) are novel, provided that 
the arylene radical Ar is different from the arylene radical Ar.sub.1 or 
Ar.sub.2. 
Those oligomers of formula (IV), (V) and (VI) are of particular interest in 
which at least one of Y.sub.1 and Y.sub.2 is --O--. 
The cyclic oligomers can be produced by several processes as follows: 
i) The procedure for producing cyclic oligomers described in U.S. patent 
application Ser. No. 204,065, filed Mar. 1, 1994, A. S. Hay et al, the 
teaching of which is incorporated by reference, may be used to produce the 
cyclic oligomers of this invention, employing, for example, thiobisphenol. 
ii) Cyclic (aryl ether sulfoxide)s oligomers can be prepared as described 
in Scheme I below: 
##STR6## 
Scheme I shows the synthesis of cyclic poly(aryl ether sulfoxide) 
oligomers. Convenient and efficient pseudo-high dilution conditions are 
employed, without the need of employing bisphenols with special geometry 
that promote cyclic formation. Such cyclic (aryl ether sulfoxide)s are 
synthesized in high yield from the corresponding bisphenol and difluoro- 
or dichloro-monomers. The buildup of cyclic products can be as high as 
0.050 M concentration. 
Furthermore, a series of co-cyclic oligomers is produced when a mixture of 
two different bisphenols (Table II) or two different difluoro- or 
dichloromonomers (Table III) are employed. Their cyclic nature can be 
unambiguously confirmed by a combination of matrix assisted laser 
desorption mass spectrometry (MALDI-TOF-MS), .sup.1 H and .sup.13 C NMR, 
reverse phase high pressure liquid chromatography (HPLC), and gel 
permeation chromatography (GPC) techniques. 
The distribution of cyclics in the mixtures as revealed by GPC are similar 
and the yield of cyclic dimers is not very high. A typical cyclic mixture 
contains 27.5% dimer, 16.1% trimer, 9.8% tetramer, 6.6% pentamer, 5.0% 
hexamer and 35.0% higher homologues. 
The sulfoxide cyclics can then be reduced to the corresponding sulfide 
oligomers by reaction with, e.g., tetrabutylammonium iodide and oxalyl 
chloride, elemental sulfur, etc. iii) Cyclic poly(arylene)sulfides can be 
prepared by a modification of the process first described by Franke and 
Vogtle (J. Franke and F. Vogtle, Tetrahedron Letters 32, 3445-9 (1984), as 
illustrated in Scheme II below: 
##STR7## 
Small amounts of poly(arylene)sulfide cyclic oligomers have also been 
identified in commercial grades of poly(arylene)sulfides and it has been 
observed that low molecular weight poly(arylene)-sulfides can be obtained 
by heating the cyclic hexamer near the melting point. (D. A. Zimmerman and 
H. Ishida, "Characterization and Polymerization of the Cyclic Hexamer of 
p-Phenylene Sulfide". Abstract of presentation at the International Union 
of Pure and Applied Chemistry, International Symposium on Macromolecules, 
The University of Akron, Akron, Ohio, Jul. 11-15, 1994, p. 160). 
The cyclic (arylether sulfoxide) oligomers produced as intermediates in the 
preparation of cyclic oligomers for use in the process of the invention, 
also form an aspect of the invention. 
Thus in accordance with another aspect of the invention there is provided a 
cyclic (arylether sulfoxide) oligomer of formula .sub.(IVA) 
##STR8## 
in which Y.sub.1 and Y.sub.2 are the same or different and are --S-- or 
--O--, Ar is as defined previously and Ar.sub.1 is a divalent arylene 
radical, for example: 
##STR9## 
and, n is an integer of 2 to 8. 
In another aspect of the invention there is provided a process for 
producing cyclic aromatic thioether oligomers which comprises reducing the 
sulfoxide groups in an oligomer of formula (IVA), as defined hereinbefore, 
with a reducing agent. 
c) Polymers 
The poly(arylene)sulfides of the invention are suitably produced as molded 
articles by carrying out the ring-opening polymerization of the invention 
in a mold. 
Suitably the cyclic oligmer may be mixed with inorganic reinforcing 
elements, for example, glass fibers or carbon fibers thereby resulting in 
a composite in which the molded article is reinforced. 
It is a particular advantage of the ring-opening polymerization of the 
invention that the resulting polymer is free of inorganic contaminants 
such as are normally present in poly(arylene) sulfides, being derived from 
the inorganic materials such as inorganic catalysts, employed in the 
polymerization. 
In addition anionic catalysts, in particular phenoxides, tend to react with 
glass fibers at elevated temperatures so that the initiator is 
deactivated. The free-radical, ring-opening polymerization of the 
invention avoids such problems. 
The polymerization process of this invention employs a polymerization 
initiator which develops free radicals for the polymerization, and the 
initiator itself is incorporated in the polymer. Thus, in the case where 
the initiator is 2,2'-dithiobis(benzothiazole), the thiobenzothiazole 
units from the initiator will occupy terminal positions in the final 
polymer. 
These polymerization initiators may, in some contexts, be thought of as 
catalysts and are sometimes referred to herein as being catalysts or being 
present in catalytic amounts, however, they are more properly considered 
as polymerization initiators. 
The linear polymers produced from the cyclic oligomers may in particular 
contain units of formulae (VII), (VIII) or (IX): 
##STR10## 
wherein Ar, Ar.sub.1, Ar.sub.2, Y.sub.1, Y.sub.2 and m are as defined 
hereinbefore. 
Those linear polymers in which Ar is different from Ar.sub.1 or Ar.sub.2 
are novel; and polymers in which at least one of Y.sub.1 and Y.sub.2 is 
--O-- are of particular interest. 
The linear polymers are, in particular, highly crystalline and of high 
molecular weight, typically about 20,000. 
EXAMPLES 
Preparation of cyclic (aryl ether sulfoxide)s oligomers 
##STR11## 
Scheme I schematically shows the general starting materials and the cyclic 
poly(aryl ether sulfoxide) oligomer products. Convenient and efficient 
pseudo-high dilution conditions have been employed, without the need of 
employing bisphenols with special geometry that promote cyclic formation. 
A number of cyclic (aryl ether sulfoxide)s have been synthesized in high 
yield (Table I) from the corresponding bisphenol and difluoro-monomers. 
The buildup of cyclic products can be as high as 0.050 M concentration. 
Furthermore, a series of co-cyclic oligomers were prepared when a mixture 
of two different bisphenols (Table II) or two different difluoro-monomers 
(Table III) were employed. Their cyclic nature has been unambiguously 
confirmed by a combination of matrix assisted laser desorption mass 
spectrometry (MALDI-TOF-MS), .sup.1 H and .sup.13 C NMR, reverse phase 
high pressure liquid chromatography (HPLC), and gel permeation 
chromatography (GPC) techniques. 
The distribution of cyclics in the mixtures as revealed by GPC are similar 
and the yield of cyclic dimers is not very high. A typical cyclic mixture 
contain 27.5% dimer, 16.1% trimer, 9.8% tetramer, 6.6% pentamer, 5.0% 
hexamer and 35.0% higher homologues. The following examples are 
illustrative and not intended to limit its scope. 
Example 1 
The cyclization reaction was conducted in a 1 L three-necked round bottom 
flask which was equipped with a Dean-Stark trap and condenser, a 
thermometer, a nitrogen inlet, and magnetic stirring. The reaction vessel 
was charged with dimethylformamide (DMF) (470mL), toluene (70 mL) and 
anhydrous potassium carbonate (5.528 g, 40.0 mmol). The mixture was 
magnetically stirred and heated to reflux under N.sub.2. The refluxing 
temperature was in the range of 145.degree.-8.degree. C. Then, a solution 
of 4,4'-difluoroplhenyl sulfoxide (4.7650 g, 20.0 mmol) and hydroquinine 
(2.2202 g, 20.0 mmol) in DMF (30 mL) was added over a period of 8 via a 
syringe pump. After the addition, the resulting mixture was kept refluxing 
for another 8 h. The reaction mixture was then cooled and filtered to 
remove salts. The solution was concentrated to 100 nriL under reduced 
pressure and added dropwise to vigorously stirred distilled water (700 mL) 
containing 10 mL of concentrated hydrochloric acid. The desired oligomers 
precipitated as white solid. The solid was collected by filtration and 
washed several times with distilled water. Then the cyclic oligomers were 
transferred to a beaker containing 200 mL methanol. After stirring for 10 
min, the cyclic oligomers were filtered and dried in a vacuum oven 
(140.degree. C.) for 24 h to give 5.7 g (92% yield) ot cyclic oligomers 1. 
Examples 2-5 
The above procedure was repeated replacing hydroquinone with 4,4'-biphenol, 
4,4'-thiodiphenol, 2,2'-bis(4-hydroxyphenyl) hexafluoropropane and 
9,9'-bis(4-hydroxyphenyl) fluorene, respectively. 
TABLE I 
__________________________________________________________________________ 
##STR12## 
Example 
Ar 
__________________________________________________________________________ 
##STR13## 92 996 
1373 
165 
363 
2 
##STR14## 96 1226 
2276 
199 
363 
3 
##STR15## 98 1711 
4943 
141 
370 
4 
##STR16## 97 2194 
7906 
177 
402 
5 
##STR17## 95 1939 
8156 
260 
412 
__________________________________________________________________________ 
a): Isolated yield. 
b): measured by GPC and calibrated against polystyrene standards; units 
g/mole. H.p.l.c. grade THF containing 0.5% w/v LiBr was used as eluent. 
c): Measured on DSC under nitrogen atmosphere (50 mL/min) with a heating 
rate of 20.degree. C./min. 
d): Temperature for 5% weight loss under nitrogen atmosphere (200 mL/min) 
with a heating rate of 20.degree. C./min. 
Examples 6 and 7 
The procedure of example 1 was repeated with replacement of hydroquinone 
with a mixture of hydroquinone and 4,4-biphenol (molar ratio of 1:4), and 
a mixture of 9,9'-bis(4-hydroxyphenyl) fluorene and 4,4'-bipheniol (molar 
ratio of 1:9) (Table II), respectively. 
TABLE II 
__________________________________________________________________________ 
##STR18## 
Example 
Ar 
__________________________________________________________________________ 
##STR19## 95 1782 
8580 
193 
369 
7 
##STR20## 96 1414 
3228 
210 
397 
__________________________________________________________________________ 
a): Isolated yield. 
b): measured by GPC and calibrated against polystyrene standards; units 
g/mole. H.p.l.c. grade THF containing 0.5% w/v LiBr was used as eluent. 
c): Measured on DSC under nitrogen atmosphere (50 mL/min) with a heating 
rate of 20.degree. C./min. 
d): Temperature for 5% weight loss under nitrogen atmosphere (200 mL/min) 
with a heating rate of 20.degree. C./min. 
Example 8 
The procedure of example 1 was repeated with replacement of 
4,4'-difluorophenyl sulfoxide with a mixture of 4,4'-difluorophenyl 
sulfoxide and 4,4'-difluorobenzophenone (molar ratio of 1:1) (Table III), 
and replacement of hydroquinone with 4,4'-thiodiphenol. 
TABLE III 
______________________________________ 
##STR21## 
Example 
Yield (%).sup.a 
Mn.sup.b 
Mw.sup.b 
Tg(.degree.C.).sup.c 
Tm(.degree.C.).sup.c 
T.sub.-5%.sup.d 
______________________________________ 
8 94 1586 5253 131 316 490 
______________________________________ 
.sup.a Isolated yield. 
.sup.b measured by GPC and calibrated against polystyrene standards; unit 
g/mole. H.p.l.c. grade THF containing 0.5% w/v LiBr was used as eluent. 
.sup.c Measured on DSC under nitrogen atmosphere (50 mL/min) with a 
heating rate of 20.degree. C./min. 
.sup.d Temperature for 5% weight loss under nitrogen atmosphere (200 
mL/min) with a heating rate of 20.degree. C./min. 
Preparation of cyclic (aryl thioether ketone)s oligomers 
##STR22## 
Scheme II schematically shows the general starting materials and the cyclic 
poly(aryl thioether ketone) oligomer products. In the particular examples 
shown below, 4,4'-bis(4-fluorobenzoyl)diphenylsulfide (n=1, X=F) was used 
as the dihalide monomer. Since the solubility of 
4,4'-bis(4-fluorobenzoyl)diphenylsulfide in DMF was limited, the 
pseudo-high dilution conditions can not be used, instead, high-dilution 
conditions have been applied and high yields of cyclic oligomers were 
formed without the need of employing bisphenols with special geometry that 
promote cyclic formation. In this way, the yield of cyclic dimers is 
extremely high. A typical cyclic mixture contain 71.3% dimer, 15.7% 
trimer, 6.6% tetramer, 3.0% pentamiier and 3.4% higher homologues. The 
following examples are illustrative and not intended to limit its scope. 
Example 9 
To a 1 L three-necked, round-bottom flask equipped with a thermometer, 
magnetic stirring, nitrogen inlet and Dean-Stark trap with attached 
water-cooled condenser, DMF (750 mL), toluene (100 mL), anhydrous 
potassium carbonate (1.658 g, 12.0 mmol) were charged. Then, 
4,4'-bis(4-fluorobenzoyl)diphenyl sulfide (2.5828 g, 6.0 mmol) and 
hydroquinone (0.6607 g, 6.0 mmol) were added. The reaction mixture was 
magntetically stirred and heated to reflux under nitrogen atmosphere. The 
mixture was kept refluxing for 15 h at 145-8.degree. C. At the end of 
reaction, the reaction mixture was cooled and filtered to remove salts. 
The filtrate was then concentrated to 100 mL under reduced pressure. The 
concentrated solution was added dropwise to vigorously stirred distilled 
water (700 mL) containing 10 mL of concentrated hydrochloric acid. the 
desired oligomers precipitated as a white solid. The solid was collected 
by filtration and washed several times with distilled water. Then, the 
cyclic oligomers were transferred to a beakeir containing 200 mL methanol. 
After stirring for 10 min, the cyclic oligomers were filtered and dried in 
a vacuum oven (140.degree. C.) for 24 h to give 2.7 g (90% yield) of 
cyclic oligomers 9. 
Examples 10 and 11 
The above procedure was repeated with replacing hydroquinone with 
4,4'-biphenol, and 4,4'-thiodiphenol respectively (Table IV). 
TABLE IV 
__________________________________________________________________________ 
##STR23## 
Example 
Ar T.sub.-5%.sup.e 
__________________________________________________________________________ 
##STR24## 90 
1361 
1683 
143 301 501 
10 
##STR25## 95 
--.sup.c 
--.sup.c 
--ND 
334,377 
504 
11 
##STR26## 97 
930 
1171 
139 399 467 
__________________________________________________________________________ 
.sup.a Isolated yield. 
.sup.b measured by GPC and calibrated against polystyrene standards; unit 
g/mole. H.p.l.c. grade chloroform was used as eluent. 
.sup.c not soluble in chloroform. 
.sup.d Measured on DSC under nitrogen atmosphere (50 mL/min) with a 
heating rate of 20.degree. C./min. ND: not detected. 
.sup.e Temperature for 5% weight loss under nitrogen atmosphere (200 
mL/min) with a heating rate of 20.degree. C./min. 
Example 12 
The procedure of example 1 was repeated with replacement of hydroquinone 
with 4,4'-thiodiphenol, and replacement of 4,4'-difrluorophenyl sulfoxide 
with 1,2-bis(4-fluorobenzoyl)-3,6-diphenylbenzene (Table V). 
Example 13 
The procedure of example 1 was repeated with replacement of hydroquinone 
with 4,4'-thiodiphenol, and replacement of 4,4'-difluorophenyl sulfoxide 
with 4,4'-difluorobenzophenone. The crude cyclic oligomers contained 10% 
high molecular weight polymer. The cyclic was then purified by soxhlet 
extraction using ethyl acetate as solvent to give 80% yield of 
polymer-free cyclic oligomers 13 (Table V). 
TABLE V 
__________________________________________________________________________ 
##STR27## 
Example 
Ar 
__________________________________________________________________________ 
12 
##STR28## 90 
1572 
5358 
193 
385 
462 
13 
##STR29## 80 
443 
663 
121 
381 
479 
__________________________________________________________________________ 
a): Isolated yield. 
b): measured by GPC and calibrated against polystyrene standards; units 
g/mole. H.p.l.c. grade chloroform was used as eluent. 
c): Measured on DSC under nitrogen atmosphere (50 mL/min) with a heating 
rate of 20.degree. C./min. 
d): Temperature for 5% weight loss under nitrogen atmosphere (200 mL/min) 
with a heating rate of 20.degree. C./min. 
Preparation of Cyclic (Aryl Ether Sulfide)s Oligomers 
Cyclic (atyl ether sulfoxide) oligomers can be easily reduced to the 
corresponding sulfide oligomers thus providing a new class of cyclics. 
Scheme III shows one method to convert sulfoxide oligomers to the 
corresponding sulfide oligomers. 1,1,2,2-Teti-achloroethane was used as 
reaction medium, other chlorinated solvents can also be used. A suitable 
range of temperatures for the reaction is from room temperature to 
80.degree. C., with 40.degree.-60.degree. C. being preferred. The 
following examples are illustrative and not intended to limit its scope. 
The complete reduction of sulfoxide oligomers to the corresponding sulfide 
oligomers, and their cyclic nature have been unambiguously confirmed by a 
combination of matrix assisted laser desorption mass spectrometry 
(MALDI-TOF-MS), .sup.1 H and .sup.13 C NMR, reverse phase high pressure 
liquid chromatography (HPLC), and gel permeation chromatography (GPC) 
techniques. 
Scheme III 
##STR30## 
Example 14 
To a 250 mL three-necked round-bottom flask, equipped with magnetic 
stirring, nitrogen inlet and condenser, cyclic oligomers 1 (3.0 g, 9.73 
mmol), tetrabutylammonium iodide (9.153 g, 24.31 mmol) and 
1,1,2,2-tetrachloroethane (125 mL) were charged. The mixture was 
magnetically stirred and heated to 50.degree. C. under a slow stream of 
nitrogen. Once the cyclic oligomers were dissolved, oxalyl chloride (1.04 
mL, 11.68 mmol) was added rapidly via syringe to the rapidly stirring 
solution. Immediately upon introduction of the oxalyl chloride, iodine was 
liberated, gas (presumably carbon monoxide and carbon dioxide) was 
evolved, and the corresponding sulfide cyclic oligomers precipitated in 
the form of fine particles. The reaction mixture was stirred at 50.degree. 
C. for 10 min, then poured into vigorously stirred methanol (500 mL) and 
filtered. The cyclic oligomer particles were washed several times with 
methanol, and transferred into a beaker containing a 5% w/v aqueous 
solution of sodium thiosulfate (300 mL). After stirring for 20 min, the 
cyclic oligomer was again collected by filtration and washed several times 
with distilled water (1 L) followed by methanol (200 mL). the cyclic 
oligomers were filtered and dried in a vacuum oven (140.degree. C.) for 24 
h to give a quantitative yield of cyclic oligomers 14. 
Examples 15-18 
The above procedure for cyclic oligomers 14 was repeated replacing cyclic 
oligomers 1 with cyclic oligomers 2, 3, 4 and 5 respectively (Table VI). 
TABLE VI 
__________________________________________________________________________ 
##STR31## 
Example 
Ar 
__________________________________________________________________________ 
14 
##STR32## -- b 
-- b -- ND 
237 457 
15 
##STR33## -- b 
-- b -- ND 
351 550 
16 
##STR34## -- b 
-- b 82 267 518 
17 
##STR35## 3123 
11158 
137 -- ND 
526 
18 
##STR36## 1924 
10578 
221 411 546 
__________________________________________________________________________ 
a: measured by GPC and calibrated against polystyrene standards; units 
g/mole. H.p.l.c. grade THF containing 0.5% w/v LiBr was used as eluent. 
b: not soluble in THF. 
c: Measured on DSC under nitrogen atmosphere (50 mL/min) with a heating 
rate of 20.degree. C./min 
ND: not detected. 
d: Temperature for 5% weight loss under nitrogen atmosphere (200 mL/min) 
with a heating rate of 20.degree. C./min. 
Examples 19 and 20 
The above procedure for cyclic oligomcis 14 was repeated replacing cyclic 
oligomers 1 with cyclic oligomers 6 and 7 respectively (Table VII). 
______________________________________ 
##STR37## 
Ex- 
am- 
ple Ar Tg(.degree.C.).sup.a 
Tm(.degree.C).sup.a 
T.sub.-5%.sup.b 
______________________________________ 
19 
##STR38## --ND 297 516 
20 
##STR39## -- ND 310 542 
______________________________________ 
.sup.a Measured on DSC under nitrogen atmosphere (50 mL/min) with a 
heating rate of 20.degree. C./min. 
ND: not detected. 
.sup.b Temperature for 5% weight loss under nitrogen atmosphere (200 
mL/min) with a heating rate of 20.degree. C./min. 
Example 21 
The above procedure for cyclic oligomers 14 was repeated replacing cyclic 
oligomers 1 with cyclic oligomers 8 (Table VIII). 
TABLE VIII 
______________________________________ 
##STR40## 
Example Mn.sup.a Mw.sup.a 
Tg(.degree.C.).sup.b 
Tm(.degree.C).sup.b 
T.sub.-5%.sup.c 
______________________________________ 
21 1817 7828 105 233,287 
515 
______________________________________ 
.sup.a measured by GPC and calibrated against polystyrene standards; unit 
g/mole. H.p.l.c. grade THF containing 0.5% w/v LiBr was used as eluent. 
.sup.b Measured on DSC under nitrogen atmosphere (50 mL/min) with a 
heating rate of 20.degree. C./min. 
.sup.c Temperature for 5% weight loss under nitrogen atmosphere (200 
mL/min) with a heating rate of 20.degree. C./min. 
Polymerization of Cyclic Poly(aryl thioether ketone) Oligomers 
Although aryl thioether and aryl thioether polymers are well known for 
thermal stability and chemical resistance, the applicants have discovered 
a catalyst system that causes the cyclic thioethers to ring open, 
ultimately producing high molecular weight polymers. The catalysts which 
can be used for the free-radical ring-opening polymerization include 
various compounds which generate sulfur radicals upon treatment at 
elevated temperatures. This process is schematically shown in scheme IV. 
##STR41## 
This process is applicable to a wide variety of thioether containing cyclic 
oligomers. The preferred catalysts are elemental sulfur and organic 
disulfides such as 2,2'-dithiobis(benzothiaole) (DTB) or 
diphenyldisulfide. The polymerization is typically effected by simply 
contacting the cyclic oligomers with the catalyst at temperatures up to 
400.degree. C., preferably about 300.degree.-360.degree. C., until 
polymerization has proceeded to the extent desired. Although the use of a 
solvent is within the scope of the invention, it is generally not 
preferred. In general, the amount of catalyst used is about 0.5-5.0 (mole) 
% based on structural units in the cyclic oligomers. The following 
examples are illustrative and not intended to limit its scope. 
Examples 22-25 
##STR42## 
Cyclic poly(aryl ether thioether ketone) oligomers from example 12 (2.0 g), 
having a number average molecular weight of about 1600, and a catalytic 
amount of 2,2'-dithiobis(benzothiazole) (DTB) or elemental sulfur were 
mechanically mixed with m-terphenyl (2.0 g) in a 50 mL test-tube, equipped 
with a nitrogen inlet and outlet. The mixture was then heated under 
nitrogen at 350 .degree. C. for 30 min, after which the reaction mixture 
was cooled and dissolved in chloroform and the resulting solution was 
added dropwise into a vigorously agitated large excess of methanol. A 
filbrous polymer was precipitated and filtered. The resulting polymer was 
analyzed by GPC, and the relevant parameters and results are shown in 
Table IX. 
TABLE IX 
______________________________________ 
Conversion of cyclic 
Example 
Catalyst to polymer (%) 
Mn.sup.b 
Mw.sup.b 
______________________________________ 
22 none 48 40,750 
185,550 
23 2.0 (mole) % S 
80 53,760 
266,590 
24 2.0 (mole) % DTB.sup.a 
84 34,950 
228,310 
25 2.0(mole) % S + 
92 36,300 
203,500 
2.0 (mole) % DTB.sup.a 
______________________________________ 
.sup.a): 2,2dithiobis(benzothiazole). 
.sup.b): measured by GPC and calibrated against polystyrene standards; 
units g/mole. H.p.l.c. grade chloroform was used as eluent. 
Example 26-30 
##STR43## 
Cyclic poly(aryl ether thioether ketone) oligomers from example 12 (2.0 g), 
having a number average molecular weight of about 1600, and catalytic 
amount of 2,2'-dithiobis(benzothiazole) (DTB) were mechanically mixed in a 
50 mL test-tube dipped with a nitrogen inlet and outlet. The mixture was 
then heated under nitrogen at 380.degree. C. for 30 min. The resulting 
polymer was removed by breaking the test tube. A portion of the material 
was dissolved in chloroform and analyzed by GPC. The relevant parameters 
and results are shown in Table X. 
TABLE X 
______________________________________ 
Conversion of cyclic 
Example 
Catalyst to polymer (%) 
Mn.sup.b 
Mw.sup.b 
______________________________________ 
26 none 67.5 18,27 58,98 
27 0.5 (mole) % DTB.sup.a 
84 33,68 83,57 
28 1.0 (mole) % DTB.sup.a 
86 31,84 76,38 
29 2.0 (mole) % DTB.sup.a 
91 28,24 64,49 
30 5.0 (mole) % DTB.sup.a 
100 8,040 35,41 
______________________________________ 
.sup.a): 2,2 
.sup.b): measured by GPC and calibrated against polystyrene standards; 
units H.p.l.c. grade chloroform was used as 
Example 31 
##STR44## 
Cyclic poly(aryl ether thioether ketone) oligomers from example 13 (2.0 g), 
having a number average molecular weight of about 443, and a catalytic 
amount of 2,2'-dithiobis(benzothiazole) (DTB) (16.8 mg) were mechanically 
mixed in a 50-mL test-tube, equipped with a nitrogen inlet and outlet. The 
mixture was then heated under nitrogen at 380.degree. C. for 30 min. The 
resulting polymer had a glass transition temperature of 138.degree. C. (a 
17.degree. C. increase compared to the starting oligomers of example 13), 
and was very tough and insolulbe in most organic solvents. 
Polymerization of Cyclic Poly(aryl ether sulfide) Oligomers 
Example 32 
##STR45## 
Cyclic poly(aryl ether sulfide) oligomers 14 (0.5 g) and a catalytic amount 
of 2,2'-dithiobis(benzothiazole) (DTB) (5.8 mg) were mechanically mixed in 
a 50-mL testing-tube, equipped with a nitrogen inlet and outlet. The 
mixture was then heated under nitrogen at 340.degree. C. for 60 min. The 
resulting polymer was tough and insolube in most organic solvent. DSC 
analysis revealed that the material was highly crystalline and had a Tg of 
98.degree. C., a Tm of 240.degree. C. and a melting enthalpy of 28.0 J/g. 
Examples 33-35 
##STR46## 
Cyclic poly(aryl ether sulfide) oligomers from example 15 (0.5 g) and a 
catalytic amount of 2, 2'-dithiobis(benzothiazole) (DTB; 0.5 to 1.0 
(mole)% catalyst) were mechanically mixed in a 50 mL test-tube, equipped 
with a nitrogen inlet and outlet. The mixture was then heated under 
nitrogen at temperatures ranging from 340.degree.to 370.degree. C. for 30 
to 60 min. The resulting polymer was very tough and insolube in most 
organic solvent, but Soluble in boiling 1-chloronaphthalene. DSC analysis 
revealed that the material was highly crystalline and readily recrystlized 
upon heating after quenching without any annealing. The results are shown 
in Table XI. 
TABLE XI 
__________________________________________________________________________ 
Example 
Catalyst Reaction conditions 
Tg(.degree.C.).sup.b 
Tm(.degree.C.).sup.b 
.DELTA.Hm(J/g).sup.c 
__________________________________________________________________________ 
33 1.0 (mole) % DTB.sup.a 
340.degree. C., N.sub.2, 60 min 
150 332 37 
34 0.5 (mole) % DTB.sup.a 
370.degree. C., N.sub.2, 30 min 
149 327 32 
35 1.0 (mole) % DTB.sup.a 
370.degree. C., N.sub.2, 30 min 
150 329 30 
__________________________________________________________________________ 
.sup.a): 2,2dithiobis(benzothiazole). 
.sup.b): measured on DSC under nitrogen atmosphere (150 mL/min) with a 
heating rate of 20.degree. C./min. 
.sup.c): measured on DSC under nitrogen atmosphere (150 mL/min) with a 
heating rate of 20.degree. C./min. and calibrated against Indium. 
Example 36 
##STR47## 
Cyclic poly(aryl ether sulfide) oligomers from example 16 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (4.2 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 300.degree.or 
340.degree. C. for 60 min. The resulting polymer had a glass transition 
temperature of 94.degree. C. (a 12.degree. C. increase compared to the 
starting oligomers of example 16), and was tough and insolulbe in most 
organic solvent. 
Example 37 
##STR48## 
Cyclic poly(aryl ether sulfide) oligomers from example 17 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (16.3 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 340.degree. C. 
for 60 rain. A portion of the resulting polymer was dissolved into 
chloroform and analysed by GPC to give a Mn of 16,670 and a Mw of 44,130. 
Example 38 
##STR49## 
Cyclic poly(aryl ether sulfide) oligomers from example 18 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (15.7 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 380.degree. C. 
for 30 min. The resulting material was tough and only partially soluble in 
chloroform. The soluble fraction was analyzed by GPC to give a Mn of 
16,720 and a Mw of 52,980, and there was only a very small fraction of 
cyclic dimer remaining. 
Example 39 
##STR50## 
Cyclic poly(aryl ether sulfide) oligomers from example 19 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (4.8 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 340.degree. C. 
for 60 min. The resulting polymer was very tough and insoluble in most 
organic solvents. DSC analysis revealed that the material was highly 
crystalline and had a Tg of 140.degree. C., a Tm of 286.degree. C. and a 
melting enthalpy of 18.2 J/g. 
Example 40 
##STR51## 
Cyclic poly(aryl ether sulfide) oligomers from example 20 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (5.8 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 340.degree. C. 
for 60 min. The resulting polymer was very tough and insoluble in most 
organic solvents. DSC analysis revealed that the material was highly 
crystalline and had a Tg of 163.degree. C., a Tm of 310.degree. C. and a 
melting enthalpy of 24.6 J/g. 
Example 41 
##STR52## 
Cyclic poly(aryl ether sulfide) oligomers from example 21 (0.5 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (4.2 mg) were 
mechanically mixed in a 50 nL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 340.degree. C. 
for 60 min. The resulting polymer had a glass transition temperature of 
113.degree. C. (an 8.degree. C. increase compared to the starting 
oligomers of example 21). The material was tough and insoluble in most 
organic solvents. 
Polymerization of Cyclic Poly(1,4-phenylene sulfide) Oligomers 
Macrocyclic 1,4-phenylene sulfides such as the hexamer are known. (Frank, 
J. and Vogtle, F. Tetrahedron Lett., 25, 3445 (1984). The cyclic 
poly(1,4-phenyllene sulfide) oligomer mixtures used for the following 
polymerization example were prepared using a method similar to that 
reported. 
Preparation of cyclic poly(1,4-phenylene sulfide) oligomers 
##STR53## 
To a 1 L thee-necked, round-bottom flask equipped with a thermometer, 
magnetic stirring, an argon inlet and a water-cooled condenser, 
fresh-distilled quinoline (400 mL) and copper (I) p-bromo-thiophenoxide 
(0.60 g) were charged. The mixture was heated and the copper salt 
dissolved. The solution was then kept at 195.degree.-200.degree. C. for 8 
h after which 0.60 g of the copper salt was added and the reaction 
solution was kept at temperature for another 8 h. This process was 
repeated evey 8 h until, overall, 3.60 g (14.31 mmol) of the copper salt 
was added to give a final concentration of product of 35.8 mM. At the end 
of reaction, the solution was concentrated to 50 mL under reduced presure. 
Then, the concentrated solution was added dropwise into 800 mL of 50% 
(aqueous) methanol containing 20 mL of concentrated hydrochloric acid, and 
the product precipitated as a gray solid. After filtration, the gray solid 
was stirred with 100 mL of concentrated hydrochloric acid for 10 min, and 
then washed with distilled water until HCl free. The dried solid was 
redissolved in chloroform, filtered through a thin-layer of Celite and 
reprecipitated into methanol. The precipitate was filtered and dried. The 
crude product Was then extracted with warm ethyl acetate to remove any 
linear oligomers to give a 50% yield of cyclic poly(l,4-phenylene sulfide) 
oligomeis. 
The cyclic nature of the product was confirmed by a combination of .sup.1 H 
NMR, GPC and HPLC. GPC and HPLC analyses revealed that the cyclic mixtures 
contain 20% tetramer, 40% pentamer, 20% hexamer and 20% higher homologues. 
DSC analysis showed that the cyclic oligomers had a Tg of 63.degree. C., a 
Tm of 217.degree. C. and a melting enthalpy of 35.0 J/g followed by an 
extherom peak centered at 379.degree. C. 
Example 42 
##STR54## 
The above cyclic poly(l,4-phenylene sulfide) oligomers (0.10 g) and a 
catalytic amount of 2,2'-dithiobis(benzothiazole) (DTB) (3.1 mg) were 
mechanically mixed in a 50 mL test-tube, equipped with a nitrogen inlet 
and outlet. The mixture was then heated under nitrogen at 300.degree. or 
340.degree. C. for 60 min. The resulting polymer was insoluble in most 
organic solvents. DSC analysis revealed that the material was highly 
crystalline and had a Tg of 85.degree. C., a Tm of 279.degree. C. and a 
melting enthalpy of 46.8 J/g.