CA1037659A - Fluorination and sulfo-fluorination of synthetic resins and fibers - Google Patents

Abstract

FLUORINATION AND SULFO-FLUORINATION
OF SYNTHETIC RESINS AND FIBERS

ABSTRACT OF THE DISCLOSURE

The present invention relates to surface modification of synthetic resin fiberform materials, notably polyamide, poly-ester, polyolefin, and polyacrylonitrile fiberform materials whose surface has been modified by treatment with elemental fluorine, and to the fluorination process.
Also, the properties of synthetic resins are greatly improved if treated with a gaseous reaction medium containing from about C.1-20% by volume of elemental fluorine, 0.1-50%
by volume of sulfur dioxide and 0-21% by volume of oxygen.
Fiber form resins selected from the group consisting of polyamides, polyesters, polyolefins and polyacrylonitriles are surface fluorinated carboxylated and apparently, sulfoxylated.

Description

1~3'7~9 The advent of synthetic resin films and fibers with chemical make up substantially different from the long known natural products like wool and cellulose has required the art to intensively investigate various methods of surface treatment of films and fibers to improve heat sealing of films, printing on films, dyeing fabric and the like. The workers in the art had a natural tendency to equate film treatment with fiber treatment, to equate treatment of polyolefins, polyamides, poly-esters, polyacrylonitriles, etc., to equate chlorine with fluor-ine. In addition, the art has focused on a relatively limitednumber of properties, notably heat sealing, adhesion, dye or printing ink receptivity.
However, other surface characteristics are important, particularly when the material under consideration is in an already dyed fabric form. Good soil and stain release and water absorp-tivity are highly desirable characteristics.
The present invention involves subjecting fiber form synthetic resins selected from the group consisting of polyesters, polyamides, polyolefins, and polyacrylonitriles to a fluorina-tion treatment. Such treatment is effected in an atmosphere oflow oxygen content for relatively brief periods of exposure.
A mild fluorination treatment is intended. In no event is the fiber form resin fluorinated to a combined fluorine content in excess of 5% and preferably far less than 1% by weight of the fiber.
More specifically, the present invention relates to a method for surface treating a fiber form synthetic resin selected from the group consisting of polyamide, polyester, polyolefin and polyacrylonitrile which comprises contacting the fiber form (synthetic) resin for less than fifteen minutes with a fluorine-containing gas having less than about 5% by volume of elemental oxygen and from about 0.1 to about 20% by volume of elemental ~.~
~ -2-:~! ,;, lQ37~
oxygen and from about 0.1 to about 20~ by volume of elemental fluorine and recovering a fluorinated fiber form (synthetic) resin having a combined fluorine level from 4 x 10 7 to 4 x 10 1 mg F/cm .
In addition the present invention relates to an oil stain release moisture transporting fiber form synthetic resin made in accordance with the above method selected from the group consisting of polyamides, polyesters, polyolefins and polyacrylon-itriles, said fiber form resin being surface fluorinated from about 4 x 10 7 to 4 x 10 1 mg F/cm2 and having a fluorinated carboxyl-ated layer with the fluorine and carboxylate groups being con-centrated at the fiber surface and within about 70 A for poly-amide and polyester, and within about 300 A for polyo:Lefin and polyacrylonitriLe, said fluorinated iber form resin exhibiting a neutralization equivalent of below about 1 x 106.
It has also been discovered that conduct of the fluor-ination in the presence of sulfur dioxide creates enhanced moisture transport.
As a result of the fluorination treatment, the fiber form material will be fluorinated in the surface layers only.
The fluorination level can be expressed as being from 4 x 10 7 to 4 x 10 1 mg F/cm .

2~

1~376~
In accordance with the present invention, polyester or polyamide materials are directly fluorinated in an atmosphere considered substantially free of oxygen. That is to say a mixture of carrier gas and fluorine gas, virtually free of any oxygen, is preferred, i.e., less than about O.lg by volume.
Substantially oxygen free, as use~ herein, is intended to denote both the fluorination gas mixture charge into whatever reactor is employed and the fluorination locus of the reactor when charged with said gas mixture. However, commercially available fluorine, as well as inert carrier gases, like nitrogen, may contain minor quantities of oxygen and the essentially unavoid-able oxygen present in such gases, and that remaining in the reactor mus~ be accepted as falling within the sense of a sub-stantially ~ree-of-oxygen fluorination.
Polyol~fins or polyacrylonitrile materials are fluorinated in the presence of elemental oxygen, that is to say, by a mix-ture of carrier gas, elemental fluor ne, and elemental oxyg~r~..
Low levels c,f elemental oxygen are preferred. ~igh levels arQ
detrimental to the treatment. However, commercially availablQ
fluorine, as well as co~lmercially available inert carrier gasss, like nitrogen, may contain minor quantities of oxygen and the essentially unavoidable oxygen present both in the gases, and in the equipment employed for fluorinations will often suffic~
to provide the required oxygen content.
As a practical matter, the fluorination may be success-fully prac-ticed with oxygen being present, up to about 5% by volume in t~e fluorination locus. Nevertheless, most optimally, it is preferred that for polyester and polyamide materials th~
level of oxygen present be minimized to less than 0.1% by volume. E`or polyamide and polyacrylonitrile materials, it is preferred that the level of oxygen present be less than 2%, .

1C1376~
with less than 1~ belng preferred, and 0.2-1.0% the preferred range.
Thus, in carrying out the objectives of the present in-vention a fluorinating mixture comprising generally from about 0.1~ to about 20% elemental fluorine, not more than 5~ elemental oxygen and correspondingly from about 99.9% to about 75~ of carrier gas may be used to fluorinate the fiber form polyalnide, polyester, polyolefin or polyacrylonitrile resins. For most applications, the quantity of fluorine in the gaseous mixture feed to the fluorination will range from 0.1~ to about 10%, the balance being carrier. A more preferable and economical range is fr~m about 0.5% to about 10~ fluorine. The fluorine content at ~he fluorination locus is always lower, sometimes as low as 0.1%.
During fluorination of polyesters, polyamides, polyolefins and polyacrylonitriles in accordance with the present invention, a fluorinated carboxylated layer is formed on the polymer su~- ~
face. The formation of such a layer has been confirmed by means of an electron microscope, by infra-red spectoscopy and by direct tLtration tests made after the fluorinated product has been suhjected to a standard wash cycle.
The combined fluorine groups and the carboxylate groups are concent~ated at the fiber surface, i.e., within about 70 of the fibe~ surface for polyester and polyamide treated materials and within about 300A of -the fiber surface for , polyolefin .~nd polyacrylonitrile tre~ted materials. Thus, fluorination is a surface reaction with relatively little suk-surface pen~tration by the fluorine.
The fluorinated polyester, poly~lefin or polyacrylonitrile resin fiber has exceedlngly desirable properties, notably re-lease of oil stainlng and good water adsorption or molsture 1~37~59 transport. The moisture transport property, measured by a wicking test, is attributable to the presence of the carboxy-late groups. Improved moisture transport is achieved in poly-esters, polyamides, polyolefins, and polyacrylonitriles. The improvement in oil stain release is most striking in polyesters and polyolefins.
Untreated fabrics formed from polyester or polyolefin resin fibers are permanently stained by hydrocarbon and triglyc-eride oils. Such stains lift off under ordinary washing condi-tions from the fluorinated fiber fabrics. Even when the oilstain has litera]ly been forced into the fabric, washing of the f~uor:inated fabric appears to remove much of the oil stain.
Should a pale s~ain r~app~ar at the site of the ori~inal stain, a phenomenon apparently due to migration of oi:L from beneath the fiber surfaces, repeated washin~ removes this secondary stain. Since polyamides and polyacrylonitriles already exhibit good stain release properties, the improvement which occurs upon fluorination is nominal, as a practical matter, and the stain release improvement is limited to polyesters and polyole-fins.
The cacboxylate groups do not detract from the stain re-lease qualities imparted by fluorination and may even enhance tXis proper~y. The carboxylate groups created by fluorination are believed to be most advantageous, being directLy account~ble for the higher water adsorbency of the fluorinated polyester, polyamide, I?olyolefin, and polyacryl~nitrile fiber.
BasicaLly, the wicking test is a test to determine the moisture~ tr~nsport of the fiber and fabrics formed therewith.
The synthet:ics, including the polyamides, polyesters, polyolefins and polyacrylonitriles, have long been condemned for their lack of water absorptivity. They have been called clammy, hot, 1~37~i9 sticky, because all but the smallest amount of free moisture on the surface o-E such fabrics made from synthetic resins remain there as free moisture. The fabric is unable to absorb or wick away the moisture. Moisture absorbency is one material property where cotton and rayon are superior to the polyamide, polyester, polyolefin, and polyacrylonitrile fibers. The sharply enhanced wicking of the surface fluorinated and car-boxylated synthetic fibers constitutes a measure of the higher water adsorptivity so long desired for the polyamide, polyester, polyolefin, and polyacrylonitrile resin fabrics.
Although carboxylate groups on the fiber surface are an ultimate reaction product, they may not be created until the fiber is washed. Some possibility exists that the carboxylal:e groups form as the acyl fluoride, and only later hydrolyze to the carboxy~ate. Certainly a substantial loss o~ ~luoride occurs upon an initial washing, and thereafter little or no loss of fluoride occurs upon repeat washing. Laundering with its alkaline co~ditions will, in theory, at least, convert any free carboxylic acid surface groups to the sodium carboxylate fornl.
In this connection, treated fabrics washed then specially aciid rinsed exhibit the same wicking level as like fabrics water rinsed in d~ionized water or laundered under alkaline conditions.
Age and repeated laundering or dry cleaning do nok seem to material]y affect fluorine content and carboxylate groups con-tent of t~e fibers. Fabrics flu~rinated according to practice of this invention have been laundered repeatedly without losing their good wicking properties or in the instance of polyesters and polyolefins, their stain release properties and their good anti-redeposition prOpQrties.
Surface fluorination of polyester, polyamide, polyolefin, and polyacrylonitrile resins do create surEace carboxylate -G-:~37~9 groups. In this respect, fluorination is quite different from chlorination, even chlorination effected in the presence of activation`(e.g. by ultra violet light), since chlorination does not create surface carboxylate groups to any significant degree. Accordingly, a substitution of chlorination for the fluorination fails to produce surface treated ~ibers with good wicking properties.
Allusion has been made to some decrease in tensile strength incident to fluorination. The decrease is minor, desirably less than 5%, preferably less than lb% and in all events for practice of this i~vention less than 20%. The exact reason for the loss o~ strength upon fluorinatioll is not known. The loss seems greater th~n can be attribu~ed to the degr~e o~ fluorination and carboxylate formation. Conceivably the energy released by the reaction causes localized deorientation (of the stretch oriented polymer) of the fiber. Fluorination of polyesters to different levels seems to cause an increasing loss in fiber tensile strength. However, up to akout 0.5 wt. ~ fluorine pickup (measured before wash) causes nominal loss in strength, with tests indicating tensile strength retention oE 90~ or bet-ter.
In the case of polyamides tensile strength has also been found to decrease upon extended fluorination. However, the tensile strength is more sensitive to process conditions than are the polyesters. Incorporation of 1 7% by wt. of F (at 10~
F2 reaction) in polypropylene did not decrease tensile strenyth.
In the case of polyacrylonitriles, a mild fluorination is pr~-ferred to avoid discoloration, i.e., yellowing of the fiber.
Tensile strength measurement is therefore a measurement of the fluorination reaction~ quantitatively as well as qual~-tatively. lrensile strength loss should, of course, be minimj~ed.

~37659 Accordingly, practice of this invention involves fluorination to the least reasonable extent, employing the most dilut~
fluorine (in a carrier gas), consistent with the level of reac-tion desired with never more than 20~, preferably less than 10~, fluorine content in the gas. A low fluorine content in the gas helps cool the reaction and facilitates preferential reactions desired for achieving uniform fluorination of fiber surfaces.
One realistic measurement for the fluorination reaction is, of course, the number of fluoride groups present on the fiber surface, with the meaningful value' for fluorine content being the wt. (mg) of fluorine per cm of fiber surface, pre~-erably measured after washing the fluorinated fiber.
Measurement convenience w:ill often dictate testing some wei~ht of fiber or fabric then computing the carboxylate and fluoro groups present on the surface from fiber diameter, and density.
The fluoride content range for both polyester and nylon are the sa~e; about 4 x 10 7 to 4 x 10 mg F/cm , with pre-'ferred ranges of about 4 x 10 6 to 1 x 10 3 mg F/cm and thefluoride cGntent range for both polyolefin and polyacrylonit~ile are the same; about 4 x 10 to 4'x 10 mg F/cm ; with pre-ferred ranges of about 6 x 10 to 1 x 10 my F/cm . ~lowever, actual practice of the invention always involves a particula~
treatment level, e.g. 1 x 10 for a specific fiber material.
The preferred treatment level will be different for each class of substrates, e.g. for nylon 6, nylon 6.6, polyethylene terephthalate etc., and usually takes int~ account fiber siz~, fabric wea~e count, etc. Treatment conditions are of course selected for the minimum treatment level consistent with the ~' ~ circumstances at hand. For example, iF D~CRON polyester ... .

~ t ~

1(~376~9 filaments are being treated, a fluorination treatment to achieve 1 x lû 5 mg F/cm2 will be preferred. On the other hand, treatment of bulk fabric wound on a spool may well require fluorination treatment of 1 x 10 3 to 3 x 10 3 mg F/cm in order to be certain that the fabric had bee;n fluorinated throughout.
If polyacrylonitrile filaments are being treated, a fluorina-tion treatment to achieve 1 x 10 4 mg F/cm2 will be preferred.
Polypropylene may be more heavily fluorinated, e.g. 1.5 x 10 4 mg ~/cm and 6.5 x 10 3 mg F/cm , the latter involving a car-10 .boxyl content increase from 0 meq/cm (control) to 9.57 x 10-6 meq/cm . All the above fluoride content values provided are after wash values.
~ n additional measurement for the fluorin~tion reAction is believed to be the number of carboxylate groups present on the fiber surface, a direct indication being the neutralization equivalent. The carboxylate content in milliequivalents per cm would seem`more definitive of the fluorination reaction product than wicking, since a wicking test is likely to depend on the fabric form, e.g. weave or knit; and the fiber, e.g. twist, mono-filamen~, etc.
Unfortunately, accurate measurement of carboxyl content has proven d~fficult, and the neutralization values obtained may be unreliable. However, the increase in free carboxyl con-tent relativ~ to a comparable unfluorinated control is clear and substantial. Both polyamide and polyester fibers exhibit increases of up to 10 and even more times the carboxyl content present in the control. Since excessive fluorination may not create a corresponding increase in carboxyl~tion levels (after wash), a 10 fold carboxyl content increase is believed to be a reasonable maximum increase for pra~tice of this invention.
In absolute numbers, a high degree of fluorination and 1~376~9 carboxylation has increased samples of nylon ~6 from 1.3 x 10 me~/cm to 15.9 x 10 meq/cm , and a polyester sample from 2.9 x 10 6 meq/cm to 15.5 x 10 meq/cm .
Polyacrylonitrile and polyolefin fibers contain a signifi-cant carboxyl content of up to about 1 x 10 meq/cm . Since excessive fluorination is undesirable, and carboxylation levels are not the only factor affecting wicking, practice of this invention will usually involve a much lower meq/cm .
For treatment of bulk fabric, practice of this invention may involve fluorination after the fabric has been dyed.
Fluorination has no adverse effect on most dyed polyamides, polyesters, polyolefins, and polyacrylonitriles and in the instance of bulk fabrics the almost inevitable minor degree oE
nonuniformity in fluorine content and wicking characteristics in the fabric will be immaterial to fabric appearance, use, and strength.
Also, in accordance with the practice of this invention, the surfaces of shaped artic~les formed from synthetic polymers can be reacted with a gaseous treating medium comprising from 0.1-20~ by volume elemental fluorine, 0.1-50% by volume sulfur dioxide, not more than about 21~ by ~olume of elemental oxygen, e~g. air, the balance may be inert. Particularly improved are fiber form synthetic resins selected frGm the group consistin~
of.polyesters, polyamides, polyolefins, and polyacrylonitriles.
The reactio~ contact time is less than about 60 minutes, less than 30 minutes being more desirable, and less than 5 minutes preferred. For fiber form materials 0.5-5 minutes constitute the preferred treatment time.
Within the context of this invention, fluorination in the presence of sulfur dioxide, iOe. sulfo~fluorination, is n~t limited to a gaseous reaction mixture containing elemental .

~37~
fluorine and free sulfur dioxide. It has been observed that elemental fluorine reacts with sul~ur dioxide to an unknown degree to form sulfuryl fluoride. Confirmatory tests indicate a mixture of sulfuryl fluoride and fluorine can be employed for sulfo-fluorination and therefore, both sulfur dioxide, as such, and sulfuryl fluoride are considered sulfur dioxide for the purpose of practice of this invention within the context thereof.
The desirability of maintaining a low level of oxygen in the fluorinating medium is set out. One of the major reasons for limiting oxygen is to allow a rapid fluorination rate. (Oxygen has been shown to retard fluorine incorporation.) However, sulfur dioxide either as such or as sulfuryl fluoride in the gaseous sulro-fluorination reaction Medium inhibits substrate fluorine incorporation to an equal o~ greater degree than does elemental oxygen. Therefore, the presence of oxygen in the sulfo-fluorination medium will not have the same drastic effect of retardin~ fluorine incorporation. The reduced efect of oxygen on the rate of fluorine incorporation through sulfo-fluorination, permits use of air as the carrier gas. Addition of sulfur dioxide and elemental fluorine to air in order to create the ~ulfo--fluorination reactit~n gas is contemplated for practice of this invention.
Althou~h sulfo-fluorination according to practice of this invention h~s been posed largely within a context of fiher form polyesters, polyamides, polyolefins, and polyacrylonitriles, this invent~on is not limited to fiber forms of these resins, nor indeed even to the above specified preferred resin materials.
Other instances exist where surface ~luorination-carboxylation in the presence of sulfur dioxide, i.e. sulfo-fluorination,

3~ will greatly improve a shaped synthetic polymer, regardless of the substrate material involved.

1~)3~7~ 3 Sulfo-fluorination according to practice of this invention is applicable across the board to synthetic resins as a class, including for example, those already named as well as poly-styrene, polyvinyl acetate, polyvinyl chloride, polyacrylates, polyvinylidine chloride, polyimides, polyarylsulfanes, poly-urethanes, polycarbonates, etc., in all shaped polymer, copoly-mer or admixture modes.
In accordance with preferred practice of the present in-vention, fluorinated carboxylated polyesters and polyamides are obtained by short cycle, direct fluorination in an atmosphere substantial]y free of oxygen and fluorinated carboxylated polyolefins are obtained by short cycle, direct fluorination in an atmosphere with low oxygen content as described above.
By short cycle is intended gas-solid reaction contact time of less than 15 minutes, preferably less than 5 minutes between fiber and f:Luorine. The resulting fluorinated carboxylated materials p~epared by short cycle fluorination have increasec~
water transport and soil release characteristics.
Brief ~eaction contact times, i.e r less than 15, prefer~bly less than 5 minutes is desirable for polyamides, as for poly-esters. Polyesters fluorinate readily, can be f~uorinated satisfactorily in less than l minute. Polyamides are more s~n-sitive than polyesters, require a more carefully controlled fluorination, normally invo].ving a s~veral minute treatment ~nd a more care~ul cut and try adjustment for the equipment, fib~r form and substrate resin.
In any event, all commercial polyesters and polyamide fiber form resin~ can be fluorinated-carboxylated in accordance with practice of the present invention.
In general, the polyesters having the repeatin~ structure -CORCO2Rl-l where R is selected from the cyclic hydro~arbons 1~37t~9 C Hlo and linear hydrocarbons C H2 ~ where n is an integer of 1 to 18 t and ~1 is selected from the cyc1ic hydrocarbon radicals C6H1oO and C6H4O and linear hydrocarbon radicals CnH2 O, where n is an integer of 1 to 18, and (CH2CH2O)b, where b is an integer of 2 to 10. Such polyesters are prepared in the con-ventional manner by reaction of a carboxylic acid with an alcohol.
Among the polyester materials which can be used in accord-ance with the present invention are polymeric materials having 10 .the following repeating structures:

~CO-~c6H4~cO2(cH2~2 ~CO~c6H4~cO2(cH2)18 ~Cotc6Hlotco2~c6 4 ~CO~c6H~tcO2(cH2)12 (cH2)6 (cH2) fcotC6H4tC02 (CH2CH2) ,2~
~Cotc6Hlotco2(cH2c 2 10 .

: 20 Among the polyamides which can ]~e used in accordance with the present invention are polymeric materials having the follow-ing repeating structures:

O O
1) -(-N-R -N-C-R2-C-) ¦ 1 ~ n : where R1 and R = linear hydrocarbon (C H , where n = 1-13) n 2n , la3~s 2) (-I-R-C )n where R = linear hydrocarbon (C H , where n = 1-18) 3) #.1 where Rl = cyclic hydrocarbon (C6Hlo or C6H ) R = cyclic hydrocarbon (C6Hlo or C6H4)

4) #2 where R = cyclic hydrocarbon (C6Hlo or C6H4)

5) #1 where Rl = linear hydrocarbon (CnH2 , where n = 1-1~) R2 cyclic hydrocarbon ~C6Hlo or C6H4)

6) #1 where Rl = cyclic hydrocarbon (C6Hlo or C6H~) R = linear hydrocarbon (CnH2n, where n = l-ln) Esp~cially th~ following polyamides 1) -(-NH-C5Hlo )n poly ~w-aminocaproic c~cid) (nylon 6) O C.) 2) -(-NHC6H12-NH-C C4H8 C )n poly (hexamethylene aclipamide) nylon 6.6 3) -~-NHC6H12~NH~C~c8~ll6~c-)n poly (hexamethylene sebacamide) nylon 610 ~L~37~9 10 20 n poly ~ll-amino undecanoic acid) nylon 11 ' ~ 1l 5) -(-NCll H22 C )n poly ~12-amino dodecanoic acid) nylon 12 6) -~C-C6H4-C-NElC6H4 NH ~n poly (paraphenylene terephthalamide~
Fiber B

Practice of this invention is also applicable to fibers rom polyolefins and polyacrylonitriles, including homopolymers and resin mixtures and copolymers. Preferred by far for the fluorination carboxylation treatment are the polypropylene and polyacrylonLtrile resin fiber form m~terials. The polypropylene materials fluorinate carboxylate rea~ily. The polyacrylonitrile materials should be subjected to rel~tively mild fluorination conditions in order to avoid discoloration.
The fluorination carboxylation can be carried out on a continuous basis, for example, by passing a fiber form material, such as yarn, fabric, etc. through the fluorine carrier gas ~ix-ture in a suitably sealed chamber through which the fiber form material pa~ses. Alternatively, the material can be unrolle~
and rerolled inside the treatment chamber.
Instead of a continuous treatment such as described above, the treatment may be a batch operation in which the fiber form material is exposed to the fluorine carrier g~s mixture in a ~ 3t7G~g reactor: the material being permitted to remain in contact with the gas mixture for a brief time interval.
Within the limits of the material (e.g....melting point, etc.), the temperature and pressure at which the fiber form material is treated is not critical. However, the preferred temperature is room temperature, but higher temperatures, such as those ranging up to about 150C or higher can be employed.
Pressure inside the reaction vessel will ordinarily correspond to standard environmental pressures, although elevated pressures can be used without adverse effect.
As previously mentioned, direct fluorination in an atmos-phere substantially free of oxygen r~quires only a brief reac-tion time for a fluorinated carboxyl~ted sur~ace layer ~o Eorn~
on the material. It has been found, according to the present invention, that exposure time for most types of polyester, polyamide, polyolefin, and polyacrylonitrile resin fiber form materials generally requires Iess th~n five minutes. However, frequently less than one minute cont~ct time is all that is needed in order to fo~m a fluorinated carboxylated surface layer and such is a preferred mode here It is well to keep in mind, however, the exposure period wlll vary with the concentration of fluorine in the gas mixture, in which case the time will be shortened when the concentration of fluorine is higher. Longer exposure times may be used, but in most instances are neither required nor considered desirable, especially from an economi~
viewpoint.
~ gain and again reference has been made to the desirabil-ity of limiting the oxygen content of the fluorinating gas.
Water and wa~er vapor are somewhat detrimental also and desir-ably should be avoided. In a preferrea mode of this invention,the fabric should not be wet, i.e. should not e~ceed equilibrium 1~37fGj59 with ambie~t moisture (i.e., less than about 0.5% H2O by wt.
for polyesters, 4% for 6.6 nylon), and the fluorinating ~as con-tain 0-1% oxygen and from 1-3% fluorine for polyesters and 1-5% for polyamides, polyolefins and polyacrylonitriles, the balance of the fluorinating gas may be inert e.g. nitrogen, and such is preferred. However, practice of this invention does contemplate fluorination in the presence of co-reactant gases.
For example, fluorination and chlorination will both occur if chlorine is included in the carrier gas, even though chlorina-tion by itself, would not occur without (light) activation.
Accordingly, presence of other reactants in the carrier gas is not inconsistent with fluorination, and, indeed, most co-reactions will normally take place only as inaident to the fluorinatio~.
The significant process aspects for practice of this inven-tion may be recapitulated as follows:
1. A reaction contact time between fiber form resin ancl reaction gases of less than about 15 minutes, less than 10 minutes bei~g more desirable, and less than 5 minutes preferred.
2. A reaction gas composition having, by vo]ume:
(a) up to 20% elemental fluorine, less than 10~ pre-ferred, 0.1~5% being more desirable; specifically preferred is 1-3% for treatment of polyesters, 1-5~ for treatment of poly-amides, pol~olefins, and polyacrylonitriles.
(b) for polyamides and polyesters: limiting elemental oxygen content to below 5%, desirably to less than 1%, prefer-ably less than 0.1%.
for polyolefins and polyacrylonitriles: limiting elemental o~ygen content preferably to below 1.5 O2/F2 (e.g. 0.2-1.0~) for the preferred 1-5% F2 range. To the extent possible a reaction gas substantially free of elemental oxygen ~;37~
is preferred.
(c) balance of reaction gas preferably dry and inert.
When 'following the conditions noted above for fluorina-tion according to practice of one embodiment of the present in-vention, it has been found the material will not char; there is little loss of other desirable characteristics of the material such as strength; low levels of fluorine are taken up by the fiber rather uniformly. Of course, the reaction vessel used in the ~luorination process must be able to withstand the ' 10 presence of fluorine and'of hydrogen fluoride product of the reactions. - ' In the discussion of fluorination, exemplary values and preferred ranges have been provided. The values given for eXem-plary purpo~es are the fluorine content at the first realistic opportunity to measure same. Normal handling of the fiber form resin such as laundering will remove some but not all of the fluorine initially combined with the fiber form resin materi~l.
Except when indicated as pre-washing, the fluoride content values and ~he carboxyl values, too, are after a first washing of the material.
The fluorinated-carboxylated polyesters and polyamides prepared ac~ording to practice of this invention have a neutral-ization equivalent of about 25,000 or less, preferably less than 15,000. The fluorinated-carboxylated polyolefins and poly-acrylonitriLes prepared according to practice of this invention have a neut~alization equivalent of about 1 x 106 or less, preferably less than 2 x 10 .
The neutralization equivalent (~.E.) is determined by dividing the weight (grams) of the a-id times 1,000 by the milliliters of base times the normality of the base i.e. the "meq. of base".

-l8-~3~7~;S9 wt~ of Acid x 1,000 N.E
meqO of base The neutralization equivalent is measured by an acid-base potentiometric titration.per~ormed in abs~lute methanol using a glass electrode as an indicator against a calomel reference electrode. The potential is measured on a pH meter ~e~g. Beck-man pH meter).
The carboxyl content of the fiber form resins may be deter-mined in several ways. ~ccording to one procedure, the fluori-nated material, e.g. a fabric, is first washed in dilute HCl, then thorou~hly rinsed with distilled water, dried and weigh~d.
Thereafter the material i~ immersed in a known amount o 0.0995 N me~hanolic sodium hydroxide, allowed to stand for 24 hours, then carefully rinsed with methanol to wash adhering base bac~ into solution. The solution is then titrated with aqueous hyd~ochloric acid. The difference between the initial amount of NaOH and that m asured represents the degree of acidity of ~he fabric.
An alt~rnative procedure, interchangeable ~ith the above, is the process of H. A. Pohl, Analytical Chemistry, Vol. 26, pg. 1614 (1954).
At low fluorination levels, the degree of carboxylation of polyester and polyamide will depend upon both reaction time and ~ F2 in the reaction medium. The degree of carboxylatio~
of polyolefins and polyacrylonitriles will depend upon reaction time, 2~ and F2% in the reaction medium. ~t a given reaction time, carboxylation increases as % fluorine incorporation in-creases. Selecting specific fluorination process conditions for a particular fabric may require a cut and try approach within the already described reaction time and fluorine ~ 37~ 9 concentration ranges. In this connection, the degree of car-~o~ylation of polyester, polyamide, polyolefin and polyacrylo-nitrile are not believed to be related, since the chain cleavage rates for their linkages may differ. Thus nylon 6.6 treated to have between 4 x 10 5 and 3 x 10 mg F/cm , a preferred range will have a carboxyl content between 2 x 10 5 and 15 x 10 millieguivalents/cm2 against a control measurement of 1.3 x 10 meq/cm . A polyester (i.e. PET) control measured at 2.9 x 10 meq/cm and a highly carboxylated and fluorinated specimen contained 15.5 x 10 meq/cm . Overall practice of this invention involves an increase in the free carboxyl content of the fibec form polyester or polyamide resin of at least 5~%.
Polyacrylonitrile treated to have between 6 x 10 5 and 1 x 10 2 mg F/cm2, a preferred ranye, will have a carboxyl content be-tween 2 x 1~ and 1 x 10 milliequivalents/cm against a con-trol measurement of 0 meq/cm . A polyolefin control measured t 0 meq/cm and a highly carbo~ylated specimen contained ~ 5 2 1 x 10 meq/cm .
The sulfo-fluorination conducted according to practice of the present invention is of course particularly adapted to the fiber form of polyesters, polyamides, polyolefins, polyacrylo-nitriles including, for example, fibers, filaments, yarns, threads, ribbons, etc. and articles formed therefrom, such as cloth and fabrics, knit, woven, non-woven. The treatment can be conducted on a continuous basis by passing polymeric fiber form materials through the gaseous treating medium within a suitable sealed reaction chamber equipped with gas-tight seals through whi~ch the material passes; if available on rolls the material ma~ be treated by being rol~ed and rerolled within the sealed chamber. Alternatively the treatment may be a batch operation, in which the polymeric material ~which may be in a ..

~376~9 roll) is exposed to the gas form reaction medium for a rela-tively short period of time, deslrably at or near ambient temperature and pressures.
The gas composition and reaction conditions have been described above in an overall sense. To obtain best results with any particu]ar material a cut and try approach may be re-quired, reference being made to the specific examples herein-after appended for sulfo-fluorination details which might be applicable thereto.
Films, sheets, moldings, entire article, particularly of polyesters, polyamides, polyolefins and polyacry]onitriles can be sulfo-fluorinated under exactly the same conditions as Eiber forms. ~hu.~, in a pr~erred embodim~nt of this invention, polyolefin articles, notably blow mo~ded containers made from polyethylene, are sulfo-fluorinated ~o achieve superior solvent resistance.
Inclusion of sulfur dioxide as such or in the form of sulfuryl fluoride within the reactio~ gas in the blow molding of a polyethylene container as is herein contempla~ed, improves the resulting solvent barrier properties still further than with the use of fluorine alone; Thus, the sulfo-fluorination of the present invention can, for shaped articles be affected much more rapidly than the 0.5-5 minute contemplated for fiber forms, and no lower limit for reactic>n time can reasonably be provided.
Although there is no intention of being bound by any one theoretical ~xplanation of the natur~ of the treatment, it is believed that in sulfo-fluorination the fluorine randomly re-places hydro~en molecules in the polymeric chain under treat-ment and that chain scission and car~oxylate formation takesplace. It is believed that in addition the sulfur dioxide ~; .

.~37 reacts with the fluorine to form -SO2F radicals which randomly `replace hydrogen atoms in the chain to add pendant acidic groups on the surface of the shaped polymeric material.
Sealed reaction chambers used for the method of the present invention must be constructed to withstand the corrosive nature of the reactive gases, especially the elemental fluorine. The chamber should-be designed to permit uniform contact between the gaseous treating medium and the polymeric material to be treated.
The following Examples illustrate embodiments of this invention. It is to be understood, however, that these are for illustrative purposes only and do.no~ purFort to be wholly definitive as to condition and scope Eor preferred practice oE
the invention.
Example I
(A) A strip of 100% polyethyleneglycolterephthalate fabric having a dimension of 8 inches by 16 feet, weighing 230.5 grams, was draped in a 28 liter "Kynar" lin~d (polyvinylidene fluoride) reactor, The reaction vessel was th~n alternately evacuated and purged with nitrogen three times in order to eliminate as far as possible any residual oxygen. Subsequently, a gas mix-ture of 4~ fluorine and 96% nitrogen from separate cylinders was blended before being charged into the reactor. The rate of flow from the fluorine cylinder was 0.6 liters/minute and 14.4 liters/minute from the nitrogen cylinder. The fluorine used was 99.7% pure with 0.3~ impurities comprising about 90~ nitro- ~
gen and about 10% of a mixture of oxygen, sulfur hexafluoride and carbon ~etrafluoride. The nitro~en used was 100~ pure.
The fabric was exposed to the substantially oxygen free gas mixture for 5~minutes and the reactor was then evacuated and purged with nitrogen prior to removal of the sample. The i~ tR~4Pf~ ~/~

--~2--1~37~5g sample was washed, dried and found to have 0.1% fluorine by welght .
The fluorine pickup was 8 x 10 mg F/cm .
(B) For purposes of comparing the rate of reaction (percent fluorine pickup) with the oxygen-free fluorination system of part (A) above, a strip of 100% Dacron fabric of simi-lar dimension was treated in a similar manner. However, in this instance 10% oxygen was blended into the gaseous feed stream also along with 4% fluorine. The exposure time of the fabric to this gas mixture was also for 5 minutes.
After removal of the abric from the reactor, it was .. washed, dried and found to have o~ly about 0.018~ :Eluorine by weight.
(C) The same procedure of part (B) was followed onceagain, also using an untreated strip of 100% Dacron of known weight, exposed for 5 minutes to ~ ~9j fluorine gas mixture.
However, in this particular run 40~ oxygen was mixed with the fluori.ne before being charged into t~e reactor After a 5 minute exposure period the sample was washed, dried and found ~0 to have 0.01% by weight fluorine lnc~rporated onto the fabric..
The percent fluorine impregnated onto the particular poly-ester material was determined in all instances using the Schoniger Co~bustion and Specific Io~ Electrode Techniques according to the following procedure:
Combust approximatel.y 150 mg. s~mple in a Schoniger flas};
containing 25 ml. of 0.02 N sodium hydroxide. The solution con-taining the ~ombustion products are then transferred to a lO0 ml.
volumetric `flask. Ten ml. of standaYd TISAB solution (sodium nitrate, sodium citrate, acetic acid and sodium acetate mixture having a pH of 5.5) are added to the flask and diluted to vol--ume. Standa.rd fluoride solutions are prepared which encompass 7t~9 the expected levels of fluoride in the sample. The potential obtained with a specific fluoride ion electrode for the sample and standard solutions is recorded. Using a standard curve generated from the data for the stanclard fluoride solutions, the potential is recorded ~or the sample and the sample weight, and the fluoride percentage in the sample is then calculated.

Examples II - XIV
For purposes of determining the effect of longer exposure times on the rate of fluorination of polyester materials, further direct-fluorination ba~ch runs were conducted using 10~ Dacron fabric, employing both oxygen free gaseous mixtures and systems having both fluorine and oxygen present. Procedures in accordance with the methods of Example I, parts (A)-~C) we~e followed, Results are yiven in Table I below, -~4- .

~L~3~7~9 TABLE I

Treatment Neutral-Time %F. by wt. ization Example Gas Mixture(minutes) Incorporated Equivalent 2 2 10 0.235 6,917 III do 25 0.300 7,356 IV do 40 0.455 7,654 V do 65 0.515 5,576 VI4% F2/10~ O2/86% N2 10 0.031 --10VII do 30 0.06S 11,523 VIII do 60 0.095 10,527 IX do 180 0.100 11,249 X do 360 0.090 9,280 XI4% F2/40~ O2/56% N2 10 0.019 --XII do 30 0.056 9,836 XIII do 180 0.090 11,220 XIV do 360 0.090 11,223 It may be concluded from Examples I - XIV that the per-cent fluorin- incorporated onto the fabric per unit o time is significantl~ greater using a system substantially free of oxygen. This is aptly demonstrated ~nter alia by Example II
which shows that after a 10 minute exposure to 4% fluorine and no oxygen, about eight (8) times more 1uorine was taken up by the fabric than Example VI also having 4% 1uorine, but with 10% oxygen present. Furthermore, as the amount of oxygen was increased, according to Example XI (40~ 2) the take-up of fluorine by the polyester material diminished even urther.

As a whole, Table I demonstrates that the presence of oxygen inhibits fluorination.

Example XV ~ ~37~
ThQ following short cyc]e procedure was employed in the continuous, direct-fluorination of polyester fabric:
`A roll of polyester double knit fabric having the dimen-sion of 12 inches x 50 feet was placed in a standard continuous treatment reactor having a volume of 708 liters. The system was then purged with nitrogen to eliminate all traces of oxygen.
Purging continued for 12 hours at a flow rate sufficient to displace the volume of the reactor six times over.
A gas mixture comprising fluorine and nitrogen was introduced into the reactor at the rate of 3.5 liters/minute fluorine and 10.6 liters/minute nitrogen. The nitrogen used was 100% pure and the fluorine was 9~.7% pure: the remaining 0.3~ consisted of trace amounts of dlfferent P:Luorocompounds and oxygen. This gas mixture was pe~mitted to flow for 20 minutes while the fabric passed slow~y through the reactor chamber. This first exposure period was to provide for reactor equilibraticn.
Subse~uently, the flow of gas was adjusted so that only 0.6 liters/minute fluorine and 1.8 liters/minute nitrogen entered into the reactor providing a mixture of 10~ fluorine and 90~ nitrogen. With this reduced flow of gas in operation the exposure time of the fabric was adiusted so that contact time of the fabric with the gas was only two (2) minutes.
~ fter approximately 15 feet oE fabric was treated at this two (2) minute exposure time the speed of the rewind roll was increas~d, so that the exposure ~ime to the gas was adjusted to 30 seconds. An additional 15 feet of fabric was then treated.

~L~3~
Six samples taken at random from the exposed fabric were then washed in distilled water, dried and found to have taken up fluorine in the amount shown in the table be]ow.

TABLE II
.

Exposure Time % Fluorine Incorporated 30 Seconds 0.41 do 0.39 do 0.39 ? Minutes 0.52 10 do 0.51 do 0.47 Samples of the 2 minute and 30 second exposed fabrics were tested for soil release properties. A drop of dyed mineral oil was applied to each of the two by one inch samples and on a control sample of untreated fabric. The samples were then sub-- merged in a 0.1~ solution of Ivory soap in deionized water.
Each of the fluorinated-carboxylated samples released their o;1 stains within three (3) minutes whereas the control sample dicl not release the stain even after a 24 hour period.
It may be concluded from Example XV that fluorination of the substrate after 30 seconds of exposure was sufficient to impart the desired properties throug~out the polyester fabric, and that protracted exposure time although offering greater fluorine pictcup, nvertheless provided no perceptable advantages over the sho~ter exposure period.

Example XVI
Samples for wicking data were secured from a 14 ft. strip 6.25 inches wide (Raschel knit) polyester wound on a 2 inch core.

~, ~3~7~S9 The wound roll (3.5 inches diameter) was fluorinated with 1% F2/99% N2. Samples (1 inch by 10 inches), taken from the outside, the inside and two intermediate intervals of the fabric, were submitted to wicking tests.
The wicking test procedure involves suspending a length of sample (e.g. 1 inch by 10 inches running with the grain of the fabricj above a beaker of (dyed) water. The bottom 1/4"
of sample is submerged in the water, at which time a stopwatch is activated. Readings should be taken periodically, i.e. 20 seconds, 1 minute, 3 minu~es, 5 minu~es; 5 minute intervals to determine (millimeter) rise of water versus time, measuring thereby moisture transport ~of the dyed water).
~ he following table shows that ~elatively uni~orm wickincJ
resulted:

TABLE III

Outside Inside Edqe Inside Insid~Edge ~ime ~1 ft.) ~5 ft.~ (10 f~.)(14 ft.) 20 sec. 17 mm. 9 mm. 29 mm.4 mm.

201 min. 31 20 50 56 '5 ~ 84 42 89 111 ~49 87 135 160 !

i84 - 1~7 157 183 30~5 18~ 147 157 183 1~337~
Example XVII
A multiplicity of tests were conducted on 100% PET
(DACRON) using the following test procedures:
Polyester fabric was scoured, triple rinsed and tumble dried prior to fluorination. An 8" x 10" sample was then sus-pended in a 2 liter monel reactor. For static reactions the reactor was evacuated and purged with nitrogen four (4) times.
After the fifth evacuation the reactor was brought to atmos-pheric pressure by filling with the fluorine/nitrogen/oxygen (if any) mixture. The fill time was 30 seconds and reaction contact time was 2 minutes. Flow reactions were run by evacuat-ing the reactor, purging with nitrogen, evacuating and applying a flow of F2/N for 2 minutes.
At the end of the two minute reaction time, the fabric was removed from the reactor and washed hy standard AATCC wash pro-cedure. After tumble drying, the fa~)rics were ready for wicking and tensile strength tests.
The test results were as followc;:

A. TE~SILE STRENGTH LOSS
Tensile Strength l~s.
- . ''': .
~6 F Flo-~7 St~kic S~al:ic 1~. 2 Control 87 . 5 . 87 . 5 87 . 5 O . 5 90 .87 86 82 8~ 75 3 ~2 8~ - 68

7 26 7~ , 75 Burned 6~ 4 37~
The results indicate that a flow reaction decreases tensile strength faster than a static reaction, and that addi-tion of 1% oxygen lowers tensile strength.

B. WICKING PROPERTIES
Wicking Height mm.

% F ~low St.atic Static 1~ O~

Control ~O 10 lO
0.~ -- 77 8 1 70 lOi 8~
- 10 3 61 109 ~0 Burned 90 . 32 .~ .... ............ . . ..... .. . .... . . .

The test results indicate that a flow reaction gives a product having poorer wicking properties than a static method and that pr~sence of oxygen decreases wicking properties.
The effect of oxygen content on tensile strength and wicking in a static test, 1% F2, is shown by the following tal~le:

.. _ .. .. .... .... _ .. . . .. . . . .. .. . .. . . .

1~37~Sg C. EFFECT OF OXYGEN
Tens_le Strength anci Wi~kin~

~ 2 Tensile lbs. - Wikin~, mm.
Control 87~5 10 0.5 85 95 -l.Q 75 93

8 - 70 86 6g ' 85 The test results indicate that increasing oxygen concentra-tion brings about decreased tensile strength and wicking proper-ties.

D. The observed carboxyl content was determined for the control and a highly fluorinated carboxylated specimen.

Control - 2.91 x 10 6 meq/cm2 (1.75 x 1015COOH/cm ) Fluorinated - 15.5 x 10 meq/cm (9.33 x 10 COOH/cm ) Example XVII
Nylon ~,.6 (Testfabrics Style 35g) was placed in a monel reactor and then evacuated and purged wit~ nitrogen four (4) times to ren~ove any oxygen present in the reactor. Various mixtures of fluorine/nitrogen were admitted to the reactor at varying (static) reaction times. Table 17-1 gives several examples of the fluorine concentrations and reaction times used.
It can be seen from Table 17-1 that high fluorine concentrations ~.

~37~i~9 or long reaction times increase the percent fluorine incor-porated.

% F2~ Reac. Tm. %~ meq/c~
Sample N2 (Min) Illcorp. x 10 5 ; ~833-12-14/96 3 0.1-7 4.27 1833-12-2 4/96 6 . 0.16 . 3.70 1833-12-3 4/96 11 0.14 3.58 1833-12~4~/9~ 25 Q.~

1833-1~ /92 3 1.3~ ~.80 1833-14-2 8/92 6 2.13 . 7.8 1833-~4-3 8/92 11 ~.~5 15.89 1833-1~-4 8/92 ~5 6.43 1833-15 10/90 3 2.59 8.~3 1833-17-1 4/96 1 0.31 ~2.5~
1833-17-2 8/g2 1 1.57 3.78 1833-17-3 10/90 1 2.63 6.37 Control . . 1.31 Nylon that was fluorinated at l~w fluorine concentrations or short reaction times showed less loss of tensile strength than high fluorine concentrations or long reaction times. The nylon increases in acidity with longer reaction times and with increasing fluorine concentration in the reaction.
Nylon that was fluorinated at 1GW fluorine concentratione or short reaction times showed better wetting (AATC test method 39-1971) than the control (Table 17-2). Fluorinations at hig~

fluorine concentrations or long reaction ~imes reduces the wettability versus short reaction times or low fluorine conce~-trations.

.

.
~.

Reac~ion Wetting Sample /~F2 ~~Zimes (min) Time (se~) Control 11,911 1833-12-1 ~/g6 3 117 1833-12-2 4/96 6 92.5 1833-12-3 4/96 11 128.7 1833-12-4 4/96 ~5 636 1833-14-2 ' 8/92 6 8,802 1833-14-3 8/~2 11 ---.. . . . . .

Nylon that was fluorinated at low fluorine concentrations or short reaction times showed bettel water transport (wicking) than the control. The material was cut into one inch strips and the ends immersed in an aqueous c~ye solution. The rate o~
climb of li~uid was then measured. Table 17-3 provides the wicking height results for the different F concentrations and reaction times.

wicking Hei~hts 8% F~
~icking ~ime Minutes 1 min~ 3 min. 25 ~in.3 min. 8 min.

~ 12 40 94 _ _ _ ~ 121 70 ~0 36 12~ -37 ~ ~7 ~5 85 52 1~ 132 57 87 57 , -~3-.~

~7~9 Example XVIII
Nylon that was fluorinated in the presence of small oxygen concentrations showed a decrease in the % F incorporated;
thus, oxygen inhibits the rate of fluorine incorporation (Table 18-1).

Reaction % F Tensile Sample %F2/O2/N2 Time (min) Incorp. Strength (lbs) Control 59 1824-29 4/-/96 6 1.7~ 56 1833-34-1 ~/1/95 6 0.69 ~3 1833-34-2 ~/2/94 6 0.41 45 1833-34-3 4/3/93 6 0.42 39 1833-34-4 4/5/91 6 0.31 41 1833-44-2 4/1/95 3 0.75 --1833-44-3 4/5/95 3 0.54 --Nylon that was fluorinated in the presence of small oxygen concentrations showed greater tensile strength loss than when oxygen was excluded fro~ the reaction media. All the reactions were run Xor six minutes.

Example XIX
To demonstrate the inter-relationship of oxygen and fluo-rine in the fluorination/carboxylation reactions, polyethylene film was employed (rather than fiber for test convenience reasons).
An infra-red monitoring technique was devised to measure carbon-fluorine formation in polyethylene film as a function of time at constant fluorine concentration (30~ by volume) and varying oxygen concentration (0-70~ by volume) with nitrogen being present as an inert ingredient, An infra~red gas cell was equipped internally at each end ~37~S9 with polyethylene film (1 ml) and externally with sodium chloride plates. A flow mixture of fluorine/ox~gen/argon was allowed to pass through the cell and the rate of C-F formation on the polyethylene film was monitored at one or two minute intervals up to about 40 minutes of reaction time. The C-F
absorbance at 9.0 microns recorded in the infra-red spectrum was then related to percent fluorine incorporation. The follow-ing Table 19 provides the weight percentage fluorine incorpo-rated in the film.

, 7~

T~E lg - .

T~ ~ O in % F
~Min, ) Med~wn Incorporated 0.38 0-5 0~26 ~ . 1.0 0.20 3.0 0.12 ~- 7.0- 0.05 3 1.02 3 n.s 0.78 1.0 0.60 3,0 0.35 7.0 û.14 ~ 0 1.70.
0.5 ~.29 ~ - . , ' 1.0 1.00 , 3.0 0.59 7.0 0.~6 0 2.02 ~. 0.5 1.52 6 1.0 . 1.20 3 o 0.68 7.0 0O30 0 5.11 1~ . , 0 . 5 3 . 82 15 ~ 1.0 3.00 3.0 1.81 7 . 0 0 . 73 ii5~

Table 19 demonstrates that the rate o~ fluorination is dramaticaily affected by the presénce of oxygen. Small concen-trations of oxygen (0.01%) bring about dramatic decreases in the rate of polyethylene film fluorination. Higher concentra tions of oxygen were also tested, resulting in somewhat lower rates of fluorination without significant difference between 7~ oxygen and 70% oxygen.
The data of Table 1~ suggests operation at low oxygen levels ~0.01-7%) so that fast rates of fluorination can be achieved using relatively low concentrations of fluorine and, yet, maintain a balance between fluorine-induced properties, oxygen-induced properties.
The inf~a-red studies evidenced ~eneration o~ acid fluoride groups on the surface of the polyethylene during the fluorina-tion. The studies also strongly indicated that the acid fluo-ride group was capable of hydrolysis to an acid which on treat-ment with base formed a sodium salt. Treatment of the sodium salt wlth 10~ HCl regenerated the acid. (Such infra-red studies could not be conducted on fiber forms.) Example XX
Polypropylene tee shirt material was scoured, triple rinsed and tumble dried prior to fluorination. An 8" x 10"
sample was t~en suspended in a 2 liter monel reactor. The re-actor was evacuated and purged with nitrogen four (~) times.
After the fifth evacuation the reactor was brought to atmos-pheric pressure by filling with the fluorine/nitrogen/oxygen mixtures. The fill time was 30 seconds and reaction contact time was two (2) minutes. At the end of the two (2) minute reaction time, the fabric was removed from the reactor and washed by standard AATCC wash procedure.

3.Q~

The test results are provided in the Tables below.

FLUORINE INCORPORATION

% %~ Fluorine 96 Fluorine Fluorine ;2 Before Wash After Wash 0~ 5 0 0 ~ 024 0 ~ 029 1~,0 0 0~113 0~089~
3 ~ 0 0 0 o 352 0 ~ ~13 5~0 0 0~907 0~853 .7~0 0~8~)0 1~014 _--r ~ . , i0.0 0 0~9~7 1.. 650 FLUORINE INCORPORATION

2 . % % Fluorine% Fluorine % Oxygen F Before WashAfter Wash 1 . 0 5% 0 . 735 0 . ~14 3.0 5% 0.672 0.537 5.0 5% 0. t32 0.502 WICKING HEIGHT - % 2 . ~ ~lu~rine W.i~
_ ... .
0.5 5 1.0 56 3.~ 0 ~-5.0 ~ :
,7.0 '10.0 0 ~L~3~6~
~ABLE 20-4 WICKING H~IGHT
~luorine ~lakir~l Ht. in Mm 0.5 . 5,0. 17 .
1.0 5.0 51 3.0 . 5.0 ~9 5.0 5.0 56 .CARBOXYLATION DATA - ABSENCE OF OXYGEN
#COOH/cm Incorporated ~ % 2 % Flaor:.ne #COOH/cm x 10 / 2 1o~6 ... ...
0.5 1.34 2.23 1.0 2.31 3.84 3.0 1.45 2.41 5.0 2.5 4.16 7.0 2.81 . 4.66 10.0 2.60 4.31 C'ARBOXYLATION DATA - PRES~NCE OF OXYGEN
#COOH/cm2 Incorporated % . ~ ~C~O~/ 15meq~c~
~luorine O~y~ cm ~x 10 _ x 10 _ 5-0 . 0-5 5~13 SoS2 500 1~0 ~ l 7~99 5~0 3~0 8~79 1~6 5~0 500 5~76 g~57 .

'i :1~37~5~

WICKING HEIGHT vs F/COOH RATIO

F/COOH Wicking Height .
Ratio in mm TENSILE STRENGTE~ vs ~ FLUORINE

g6 Tensi le Strength Fluorine in lbs.
0 (Control) 25 1. 0 Z2 . 80 3.0 24.68 5 . 0 26 . 06 7.0 27.38 10 .0 34. 40 ~3t76~5~

TENSILE STRENGTH .

% ~ Tensile Strength ~y~ Fluorine in lbs.

0.5 1.0 25.40 1.0 1.0 22.86 3.0 1.0 23.00 5.0 - 1.0 23.50 7.0 1.0 26.98 10.0 1.0 22.22 20. b 1. 0 25.64 The re~ults are evaluated as follows:

A - Rate of F incorporation.
In the absence of added oxygen, fluorine is incorporated at a rate which depends on the fluorine concentration. When oxygen is present, the rate of fluorjne incorporation is re-tarded at a rate which depends on the oxygen concentration.
The greatest retardation rate is experienced between 0 and 1~
oxygen, whiCh also is the range of g~eatest retardation found for polyeth~lene.

B - Stability of Incorporated F, In the absence of added oxygen, the amount of fluorine lost during washing is very small and within the limits of er~or in the anal~tical procedure. The adclition of oxygen to the fluorinating medium increases the amount of fluorine lost during AATCC washing.

C - Carboxyl Group Formation.
The polypropylene tee shirt material was prewashed in dilute HCl and thoroughly rinsed with distilled water, weighed :. ``"

-41~
'i 7~
and then immersed in a known amount of standardized sodium hydroxide. The fabric was allowed to stand for 24 hours and then was removed and carefully rinsed with methanol to wash any adhering base back into solution. The solution was then titrated with aqueous hydrochloric acid. The difference be-tween the amount of sodium hydroxide put in and that found after fabric soaking represented the degree of acidity of the fabric.
i. Fluorine Concentra~ion Dependence The last traces of oxygen adsorbed on polypropylene fiber cannot be easily removed and carboxylat.ion occurs even in the absenc~
of added oxygen. Increasing rate of carboxylation, in a system carefully evacuated and purged, is dependent on increasing fluorine concentration.
ii. Oxygen Concentration Dependence ~xygen addition to a constant concentration o~ fluorine led to increasing carboxylation with increasing oxygen concentration.
iii. Fluorine/Carboxyl Ratio The major influence on fluorine/carboxyl ratio is the presence of oxygen. Since oxygen has the double effect of retarding fluorine incorporation and increasin~J the rate of carboxylation, oxygen plays a very important role i~ determining the moisture txansport properties of the treated polypropylene. Highest F/COOH ratios are obtained at^-0~ 2 with the greatest rate o~
decrease between 0 and 1% 2 D - Moisture Transport Properties of Fluorinated Polypropylene Tee Shirt Fabric i. Fluorination in the Absenc~ of Added Oxygen In the absence of added oxygen only ~luorination with low per-centages of fluorine (0.1-2.0%) prov~des a fabric capable of transporting moisture. Polypropylene fabric tr~ated with 3-10 -~2 1~37~9 fluorine, and the control as well, shows little or no moisture transportD The poor wicking qualities of heavily fluorinated polypropylene indicates that the ~/COOH is significant.
ii. Fluorination in the Presence of Added Oxygen Addition of oxygen in a high F2 concentration fluorination treatment (5% F2) imparted wicking pxoperties to the fabric.

E - Tensile Strength Properties of Fluorinated Polypropylene Tee Shirt Fabric Fluorination has little or nQ effect on the tensile strength of polypropylene fabric.

Example XXI
A series of runs were conducted on polypropyl,ene fabric sample according to the procedure of Example XX. The condi-' tions and,test results are shown in ~able 21.

TREATMENT OF POLYPROPYLENE FABRIC

Soil Release Gaseous Mixture Treatment % F -Wicking Rating F202/N2, Vol. % Time, Min. Incorp. Height, mm. (Dyed Min. Oil)' .. . . .. . . . :
Control -- --' 0 1.2 201/0/99 10.17 85 ' 3.6 1/0/99 50.49 47 5.0 5/0/95 10.49 16 4.75 1/1/98 10.17 77 5.0 1/1/98 50.18 71 5.0 1/5/94' ~' 0.10 64 5.0 ~/5/94 50.26 50 5.0 4/1/95 , 10.44 61 5.0 ' 4/1/95 51.03 52 5.0 --~3--~L~237~S~
Example XXII
Polyacrylonitrile fabric ~Acrilan - 16) was fluorinated at varying fluorine concentrations and reaction times set out in the tables below. The oxygen content of the reaction media was not measured, but is estimated at below about 0.5~.
The material to be treated was placed in a monel reactor and then evacuated and purged with nitrogen to remove the oxygen present in the reactor and finally a mixture of fluorine/
nitrogen was admitted as a continuous flow, at ambient tempera-ture (about 75F) and atmospheric pressure.

Gas Flows Gas % Reac. Tm. ~ F
Sample , 2/ 2 _2/ 2 (Minutes) Incorp.

Control 0.009 1838-31-1 40 cc/min-760 cc/min 5/95 1 0.047 1838-31-3 40 ec/min-760 cc/min 5/35 3 0.137 1848-7-1 147 cc/min-14.5 l/min 1/99 1 0.03' 1848-7-3 147 cc/min-14.5 l/min 1/99 3 0.035 1848-7-6 147 cc~min-14.5.1/min 1/99 6 0.035 No expIanation is offered for the essentially constant after wash fluorine content of samples 1848. No before wash measur~-ment was made. Other data indicates that incorporation of fluo-rine does increase with reaction time, but that a eorrespond-ingly greater loss oecurs upon washing.
The fabric which had been fluorinated was cut into one inch strips and the ends immersed in an aqueous dye solution (wieking test). The rate of climb of the liquid was noted (Table 22-2~. Wicking is considered a measure of comfort. The earboxylate con~tent of fluorinated Acrilan is shown in the Table 22-3 below.

1~;

1~376~9 Liquid Height After Sample 20 Min. (MM~

Control 52 .
Reaction Conditions Milliequivalents Sample % F2 Time-Minutes cm2 x 10 5 Control - - 3.13 1857-15 1 1 3.32 - 1870-4 1 1 4.~5 1884-20-A 1 1/2 2.75 1884-20-B 1 1/2 3.81 1848~7-1 1 1 2.38 ~848-7-3 1 3 ~.61 20 1848-7-6 1 6 3.59 Example XXIII
A series of runs were conducted on polyacrylonitrile fabric according to the procedure of Example XXII except oxygen was added to the reaction medium. The conditlons and test results are shown below~

T~3LE 23 Reaction Con~itions Moisture Transport 1 Inch Rise Wicking Ht. ~F2 Stain Release 30 ~ F2 ~ 2 Time-Min ~sec.) (MM) Inc. Corn Oil _ _ _ - 52 - 5 1 1 `1 41 92 0.027 5 1 1 5 47 86 0.022 5 1 5 , 1 30 98 0.022 5 1 5 5 40 96 0.022 5 4 1 1 38 89 0.062 5 4 1 5 150 65 0.44 5 , .

~37~9 EXAMPLES XXIV, XXV, AND XXVI
Samples o~ nylon 6.6, Testfabrics style 358, were placed in a monel reactor, which was evacuated then purged with nitrogen four times to remove any oxygen present in the reactor.
Various mixtures of fluorine/sulfur dioxide/nitrogen were then admitted to the reactor at the varying reaction treatment times set forth in Table 24 below. Each gaseous mixture contained about 0.001~ by volume of oxygen~ The reaction took place at ambient temperature and pressure.
The treated samples were tested by standard procedures for the percent fluorine and sulur dioxide incorporated into the fabric.
The te~sile strength (by ASTM:D 1682-64) oE the treated fabric was ~e~sured immediately afte~ treatment, and one month after the treatment, in order to det~rmine the effect the sulfo-fluorination treatment has on tensile strength (Tah]e 24j ; An eva]uation of the wettability of the samples was made (according ~o the AATCC Test Method 39-1971) by mounting a sample of the fabric on an embroidery hoop and allowing one d~op of water at 21 + 3C to fall on the taut surface of the sampl~
every 5 seconds from a buret 1 cm above the surface. The time required for the specular reflection of the water drop to disappear was measured and recorded as wetting time, in seconds.
As indicated by the results set forth in ~able 24 below, the samples tre~ted by the method of this invention have far superior wetting times than that of the control and negligihle loss in strength has resulted.
The mi31iequivalents, according to Anal. Chem., Vol. 26, p. 1614 (1954), increases with increasing reaction time, a result which parallels fluorination in the absence of SO2.

- -~5 However, the presence of S02 has caused an increase in the acld content of the fabric over the values resulting from fluorination in the absence of S02.

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~37~5~3 -EXAMPLE XXVII
Polyester, 100%, was treated according to Examples XXIV, XXV and XXVI and tested for moisture transport and soil re-lease properties. The table below summarizes the reaction conditions and test results.

.

.
% X by Wt.
Reaction Conditions Incorporated Wicking Soil Sample %F2 %S2 Time F S ~gt. ~m Rel.
..
10 Control ~ - -- 15 2 1870-33-1 1 1 1 0.067 -- 97 5 1870-33-5 1 1 5 0.14~ 9 ~,5 1870-32-1 1 10 1 0.044 -- 106 5 1870-32-5 1 10 5 0.10~ -- 87 5 1870-34-1 4 10 1 O.lOS -- 91 5 1870-34-5 4 10 5 0.26~ -- 54 5 1833-2 4 1 6 0.07 0.017 108 --1833-4 4 4 6 0.10~ 72ppm115 --1833-5 4 8 6 0.17 75ppm116 --20 1833-6 4 10 6 Q.05 96ppm -- --EXAMPLE'S XXVIII,XXIX AND XXX
The greater enhancement in water transport and soil re-lease attributable to sulfo-fluorinat:ion over fluorination can be seen well in the instance of nylon 6. For nylon 6, fluorina-tion in the absence of SO2 can be ca]ried out so as to have a nominal ef~ct on water transport properties. Sulfo-fluorination increases water transpoxt substantially and im-proves soil release properties.
Nylon tricot jersey (Table 28) and Nylon txicot Crepe-set (Table 29) were su-l~o-fluorinated. The so treated materials - , 4L~ , ~3~76S~t showed better water transport than the ~ontrol and a fluorinated sample.

Condition Time Wicking Hgt. % Incorporated by wt.
Sample %F/%S02 Mins mm in 20 min F S

Control --- --- 43 ~~~ ~~~
1857-25 4/10 - 1 67 0.043 0.12 1867-27 4/4 1 97 .2.1 0.033 1857-28 4/16 1 102 .021 0.032 10 1857-37 l/iO 3 88 0.027 0.034 1866-1 1/~.0 1 100 0.024 0.071 1~66-3 1/~.0 3 9~ 0.023 0.059 1857-~24 4/- 1 24 0.265 ---1857-26 10/- 1 27. 0,22 ---Condition. Time Wicking H~t. ~ Incorporated by wt, Sarnple %F~%S02 Mins mm in 20 min F S
Control --- --- 30 1857-25 4/].0 1 64 0.087 0.11 20 1857-27 4/4 1 69 0.033 0.032 1857-28 4/~6 1 94 0.030 0.032 1866-1 1/1.0 1 94 0.045 0.085 1866-3 1/10 3 81 0.047 O.Q45 1~57_24 4/-- 1 17 0.14 ---1857-26 10/-- . 1 24 0.10 ---Nylon carpet was sulfo-fluorinat.ed (Table 30). This material shcwed better soil release Itoward dyed mineral oil) than either the control or the fluorinated material.

-~0 ~

~37~

The carpet was stained by mineral oil containing congo red and then placed in a beaker of warm water. The fluorinated carpet and the control did not release the mineral oil. In the sulfo-fluorinated carpet material, the mineral oil beaded and floated to the top of the water almost immediately.

.
~ Incorporated Conditions Time Soil by wt.
Sample~F~/SO~ Min. Release F S
Control ~ -- No ! 10 1866-6 1/-- 3 No 0.~29 ---1866-7 5/-- 3 No 0,039 ---1866/101/10 1 No 0.015 0.031 1866-~0 1/10 6 Yes . 0.015 0.029 1866-1~ 4/16 1 . Yes 0.007 0.043 1866-12 4/16 6 Ye~ 0.0~7 0.091 EXAMPLE. XXXI
SampleS of 100~ polypropylene fabric tfiber radius 21 x 10 3 c~) were treated in the manner described in E~amples XXIV, XXV and XXVI, then tested for n~oisture transport and soi.l release properties against control specimens.
The soil release performance of each sample was measured by staining the fabric with a corn oil stain according to the AATCC Standard Test Method 130-1969. The stain release rating ranges from 5.0 to 1.0 with 5.0 measv.ring complete stain re-moval and ;.0 measuring absence of st.ain removal.
The moisture transport data for each sample was obtained by carrying out wicking height tests. In this test, a one~inch wide stri.p Gf the sample fabric was suspended above a container of water with 1/4" of fabric immersed in the water. The height ~3~7~
of the dry fabric-wet fabric interface (above the water level) was measured as a function of time.
The results (Table 31) show that moisture transport is greatly improved by sulfo-fluorination, but that fluorination alone achieves equally superior soil release properties.

TREATMENT OF POLYPROPYLENE FABRIC
Gas Mixture Treatmen~ % F Xncor- Wicking Soil Time, Mins por~ted by wt Hgt. mm ~el Rtg.
, 10 A ___ ___ _ _ 0 1.2 B 1/0/99 1 0c17 85 3O6 C 1/0~99 5 ~. 0.49 ~7 5.0 D S/0/95 1 ~0.~9 i6 4.7 E 1/0/98~ 1 0.17 77 S~0 F 1/0/98~ 5 0.18 71 5.0~
G 1/0/94~* 1 - 0.10 64 5~0 H l/O~g4~* 5 0.26 50 5.0 I 4/0/95~ 1 0.44 61 5.0 J 4/0J95~ 5 1.03 52 5.0 20 A1/1~98 1 0.098 131 4.75 B 1/1/9 8 5 0.152 128 5.0 A 1/10,~89 1 0,079 125 ~.5 B 1/10/89 5 0.204 122 5.0 A 4~10/86 1 0~353 116 5.0 B 4/10/86 5 0~367 127 5.0 *Gaseolls mixture also contains I vol. % 2 **Gaseolls mixture also contains 5 vol. % 2 EXAMPL~~ XXXII
A spun Spandex fabric (3.9 o~/sq. yd.~ was treated in the ~7~i~9 manner described in Examples XXIV, XXV and XXVI. Spandex is a synthetic polymer which comprises at l~ast 85% by weight of a segmented polyurethane. The treated samples were tested against control specimens.

~REATMENT OF POLYURETHANE ~ABRIC
Gaseous ~xture Treatment ~ ~ Incorpor- Wic~ing Hgt.
P~SO2~N~, Vol.~ Tilne, min. ated by wt. _ mm.

1/0/99 1 0.057 ~4 l/O/g9. - 5 O.~gS ~ 2~
5/0/g~ 1 0.17 37 1~0/98* 1 0.07~ 7 1/0/98* ' 5 0.1 62 1/0/9~**' 1 0.061 71 1/0/9~** ~ 5 ~ 0~17 45 4/Q/95* . 1 ~10 57 4/0/gS* . 5 0.32 63 1~10/89 1 0~052 100 20. 1~10/8~ 5 ~.09~ 103 1/1/9~ 1 0.050 . 87 1/1/98 . 5 0.099 ~0 ~jlO/86 1 0.103 98 - 4/10/86 5 1.011 48 *Gaseous mixture also contain.s 1 vol. ~ 2 **Gaseous mixture also contai~s 5 vol. ~ 2 . .

.

i9 EXAMPLE XXXIII
A polyurethane foam was sulfo-fluorinated according to the method of Examples XXIV, XXV and XXVI, and the wetting time determined according to A~TCC Tes.~ Method 39-1971~ The results are shown in Table 33;

TAB~E 33 -Reaction Conditions ~F Incorporated Wetting Sample~ F2 %S2 Time (min) by wt. Time-Sec.
Control --- --- --- 0.018 ~2700 1838-12-14 16 1 0.104 315 1838-12-34 16 3 .255 54 EXAMPLE XXXIV
An acrylic fiber sold under the trademark ACRILAN was : treated accc,rding to the method of Examples.XXIV, XXV and XXV~
~ Table 34 s~lmarizes the reaction conditions and results:
- ~

~3'~

Reaction Conditions ~ x Incoxp. by wt. Wicking ~Igt.
%F2 ~S2 Time(min) F S mm-20 min.
Control -~ 38 1 1 1 0.021 0.14 92 1 1 3 0.019 0.15 111 1 1 6 0.025 0.18 109 1 1 25 0.18 0.18 107 1 5 1 0.018 0.19 99 1~ 1 5 3 0.032 0.21 113 1 5 6 0.03 0.23 106 1 5 25 0.16 O.lg 114 1 10 1 0.015 0.22 121 1 10 3 0.024 0.22 95 1 10 6 0.031 0.18 130 1 10 25 0.023 0.20 121 EXAMPLE XXXV
High density polyethylene bottles, average wall thicknes~
24 mil, were treated according to the method of Examples XXIV, XXV and XXVI, then tested for toluen~ permeability. The test involves retaining a (weighed) solvent containing sealed bottle in an oven ~aintalned at 122F for a total of 28 days and measuring the weight loss.
The test conditions and results are shown in Table 35:

~i;S37~

TREATMENT OF POLYEr~HYLENE B~TTLES

Gaseous Mixture Treatment %F/~S Incorpo- r~Wt.loss~12~F
F2!SO2/N2,Vol.% Time ~min) rate~ by wt. for 28 days -- Control -- -- 84.7 10/0/90 15 0.041/-- 6.64 4/10/86 15 0.015/59ppm 5.9 4/4/92 15 0.015/16ppm 5.0 10/50/4Q 15 0.017/0.017 18.3 Aside from the improvement in the oil barrier property attributable to the SO2 reaction, it is noteworthy that lower fluorine incorporation levels may be employed, an economic advantage.

EXAMPL~, XXXVI
High density and low densi.ty po.l.ye~.hylene films were treated according to the method of Examples Y.~IV, XXV and XXVI
and tested for tensile strength (AST~ D882-67) and percent elongation. The test results, shown in Tables 36-1 and 36-2, ~ show that t~e treatment can be conducted under circumstances ; 20 which retain film strength.

TABLE 36-1 .

T~.E~TMENT OF HIGEI DENSITY POLYErrHYLENE FILM
Tensile Gaseous Mi:~ture, TreatmentStrength ~ Elonga-P2/S2/N2, Vol.~Ti.m~, Min. . psi tion ---Contxol --- 3591 180 4~0/96 ~ ~0 742 10 4/0/80* 6Q 375~ ~00 1~10~89 120 3787 160 *~aseous mixture contains 16~ by volume o~ O~

~L533'7~9 TREATMENT OF LOW DENSITY.POLYETHYLENE FILM

Tensile G~seous Mixture, Txeatment - Strength % Elon~a-F2/S 2~2' Ti~ne, min. psi ~ion --Contxol --- .2973 1123 1/10/89 . 60 2925 833 1/10~89 -120 2258 620 EXAMPLE XXXVII
Samples of high density polyethylene film were treated according to the method of Examples XXIV, XXV and XXVI, then tested ~or oil barrier properties according to AST~: F 119-70.
The test results shown in Table 37 indicate that the sulfo-fluorination improves oil barrier resistance over fluorination treatment.

- ~7 ~76S~

OIL BARRIER PROPERTIES OF TREAT~D
HIGH DENSITY POLYETHYLENE FII,M

Gaseous Mixture, Txeat.m~nt Penetration Time, /SO2/N2, Vol.% . Time, n~n. ~lxs. a~ 1~0F
__ ---Control .. --- 12 5/0/95 . , ., 5 . 15 5/0/~5 10 , 27 S/0/~5 3S ~7 5/0/95 . 75 10~

~4/92 60 53 ~8/~8 60 53 4/10/80 6~ 167 ~/~0/56 ~0 192 5/10/~5 15 27 5/10/85 . 45 72 5~10/85 63 7~

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for surface treating a fiber form synthetic resin selected from the group consisting of polyamide, polyester, polyolefin and polyacrylonitrile which comprises contacting the fiber form (synthetic) resin for less than fifteen minutes with a fluorine-containing gas having less than about 5% by volume of elemental oxygen and from about 0.1 to about 20% by volume of elemental fluorine and recovering a fluorinated fiber form (synthetic) resin having a combined fluorine level from 4 x 10-7 to 4 x 10-1 mg F/cm2.

2. A method according to claim 1, wherein the fiber form synthetic resin is a polyamide or polyester and the fluorine-containing gas is substantially free of oxygen.

3. A method according to claim 1, wherein the fluor-ine-containing gas has from 0.1 - 5% by volume of fluorine.

4. A method according to claim 3, wherein the fiber form synthetic resin is a polyamide or polyester and the gaseous reaction medium is substantially free of oxygen.

5. A method according to claim 1 or 2, wherein the fiber form synthetic resin is a polyolefin or a polyacrylonitrile and the fluorine containing gas has less than a 1:5 O2/F2 ratio, contains at least 0.2% by volume O2 and from 1% - 5% by volume F2 and the treatment time is less than 5 minutes.

6. A method according to claim 1 or 2, wherein the fluorine-containing gas also contains sulfur dioxide.

7. An oil stain release moisture transporting fiber form synthetic resin made in accordance with claim 1 selected from the group consisting of polyamides, polyesters, polyolefins and polyacrylonitriles, said fiber form resin being surface fluorinated from about 4 x 10-7 to 4 x 10-1 mg F/cm2, and having a fluorinated carboxylated layer with the fluorine and carboxyl-ate groups being concentrated at the fiber surfaces and within about 70 .ANG. for polyamide and polyester, and within about 300 .ANG.
for polyolefin and polyacrylonitrile.