CA1280245C - Poly(aryl ether ketones) containing sulfur - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Compositions comprising a) between 0.1 to 5% sulfur present as at least one member of the class consisting of elemental sulfur, aliphatic and aromatic dithiols, polymeric oxidation products thereof comprising repeat units of the formula -R-S-S- where R is a bivalent aliphatic or aromatic radical and inorganic sulphides by weight and b) a poly(aryl ether ketone); useful because of their high tensile modulus, high-temperature adhesive properties, and dimensional stabi-lity. In a further embodiment the composition further con-tains a reinforcing filler such as glass or carbon fibers.
In a further embodiment the composition may be made into fibers or used as adhesives.

Description

~80;~4S

This invention relate~ to polymer~ with improved performance characteristics. In particular the invention relates to compoqition~ comprisin~ a poly~aryl ether ketone) having intimately di per3ed therein from about 0.1 to 5%
sulfur, by weight~ based on the weight of poly(aryl ether ketone).

Polylaryl ether ketone~) are known in the art and are tough, rigid, high-performance thermoplastics which have excellent mechanical and electrical properties. Articles formed from them maintain their properties over a wide temperature range and can be u~ed continuously at high lS temperatures.

IN U.S. Patent No. 3,993,628 to Jarrett et al it is disclo3ed that mixture~ of an aromatic copolyether-ketone/sulfone, containing 3 to 9 ketone~ links per sulfone milaago, with sulfur or a sulfur compound exhibit an increa~e in molecular weight and the polymer cross-linked upon heating. It is reported that the corre3ponding polyetherketones, i.e. without any sulfone link~, do not exhibit an increase in molecular weight upon heating. It is further reported that when a polyetherketone was and 1~ ele-mental sulfur were powder blended and then compre~sion moldedat 400C for lS minutes, the polyetherketone wa~ found to havs decomposed without forming of a coherent film.

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-2 ~ 124~;

We have now discovered that if sulfur or a sulfur com-pound as hereinafter defined i5 uniformly dispersed in a polyarylether ketone the properties of the polymer are significantly and surprisingly improved. In particular we have found that a poly(aryl ether ketone) having uniformly disper~ed therein sulfur or a sulfur compound exhibit improved tensile mwdulus, creep re~istance and in particular their adhesive properties, ecpecially at high temperatures.

The invention comprises compo~ition~ comprising a poly~aryl ether katone) having intimately di~persed therein f rom about 0.1 to about 5~ ~ulfur, by weight, based on the weight of the poly~aryl ether ketone), the sulfur pre~ent a~
at lea~t one member of the class con~isting of elemental sulfur, aliphatic and aromatic dithiols, polysulfides of the formula -R-S-S- where R is a bivalent aliphatic or aromatic radical and inorganic ~ulphides. These compo~ition~ are u3eful for their high tensile modulus, their high-temperature adhe~ive properties, and their dimensional stability. The invention further relate~ to a composition comprising al a poly(aryl ether ketone) having intimately disper~ed ~herein from about 0.1~ to 5~ sulfur, by weight, ba~ed on the weight of the polytaryl ether ketone), the sulfur present as at lea~t one member of the cla3s consisting of elemental sulfur, aliphatic and aro~atic dithiols~ polyqulfides of the formula -R-S-S- where R is a bivalent aliphatic or aromatic radical and inorganic sulphide~ and b) a reinforcing filler. The composition provides a stable reinforced poly~aryl ether ketone) composition.

~ 2 ~ S

Figure l is a stress strain curve at 200C for annealed samples of poly(aryl ether ketone) both with and without sulfur.

S Figure 2 is a stre~3 versus time graph for annealed samples of a poly(aryl ether ketone) both with and without sulfur.

Figures 3 and 4 are stre~3q relaxation curves for annealed qamp}e-~.

Figures 5 and 6 are graphs 3howing creep strain %
verses time at 2&0C for poly~aryl ether ketone~ with and without sulfur.

DETAILED DEscRlps~o~ OF T~E INVENTION

Elemental sulfur, which ha~ an atomic w2igh~ of 32.06, lS existq in two crystalline form~ at room temperature and melting point of about 114C. It is inqoluble in water;
soluble in carbon disulfide. The composition of the invention contains from about 0.1% to about 5~ sulfur on a weight b~sis. A preferred concentration of sulfur in the invention is between 0.25% and 2%.

,.~

302~^S

In the practice of this invention the sulfur may be dispersed in the poly(arylether ketone) in the form of a compound as described above. Of the dithiols, aromatic dithiols of the type HS-R-SH where R is a bivalent aromatic radical are preferred.
Preferred aromatic dithiols are biphenyl-4,4'-dithiol, 4,4'-dimer-captodiphenyl ether and bis-(4-mercaptophenyl) sulphone. Polydi-sulphides comprising repeat units having the formula -R-S-S- where R is a bivalent aliphatic and/or aromatic radical may also be used.
A preferred inorganic sulphide is MoS2. The weight of sulfur is calculated as the amount of sulfur present as elemental sulfur, sulphide which includes mercaptan and thiol, or disulphide.

- .. ; .- , ~

-5- ~ ~80~4~' The term poly(aryl ether ~etone) referq to polymers having the repeat unit of the formula -C0-Ar-C0-Ar'-wherein Ar and Ar' are aromati.c moieties at least one of which containing a diaryl ethe!r linkage forming part of the polymer backbone and where!in both Ar and Ar' are covalently linked to the carbonyl group~ through aromatic carbon atom~.

Preferably, Ar and Ar' are independently 3elected from substituted and unsub~tituted phenylene and ~ubstituted and un~ubstituted polynuclear aromatic moieties. The term polynuclear aromatic moieites i9 used to mean aromatic moieties containing at lea~t two aromatic ring~. The rinq~
can be fused, joined by a direct bond or by a linking group.
Such linking group~ include for example, carbonyl, ether sulfone, sulfide, amide, imide, a20, alkylene, perfluoro-alkylene and the like. A3 mentioned above, at least one of Ar and Ar' contain~ a diaryl ether linkage.

The phenylene and polynuclear aromatic m3ietie~ c~n contain substituent~ on the aromatic ring~. These sub~ti-tuent~ ~hould not inhibit or otherwi~e interfere with the poly~erization re~ction to any 3ignificant extent. Such ~ub3tituent~ include, for example, phenyl, halogen, nitro, cyano, alkyl, 2-alkynyl and ~he like.

~C)24~

Poly(aryl ether ketones) having the following repeat units (the simplest repeat unit being de~ignated for a given polymer) are preferred:

o-~c -~o @~-o~ c-~) o ~ r ~ o ~) 8 ~c ~ _ ~ o I ~) ~ .1 ~ c ~ - ~ D ~ C -~ ~a OE) ~ ~3 -~_ ~7~ 1 ~ ~0~ 4 ~

Poly~aryl ether ketones) can be prepared by known method~ of synthe~ Preferred poly~aryl ether ketones) can be prepared by Friedel-Craftq polymerization of a monomer system comprising:

I~ (i) phosgene or an aromatic diacid dihalide together with (ii) a polynuclear aromatic comonomer comprising:

(a) H-Arn-O-Arn--8 (b) H-(Ar~-O~n-Ar~-~
wherein n i~ 2 or 3 (c) H-Ar~-0-Ar~-(CO-Ar~-0-Ar~)m-8 wherein m i~ 1, 2 or 3 or (d) H-(Ar~-O)Q-Ar~-CO-Ar~-(0-Ar n )m_H
: 15 w~erein m is 1, ~ or 3, and n i~ 2 or 3 or II~ an acid halide of the formula:
~-Ar~-O-t(Ar~-co)p-~Ar~-o)q-(Arn-~o)r]k-Ar~-co-z wherein Z i~ halo~en, k i~ 0, l or 2, p is 1 or 2, q i~ 0, l or 2 and r i Q O ~ 1 or 2;

~ ox~

o~

III) an acid halide of the formula:
H-lAr"-O)n-Ar"-Y
wherein n i~ 2 or 3 and Y iR CO-Z or CO-Ar~-CO Z
S where Z is halogen;

wherein each Ar~ is independen~ly ~elected from ~ub~ti-tuted or unsubstituted phenylene, and substituted and un~ub~tituted polynuclear aromatic moietie~ free of ketone carbonyl or ether oxygen group~, in ~he presence of a reaction mediu~ comprising:

A) A Lewis acid in an amount of one equivalent per equivalent of carbonyl group~ pre~ent, pluR one equivalent per eguivalent o~ Lewis ba~e, plu~ an a~ount effective to act a~ a cataly4t for the polymerization;

8) a Lewis ba~e in an amount from 0 to about 4 equivalent3 per equi~alent of acid halide groups pre~ent in the monomer ~y~tem;

and C) a non-protic diluent in an amount from 0 to about 93~ by w~ight, ba~ed on the weight of the total reac~ion mixture.

~0~ 5 The aromatic diacid dihalid~ employed is preferably a dichloride or dibromidæ. IllugtratiYe d.iacid dihalides which can bo usQd i~clude, for examplo Clll~ ~~ ~11 ''I'~B ~ 1l Il ~
~IC~C~l Ct:~CJ ~le~ $~C-I
O O O
wher~in ~ i~ 0 ~.

-10~ 30245 Illu3trated polynuclear Aromatic comonomers which can be used with such diacid halides are:

(a~ ~-Ar''-O-ArU-H, which include~, for example:

( b ) ~- (Ar "-O ~ ~ O--~--O--and ~ -~
~c) H-Ar~-O-Ar"-~CO-Ar''-O-Ar~)m-H, which includeq, for example:

0 -~ C, - ~ O ~

and td) H-tAr"-O)n-Ar~-CO-Ar~-~O-Arn)m-H which inclùdes, f or example:
~3 ~3 ~ (~
Mono~o~r ~ystems II and III comprise an acid halide. tThe term acid halida is used herein to refer to a monoacid monohalide. ) In monomer 3y9t:elll II, the acid halid~ i9 of the formula-H-Ar"-O-[~Ar"-CO)p-~Ara-O)q-tAr"-CO)r]k-Ar"-CO-Z

o~v~
Such monom~rs include for example, where k - O

~`~C~ o-~c ~~ '~--C~ C'Cl ~n~ ~her@ Lt _ 1 O

~\0/~ ~~,CIC1 .~ O

~O~ C~ Ct O

~ ~ -12-0~5 In monomer sy tem III, the acid halide is of the formula H-(Ar"-O)n-Ar"-Y

Examples of such acid halides include o ~.0~ 1 "

and 0~ ~ r 1 It i9 to be understood that combina~ions of monomers can be employed. Por example, one or more diacid dihalides can be used with one or more polynuclear aromatic comonomers as long aq the correct stoichiometry is maintained. Further, one or more acid halides can be included. In addition monomer~ which contain other linkages such as those speciied above, can be employed as long as one or more of the comonomers used contain~ at lea~t one ether oxygen linkage. Such comonomers include for example:

~ O~ 5 ~ ~ ~ CH~

~8~)~4~i 26775-63 which can be used as the sole comonomer with an ether containing diacid dihalide or with phosgene or any diacid dihalide when used in addition to a polynuclear aromatic comonomer as defined in I(ii) (a), I(ii) (b), I(ii) (c) or I(ii) (d). Similarly ~C~2\[~

can be used as a comonomer together with an ether-containing polynuclear aromatic acid halide or as an additional comonomer together with a monomer system as defined in I.
The monomer system can also contain up to about 30 mole % of a comonomer such as a sulfonyl chloride which polymerizes under Friedel-Crafts conditions to provide ketone/sulfone copolymers.
~urther details of this process for producing poly(aryl ether ketones) can be found in Canadian application Serial No.
450,962.

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~ -i4~ 245 Additives may be included with the poly(aryl ether ketone) compo~itions of this invention. These additives include, for example, pla~ticizers and pigments, non-reinforcing filler~, thermal 3tabilizer ; ultraviolet-light stabilizers, proce3~ing aids, impact modifiers, carbon black, and the like. The invention al~o relate~ to a reinforced compo~ition compri~ing the composition and a reinforcing filler such aq carbon or glass fibers or other polymeric fiber~ ~uch a~ polyamides or relnforcing fillers such a graphite thus further increa~ing the strength of the compo~ition. It i9 preferred that the reinforcing filler be present in an amount of from about 2% to about 30~ by weight and the compo~ition. Where fillers are used they may be blended into the poly(aryl ether ketone) compo~ition at any convenient point in the operation.

The sulfur, in a concentration of from about .1%
to about 5~, may be intimately di~per~ed in the poly(aryl ether ketone) by mixing or blending at a temperature of at lea~t about the melting point of the poly(aryl ether ketone). For example, the culfur may be mixed at the proces~ing temperature using a me~hanical mixin~ apparatus A preferred method of mixing i9 by extru ion. A mixture blended at a te~perature lower than the temperature may be heated to proce~3ing temperature, say e.g., by extru~ion proce~, and then mixed further at ~uch temperature.

The compo3ition~ of the invention have variou~ u~es.
The compo~ition can be for~ed into high-ten3ile-modulu~
fiber3. Poly~aryl ether ketones) by them elves are dif-ficult to use a~ high-temperature hot-melt adhe~ives because their visco~itie~ are too high even at their melt temperature~. However, compo3ition~ of the invention 4~

can have lower vi~cosity before curing. Upon po~t curing at high temperature, cros~linking occurs within the material, and thereby improves the creep re~istance at high temperatures. Hence, thi modified material performq well as an adhesive at high temperature Another use for the compositions of the invention comprise~ the manufacture of molded or extruded article 3 which would show greater dimensional stability due to increased modulus and may be useful, for example, in well and minin~ applications where service life i~ critical.

The following example-~ serve to further deqcribe and illustrate the practicing of the invention. Further, the examples demonstrate the improvement~ and desirably useful properties of the compo~itions deqcribed herein. One skilled in the art would readily be able ~o make substitutions of polymers or make adju~tment3 in temperature, mixing condition~, etc. The example~ are not intended in any way to limit the scope of the invention.

DESCRIPTION OF T~E PREFERRED EMBODIMEN~S

Example 1 - Procedure ~ he samples in examples 2-5 were all prepared and tested in a similar fashion. The poly(aryl ether ketone) for the adhe~ive was poly (carbonyl-p-phenylene-p-oxy-phenylene-p-oxy-phenylene) FQrmula IV (vitrex~Peek from ICI Americas hereafter PEE ~ . Elemental sulfur was added to the said polymer in weight percentage3 of 0, 0.5, and 1.0 and extruded on a ZSR extruder. The pellet~ were then pressed into slabs approximately 16 in2 and 0.020 - 0.030 inches thick. A polyimide film (commercially available as Kapton~
film from DuPont) wa~ used to prevent the polymer from ~trad~m~

-16- ~ ~ ~ox~5 sticking to the press plates. This pre~sing was done at 350Cr 10,000 lbs. ram force, and for four minute. After the hot pressing, the slab was put into a cold press for two minute~ at 1000 lbs. ram force. The cold slabs were then cut into l-inch by l-inch pieces. In some instances the raw material was Qcraped with a razor blade and wiped with methanol. This wa9 done to remove dirt, sand and Xap~on that had accumulated on the aclhesive ~urface.

Once the subRtrate either cold rolled steel or titanium a~ indicated below, and adhesive were cleaned, the two were bonded. The l-inch by l--inch adhesive slab was taped between two substrate~ with l-inch aluminum tape. Thus the bonding area wa~ one ~quare inch. The sample~, including tape, adhe~ive, and two ~ubstrate~, were abou~ about 0.130 inche3 thick. A presQing window of 0.120 inch wa~ used to bond the sample. All pre~singq were done a 371C (700F), at pressure~ ranging from 250 psi to 5000 p~i, and with bonding times varying from 3 minuteq to 20 minutes. After the hot pres~, 3amples were immediately cold pres~ed at approximately 250 p9i for four minutes. Once bonding was fini~hed, the tape wa9 removed and any adhe~ive present on the edges wa~ removed with a razor blade.

Room-temperature lap-~hear testing wa~ done on a 10,000~1b. In~tron. A cro3shead speed of 2 inche~ per minute wa~ u~ed.

-17- ~ 2 ~ 4S

Example 2 - Control LAP-SHEAR STRENGTH OF PEEX *

Mea:n Lap-Substrate** Shear Strlen~th ~i) No. of SamPles Cold-Rolled Steel 810 4 C~ld-Rolled Steel 910 5 Cold-Rolled Steel 790 4 Cold-Rolled Steel 980 4 Cold-Rolled 5teel 760 4 Titanium 400 4 Titanium 200 6 Overall Mean Stren~th (PSi ) S~eel Substrate, 21 Sample~ 850 + l50 Titanium Substrate, l0 Sample3 300 + ll0 5 *Cleaning of ~ub~trate - Sa~dinq, water rinse, acetone dip; polymer ~craped, wiped with MeOH.

** Each entry represents an indepe~dent experiment.

Pressed - 10 minutes, 670 psi, 371C

~` -18- ~.2~3024~

Example 3 LAP-S~EAR STRENGTH OF_PEEX + O.5~5*

Mean Lap-Sub3trate** Shear_Strenqth (psi) No. of Sam~les Cold-Rolled Steel 2030 4 Cold-Rolled Steel 2470 4 Cold-Rolled Steel 2300 3 Cold-Rolled Steel 2500 4 Cold-Rolled Steel 2340 2 Titanium 1430 5 Overall Mean Strenqth (PSi ) ; Steel Sub trate, 17 Samples2330 + 240 Titanium Substrate, 5 Sample-~ 1430 + 60 *Cleaning of substrate - Standing, water rin~e, acetone dip; polymer scraped, wiped with MeO~.

** Each entr~ repre~ent~ an independent experiment.

Pr~ssed - 10 minutes, 500 - 1000 p3i, 371C

~ 19- ~ 4`5 ExamPle 4 LAP-SHEAR STRENGTH OF PEER ~ 1~ S*

Mean I ap -SubRtrate** Shear Strength ~p9i ) No. of Samples Cold-Rolled Steel 2220 4 Cold-Rolled Steel 1980 Cold-Rolled Steel 1850 2 Cold-Rolled Steel 2430 3 Cold-Rolled Steel 1930 4 Cold-Rolled Steel 2070 3 Cold-Rolled Steel 2240 Titanium 1930 3 : Overall Mean Strenqth (~si ?
Steel Substrate, 23 Samples 2140 + 290 Titanium Sub3trate, ~ Sample 1930 + 150 *Cleaning of sub3tr~te - Sanding, wat~r rinse, acetona dip; polymer ~craped, wiped with MeOH.

** Each entry repre~ents an independent experiment.

Pre~ed - 10 minutes, 670 p~i, 371C

.. ,.. : ..-. . . .
- - -- - - ~ o -1~30Z45 Example 5 1~P-SHEAR STRENGTR OF ANNEALED SAMPLES *

Mean Lap-Set Substrate*~ Shear Stren~th (psi) No. of Sam~l_s M PEER - Steel 1390 4 BB PEEX - Steel 1410 5 X PEE~ ~ 1% S - Steel 2540 5 BB PEER + 1~ S - Steel 2460 6 AD PEE~ + 13 S - Steel 2540 4 3~ PEER + 1% S - Steel 2540 4 Overall Mean Strenqth (p~i) PEER - Steel, 9 Sample~ 1400 PE~ + 1~ S - Steel, 19 Sample~ 2510 *Cleaning of ~ub~trate - Standing, water rin~e, acetone dip; poly~er ~craped, wiped with MeOH.

** Each entry repre~ent3 an independent experiment.

Pressed - 10 minutes, 600 - 1000 psi, 371C
Annealed - 210C/18 hours -' ~'~`` ., ~ -~`` -21- 1 2 ~lOZ4 5 Example 6 - Procedures Polymers of Formula I or IV (PEE~) as pellets were mixed with elemental Sulfur in a plastic container. The polymer pellet~ were usually clried at 150C for 4 hours before they were proce~sed. 1'he sulfur-concentration ranges of 0.25-2~ by weight were uced. In addition, two dithiols (4-4' biphenylidithiol and 4-4' dimercaptoether) and one inorganic 3ulphide (MoS2) were u~ed in the for-mulations. The mixture~ of Formula I or Formula IV with each of 3ulfur, dithiol, and c~ulphide were compounded using either the ZSK or ZSE extruder. H2S wa~ evolved during the mixing process.

It should be noticed that attachment of a vacuum outlet at the exit of ths die would help to eliminate gases, such as H2S formed during processing. Thu3, it reduces the poro-sity of the pellet The re~ulting ZSK- or ZSE-compounded pellet~ were used in injection-molding of tensile barq (T-bar~ and in extrusion of tapY and fiber~.

Stre~s-Strain Tests Stre~-strain test were performed on an Instron. The tests wer~ chossn to run at room temperature and 200C. The jaw-~eparation speed was chose~ to ba 2~/min and 0.5"/min at roo~ temperature and 200C, re~pectively. The high test temperature wa9 cho~en to be 200C becau~e it i~ higher than the Tg of both Formula I and PEE~ (Tg - 145bC and 165C for PEER and Formula I re~pectively). All the sample~ were annealed for 4 hours at 240C.

Figure l shows stres~-strain curves mea~ured at 200C
for a ~et of injection-~olded T-bars for PEEK. Tables L and -22- ~2~0~ ~ ~

2 summarize all tencile-elongation properties mea5ured at room temperature and 200C, respectively, for this set of sampleq. Two intere4ting feature~ can be observed directly in Table 2: an increase of Young'~ modulu~ a~ well a~
elongation-at-break i5 ob erved as a function of the sulfur concentration and the addition of the dithiolq produce~
similar effect~ a~ elemental ~ulfur does. The room-temperature data agre~ with what we generally observe for materials that are crosslinked--a decrea~e in elongation-at-break and no 3ignificant increase in ten~ile dulus at tem-perature balow Tg. However, the 200C data show a maximum increase of 50~ both in the Young's modulus and elongation-at-break at sulfur concentration of l~.

Example 7 ~ii) Stress-relaxation and creeP measurement-~

Creep and stres~-relaxation are two important tests, whi~h measure the dimen~ional ~tability of a material.
Streq~-relaxation, which i~ the counterpart of creep, can be easily performed on an In~tron. The sample i~ 3ubjected to a con~tant strain tS% ~train wa~ u~ed) and the de~ay of stresR a~ a function of time iq observed. In a creep experiment, a con~tant force i~ applied to the sample by a weight and the ~train a3 a function of time i3 measured by means of a transducer. To observe th~ effect~ both stress-relaxation and creep expsriments were performed at 200C,which i~ above the Tg of both PEER and the polymer of Formula I. Tha ~amples were annealed at 240C for 4 hour~
before experimentQ.

Fi~ure 2 ~how~ a set of ~tre~-relaxation curves at 200C for four ~amples: curve (A) Formula I, curve tB) _~ -23- ~ z ~ 5 - Formula I + 0~25~ S, curve (C) - Formula I + 0.5~ S and curve (D) - Formula I + 1% S. Curves ~A-C) appear to have a very similar relaxation time since their gradients are very cimilar. However; the initial and final stresses of the Formula I ~ 1~ S are approximately 100~ higher than thoYe of the control sample. Thi3 mean3 that the Formula I
+ 1~ S material i9 a much betl:er material for making high-temperature ~tructural parts because under a con~tant stres~, it would have a much :Les~ deformation (elongation).
Similar result~, but les~ drar~tic, are observed for the Formula I 9amples with lower sulfur concentration3 as shown in Figure 2. Figures 3 and 4 show ~imilar curves for PEER samples. Sulfur has ~imilar effect on PEEX as it ha~ on Formula I. The two dithiol~ and MoS2 also improve P~EX' 3 performance in the stres~-relaxation experiment.

Creep data, which are more useful to engineer~ than stress-relaxation data are shown in Figures 5 and 6. The samples used in this experiment were extruded taps of PE~K
and PE~R + 0. 25~ ~r In Figure 5 the two ~amples were kept under a constant stress approximately equal to 1300 psi.
The initial ~train (t-0) and final strain (t-100 min) of the PEEK + 0.25~ S sample are much les-~ than those of the control sample. A similar trend is observed in Figure 6 for the te~t performed at different stres~e~. In addition, at high stress ( a-2100 p3i ), the control sample appears to have a higher creep rate than ~ulfur-modified ~ample. The creep re ult~ are in good agreement with the stres~-relaxation data.

-- -24- i ~O~4-~

Exam~le 8 Mechanical Properties of sulfur-modified PEEX fiber~

Two sets of fibers ~100~ PEE~ and 99.5% victrex PEER
and 0.5~ sulfur) were extrdued. The extruded fiber~ were aged at 260 and 300C for various length~ of time. The room-temperature an~ 200 C m~chanical properties of thece fibers were measured. The re3ult~ were ~ummarized in Tableq 3-6. The 200-C Young's modulu~ of the extruded sulfur-modified PEER fiber~ i~ about twice that of the control fibers. It is known that the Young's modulus of Victrex PEER and Formula I will increase upon annealing at high temperature in air. The re-~ults shown in Tables 3-S
do show an increase of the Young's dulu~ as a function of aging time. However, the 200C Young's modulus of the sulfur-modified Victrex PEER fibers i~ close to a factor of two higher than that of con rol counterparts at variou~
length~ of aging time. These reqult~ indicate positively that sulfur can increase the high-temperature mechanical properties of Victrex PE~ or Formula I beyond what can be achieved by annealing ths polymer~ at high temperatures in air.

-25- ~.2~30~45 Table L
mechanical pro~erti~s of peek at R. T.

,ample ~(P i x ~oo~ (:rb(P~i % 100) ~b (%) ~5 13.8 40 2 211 14.2 23 3 204 1 3.5 ~8 4 2~2 14.~ 25 18~ ~5.1 ~7 6 216 13.5 10 7 ~98 13.7 13 8 ~01 14.5 28 9 208 14.5 25 peek~sample ~nn~aled at 240 C for 4 hr.
2 pa~k 0~.25%~i~(zse): injection-m~lded T-bar 3 pel~k 0.25~oS
4 poQk 0.5VoS
peek 1.0%S
8 peek 3~ 4-4 b~henyl dithitoz~
~r~Q,o a~e~/e ~ ~ ~' 7 pe~k 3~0 4-4 ~L=~r 8 p~ek 3~ MoS
9 po~k 3~ Mo-~ 0.2S% S

26- ~ 2802 Ta~ie 2 m@chanlcal prop@rti~s of pe~k at 2û0 C

sampl~ E sp~i XloO) Crbl~P~ x tO0) ~b(%) 2201 5~ . 160 2 2703 6.3 198 3 3~.3 $~2 220 4 3~.0 6. 1 ~0 30.4 6.~ 2~7 6 3 ~ .4 ~.2 2~2 7 25.9 6.4 210 PQek 2 pe~k Or2~
3 p~k O.S$S
4 p~k l.Oa'oS

5 p~k 3% 4~ he~nyldithitol O .~er ~7~Od~ é~y/e7~ r pe~k 3~b 4-4 7 pe~k 3$ Mo~3 ~(Z~ inJ~ctlon-mold~ld T-bar ~samplo annQaled at 240 C ~or 4 hr.

-" ~1 2~3~)245 Table 3: Room-temperature mechanical properties of the control and sulfur-modified Victrex PEEX fibers aged at 260C

Aging time 5(day~) 0 1 2 5 8 14 22 30 40 _ _ Samples Young's n~odulu~ x 1000 p~i control 240 325 318 271 261 422 386 353 377 0.5%-S 219 32~ 432 414 396 439 460 470 473 . _ Sample~ Tensile strength x 1000 psi 10control 20 23 24 24 24 23 22 2222 0.5~-S 20 24 28 28 27 27 25 2728 _ _ _ _ _ Sample~ Elongation (~) control 160 110 105 108 107110 102 9090 0.5~-S 140 43 60 55 53 70 53 4037 _ -2~-~.2~30~.5 Table 4: 200C mechanical propertiec of the control and sulfur-modified Victrex PEEK fiber~
aged at 260C

Aging time 5(day~) 0 1 2 5 8 14 22 30 40 Samples Young's ~dulu-~ x 1000 pqi control 13 39 42 42 42 36 50 51 52 0.5~-S 25 60 70 66 69 71 ~2 84 99 Samples TenQile strength x 1000 psi 10control 9 1010 10 10 10 12 14 15 0.5%-S 10 1012 1~ 11 14 13 12 13 .
Samples Elonqation (%) control 181 137140 147 133 165 178 192 183 0.5~-S 155 97123 103 90 128 100 83 80 .. _ . . . .

., .. : ~ ~

29~ 0 2~A5 Table 5: Room-temperatUre mechanical properties of the control and sulfur-modified fibers aged at 300C

Aging time tdays) 0 1 2 5 8 14 22 30 40 .
Samples Young'q modulu~ x 1000 p3i control 240 292 308 280 418 397 374 394 352 0.5~-S 219 403 382 387 587 ~38 435 378 41 . , _ _ _ . . . .
Samples Ten3ile ~trength x 1000 p~i control 20 2421 22 24 22 21 22 20 0.5~-S 20 2829 29 28 23 23 23 21 -Sample~ Elongation (%) control 160 10788 60 50 33 20 12 12 0.5~-S 140 ~058 43 2~ 19 12 9 6 .

... . . ~ ~

~.2,~0~ 4 ~

Table 6: 200C mechanical properties of the control and sulfur modified Victrex PEER fibers aged at Aging time 5 (days) 0 1 2 5 8 14 22 30 40 .
Samples Young'~ modulus x 1000 p3i control 13 39 40 45 53 87 187 170 167 0.5~-S 25 60 58 81 122 170 298 270251 Samples Ten~ile ~trength x 1000 psi 10control 9 1012 11 12 14 12 1310 0.5%-S 10 1314 14 15 14 13 1313 , Sample~ Elongation ~%) control 181 130132 95 63 38 16 10 3 0.5~-S 15~ 80 68 32 27 23 10 g 5

Claims (15)

1. A composition comprising a poly(aryl ether ketone) having intimately dispersed therein from about 0.1% to about 5% sulfur, by weight, based on the weight of the poly(aryl ether ketone), the sulfur present as at least one member of the class consisting of elemental sulfur, aliphatic and aromatic dithiols, polymeric oxidation products thereof comprising repeat units of the formula -R-S-S- where R is a bivalent aliphatic or aromatic radical and inorganic sulphides.

2. A composition according to claim 1 comprising from about 0.25% to 5% sulfur.

3. A composition according to claim 1 which further comprises a reinforcing filler.

4. A composition according to claim 3 wherein the rein-forcing filler is present in amounts of from about 2% to 30% by weight.

5. A composition according to claim 1 wherein the poly (aryl ether ketone) is of the formula:

6. A composition according to claim 1 wherein the poly(aryl ether ketone is of the formula:

7. A composition according to claim 1 wherein the poly (aryl ether ketone) is of the formula:

8. A composition according to claim 1 wherein the poly(aryl ether ketone) is of the formula:

9. A composition according to claim 1 wherein the poly (aryl ether ketone) is of the formula:

10. A composition according to claim 3 wherein the reinforcing filler comprises a) glass fibers; b) carbon fibers; c) polymeric fibers; or d) graphite.

11. A shaped article comprising a composition comprising a poly(aryl ether ketone) having intimately dispersed therein from about 0.1% to about 5% sulfur, by weight, based on the weight of the poly(aryl ether ketone), the sulfur present as at least one member of the class consisting of elemental sulfur, aliphatic and aromatic dithiols, polymeric oxidation products thereof comprising repeat units of the formula -R-S-S- where R is a bivalent aliphatic or aromatic radical and inorganic sulphides.

12. A shaped article according to claim 11 wherein the article is a fiber.

13. An article according to claim 12 wherein the article contains a reinforcing filler.

14. An article according to claim 13 wherein the reinforcing filler comprises a) glass fibers; b) carbon fibers; c) polymeric fibers; or d) graphite.

15. A method of forming any intimately dispersed mixture of a poly(aryl ether ketone) and sulfur which comprises mixing sulfur and a poly(aryl ether ketone) at a temperature at least about the melting point of the poly(aryl ether ketone).