Aromatic sulfide/sulfone polymer production

Aromatic sulfide/sulfone polymers of increased molecular weight are produced by contacting a dihalo aromatic sulfone, at least partially hydrated alkali metal sulfide, and an organic amide under polymerization conditions which produce a higher molecular weight aromatic sulfide/sulfone polymer. The use of at least one at least partially hydrated alkali metal sulfide other than lithium sulfide results in polymers of increased molecular weight having utility as coatings, films, molded objects, filaments, fibers, and the like.

This invention relates to the production of polymers from aromatic 
compounds. 
In accordance with another aspect, this invention relates to a process for 
the production of aromatic sulfide/sulfone polymers of increased molecular 
weight by contacting a dihalo aromatic sulfone, a selected at least 
partially hydrated alkali metal sulfide, and an organic amide under 
polymerization conditions. 
In accordance with a further aspect, this invention relates to the 
production of aromatic sulfide/sulfone polymers by contacting a dihalo 
aromatic sulfone, a selected at least partially hydrated alkali metal 
sulfide, and an organic amide under polymerization conditions, with the 
proviso that the reactants have not been treated prior to polymerization 
to remove free water and water of hydration. 
In recent years, a wide variety of high polymers have been prepared, many 
of which are currently being produced and marketed on a large scale. While 
such polymers are useful in many areas, one property of high polymers, 
particularly those of the thermoplastic type, which needs to be improved 
is the ability to withstand high temperature. Since thermoplastic 
materials can be molded rapidly and efficiently into almost any desired 
shape, they lend themselves to mass production. The high polymer, 
especially a thermoplastic material, which would stand very high 
temperatures and could be used in such areas as electrical components, 
wire coatings, automotive parts, and the like has been the objective of a 
great deal of research. 
Accordingly, an object of this invention is to produce aromatic 
sulfide/sulfone polymers exhibiting high molecular weight. 
Another object of this invention is to provide a process for producing high 
molecular weight aromatic sulfide/sulfone polymers exhibiting good 
processability properties. 
Other objects and aspects, as well as the several advantages of this 
invention, are apparent from a study of this disclosure and the appended 
claims. 
In accordance with this invention, aromatic sulfide/sulfone polymers 
exhibiting higher molecular weight than normally obtained are produced by 
contacting at least one dihalo aromatic sulfone, at least one organic 
amide, and at least one at least partially hydrated alkali metal sulfide 
other than lithium sulfide under polymerization conditions for a period of 
time sufficient to form an aromatic sulfide/sulfone polymer. 
In accordance with one specific embodiment of the present invention, at 
least one dihalo aromatic sulfone such as a bis(p-halophenyl) sulfone, at 
least one organic amide, and at least one at least partially hydrated 
alkali metal sulfide other than lithium sulfide containing a total of up 
to about 10 moles of free water and water of hydration per mole of alkali 
metal sulfide are contacted under polymerization conditions for a period 
of time sufficient to form an aromatic sulfide/sulfone polymer exhibiting 
higher molecular weight than normally obtained. 
In accordance with this invention, in the production of an aromatic 
sulfide/sulfone polymer by employing a dihalo aromatic sulfone, an organic 
amide, and an at least partially hydrated alkali metal sulfide selected 
from sodium sulfide, potassium sulfide, rubidium sulfide, and cesium 
sulfide, it has been found that a polymer of higher molecular weight is 
obtained by conducting the polymerization step without a prior dehydration 
(or distillation) step to remove water than is obtained when water is 
removed prior to the polymerization step. This discovery was surprising 
since it previously had been observed that poly(p-phenylene sulfide) of 
higher molecular weight was obtained using p-dichlorobenzene, partially 
hydrated sodium sulfide, and N-methyl-2-pyrrolidone if the polymerization 
step was preceded by distillation of water from a mixture of the partially 
hydrated sodium sulfide and N-methyl-2-pyrrolidone than if such a 
distillation step was omitted. 
In the present invention, at least one dihalo aromatic sulfone, at least 
one organic amide, and at least one alkali metal sulfide selected from the 
group consisting of sodium sulfide, potassium sulfide, rubidium sulfide, 
and cesium sulfide, the alkali metal sulfide being at least partially 
hydrated, are contacted under polymerization conditions for a period of 
time sufficient to form an aromatic sulfide/sulfone polymer. 
Dihalo aromatic sulfones that can be employed in the process of this 
invention can be represented by the formula 
##STR1## 
where each X is selected from the group consisting of fluorine, chlorine, 
bromine, and iodine; Z is a divalent radical selected from the group 
consisting of 
##STR2## 
m is 0 or 1; n is 0 or 1; A is selected from the group consisting of 
oxygen, sulfur, sulfonyl, and CR.sub.2 ; and each R is selected from the 
group consisting of hydrogen and alkyl radicals having 1 to about 4 carbon 
atoms, the total number of carbon atoms in all of the R groups in the 
molecule being 0 to about 12. Preferably, m is 0. 
Examples of some dihalo aromatic sulfones that can be employed in the 
process of this invention include bis(p-fluorophenyl) sulfone, 
bis(p-chloro-phenyl) sulfone, bis(p-bromophenyl) sulfone, 
bis(p-iodophenyl) sulfone, p-chlorophenyl p-bromophenyl sulfone, 
p-iodophenyl 3-methyl-4-fluorophenyl sulfone, bis(2-methyl-4-chlorophenyl) 
sulfone, bis(2,5-diethyl-4-bromophenyl) sulfone, 
bis(3-isopropyl-4-iodophenyl) sulfone, bis(2,5-dipropyl-4-chlorophenyl) 
sulfone, bis(2-butyl-4-fluorophenyl) sulfone, 
bis(2,3,5,6-tetramethyl-4-chlorophenyl) sulfone, 2-isobutyl-4-chlorophenyl 
3-butyl-4-bromophenyl sulfone, 1,4-bis(p-chlorophenylsulfonyl)benzene, 
1-methyl-2,4-bis(p-fluorophenylsulfonyl)benzene, 
2,6-bis(p-bromophenylsulfonyl)naphthalene, 
7-ethyl-1,5-bis(p-iodophenylsulfonyl)naphthalene, 
4,4'-bis(p-chlorophenylsulfonyl)biphenyl, 
bis[p-(p-bromophenylsulfonyl)phenyl] ether, 
bis[p-(p-chlorophenylsulfonyl)phenyl] sulfide, 
bis[p-(p-chlorophenylsulfonyl)phenyl] sulfone, 
bis[p-(p-bromophenylsulfonyl)-phenyl] methane, 
5,5-bis[3-ethyl-4-(p-chlorophenylsulfonyl)phenyl] nonane, and the like, 
and mixtures thereof. 
As indicated above, the alkali metal sulfide can be sodium sulfide, 
potassium sulfide, rubidium sulfide, or cesium sulfide, the alkali metal 
sulfide being at least partially hydrated. If desired, mixtures of alkali 
metal sulfides can be employed. Optionally, free water as well as water of 
hydration can be present. Although the sum of the amounts of water present 
as free water and as water of hydration can vary considerably, generally 
it will be within the range of about 1 mole to about 10 moles, preferably 
about 2 moles to about 9 moles, per mole of alkali metal sulfide. Thus, 
the alkali metal sulfide composition can comprise a mixture of hydrated 
alkali metal sulfide and either anhydrous alkali metal sulfide or free 
water. Examples of some suitable alkali metal sulfides include sodium 
sulfide nonahydrate, potassium sulfide pentahydrate, rubidium sulfide 
tetrahydrate, and cesium sulfide tetrahydrate. The alkali metal sulfide 
presently preferred is sodium sulfide containing about 60 weight percent 
Na.sub.2 S and about 40 weight percent water of hydration, corresponding 
to an average of about 2.8 molecules of water of hydration per molecule of 
sodium sulfide. 
The organic amides used in the method of this invention should be 
substantially liquid at the reaction temperatures and pressures employed. 
The amides can be cyclic or acyclic and can have 1 to about 10 carbon 
atoms per molecule. Examples of some suitable amides include formamide, 
acetamide, N-methylformamide, N,N-dimethylformamide, 
N,N-dimethylacetamide, N-ethylpropionamide, N,N-dipropylbutyramide, 
2-pyrrolidone, N-methyl-2-pyrrolidone, .epsilon.-caprolactam, 
N-methyl-.epsilon.-caprolactam, N,N'-ethylenedi-2-pyrrolidone, 
hexamethylphosphoramide, tetramethylurea, and the like, and mixtures 
thereof. 
The aromatic sulfide/sulfone polymers produced by the process of this 
invention can be characterized as having recurring 
##STR3## 
units, where each R, Z, and m is as defined above. 
Although the mole ratio of dihalo aromatic sulfone to alkali metal sulfide 
can vary over a considerable range, generally it will be within the range 
of about 0.9:1 to about 2:1, preferably about 0.95:1 to about 1.2:1. The 
amount of organic amide can vary greatly, generally being within the range 
of about 100 grams to about 2500 grams per gram-mole of alkali metal 
sulfide. 
Although the reaction temperature at which the polymerization is conducted 
can vary over a considerable range, generally it will be within the range 
of about 150.degree. C. to about 240.degree. C., preferably about 
180.degree. C. to about 220.degree. C. The reaction time can vary widely, 
depending in part on the reaction temperature, but generally will be 
within the range of about 10 minutes to about 3 days, preferably about 1 
hour to about 8 hours. The pressure should be sufficient to maintain the 
dihalo aromatic sulfone and organic amide substantially in the liquid 
phase. 
The aromatic sulfide/sulfone polymers produced by the process of this 
invention can be separated from the reaction mixture by conventional 
procedures, e.g., by filtration of the polymer, followed by washing with 
water, or by dilution of the reaction mixture with water, followed by 
filtration and water washing of the polymer. If desired, at least a 
portion of the washing with water can be conducted at an elevated 
temperature, e.g., from about 130.degree. C. to about 250.degree. C. 
The aromatic sulfide/sulfone polymers produced by the process of this 
invention can be blended with fillers, pigments, extenders, other 
polymers, and the like. They can be cured through crosslinking and/or 
chain extension, e.g., by heating at temperatures up to about 480.degree. 
C. in the presence of a free oxygen-containing gas, to provide cured 
products having high thermal stability and good chemical resistance. They 
are useful in the production of coatings, films, molded objects, and 
fibers.

EXAMPLES 
In Examples I and II, values for inherent viscosity were determined at 
30.degree. C. in a 3:2 mixture, by weight, of phenol and 
1,1,2,2-tetrachloroethane at a polymer concentration of 0.5g/100 ml 
solution. In Examples III and IV, values for inherent viscosity were 
determined at 206.degree. C. in 1-chloronaphthalene at a polymer 
concentration of 0.4g/100 ml solution. In each of the Examples, values for 
glass transition temperature (T.sub.g) and crystalline melting point 
(T.sub.m), where shown, were determined on premelted and quenched polymer 
samples by differential thermal analysis. The values for polymer-melt 
temperature (PMT) were determined by placing portions of the polymer on a 
heated bar with a temperature gradient. The name poly(p-phenylene 
sulfide/sulfone) is used to describe an aromatic sulfide/sulfone polymer 
having recurring 
##STR4## 
EXAMPLE I 
In a control run outside the scope of this invention, employing a 
dehydration step, 65.2g (60 percent assay, 0.5 mole) sodium sulfide, 0.2g 
sodium hydroxide (to react with sodium bisulfide and sodium thiosulfate 
present in trace amounts in the sodium sulfide), and 158.3g 
N-methyl-2-pyrrolidone were charged to a stirrer-equipped, 1-liter 
autoclave, which was then flushed with nitrogen. Dehydration of the 
mixture by heating to 205.degree. C. yielded 16 ml of distillate 
containing 14.1g water. To the residual mixture were charged 143.6g (0.5 
mole) bis(p-chlorophenyl) sulfone and 40g N-methyl-2-pyrrolidone. The 
resulting mixture was heated for 5 hours at 200.degree. C. at a pressure 
of 40-55 psig. The reaction product was washed repeatedly with hot water 
and dried at 80.degree. C. under nitrogen in a vacuum oven to obtain a 
yield of 121.9g of amorphous poly(p-phenylene sulfide/sulfone) having an 
inherent viscosity of 0.29, a T.sub.g of 203.degree. C., and a PMT of 
275.degree. C. 
EXAMPLE II 
In a run within the scope of this invention, without the use of a 
dehydration step as employed in Example I, 65.2g (60 percent assay, 0.5 
mole) sodium sulfide, 0.2g sodium hydroxide (to react with sodium 
bisulfide and sodium thiosulfate present in trace amounts in the sodium 
sulfide), 198.3g N-methyl-2-pyrrolidone, and 143.6g (0.5 mole) 
bis(p-chlorophenyl) sulfone were charged to a stirrer-equipped, 1-liter 
autoclave, which was then flushed with nitrogen. The resulting mixture was 
heated for 5 hours at 200.degree. C. at a pressure of 45-55 psig. The 
reaction product was washed repeatedly with hot water and dried at 
80.degree. C. under nitrogen in a vacuum oven to obtain a yield of 109.5g 
of amorphous poly(p-phenylene sulfide/sulfone) having an inherent 
viscosity of 0.36, a T.sub.g of 209.degree. C., and a PMT of 275.degree. 
C. 
Thus, based on inherent viscosity, the poly(p-phenylene sulfide/sulfone) 
produced in this Example was of substantially higher molecular weight than 
that produced in Example I, in which a dehydration step was employed prior 
to the polymerization step. 
EXAMPLE III 
In a run outside the scope of this invention, employing a dehydration step 
in the preparation of poly(p-phenylene sulfide) instead of 
poly(p-phenylene sulfide/sulfone), 127.2g (61 percent assay, 1.0 mole) 
sodium sulfide and 276.7g N-methyl-2-pyrrolidone were charged to a 
stirrer-equipped, 1-liter autoclave, which was then flushed with nitrogen. 
Dehydration of the mixture by heating to 215.degree. C. yielded 22 ml of 
distillate containing 21.2g water. To the residual mixture were charged 
149.9g (1.02 moles) p-dichlorobenzene and 50g N-methyl-2-pyrrolidone. The 
resulting mixture was heated for 3 hours at 245.degree. C. at a pressure 
of 20-100 psig. The reaction product was washed with hot water and dried 
to obtain a yield of 100.8g of poly(p-phenylene sulfide) having an 
inherent viscosity of 0.16, a T.sub.g of 85.degree. C., a T.sub.m of 
288.degree. C., and a PMT of 271.degree. C. 
EXAMPLE IV 
In a run outside the scope of this invention, comparable to the run in 
Example III except that a dehydration step was not employed prior to the 
polymerization step, 127.2g of (61 percent assay, 1.0 mole) sodium 
sulfide, 326.7g N-methyl-2-pyrrolidone, and 149.9g (1.02 moles) 
p-dichlorobenzene were charged to a stirrer-equipped, 1-liter autoclave, 
which was then flushed with nitrogen. The resulting mixture was heated for 
3 hours at 245.degree. C. at a pressure of 120-175 psig. The reaction 
product was washed with hot water and dried to obtain a yield of 92.2g of 
poly(p-phenylene sulfide) having an inherent viscosity of 0.12, a T.sub.g 
of 71.degree. C., a T.sub.m of 285.degree. C., and a PMT of 275.degree. C. 
Thus, the observation that use of a dehydration step in the preparation of 
poly(p-phenylene sulfide), as in Example III, resulted in a polymer of 
higher molecular weight than that obtained without the dehydration step, 
as in Example IV, rendered surprisingly the opposite effect subsequently 
observed in the preparation of poly(p-phenylene sulfide/sulfone), as 
illustrated in Examples I and II.