CA1335030C - High strength fibers of stereoregular polystyrene - Google Patents

Abstract

The invention is a crystalline fiber comprising syndiotactic polystyrene, or a mixture. Preferably the fiber is a high strength fiber isotactic polystyrene and syndiotactic polystyrene wherein the fiber is monoaxially oriented, has a tensile strength of 10,000 psi or greater, and a modulus of 1,000,000 psi or greater.
In another aspect the invention is a process for the preparation of fibers of syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactic polystyrene which comprises:
A. contacting syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactic polystyrene with a solvent for the polystyrene at elevated temperatures under conditions such that a homogeneous solution is formed which has sufficient viscosity to be extruded;

B. extruding the solution through an orifice to form a fiber at elevated temperatures;
C. quenching the fiber by passing the fiber through one or more zones under conditions such that the fiber solidifies;

D. removing the solvent for the polystyrene from the fiber; and E. cooling the fiber to ambient temperature.
In the embodiment where it is desirable to prepare high strength fibers, the fibers are further exposed to the following process steps:
F. heating the fiber to a temperature above the glass transition temperature of the polystyrene;
G. redrawing the fiber to elongate the fiber, maximize crystallinity, and induce monoaxial orientation of the polystyrene in the fiber.

Description

HIGH STRENGTH FIBERS OF STEREOREGULAR POLYSTYRENE

Thi~ invention relates to fiber~ of stereo-regular polystyrene, in particular isotactic and syndiotactic polystyrene. This invention further relates to a process for the preparation of such fibers.
In many indu~tries there is a drive to replace the metal~ u!~ed as ~tructural material~ with plastic material~. Plastic material~ offer several advantage~
in that they are frequently lighter, do not interfere with magnetic or electrical signals, and often are cheaper than metal~. One major di~advantage of plastic material~ is that they are significantly weaker than many metals. To provide plastic structural article~ and part~ which have sufficient strength for the intended u~e, it is common to use composite material~ which comprise a polymer or plastic matrix with high strength fiber~ in the plastic or polymer matrix to provide enhanced strength. Examples of compo~ites made using such high strength fibers can be found in Harpell et al., U.S. Patent 4,457,985 and Harpell et al., U.S.
~atent 4,403,012.

36,514-F _1_ 1 335~3~
A series of patents have recently issued which relate to high strength fibers of polyethylene, polypropylene or copolymers of polyethylene and polypropylene. Such fibers are demonstrated as being useful in high strength composites. See Harpell et al., U.S. Patent 4,563,392 ; Kave~h et al., U.S. Patent ~,551,296; Harpell et al., U.S. Patent 4,543,286; Kavesh et al., U.S. Patent 4,536,536 ; Kavesh et al., U.S.
Patent 4,413,110; Harpell et al., U.S. Patent 4,455,273;
and Kavesh et al., U.S. Patent 4,356,138. Other polymers which have been used to prepare fibers for com-po~ites include polyphenylene sulfide, polyetherether-ketone and poly(para-phenylene benzobisthiazole).

The polyethylene and polypropylene fibers although exhibiting excellent modulus and tensile properties, have a relatively low heat di~tortion temperature and poor solvent resi~tance. The polyphenylene ~ulfide, polyetheretherketone, and poly(p-phenylene benzobisthiazole) polymers exhibit excellent heat distortion temperatures and solvent resistance, but are difficult to process and quite expensive.
What are needed are fibers useful in compo~ites 25 which exhibit good solvent resistance and heat distortion properties, are processible, and prepared from materials which have reasonable co~ts. What are further needed are ~uch fibers with high ~trength.
The invention i~ a crystalline fiber compri~ing syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene. Preferably the fiber is a high strength fiber of isotactic polystyrene and syndiotactic polystyrene wherein the fiber is monoaxially oriented, has a ten~ile strength of 36,514-F -2--10,000 psi or greater, and a modulus of 1,000,000 psi or greater.

In another a~pecl ~he invention is a proces~
for the preparation of fiber~ of syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactio polystyrene which comprises:
A. contacting syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactic polystyrene with a solvent for the poly~tyrene at elevated temperatures under conditions such that a homogeneous solution is formed which has sufficient viscosity to be extruded;
B. extruding the solution through an orifice to form a fiber at elevated temperatures;
C. quenching the fiber by passing the fiber through one or more zones under conditions such that the fiber solidifie~;
D. removing the solvent for the polystyrene from the fiber; and E. cooling the fiber to ambient temperature.
In the embodiment where it is desirable to prepare high strength fibers, the fibers are further exposed to the following process steps:
3 F. heating the fiber to a temperature above the glass transition temperature of the polystyrene;

36,514-F -3-G. redrawing the fiber to elongate the fiber, maximize crystallinity, and induce monoaxial orientation of the polystyrene in the fiber.
The fibers of this invention exhibit excellent solvent resistance and heat distortion properties, and may be processed and prepared with relative ease. The starting materials used to prepare these fibers can be prepared at a relatively low cost.

The fibers of this invention may be prepared from ~yndiotactic polystyrene or a mixture of syndiotactic and isotactic polystyrene. Syndiotactic polyqtyrene is polystyrene whereby the phenyl groups which are pendent from the chain alternate with respect to which side of the chain the phenyl group is pendent.
In other words, every other phenyl group is on the oppoqite side of the chain. Isotactic polystyrene haq all of the phenyl rings on the same side of the chain.
Note that standard poly~tyrene iq referred to as atactic, meaning it has no stereoregularity, and the placement of the phenyl groups from the styrene with respect to each side of the chain is random, irregular, and follows no pattern.
The fibers of this invention are monoaxially oriented to improve the tensile strength and modulus of the fibers. Preferably the fibers have a tensile strength of 10,000 psi or greater, more preferably 20,000 psi or greater and most preferably 30,000 psi or greater. The fibers of this invention preferably have a modulus of 1,000,000 psi or greater, more preferably 2,500,000 psi or greater, and most preferably 5,000,000 psi or greater. The fibers of this invention may be extruded into any size, shape or length desired.

36,514-F -4-Preferably the fibers of this invention have a heat distortion temperature of 150C or greater, more preferably 170C or greater and most preferably 190C or greater. Preferably the fibers of this invention have a crystalline melting temperature of 200C or greater, more preferably 220C or greater, and most preferably 240C or greater.

Isotactic and syndiotactic polystyrene may be prepared by methods well known in the art. For procedures for the preparation of isotactic polystyrene, see Natta et al., Makromol. Chem., Vol. 28, p. 253 (1958). For procedures for the preparation of syndiotactic polystyrene, see Japanese Patent 104818 (1987) and Chshihaora, Macromolecules, 19 (9), 2464 (1986).
The fibers of this invention may be prepared by a solution spinning proces~, or melt spin process. In the solution ~pinning proce~s, the polystyrene i~
contacted with a ~olvent for the polystyrene at elevated temperatures. The weight percent of the polystyrene in the solvent should be such that there is sufficient viscosity to extrude the polymer. If the viscosity is too low the fibers coming out of the extruder will have no phy~ical integrity, and if the viscosity i~ too high the mixture is not extrudable. Preferably the solution ha~ an upper limit on viscosity at the extrusion sheer rate of 1,000,000 poise, more preferably 500,000 poise 3 and most preferably 100,000 poise. Preferably the solution has a lower limit on vi~cosity at the extrusion sheer rate of 100 poise, more preferably 1,000 poise and most preferably 10,000 poise.

36,514-F _5_ The polystyrene molecular weight should be ~ufficient such that fibers with reasonable integrity may be formed. The preferred upper limit on molecular weight (Mn) is 4,000,000, with 1,000,000 being more preferred. The preferred lower limit on molecular weight (Mn) is 200,000, with 400,000 being more preferred. Preferably the mixture or solution which is extruded contains up to 40 weight percent of polystyrene, more preferably between about 3 and 3 weight percent of polystyrene and most preferably between 5 and 15 percent polystyrene. The amount of polystyrene which may be dissolved in the various solvents is dependent upon the molecular weight, of the poly~tyrene as the molecular weight of the polystyrene goes up the weight percent of the polystyrene which may go into solution may be lower.
The temperature at which the material~ are contacted is such temperature at which the solution has ~ufficient viscosity to be extrudable and which doe~ not degrade the poly~tyrene. The upper temperature i~
either the degradation temperature of the polystyrene or the boiling point of the solvent, and the lower temperature is that temperature at which the mixture is a single phase liquid. Above 250C the polystyrene undergoes degradation. The upper temperature for the mixing step is preferably 275C, and more preferably 160C. The lower temperature for the mixing step is preferably 100C and more preferably 140C.
It is desirable, although not essential, that the hot solution of polymer in solvent becomes gelatinous, or more preferably a rigid gel, when it i~
cooled to lower temperatures. Solutions of syndiotactic polystyrene usually readily form gels, when they are 36,514-F -6-cooled to lower temperature~ otactic poly~tyrene solutions may also form gel~ under such condition~. The ability to form gel~ from ~GI~tiQns containing both ~yndiotactic and i~otactic polymers can often be controlled to advantage by selection of the proper ratio of each polymer and the ~election of the proper solvent.
Where a fiber i~ to be prepared from both ~yndiotactic polystyrene and isotactic poly~tyrene the ratio of ~yndiotactic poly~tyrene to i~otactic polystyrene in the blend i~ any ratio which give~ fiber with ~tructural integrity and i~ preferably between 0.1 (1:1) and 20 (3:1), more preferably between 1 and 3, mo~t preferably between 0.75 and 1.25.
1~ Solvent~ u~eful in thi~ invention are those which are a liquid at extru~ion temperatures and which di~olve a ~ufficient amount of the polymer to re~ult in a ~olution vi~cous enough to extrude. Preferred ~olvent~ include ~ub~tituted benzene~ of the formula~

(R1) ~ or (R2)b ~ C-R3)C

wherein Rl i~ alkyl, hydrogen, cycloalkyl, halo, or nitro; o R i~ alkyl;
R3 i~ aryl, alkyl, carboxyaryl, or alkoxy;
a i~ an integer of from 1 to 3 36,514-F -7--8- l 3 3 ~ ~ 3 ~

b i~ an integer of from O to 3 c is an integer of from l to 2.
Other preferred ~olvent~ include alkyl, cycloalkyl, aryl or aralkyl 3ub~tituted pyrrolidinone~;
chloronaphthalene~; hydrogenated and partially hydrogenated naphthalenes; aryl ~ub~tituted phenols;
ethers of the formula ~--o-R4 wherein R4 i~ alkyl cycloalkyl or aryl; diphenyl sulfone; benzyl alcohol; caprolactam; alkyl aliphatic e~ters containing a total of from 7 to 20 carbon atoms;
alkyl aryl 3ub~tituted formamide~; dicyclohexyl;
terphenyls; partially hydrogenated terphenyl~; and mixture~ of terphenyl~ and quaterphenyl~.
Preferred ~ub~tituted benzene ~olvent~ include o-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, xylene, nitrobenzene, acetophenone, methyl benzoate, ethyl benzoate, diphenyl phthalate, benzil, methyl ~alicylate, benzophenone, cyclohexyl benzene, n-butylbenzene, n-propylbenzene, phenol, and dimethyl phthalate. Example~ of preferred ether~
include phenetole (phenyl ethyl ether), diphenyl ether, 3 and ani~ole. Example~ o~ preferred pyrrolidinone ~olvent~ include 1-benzyl pyrrolidinone, 1-cyclohexyl pyrrolidinone, l-ethyl pyrrolidinone, l-methyl pyrrolidinone, and 1-phenyl pyrrolidinone. More preferred pyrrolidinone solvent~ include the alkyl and cycloalkyl sub~tituted pyrrolidinone~. Even more 36,514-F -8-1 33~030 preferred pyrrolidinone solvents include l-cyclohexyl pyrrolidinone, 1-ethyl pyrrolidinone and 1-methyl pyrrolidinone. Preferred ether solvents include anisole and diphenyl ether. Preferred hydrogenated naphthalene solvents include decahydronaphthalene (decalin) and tetrahydronaphthalene (tetralin). Examples of terphenyls and partially hydrogenated terphenyls preferred include partially hydrogenated terphenyls, available from Monsanto under the tradename Therminol~ 66; mixed terphenyls and quaterphenyls, available from Monsanto under the tradename Therminol~ 75; and mixed terphenyls available from Monsanto under the Santowax~ R tradename.

More preferred aliphatic esters are those methyl aliphatic esters with a total of from 10 to 14 carbon atom~, with methyl laurate being mo~t preferred.
More preferred solvents include 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1-ethyl-2-pyrrolidinone, l-methyl pyrrolidinone, 1-cyclohexyl-2-pyrrolidinone, acetophenone, anisole, benzil, benzophenone, benzyl alcohol, caprolactam, decahydronaphthalene, tetrahydronaphthalene, diphenyl ether, ethyl benzoate, methyl ~alicylate, ortho-dichlorobenzene, mixed terphenyls and partially hydrogenated terphenyl~. Even more preferred solvents include 1,2,3-trichlorobenzene, 1-ethyl-2-pyrrolidinone, anisole, tetrahydronaphthalene, and ortho-3 dichlorobenzene. The most preferred solvent is ortho-dichlorobenzene.
Once the mixture ha~ been prepared it is extruded through a die of a desired shape, usually a circular die, into the form of a fiber. The extrusion 36,514-F _g_ is performed at elevated temperatures, the upper limit on the temperature is the lower of the boiling point of the solvent or the degrada~ion temperature of the polystyrene. The lower limit on temperature is the lowest temperature at which the mixture is a ~ingle pha~e homogeneous solution and extrudable. Preferred upper limit on temperature is 250C, with 160C being most preferred. The preferred lower limit on temperature is 100C with 140C being mo~t preferred.
The temperature used to extrude the material is dependent upon the polymer concentration and molecular weight of the polystyrene, as the polymer concentration goes up the temperature neces~ary to extrude the fibers goes up.
From the extruder the fiber is pas~ed through one or more quench zones. Such quench zones may be gaseous quench zone~, liquid quench zones or a combination thereof. In the quench zones the fiber i~
cooled, solidified and drawn down. In a gaseous quench zone the fiber i~ pa~ed through a ga~eou~ zone, ~uch zone may be at a temperature of between 0 and 100C, preferably the temperature i~ ambient temperature. The length of the gaseou~ quench zone i~ a~ ~hort as possible, preferably between 0 and 45.72 cm (18 inches), more preferably between 0 and 15.24 cm (6 inches). The preferred gas i~ air. In a liquid quench zone the fiber i~ cooled and ~olidified, and a portion of the solvent may be removed from the fiber at this time. The liquid which may be used for the liquid quench is a liquid which is a solvent ~or the polystyrene solvent but which does not dis~olve the polystyrene~ Preferred quench zone materials include water, lower alcohols, halogenated hydrocarbons, and perhalogenated carbon 36,514-F -10-1 33503û

compound~. Perhalogenated carbon compound~ are material~ with a carbon backbone wherein all of the hydrogen atoms have been replaced with halogen atoms.
Preferred quench materials include water and lower alcohols with lower alcohol~ being most preferred.
Preferred lower alcohols are C1_4 alcohol~. The lower limit on the temperature of a liquid quench zone i~ that temperature at which the quench material freeze~. The upper limit on the temperature of a liquid quench zone i~ the lower of the boiling point of the ~olvent, or that temperature above which the fiber does not undergo solidification when in contact with the quench material.
Preferably the upper limit on temperature i~ 80 and more preferably 30C. Preferably the lower limit on temperature is 0C.
In a preferred embodiment, the quench zone compri~e~ an air quench zone and a liquid quench zone.
In the air quench zone the fiber undergoes partial ~olidification and los~ of ~ome of the ~olvent, and in the liquid quench zone ~olidification i~ completed and more of the solvent i~ removed. During the quench period the fiber is al~o drawn down. Preferably the lower limit on the draw down i~ from 10:1, more preferably 50:1. Preferably the upper limit on the draw down i~ 100:1. Drawing down means the fibers are ~tretched ~uch that the cros~ sectional area of the fiber i~ smaller at the end of the proce~ and the draw down ratio i~ the ratio of the beginning cross sectional area to the final cro~s ~ectional area. The residence time of the fiber in a liquid quench bath i~ preferably greater or equal to 1 ~econd, more preferably between 1 and 10 seconds.

36,514-F -11--12- 1 3~3~

After quenching the fiber, the fiber is subjected to a leach step wherein the remainder of the solvent in the fiber is removed. The material in which the leaching occurs i~ a material which is a ~olvent for the polystyrene solvent and which does not di~solve the poly~tyrene. The material~ which may be u~ed in the leach are the ~ame material~ which may be u~ed in a liquid quench. Temperatures of the leach bath are tho~e temperatures at which the remaining solvent in the fibers is sub~tantially removed. Preferably the leaching occurs at ambient temperatures, between 20 and 40C more preferably between 20 and 30C. The residence time in the leach bath is sufficient time ~uch that the ~olvent is substantially removed. Preferably the residence time and leach bath is greater then 30 seconds, more preferably between 1 minute and 48 hours and most preferably between 1 minute and 2 hours. The leach may either be performed in a continuou~ on-line process, or may be performed in a batch fa~hion. The re~idence time is dependent upon the particular solvent, the fiber size, and the kinetic~ for removing the solvent from the ~iber.
After forming the fiber and removing the solvent the fiber i~ then allowed to cool to ambient temperature.
When it is de~ired to improve the strength of the fiber, the fiber is reheated to a temperature at 3 which the fiber can be redrawn. It is in the redraw proce~s that the fiber is oriented such that the fiber has monoaxial orientation. The fiber is heated to a temperature between its gla~s transition temperature and its melting point. Preferable upper temperature~ are 280C or below and more preferably 270C or below.

36,514-F -12-s 1 3~5030 Preferable lower temperatures are 150C or above and more preferably 250C or above. Thereafter the fiber is redrawn by stretching ~he fiber with tension; this is usually performed by running the fibers over a set of godets wherein the latter godets are going at a much faster rate than the earlier godets. The fiber is elongated at a ratio of between 1.5:1 and 10:1.
Preferably the rate of elongation is 1 foot per minute or less. The redraw occurs while the fiber is at or near the temperature to which it was preheated. The fiber may be drawn in one or more stages with the options of using different temperatures, draw rates, and draw ratios in each stage.

In another embodiment, the fibers of this invention may be prepared by a melt spin process. In the melt spin process, the neat polymer is heated to a temperature between its crystal melting point and the temperature at which the polymer undergoes degradation.
The particular temperature depends upon whether ~yndiotactic poly~tyrene or a mixture of i~otactic and syndiotactic polystyrene is used. Generally the crystal melting temperature of isotactic polystyrene is somewhat lower than that of syndiotactic polystyrene. The neat polymer is first melted to a temperature at which the material has ~ufficient viscosity to extrude. The viscosity should be high enough such that the fiber extruded has integrity yet not so high that the polymer is too viscous to be extruded. The preferred upper limit on viscosity is 1 x 106 poise (3.6 x 106 kg/m-hr), with 5 x 105 poise (1.8 x 106 kg/m-hr3 more preferred, and 1 x 105 poise (3.6 x 105 kg/m-hr) most preferred.
The preferred lower limit on viscosity is 1 x 102 poise (7.6 x 102 kg/m-hr), with 1 x 103 poise 36,514-F -13-~ 335030 (3.6 x 103 kg/m-hr) more preferred, and 1 x 104 poise (3.6 x 104 kg/m-hr) most preferred. The molecular weight of the polystyrene should be suc~ that fibers of reasonable integrity may be formed. The preferred upper limit on molecular weight (Mn) i9 4 x 106, with 3 x 106 being more preferred, and 2 x 106 most preferred. The preferred lower limit on molecular weight is 2 x 105, with 5 x 105 being more preferred and l x 106 most preferred. Preferably the polymer is melted to a temperature of between 270 and 300C. Thereafter the fiber is extruded at such temperatures. Preferred extrusion temperatures are between 270 and 300C.
Thereafter the fiber is passed through a quench zone.
The quench zone may be either a gaseous quench zone or a liquid quench zone. For a melt extrusion generally an air quench zone is preferred. The air quench zone is generally long enough to quench and solidify the fiber.
Such zone is preferably 30.48 and 182.88 cm (between 1 and 6 feet). The temperature of the quench zone can be any temperature at which the fiber undergoe~ a reasonable rate of cooling and solidification. The preferred lower temperature is about 0, most preferably 20. The preferred upper temperature is 100C, most preferably 50C. During the quench period the fiber is drawn down from between 10:1 to 100:1. After the quench period, the fiber is allowed to cool to ambient temperature~. To prepare high strength fibers, the fiber is thereafter heated to between the Tg of the polymer and the melting point of the polymer. The preferred upper temperature is 280C with 270C being most preferred. The preferred lower temperature is preferably 150C, and more preferably 160C. While the fiber is still between its Tg and its melting tempera-ture the fiber is redrawn as described previously. The 36,514-F -14-slower the rate the better the orientation and stronger the fiber will be. Generally the elongation will be up to a ratio Gf 4 to l.

The fibers of thi~ invention as discussed before can be incorporated into composite~. The methods for such incorporation and the composites in which the fibers can be used in are well known to those ~killed in the art.
The following examples are included for illustrative purpo~e~ only. Unless otherwise ~tated all parts and percentage~ are by weight.
Example 1 Six percent isotactic polystyrene, 6 percent ~yndiotactic poly~tyrene, and 88 percent o-dichloro-benzene are mixed at 120C for 10 minute~. The resulting mixture, containing dissolved and partially di~olved polymer, i~ added to the melt pot of a pot extruder. Thi~ mixture i~ then heated to 170C and ~tirred for one hour under a nitrogen atmosphere. The mixture is then extruded at 110C through a 1.0 mm diameter spinnerette into a methanol bath to form a gel fiber. The fiber is collected and extracted in methanol for 24 hour~ to remove the o-dichlorobenzene. The extracted fiber is ~tretched 350 percent at 100C to produce a fiber with a tensile ~trength of 10,700 p~i and a modulu~ of 1,300,000 p~i with an elongation of 1.9 percent.
Example 2 Seven percent i~otactic polystyrene, 3 percent syndiotactic polystyrene, and 90 percent o-dichloro-36,514-F _15_ -16- l 335 ~30 benzene are mixed at 120C for 10 minutes. The resulting mixture, containing dissolved and partially dissolved polymer, is added to the melt pot of a pot extruder. This mixture is then heated to 170C and stirred for one hour under a nitrogen atmosphere. The mixture is then extruded at 110C through a 1.0 mm diameter spinnerette into a methanol bath to form a gel fiber. The fiber is collected and extracted in methanol for 24 hours to remove the o-dichlorobenzene. The extracted fiber is stretched at a ratio between 3:1 and 4:1 at 150C to produce a fiber with a tensile strength of 23,000 psi and a modulu~ of 500,000 psi. The final elongation is 25 percent.
Example 3 Three point five (3.5) percent isotactic polystyrene, 1.5 percent syndiotactic polystyrene, and 95 percent o-dichlorobenzene are mixed at 120C for 10 minutes. The resulting mixture, containing dissolved and partially dissolved polymer, is added to the melt pot of a pot extruder. This mixture i~ then heated to 170C and stirred for one hour under a nitrogen atmosphere. The mixture is then extruded at 130C
through a 1.0 mm diameter spinnerette into a methanol bath to form a gel fiber. The fiber is collected and extracted in methanol for 24 hours to remove the o-dichlorobenzene. The extracted fiber is stretched 900 percent at 150C to produce a fiber with a ten~ile 3 strength of 14,000 p~i and a modulus of 1,300,000 psi.
Example 4 Five percent isotactic polystyrene, 5 percent syndiotactic polystyrene, and 90 percent o-dichloro-36,514-F -16-~ -17- 1 33503~

benzene are mixed at 120C for 10 minute~. The re~ulting mixture, containing di~olved and partially dissolved polymer, i~ added t~ the melt pot of a pot extruder. Thi~ mixture is then heated to 170C and stirred for one hour under a nitrogen atmosphere. The mixture i~ then extruded at 110C through a 1.0 mm diameter ~pinnerette into a methanol bath to form a gel fiber. The fiber is collected and extracted in methanol for 24 hours to remove the o-dichlorobenzene. The extracted fiber i~ ~tretched 300 percent at 130C to produce a fiber with a ten~ile ~trength of 29,000 psi and a modulu~ of 2,700,000 p~i with a final elongation of 2.2 percent.

Example 5 Seven percent syndiotactic poly~tyrene, and 93 percent o-dichlorobenzene are mixed at 120C for 10 minute~. The resulting mixture, containing dissolved and partially di~olved polymer, i~ added to the melt pot of a pot extruder. This mixture is then heated to 170C and ~tirred for one hour under a nitrogen atmosphere. The mixture is then extruded at 110C
through a 1.0 mm diameter ~pinnerette into a methanol bath to form a gel fiber. The fiber is collected and extracted in methanol for 24 hours to remove the o-dichlorobenzene. The extracted fiber i~ stretched 200 percent at 150C to produce a fiber with a tensile ~trength of 10,000 p~i and a modulu~ of 1,300,000 p~i.
Example 6 Syndiotactic poly~tyrene, with a molecular weight of 300,000 Mw, is placed in the heating zone of an extruder and heated to 250C. The polystyrene is 36,514-F -17-~ ` ~

l 335030 extruded at 250C through a l.0 mm diameter spinnerette into an air quench zone. The fiber after quenching i~
taken up and allowed to cool to ambient temperature.
The fiber exhibits a tensile strength of 15,000 psi, and a modulus of 1,200,000 psi with a final elongation of 5.6 percent.
Example 7 Syndiotactic poly~tyrene, with a molecular weight of 700,000 Mw, i~ placed in the heating zone of an extruder and heated to 260C. The poly~tyrene is extruded at 260C through a 1.0 mm diameter spinnerette into an air quench zone. The fiber after quenching is taken up and allowed to cool to ambient temperature.
The fiber is redrawn 100 percent at 180C. The fiber exhibits a tensile strength of 19,000 p~i, and a modulu~
of 830,000 psi with a final elongation of 4.1 percent.
Example 8 Syndiotac'cic poly~tyrene, with a molecular weight of 700,000 Mw, is placed in the heating zone of an extruder and heated to 260C. The polystyrene is extruded at 260C through a 1.0 mm diameter spinnerette into an air quench zone. The fiber after quenching is taken up and allowed to cool to ambient temperature.
The fiber is redrawn 160 percent at 280C. The fiber exhibits a tensile strength of 15,000 psi, and a modulus of 950,000 p~i with a final elongation of 3.9 percent.
Example 9 Syndiotactic polystyrene, with a molecular weight of 800,000 Mw, is placed in the heating zone of an extruder and heated to 275C. The polystyrene is 36,514-F -18-~ `

extruded at 275C through a 1.0 mm diameter spinnerette into an air quench zone. The fiber after quenching is taken up and allowed to cool to ambient temperature.
The fiber exhibit~ a tensile strength of 10,000 p~i, and a modulus of 410,000 psi with a final elongation of 5 3.7 percent.
Example 10 Syndiotactic poly~tyrene, with a molecular 10 weight of 800,000 Mw, i~ placed in the heating zone of an extruder and heated to 275C. The poly~tyrene i~
extruded at 275C through a 1.0 mm diameter spinnerette into an air quench zone. The fiber after quenching i~
taken up and allowed to cool to ambient temperature.
The fiber i~ redrawn 50 percent at 280C. The fiber exhibit~ a tensile ~trength of 8,000 p~i, and a modulu~
of 470,000 p~i with a final elongation of 2.1 percent.
Example 11 Syndiotactic poly~tyrene, with a molecular weight o~ 3,000,000 Mw, i~ placed in the heating zone of an extruder and heated to 300C. The poly~tyrene i~
extruded at 300C through a l.0 mm diameter ~pinnerette 25 into an air quench zone. The fiber after quenching is taken up and allowed to cool to ambient temperature.
The fiber exhibit-~ a tensile ~trength of 12,000 p~i, and a modulu~ of 450,000 p~i with a final elongation of 30 6.3 percent.
Example 12 Syndiotactic polystyrene, with a molecular weight of 3,000,000 Mw, i~ placed in the heating zone of an extruder and heated to 300C. The poly~tyrene i~

36,514-F -19--20- 1 3 3 ~ ~ 3 ~

extruded at 300C through a 1.0 mm diameter spinnerette into an air quench zone. The fiber after quenching i~
taken up and allowed to cool to ambient temperature.
The fiber i~ redrawn 50 percent at 280C. The fiber exhibit~ a ten~ile ~trength of 14,000 p~i, and a modulu~
of 700,000 p~i with a final elongation of 3.8 percent.
Example 13 Mixtures consi~ting of approximately five 10 weight percent polymer, either in variou~ organic compounds are prepared in two dram-capacity gla~ vials that are sub~equently sealed with aluminum Poil liner~.
The mixture~ are weighed to a preci~ion of one milligram. The vial~ are placed in an air-circulating oven at about 125-140C. Di~olution behavior i~
ob~erved by transmitted light at close range from an A0 univer~al micro~cope illuminator at progre~ively increa~ing temperature~ until complete di~solution i~
20 observed, until the boiling point of the solvent i~
clo~ely approached, or until 300C i~ reached (the approximate ceiling temperature of the poly~tyrene).
The temperature i~ increa~ed in about 25C increment~.
The mixture~ are allowed to remain at a given 25 temperature for at lea~t about 30 minute~ before the temperature i~ increa~ed further. The hot mixture~ were cooled to room temperature; their appearance was noted after they were allowed to ~tand undi~turbed overnight at room temperature. The result~ are compiled in Table 3 I. The polymer noted a~ "IPS42" refers to a ~ample of i~otactic poly~tyrene with a visco~ity average molecular weight in exces~ of 2.6 x 106 dalton~ and contains about 9.4 percent atactic poly~tyrene (i.e., polymer extractable with hot methyl ethyl ketone~. The polymer noted a~ "SYNDI02" i~ a sample of syndiotactic 36,514-F -20-polystyrene with a weight-average molecular weight of about 5.6 x 105 daltons. The polymer noted as "SYNDI0"
is a sample of syndiotactic polystyrene with a l~wer molecular weight.

3o 36,514-F -21-w I'OLYMl~l~ Wc~r , SOLVKNT APPKOX. rr'MP SOI.UBII ITY Alll'llAl~ANCr ATKOOM'I'UMI' IPS42 5.01 1,2,3-lrichlorob~nYene 218 191 Soluble Hard opaque solid IPS42 5.08 1,2,4-trichlorobenzene 214 190 Partly soluble If'S42 5.08 1,2,4-trichlorobenzene 214 202 Soluble Clear liquid II'S42 5.14 1-benzyl-2-pyrrolidinone 420 275 Soluble Amberclearviscousiluid II'S42 5.14 1 -henzyl-2-l)yrrolidinone 420 250 l'artly ~oluble IPS42 5.83 l-chloronaphthalene 258 225 Partly solublc IPS42 5.83 1-chloronaphlhalene 258 250 Soluble Clear moderately viscous fluid IPS-~2 5.24 1-cyclohexyl-2-pyrrolidinone 301 200 I'artly soluble TPS42 5.24 1 -cyclohexyl-2-pyrrolidinone 301 224 Soluble Amber clear thin jelly IPS42 5.21 1-eLhyl-2-pyrrolidinone206 141 Swollen gel IPS42 5.21 1-ethyl-2-pyrrolidinone206 190 Soluble Yellow clear viscous ~luid (~
IPS42 5.02 1-methyl-2-pyrrolidinone 202 190 Partly soluble IPS42 5.02 1 mclhyl-2-pyrrolidillone 202 202 Solublc YellowcleL~rviscou~lluid IPS42 5.09 1-ptleIlyl-2-pyrrolidinone 345 250 Mo~tly soluble II'S42 5.09 1 -phenyl-2-pyrrolidinone 345 274 Soluble Brown hard solid II'S42 25.29 4-phenylphenol 321 231 Soluble Opaque solid w ,~ POl.YMER WGT % SOLVENT B.P, DEG C SOLUBILITY APPEARANCEATROOMT~MP

IPS42 5.09 4-phenylphenol 321 200 Soluble l'an opaque hard solid IPS42 5 18 ilcctophenone 202 202 Soluble Clear liquid IPS4:2 5.]8 acelophenone 202 190 Partly ~oluble IPS42 5.21 allisole 154 154 Soluble Clear viscous fiuid Il'S42 5.19 bcn~il 347 200 Soluble Clear yellow viscous fluid IPS42 5.19 benzil 347 150 PartiaJly soluble II'S42 5.08 bcrl~ophcnone 305 202 Soluble Clear yellow moderately vi9cous lluid IPS42 5.08 benzophenone 305 190 I'artly ~oluble IPS42 5.42 b~nzyl alcohol 205 190 Almost soluble II'S42 5.42 bcnzyl alcohol 205 204 Soluble Cloudy firm gel IPS42 4.97 butyl stearate 343 275 I'artly soluble IPS42 4.97 butyl stcarate 343 299 llazy & soluble?? Opaque non-homogeneou~ ~emisolid IPS42 5.09 caprolactam (epsilon) 271 211 Soluble Opaque hard solid IPS42 25.12 caprolactam (epsilon) 271 231 Soluble o Il'S42 4.96 dccahydronaphthalene(decalin) 190 190 Soluble llazyliquidwithbottomgellayer ~

,~ POLYMER WGT % SOLVENT B.P, DEG C SOLUBILITY APPEARANCEATRO()MTEMP

IPS42 5.19 dimethyl phthalate 282 190 Soluble Clear liquid II'S42 4.95 diocLyl pthalatc 384 209 13adly swollen IPS42 4.95 dioctyl pthalate 384 298 lIazy & soluble?? I lazy stiff gel II~S42 5.31 diptlcnyl elher 259 190 T'artly soluble II'S42 5.31 diphcnyl ether 259 202 Soluble Clear moderately viscous fluid IPS42 5.19 diphcnyl sulfone 379 166 Almost solublc IPS42 5.19 diphenylsulfone 379 200 Soluble Lighttanopaquehardsolid IPS42 5.01 cthyl benzoate 212 202 Soluble Clear moderately viscous fluid II'S42 5.01 ethyl bcnzoate 212 190 Partly soluble II'S42 5.10 11B-40(Monsanto) 325 250 Soluble Yellowclearviscousfluid IPS42 5.10 1IB-40 (Monsanto) 325 225 Partly soluble II'S42 5.05 mc~ilylcnc(l~3~5-trimethylbenzene) 163 161 Almostsoluble llazyviscousgelatinous~uid IPS42 5.25 methyl benzoate 199 190 Partly soluble ~
IPS42 5.25 mcthyl bcnzoatc 199 202 Soluble Clear liquid W
IPS42 5.08 methyl laurate 262 202 Almost soluble IPS42 5.08 mcthyl laurate 262 225 Soluble Cloudy rigid gel w I'OI.YMI~R MG~ SOLVENT B.P.,DEG DEG C :iOl.Ul~ll.lTY APPEAI~AN(`~:ATR(~OMTklMI' IPS42 5.05 methyl salicylate 222 190 ~artly soluble IPS42 5.05 melhyl salicylate 222 202 Soluble llazy modcralcly viscous fluid IPS42 5.01 mcthylmyristute ~23 298 llazy & soluble?? White opaque sti~gcl IPS42 5.01 melhyl myri~tate 323 209 Alnloslsolllblc II'S42 5.09 mclhyl stcarale 359 249 Mo~lly ~olublc IPS42 5.09 mclhyl slearale 359 299 llazy & sollll)lc?? I'alc yellow hard solid I~S42 5.09 mclhyl stearate 359 275 ll~zy & soluble?? -I[~S42 5.07 niltobcnzene 211 202 I'arlly:;oluble Ycllowclearmodcratelyviscousfluid II'S42 5.14 N,N-dimelhylacetamide 165 166 Soluble Clear fluid with white ppt.
Il'S42 5.14 N N-dimelhyl~cetamide 165 151 Almostsoluble ll'S~2 5.08 N,N dimethylformamide 153 151 Almoslsolul)le Whileopaqueslush IPS42 5.04 N,N diphcl1ylformamide 337 2~9 S~luble l,ightbrownsolid ~
IPS42 5.04 N,N-diphenylformamide 337 225 ~elalinous o ll'S42 5.l6 oclyl accla~c 211 189 ~Imoslsolublc Il'S42 5.16 oclyl acetale 211 209 lla~y & s~luble?? Milky suspension a~
P(~l,YM(~II C(G)N.c~, SOLVEN'r APPIIOX. T 1~ Al'l'EAl~ANCEA'l'EOOM'(`l~MI' IPS42 9.86 o-dichlorobenzene 180 179 Soluble Clear fluid IPS42 5.04 Santowax R (Monsanto)364 166 Gel~linous lI'Sd~2 5.04 Santow~x R (Monsanto)364 200 Soluble Tan hard solid Il'S42 24.89 sulfolane 285 241 Soluble Sof~, opaque solid II'S42 4.86 sulfolane 285 240 Soluble Opaque solid gel IPS42 5.14 letrahydronaphthalene(tetralin) 207 141 Aln~ostsoluble IPS42 5.14 tetrahydronaphthalene(tetralin) 207 190 Soluble Yellowclearliquid IPS42 5.24 Therminol 66 (Monsanto) 340 225 Partly solul)le IPS42 5.24 'I`herminol 66 (Monsanto) 340 250 Soluble Yellow clear viscous fluid Il'S42 5.08 Thcrlllinol 75 (Monsanto) 385 200 Soluble Yellow rubbery elastic gel/solid IPS42 5.08 Therminol 75 (Monsanto) 385 166 Gelatinous IPS42 5.09 xylene 141 141 Partly soluble Ha~y jelly MlX l'UR13~ MIXT~IRE~*I-cyclohexyl-2-pyrrolidinone 301 275 Soluble Amber hazy modera~ely stiff gel MIXTURI1J* MIXTUR~* I-cyclohexyl-2-pyrrolidinone 301 259 Almo~t soluble SYNI)IO 4.72 1,2,4-trichlorobenzene214 211 Soluble Cloudysoftgel SYNI)IO 5.19 I-benzyl-2-pyrrolidinone420 211 Soluble Amberclearfirmgel Ol.YMhl~ waT I solv::Nr E.l',DEC C SOLUBll.l'l'Y APPE:AllANC~:ATUl)OM'lhMI' SYNDIO 4.86 1-chloronapht~ lene 250 211 Soluble Firm hazy gel SYNI)IO 5.08 1-cyclohcxyl-2 pyrrolidinonc 301 200 Solllhlc Ambcrsortgel SYNI)IO 4.95 1-phenyl-2-pyrrolidinone 345 200 Soluble Opaque hard solid SYNI)IO 4.97 4-phenylphenol 321 211 Soluble Opaque hard solid SYNDIO 25.12 4-phenylphenol 321 221 Soluble Opaque solid SYNDIO 5.16 benzil 347 211 Soluble Yellowhardsolid SYNnlO 5.02 benzophenone 305 200 Soluble Clear firnl gel SYN l)lO 4.70 caprolactam (epsilon) 271 211 Solul)le Opaquc hard solid SYNI)IO 24.94 caprolactam (epsilon) 271 221 Suluble Opaque hard solid SYNI)I() 5.29 diphcnyl cther 259 211 Soluble 11'irm hazy gel SYNDIO 5.35 diphenyl sulfone 379 231 Soluble Opaque h~rd solid SYNI)IO 5.08 N,N-diphenylformamide 337 200 Soluble Opaque hard solid SYNI)IO 5.21 o-dichlorobenzene 180 171 Soluble ~irm hazy gel W
SYNI)IO 4.77 sulfolane 285 217 Not soluble ~
SYNI)IO 4.77 sulîolanc 285 231 Soluble l,iquid slush W
SYNDI02 5.09 1,2,3-trichlorobenzene 218 150 Soluble Whiteopaquehardsolid~

I'OLYMI~ WGT I SOLV~NT B.P, DBG C SOLUBILITY AP~EAIIANCEA~ROO!~TEMP

SYND102 5.14 1,2,4-trichlorobPn7.~n~ 214 136 Soluble Cloudy stiffgel SYNl)l02 5.58 1-benzyl-2-pyrrolidinone 420 224 Soluhle Amber hazy stif~gel SYND102 5.58 1-benzyl-2-pyrrolidinone 420 200 Partly soluble SYNl)102 5.26 I-chloronaphthalcne 258136 Soluble Hazystiffgel SYNDIO2 5.16 1-cyclohexyl-2-pyrrolidinone 301 136 Parlly soluble SYNDIO2 5.16 1-cyclohexyl-2-pyrrolidinone 301 150 Soluble Amber soft hazy gel SYNI)102 5.13 1-ethyl-2-pyrrolidinone 296 161 Soluble Pale yellow opaque slush SYND102 5.15 1-methyl-2-pyrrolidinone 202 136 Soluble Cloudy stiffgel SYNl)102 5.04 1-phenyl-2-pyrrolidinone 345 200 Soluble Tanopaquehardsolid SYNI)102 5.09 4-phcnylphenol 321225 Soluble White opaque hard solidSYNOlO2 5.09 4-phenylphenol 321200 Almost soluble SYNI)102 5.13 acetophenone 202165 Soluble Cloudy gel above solid SYND102 5.13 acetophenone 202150 Almostsoluble W
SYNI)102 5.01 anisulc 154153 Soluble Cloudy stil~gel SYNI)102 5.04 benzil 347200 Soluble Yellow opaque hard solidSYND102 5.04 benzil 347150 Parli;llly soluble CONC ,, APPBOX. T~ ' Sol~ulllLlTy AppEARANcl:ArRooMTEMp I'OLYMER WGT % SOLVENI ., DEG C

SYNI)102 5.05benzophen-)ne 305 188 Soluble Clear stif~gelSYNI)102 5.05benzophenone 305 165 I'artly soluble SYNI)102 5.67benzyl alcohol 205 190 Almost soluble SYNI)102 5.67bcn7.yl alcohol 205 204 Soluble White op~(lue sofl gel SYNI)102 5.12buLylstearate 343 273 Soluble Whileopaque~luid SYNI)102 5.12butyl slcarale 343 250 I'arlly soluble SYNI)102 5.09caprolactam (cpsilon) 271 200 Soluble llard solid SYNI)1()2 fi 10cyclohexanonc 155 150 S{)luble Softgel SYNI)102 5.20decahydronaphthalene(decalin) 190 188 Almostsoluble Moderatelystif~slush SYNI)102 5.18dimclhylphlhalate282 200 Partly soluble SYNI)102 5.18dilllelhylphthalate 282 224 Soluble Whiteopaqueslush SYNI)102 5.02diphcnyl ether 259 150 Soluble Clear slif~gel SYNI)102 5 02diphcnylether 259 136 Partlysoluble W
SYNI)102 5.:28diptlcllyl sllll'()nc 379 225 Solublc Pule tan h~ard ~olid ~
SYNI)102 5.19elhyl benzoale 212 165 Almost soluble W
SYNI)102 5.19clhyl bcnz()alc 212 188 Soluble Stif~palc yellow huzy gcl I.YMI~ WGT $:~ ~iOl.VEN'I' APPNOX ~ MI' I\l'l'hAl~ANI'I~ A'l'l~OOM 'I'I~MI' SYND102 5 34 El13-40(Monsanto) 325 151 Partlysoluble SYND102 5.34 ElB-40 (Monsanto) 325 200 Soluble Slightly hazy pale yellow rlrm gel SYND102 5.13 Mesitylene(1,3,5-trimethyl 163 161 Almoslsoluble Stif~hetero~eneousgel ben~ene) SYNI)102 4.97 methyl benzoate 199 150 Soluble Cloudy stil~gel SYNI)1()2 5.04 meLhyl laurate 262 250 Soluble White opaque slush SYNI)102 5.04 nletllyl laulaLe 262 224 l~lmoslsolllble SYNI)102 4.96 methyl myrisl,ate 323 241 Elazy & soluble?? O
323 255 Soluble Opaque white slush SYNI)1()2 4.96 methyl myrlstate SYNI)102 5.07 Tnethyl salicylate 222 175 Soluble Cloudy stiffgel SYNI)102 5.07 n-e~hyl salicylate 222 150 Notsoluble SYN 1)102 5.06 methyl s~earate 359 273 Soluble Opaque solid SYNI)102 5.06 n ethyl stearate 359 250 Partly soluble SYNI)102 5.13 nitrob~nzene 211 151 Soluble Yellowcloudyfirmgel ~rl SYNI)102 4.82 N,N dimethyl~cet~mill~165 165 NotSoluble Whiteslush SYNI)1()2 5.04 N,N-diphenylïormamide 337 225 Soluble Brown hard solid w ,~ I'OI.YMEI~ WGT % SOI.~'ENT DI~G C Sol.U1311.ITY Al'lll:AIU~NCEATl~OOM'l`ICMI' SYND102 5.04 N,N-diphenylformamide 337 200 Almost soluble SYNI)102 5.13 o di(:hlorobcnzcne 180 150 Solublc Cloudy stiffgel SYND102 5.13 o-dichlorobenzene 180 136 Partlysoluble SYNDIO2 5.00 SantowaxR(Monsanto) 364 166 Partiallysoluble SYNL1102 5.00 Santowax R (Monsanto) 364 200 Soluble Tan hard solid SYNI)102 5.00 sulfolane 285 200 Not ~oluble SYNI)102 5.00 sulfolane 285 249 Soluble Light tan opaque firm gel w ~.
SYNI)102 5.00 slllrolanc 285 225 l~arlially solllble SYND102 5.27 telrahydrnn~l~h~ ene (tetralin) 207 136 Soluble Stiffhazy gel SY N 1)1()2 5.15 'I`h~rminol 66 (Monsanto) 340 200 Soluble Slightly hazy palc yellow soft gel SYNI)102 5.15 Thelminol66(Monsallto) 340 151 P~rtlysl)luble SYNI)102 4.99 'I'herminol75(Monsanto) 385 200 Soluble Yellowopaquefirmsolid/gel SYNI)102 5.25 xylene 141 136 Soluble Moderately s~ white opaque gel W
iPS42 5.01 cyclohcxylbenzene 239 158 Soluble Water-clear liquid ~ r~
I}'S~2 5.00 dicycloh~xyl 227 181 Almost soluble ~_~
IPS42 5.00 dicycloht!xyl 227 200 Soluble Clear liquid with ppt.

, POI.YMA~ WaT ~ SOLVENT ~p, DEG C SOLU~ILITY AppEAEANcEAT~ooMTEMp IPS42 4.99 methyl caproate 151 151 Mostly dissolved White opaque homogeneous slush IPS42 4.99 methyl caproate 151 150 lIeavily swollen IPS42 4.99 methyl caprylate 194 151 Not soluble IPS42 4.99 mclhylcapryla~e 194 169 lIeavilyswollen IPS42 4.99 methyl caprylate 194 183 Mostly soluble Opaque white homogene~us slush JPS42 4.99 melhyl enanthate 172 151 Not soluble IPS42 4.99 methyl enanthate 172 172 Mostly dissolved Opaque white homogene~.us slush IPS42 4.99 methyl valerate 128 128 Not soluble Wa~er-clear liquid with polymer 9 selli ment IPS42 5.00 n-butylbenzene 183 151 Mostly dissolved II'S42 5.00 n-butylben~.ene 183 169 Soluble Water-clear liquid IPS42 5.01 n-propylbenzene 159 158 Soluble Clear mod. viscous fluid IPS42 5.01 n-propylbenzene 159 155 Heavily swollen IPS42 4.98 phenetole 169 128 Heavily swollen IPS42 4.98 phenetole 169 151 Mostly dissolved O
IPS42 4.98 phenetole 169 169 Soluble Cle~r pink mod. viscous fluid O

a~
POLYMER WGT % SOLVENT B.P, DEG C SOLUBILITY APPEARANCEATROOMT~:MP

ll'S42 5.08 phenol 182 155 Swollen Tl'S42 5.08 phenol 182 158 Soluble&viscous Cleardarkorangeviscousfluid SYND102 4.98 cyclohexylbenzene 239 181 Soluble Cloudyfirmgel SYNDl02 4.98 cyclohexylhcn7ene 239 158 AlmostSolublc SYND102 4.99 dicyclohexyl227 200 Mostly soluble SYNDI02 4.99 dicyclohexyl227 225 Soluble llomogeneous slush SYNDI02 4.98 n1cthyl c~proate 151 151 Not soluble Clear liquid with solid polymer se~liment SYNDl02 5.01 methyl caprylate 194 194 Not soluble Milky liquid with solid sedimenl;
SYNDl02 4.94 methyl cnanthate 172 172 Not soluble W;~ter-clear liquid with polymer sediment SYNl)102 4 99 methyl valerate 128 128 Not soluble Waler-clear liquid with solid se/liment.
SYNDI02 4.96 n-butylhl~n7-ne 182 183 Mostlysolublc Whi~eopaquesoftgel SYNDl02 4.96 n-butylbenzene 182 169 lleavily swollcn SYNUI02 4.96 n-bulylbenzene 182 161 Not soluble W
SYNl)102 t;.00 n-propylbenzene 159 158 Soluble White opaque firm gel SYND102 5.04 phenetole 169 128 Swollen SYNI)102 5 04 phcnctole 169 150 Soluble llazy pink firm gcl SYND102 5.35 phenol 182155 Swollen ~Mixtu~ e - S~Jl)I02 ( 3 . 1~% ) + I ~S42 ( . 0~% ) ,~ I'OI.YM15R WGT 91, SOI.VENT BP, LBG C B5)LUBII.ITY APPEABAIIC15ATBOOM'1'15MI' SYND102 5.35 phenol 182 158 Almost soluble SYNDI02 5.35 phenol 182 181 Soluble Opaque white flrm gel ~Mixture = S~L)I02 (3.1~%) + I S42 ('.0~%) w

Claims (10)

1. A process for the preparation of fibers of syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene which comprises:
A. contacting syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene with a solvent for the polystyrene at elevated temperatures under conditions such that a homogeneous solution is formed which has sufficient viscosity to be extruded;
B. extruding the solution through an orifice to form a fiber at elevated temperatures;
C. quenching the fiber by passing the fiber through one or more zones under conditions such that the fiber solidifies;
D. removing the solvent for the polystyrene from the fiber; and E. cooling the fiber to ambient temperature.

2. A process of Claim 1 which further comprises:

F. heating the fiber obtained in step E to a temperature above the glass transition temperature of the polystyrene;

G. redrawing the fiber to elongate the fiber and induce monoaxial orientation of the polystyrene in the fiber.

3. The process of Claim 2 wherein the fiber is quenched by:
i. passing the fiber through an air zone wherein the fiber begins to solidify and the fiber is drawn down; and, ii. passing the fiber through one or more liquid zones comprising a liquid which is a solvent for the polystyrene solvent and which is not a solvent for the polystyrene, wherein the fiber is solidified and a portion of the polystyrene solvent is removed.

4. The process of Claim 3 wherein the polystyrene and the solvent for the polystyrene is contacted at a temperature of between 100°C and 275°C.

5. The process of Claim 4 wherein the homogeneous solution is extruded at a temperature of between 100°C and 250°C.

6. The process of Claim 5 wherein the temperature of the air quench zone is between 0°C
and 100°C.

7. The process of Claim 6 wherein the fiber is drawn down in the air quench zone at a ratio of between 10:1 and 100:1.

8. The process of Claim 7 wherein the liquid which is a solvent for the polystyrene solvent and which is not a solvent for the polystyrene is water, a lower alcohol, a halogenated hydrocarbon, or a perhalogenated carbon compound.

9. A fiber which comprises syndiotactic polystyrene or a mixture of syndiotactic polystyrene and isotactic polystyrene.

10. A high strength fiber of syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene prepared by the process of Claim 1 wherein the fiber is monoaxially oriented, has a tensile strength of 10,000 psi or greater, and a modulus of 1,000,000 psi or greater.