FR2550215A1 - CROSSLINKABLE CRYSTALLIZABLE POLYARYLERS AND THEIR APPLICATION TO COMPOSITE FORMATION - Google Patents

Abstract

THE INVENTION RELATES TO A MIXTURE BASED ON A CRYSTALLIZABLE CROSS-LINKABLE RESIN. IT HAS MORE PARTICULARLY DEALING WITH STRENGTH MATERIALS RESISTANT TO SOLVENTS OBTAINED FROM A MIXTURE BASED ON A CRYSTALLIZABLE RESIN CONTAINING A PARTICULAR POLYARYLETHER AND A PLASTICIZER CRYSTALLIZATION ACTIVATOR. APPLICATION TO THE MAKING OF ARMED COMPOSITES OBTAINED FROM SUCH A RESIN-BASED MIXTURE.

Description

25502 1 5

  The present invention relates to solvent-resistant tough materials derived from polyaryl ethers,

  and fiber reinforced composites made from these materials.

  Composites formed of a continuous fibrous reinforcement such as graphite, aromatic polyamide fiber and glass in a polymeric matrix constitute useful building materials, since they possess large specific strengths and large modules in comparison with metals. These composites can be used to make structures supporting loads, for example

  example in motor vehicles and aircraft.

  In most graphite-reinforced composites, systems of epoxy resins are used to form the matrix. Whereas these resins are often brittle, the composites made with them have

  tend to delaminate when they experience a shock.

  To improve the impact strength of fiber-reinforced composites, a matrix thermoplastic material such as polyarylether derived from 2,2-bis (4-hydroxyphenyl) propane (i.e. bisphenol A) and dichlorodiphenylsulfone This resin gives composites with good toughness, but is attacked by many common organic solvents such as chlorinated hydrocarbons, ketones and N, N-dimethylacetamide. The absence of limiting solvent resistance the range of applications allowing

  the use of composites based on this resin.

  Recently, attempts have been made to improve the solvent resistance of polyarylether

  derived from bisphenol A and dichlorodiphenylsulfone.

  The polymer was modified by attaching end groups which participate in the chain extension and crosslinking reactions under the effect of heat. Suitable end groups include maleimide, nadimide and ethynyl groups. Maleimide-terminated polyarylethers are described. in U.S. Patent No. 3,839,287, terminally terminated polyaryl ethers

2 2550215

  nadimide are described by CH Sheppard and collaborators in the 36 th annual conference of the Reinforced Plastics / Composites Institute, 16-20 February 1981, session 17-B, pages 1 & 5, and ethynyl terzminaison polyarylethers are described by PM Hergenrother in J Polymer Sci, Polymer Chem Ed, 20, 1982, pages 3131 & 3146 All of these polyaryl ethers are prepared with bisphenol A, as aromatic diphenol. However, none of these resin compositions

  has a high degree of solvent resistance.

  The invention is directed to a) a crystallizable crosslinkable resin comprising (i) a polyaryl ether of formula I wherein R is 20 or N is 4 to 100 and X is selected from

O O

o o

0 0

  And (c) a crystallization activating plasticizer, and (b) fiber-reinforced composites,

  made using (i) plus (ii) as the matrix-constituting resin.

  The compositions of the invention are endowed with very good solvent resistance and very good resistance to environmental stress cracking as compared to compositions containing bisphenol A-derived compound I. Reinforced composites to the fiber according to the present invention comprise a fibrous reinforcement formed at the choice of one or more fibers such as

  carbon or graphite, aromatic polyamide fibers, glass fibers or boron fibers.

  The polyarylethers of formula I have a backbone derived from a 4,4'-dihalogenodiphenylsulfone and an aromatic diphenol which is predominantly hydroquinone or 4,4'-biphenol. The dihalo-diphenylsulfone of choice is 4,4'-dichlorodiphenylsulfone and the The preferred diphenol is hydroquinone. A proportion of up to 25% of the diphenol, on a molar basis, can be replaced by bisphenol A, methylhydroquinone, hydrochloroquinone, bis (4hydroxyphenyl) methane, bis ( 4-hydroxyphenyl), bis- (4-hydroxyphenyl) sulfone, resorcinol, or hydroxyl-terminated oligomeric polyarylethers such as those described in US Patent No. 4,306,094. moles% of the dihalo-diphenylsulfone can be replaced by other monomers including 4,4-dihalobenzophenones such as 4,4-difluorobenzophenone or 4,4'-dichlorobenzophenone or s 2,6-dihalobenzonitriles

  such as 2,6-dichlorobenzonitrile.

  The end groups carried by the compound I 35 are chosen from the following groups: CECH -O Ro-C- <5 COO O IL

O O0 0

P'-H C CH

N-g and_z_H bv \ j ODCC

OCH 2 -C- = CH

  Each undergoes chain extension and crosslinking reactions by the application of heat. The process for preparing compound I is dependent on X. Si-X is a group of formula C-CH

-ORO 2 C

  it can be prepared by a two-step process comprising: i) the preparation of a hydroxyl-terminated polyarylether by condensation of a molar excess of an aromatic diphenol with dichlorodiphenylsulfone at a temperature of from about 100 to about 220 ° C in the presence of a base in a dipolar aprotic solvent. Advantageous operating conditions are described in U.S. Patent Nos. 4,108,837 and 4,200,728 and British Patent No. 1,492,366, and ) esterification of the terminal hydroxyl groups with an ethynyl substituted benzoyl chloride in the presence of an acid acceptor. Methynylbenzoyl chloride or retynylbenzoyl chloride may be used. Triethylamine is an acid acceptor

  advantageous Suitable solvents including N-

  methylpyrrolidinone, tetrahydrofuran,

methylene or mixtures thereof.

  The general operating method for carrying out the synthesis of polyarylethers when X is C-CH

-OR 02 C C

  is given in J Polymer Sci, Polymer Chem Ed, 20, 1982, pages 3131-3146.

  If X is a group o Il -Os C or C

  The polyarylether of formula I can be produced by a process involving i) the preparation of an amine-terminated polyarylether by condensation of an aminophenol, a dihalo-diphenylsulfone and an aromatic diphenol at elevated temperature in the presence of a base in a dipolar aprotic solvent, ii) the addition of maleic anhydride or nadic acid, i.e., 5-norbornene-2,3-dicarboxylic anhydride, to the terminal amino groups to form a diamic acid followed by iii) imidization of the amic acid groups by heat or addition of a dehydrating agent such as

acetic anhydride.

  This process is the method. The conditions for carrying out steps (i) to (iii) are given in U.S. Patent No. 3,839,287. Alternatively, step (i) may be driving eh-using the

  operating conditions of U.S. Patent No. 3,895,064 or British Patent No. 1,492,366, supra.

  The steps of Method A are illustrated in Scheme I in the case of the use of p-aminophenol,

  hydroquinone and nadic anhydride.

  Scheme I 2 H Oj-, NH 2 (n 1) C 14 e SO 2 / D C 1

+ N 1 10 O I

  Base (for example K 2 C 03) N-methylpyrrolidinone / toluene 180 C w If 2 -O - <NU 2 od A il ro Ln LM ru Ln Il tn (<'51 t -N <O lo CQO The molecular weight of the amine-terminated intermediate polyarylether is governed by the molar ratio of aminophenol to aromatic diphenol The amount of dihalogenodiphenylsulfone which is used is selected so that there is 0.95 to 1.05 mole of activated halide per mole of hydroxyl group. M-Aminophenol may be used

or p-aminophenol.

  If X represents O or S or a different procedure (ie, Method B) can be used for the preparation of compound I. This process involves the formation of a hydroxyl group-containing imide. from aminophenol and maleic anhydride or nadic anhydride, and ii) condensation of a dihalo-diphenylsulfone, an aromatic diphenol and the product of (i) at a temperature of from about 100 to about 180 The driving conditions of this step are similar to those indicated for the preparation of the amino terminated polyaryl ether in step i) of process A. Process B is Illustrated in Scheme II in which p-aminophenol, hydroquinone and nadic anhydride are used. The synthesis of hydroxyl-containing imide is described in the aforementioned CH Sheppard et al. Scheme II

II O ON 1 N 12

+ <20

  An Imide Containing a Hydroxyl Group o + 2 9 lu, + y (n + 1) Cl O 1

+ N H O O-0 H

  F-base (eg K 2 CO 3) N-methyl-pyrrolidinone /

toluene, 170 C.

  mad I Mi Lm Ln o ro Ul Si -X is the group

-O C-CH

N-C Q

  The polyaryl ether of formula I can be synthesized by a process involving (i) the preparation of an amino-terminated polyarylether by condensation of an aminophenol, a dihalo-diphenylsulfone and an aromatic diphenol in the presence of a base in a dipolar aprotic solvent at a temperature of 100 to 210 ° C., followed by (ii) amidation of the terminal amino groups with m or p-ethynylbenzoyl chloride in the presence of an acid acceptor between -20 ° C. and 50 ° C. In some

  In this case, the reaction solvent may serve as an acid acceptor.

  A preferred solvent for the preparation of compound I when X is the group

-O -C -C-CH

H O

  is N-methylpyrrolidinone, since it can be used

in both steps i and ii.

If X is a group

-O C-CH

  the polyaryl ether of formula I can be prepared by condensation of aromatic diphenol, a dihalo-diphenylsulfone and ethynylphenol ## STR3 ## in a dipolar aprotic solvent at a temperature of 70 to 200 ° C. in the presence of a base. ethynylphenol is described in the United States patent

N 4 108 926.

If X is a group

-OCH 2-C-CH,

  the polyaryl ether of formula I can be prepared by condensation of the aromatic diphenol, a dihalo-diphenylsulfone and propargyl chloride in a dipolar aprotic solvent in the presence of a base. Propargyl chloride is advantageously added after the formation of a

  hydroxyl-terminated polyarylether from dihalogenodiphenylsulfone and an excess of aromatic diphenol.

  In the composition, the plasticizer activating the crystallization induces crystallinity in the skeleton

  of polylarylether of I by application of heat.

  There are two types of plasticizers that activate crystallisation. The first type does not react with the polyaryl ether of formula I and is characterized by the solubility with the polyaryl ether, a glassy-glass transition temperature of less than 30 ° C., low volatility (by The second type reacts with the polyaryl ether of formula I and can optionally react with itself and is characterized by a vitreous transition temperature of less than 100.degree. at 70 ° C. and at a boiling point greater than 200 ° C. Examples of the first type are the triaryl esters of phosphoric acid, the terphenyls, the hydrogenated terphenyls, the quaterphenyls, the hydrogenated quaterphenyls and the polyphenylene oxides. o N is 2 to 15, 4,4'-dichlorodiphenylsulfone, 4,4'-dichlorobenzophenone, other diphenylsulfones or benzophenones as well as substituted diphenyl ethers, and mixtures thereof Suitable second type plastifiers include 4,4'-bis (3-ethynylphenoxy) diphenylsulfone, triallyl cyanurate and diallyl phthalate, triallyl trimellitate, bisphenol A bis cyanate, diaminodiphenylmethane, lamino-3-ethynylbenzene, 1-hydroxy-3-ethynylbenzene, 2,2'-bis- (3-ethynylphenoxy-4-phenyl) propane, adipate

  divinyl, 1,4-butanediol divinyl ether, N-phenylmaleimide, 4,4'-diaminodiphenylmethane bis-maleimide, N-vinyl-2-pyrrolidinone and mixtures thereof.

  The crosslinkable crystallizable compositions of the invention (i.e., and more the plasticizer) can be prepared by mixing the components at a temperature of about 100 ° C. to about 350 ° C. in conventional equipment for polymer formulation. For example, a Banbury mixer or an extruder. The mixing time is advantageously short and the

  mixing is low to minimize premature crosslinking.

  An inert gas atmosphere is preferable when formulating ethynyl-terminated polyaryl ethers.

  An alternative method for bringing compound I and the crystallization activator together is to dissolve or disperse them in a liquid such as N-methylpyrrolidinone, N, N-dimethylacetamide, methylene chloride, tetrahydrofuran, sulfolane or mixtures thereof The liquid may be evaporated off or poured into a liquid which dissolves the vehicle but which does not dissolve either compound I or crystallization activator for many mixtures in N-methylpyrrolidinone or N , N-dimethylacetamide, a precipitation in water is satisfactory A solid mixture

  I and the activator can then be collected by filtration, dried and cured.

  Compositions having very good solvent resistance are prepared by heating the mixture of I and the crystallization activator to a temperature of 50.degree.

  ranging from about 100 to about 350 C The duration and temperature depend on the desired degree of solvent resistance.

  The preferred temperature is greater than the passage temperature by the vitreous state of the mixture and below the point

melting pure compound I.

  The fiber-reinforced composites of the present invention are made using techniques known in the prior art. For example, thin films of the I mixture and the crystallization activator can be prepared and interfolded between layers. fibrous reinforcement in the form of a woven fabric or a unidirectional ribbon A laminate can be prepared by heating this assembly in a heated press Alternatively, composites can be made from an intimate prepreg mixed body The prepreg can be prepared by passing the fibers through a heated bath containing compound I, the crystallization activator and a solvent and then evaporating the solvent.

by application of heat.

  Other methods include applying a suspension containing compound I and the crystallization activator to a framework before heating and compressing as described, for example, in U.S. Patent No. 4,292. A prepreg reinforcement as well as a laminated sheet can be prepared using heated calenders as described, for example, in the

  U.S. Patent No. 3,849,174.

  The number average molecular weight of the polyarylether of formula I ranges from about 2000 to about 30,000, preferably from about 2,500 to about 25,000, and especially

  from about 5,000 to about 20,000 The polyarylethers of Formula I are solids that melt or soften below 380 C.

  The compositions of the invention (plus the crystallization activator) can be used with or

  without reinforcement In the absence of reinforcement, they contain up to 50% by weight of the crystallization activator.

  In reinforced compositions, the amount of I is from about 10 to about 90% by weight, the amount of crystallization activator is from 0.5 to about 25% by weight and the amount of reinforcement ranges from 5 to 10% by weight. About 85% by weight they can be extruded, compression molded and injection molded. They can also be used in the form of films, coatings, adhesives and sealing compositions. They can also be combined with fillers. particles such as carbon black, talc, mica and

  calcium carbonate Short fibers and continuous filaments can be used.

  Suitable reinforcements have a melting point or a decomposition point greater than 200 ° C. and comprise one or more materials such as alumina, titanium oxide, silicon carbide, silicon boride,

  polybenzothiazole and the reinforcements indicated above.

  Crosslinking can be carried out with the aid of free radical initiators or by irradiation. Suitable initiators include dicumyl peroxide, di-tert-butyl peroxide, 1,1,2,2-tetraarylethanes, 1,1,2,2-pentaaryléthanes, etc. EXAMPLES The following examples give further details

  details on how to implement the present invention, without in any way limiting the scope thereof.

Example 1

  129.22 g of dichlorodiphenylsulfone, 48.45 g of hydroquinone, 2.21 g of p-aminophenol, 80.85 g of potassium carbonate, 137 ml of chlorobenzene and 368 ml were charged.

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  of sulfolane in a one-liter four-necked flask equipped with mechanical stirrer, thermometer, dropping funnel, nitrogen purge, Dean-Stark separator This mixture was purged with nitrogen for half an hour at room temperature (about 25 ° C.) with stirring. It was then heated to 210 ° C. at the same time as chlorobenzene and the chlorobenzene azeotrope. The temperature was maintained at 210 ° C. for 2 hours by dropwise addition of 180 ml of chlorobenzene. The reaction mixture, which then contained an amino-terminated polyaryl ether, was cooled to 170 ° C. and added to the reaction mixture. 3.94 g of nadic anhydride After two hours at a temperature of 160 ° C. to 170 ° C., the mixture was poured into a container lined with a metal foil and allowed to cool after solidification of the reaction product. we broke it and washed it The insoluble material was collected by filtration and was washed with three portions (500 ml) of deionized water. After being suspended in 2 liters of methanol, it was dried and dried in a mixer with 2 liters of deionized water. The isolated product yield was 145 g. Infrared analysis indicated that the product was a nadimide-terminated polyarylether whose reduced viscosity was 0.50, measured in 25 C N-methylpyrrolidinone at a concentration of

0.2 g / dl.

  Control A The following ingredients were charged to the reaction flask: 43.9 g of phenoxynadimide, 85.3 g of bisphenol A, 110.07 g of dichlorodiphenylsulfone, 55.6 g of potassium carbonate and 760 ml of mixture of dimethylacetamide and toluene The contents were heated to 140 C during

72 hours.

  The reaction product had a reduced viscosity of 0.50, measured in N-methylpyrrolidinone at

   C at a concentration of 0.2 g / 100 ml.

Example 2

  Preparation of molded plates and solvent test After having been heated at 250 ° C. for several hours, molded parts of the material of Example 1 remained totally unaffected by immersion in methylene chloride or in dimethylacetamide, while molded from the material of Control A swelled considerably in these solvents when they were

ripened under the same conditions.

  This result shows the very good resistance to solvents of the composition of the invention with hydroquinone as diphenol in the polyarylether backbone compared to control A which is based on bisphenol A. However, other improvements especially as regards the resistance to cracking under the effect of ambient stresses are desirable, and a means of

  obtain is illustrated in Examples 3 and 4.

  Solvent Resistance of Nadimide-terminated Polymers A Sample Maturation Conditions Effect of Sol-B vial Control A 2 hours at 250 ° C strongly swells Unaffected Products Example 1 "Not Affected A 1 x 2 cm strips cut from a plate of 10.16 cm x 16 cm x 0.254 mm molded at 275 C under pressure of

28 M Pa.

  B The solvent was methylene chloride unless otherwise specified.

  C N, N-dimethylacetamide Control B Resistance to cracking under the effect of ambient stresses of a molded plate made from the product

from example 1

  The material of Example 1 was heated to 310 ° C and compression molded into a 10.16 cm × 10.16 cm × 0.508 mm plate and allowed to continue for 2 hours at 250 ° C. followed by an annealing step for 2 hours at 200 ° C. The resulting material was

25502 1 5

  was tested for resistance to cracking under ambient stress, with respect to acetone and methyl ethyl ketone. The time to failure was 2 seconds in dimethyl ethyl ketone and 3 seconds in acetone under duress. The modulus values as a function of temperature were determined on the material described in this example which had been molded and heated for 2 hours at 250 ° C, but not annealed at 200 ° C. The values of the secant modulus at 1% at 200 ° C., 225 ° C. and 250 ° C. were, respectively, equal to 1.4 M Pa, 0.32 M Pa. and 56 k Pa Calorimetric measurements were made by heating at 15 400 C at a rate of 10 C / minute under a nitrogen atmosphere

  on the Du Pont / 990 thermal analyzer No sign of crystallinity has appeared.

Example 3

  Resistance to cracking under ambient stresses of mixtures of the product of Example 1 and a crystallization activator The material of Example 1 (8.5 g) was suspended in an acetone solution containing 1.5 g of triphenyl phosphate After removal of the acetone by evaporation, the material was heated to 310 ° C. and compression molded into a 10.16 cm × 10.16 cm × 0.508 mm plate with The reaction was then allowed to proceed for 2 hours at 250 ° C. This operation was followed by an annealing step for 2 hours at 200 ° C. The resulting material was subjected to a crack test under the effect of Ambient stress, relative to acetone and methyl ethyl ketone The time to break was 0.08 hours in methyl ethyl ketone and 0.12 hours in

  acetone under the effect of a stress of 7 M Pa.

  The modulus values as a function of temperature were determined on the material described in this example which had been molded and heated for 2 hours at 250 ° C. but not annealed at 200 ° C.

  Temperature function revealed the existence of a semicrystalline product with a clear crystalline module plateau.

  The measured values of the 1% secant modulus at 200 ° C, 225 ° C and 250 ° C were, respectively, 60.55; 55.09; and 34.79 M Pa The crystalline melting point determined according to

  the modulus values as a function of temperature were 280 ° C. The calorimetric data were determined by heating at 400 ° C. and at a rate of 10 ° C./min under a nitrogen atmosphere on the Du Pont 990 thermal analyzer.

  Crystallinity was present The crystalline melting point was 272 C and the heat of fusion was

27.2 J / g.

Example 4

  The material of Example 1 (8.0 g) was suspended in an acetone solution containing 2.0 g of triphenyl phosphate. After evaporation of acetone, the material was heated to 310 ° C and compression molded into a plate of 10.16 cm × 10.16 cm × 0.508 mm and then allowed to react for 2 hours at 250 ° C. This operation was followed by an annealing step for 2 hours at 200 ° C. The resultant material was subjected to environmental stress cracking test against acetone and methyl ethyl ketone. The time to break results were 2.13 hours. in methylethylketone and 1.20 hours in acetone under the influence of a

stress of 7 M Pa.

  The modulus values as a function of temperature were determined on the material described in this example, which had been molded and heated for 2 hours at 250 ° C, but not annealed at 200 ° C. The modulus values as a function of temperature were revealed the existence of a semi-crystalline product with a clear crystalline module plateau. The measured values of the secant modulus at 1% at 200 ° C, 225 ° C and 250 ° C were 65.38, respectively; 56.7; and 42 M Pa The crystalline melting point determined from the module values as a function of the temperature was

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  285 C Calorimetric data were determined by heating at 400 ° C. at 10 ° C./minute under an aot atmosphere on the Du Pont 990 thermal analyzer. Crystallinity was present. The crystalline melting point was 283 ° C., and the heat of fusion was 31.4 J / g.

  The results of Examples 3 and 4 indicate that a plasticization of the polymer of Example 1 leads to an improvement of the resistance to cracking under the effect of ambient stresses.

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Claims (9)

  1 crystallizable crosslinkable resin mixture, characterized in that it comprises: (i) a polyarylether of the following formula: XDS 2 - \ O ao QSQX wherein R represents $ e or n is a value of 4 to 100 and X is chosen from -l QO N-Xu IO O oo 00 cc to CECH.   ## STR5 ## and -OCH 2 -C-CH and   (ii) a plasticizer promoting crystallization.   Mixture according to Claim 1, characterized in that the plasticizer activating crystallisation is distinguished by its solubility with the polyarylether, a glass transition temperature of less than about    C and a boiling point greater than about 300 C.   The blend of Claim 2 wherein the crystallization promoter plasticizer does not react with the polyarylether of Claim 1 and which is selected from triaryl esters of phosphoric acid, terphenyls, hydrogenated terphenyls, quaterphenyls, hydrogenated quaterphenyls, and the like. poly (phenylene oxides),   4,4'-dichlorodiphenylsulfone, 4,4'-dichlorobenzophenone, substituted diphenylsulfone, benzophenones, diphenyl ethers, or mixtures thereof.   4. Mixture according to claim 1, characterized in that the plasticizer activator of crystallization is distinguished by a temperature of passage through the state   vitreous of less than about 70 C and a boiling point of more than about 200 C.   The blend of claim 4 wherein the crystallization activator plasticizer is reactive with the polyarylether of claim 1 and which is selected from 4,4'-bis- (3-ethynylphenoxy) diphenylsulfone, triallyl cyanurate, phthalate, and diallyl, triallyl trimellitate, bisphenol A bis-cyanate, diaminodiphenylmethane, lamino-3-ethynylbenzene, 1-hydroxy-3-ethynylbenzene, 2,2'-bis- (3-ethynylphenylphenyl) propane, adipate divinyl ether, 1,4-butanediol, N-phenylmaleimide, 4,4'-diaminodiphenylmethane bis-maleimide, N-vinyl-2-pyrrolidinone and their mixtures.   Mixture according to Claim 1, characterized in that it contains up to 50% by weight of the crystallization activator plasticizer.   Composition, characterized in that it comprises: (a) the resin-based mixture as defined in claim 1, and (b) an armature formed of one or more fibers selected from carbon or graphite fibers , aromatic polyamide fibers, glass fibers, boron fibers, alumina, titanium oxide, carbide   silicon, silicon boride and a polybenzothiazole.   A composition according to claim 7 characterized in that the polyarylether in the resin mixture is present in amounts of about 10 to about % in weight.   Composition according to claim 7, characterized in that the crystallization activator plasticizer in the resin mixture is present in amounts of from 0.5 to about 25% by weight.   Composition according to Claim 7, characterized in that the reinforcement is present in quantities   from about 5 to about 85% by weight.   A composite, characterized in that it comprises: (a) the cross-linked resin mixture as defined in claim 1, and (b) a reinforcement consisting of one or more fibers selected from carbon or graphite fibers, aromatic polyamide fibers, glass fibers, boron fibers, alumina, titanium oxide, carbide   silicon, silicon boride and a polybenzothiazole.