Anisotropic copoly(imide oxetane) coatings and articles of manufacture, copoly(imide oxetane)s containing pendant fluorocarbon moieties, oligomers and processes therefor

Abstract

Copoly(imide oxetane) materials are disclosed that can exhibit a low surface energy while possessing the mechanical, thermal, chemical and optical properties associated with polyimides. The copoly(imide oxetane)s are prepared using a minor amount of fluorinated oxetane-derived oligomer with sufficient fluorine-containing segments of the copoly(imide oxetane)s migrate to the exterior surface of the polymeric material to yield low surface energies. Thus the coatings and articles of manufacture made with the copoly(imide oxetane)s of this invention are characterized as having an anisotropic fluorine composition. The low surface energies can be achieved with very low content of fluorinated oxetane-derived oligomer. The copolymers of this invention can enhance the viability of polyimides for many applications and may be acceptable where homopolyimide materials have been unacceptable.

Claims

1. A copoly(imide oxetane) having the structure represented by:
-(G-M)-(D-M)- wherein: G is represented by the formula
═N—R.sup.1—C(O)—O-J-C(O)—R.sup.1—N═ wherein: J is [CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O].sub.m or [(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.p—(R.sup.6—O).sub.q—(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.r] wherein R.sup.6 is substituted or unsubstituted aliphatic or aromatic moiety of 2 to 16 carbons; R.sup.1 is aliphatic or aromatic hydrocarbon moiety of 1 to 10 carbon atoms; R.sup.2 is —H, —F, or alkyl of 1 to 6 carbon atoms; R.sup.3 is —F, —R.sup.4H.sub.(n-a)F.sub.a, —R.sup.5—O—R.sup.4H.sub.(n-a)F.sub.a, and —O—R.sup.4H.sub.(n-a)F.sub.a, wherein R.sup.4 is an alkyl or ether moiety of 1 to 30 carbons, R.sup.5 is an alkyl moiety of 1 to 30 carbons, a is an integer of 3 to n, and n is twice the number of carbon atoms in the alkyl moiety plus 1; and m is between about 4 and 500, p is between about 4 and 150, q is between about 1 and 150, and r is an integer; M is represented by the formula
(—C(O)).sub.2-L-(C(O)—).sub.2 wherein: L is a hydrocarbyl-containing moiety of 2 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, silyl, sulfur, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; D is represented by the formula
═N—Z—N═ wherein: Z is a hydrocarbyl-containing moiety of 1 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, sulfur, silyl, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido.

2. The copoly(imide oxetane) of claim 1 wherein the omega carbon of R.sup.4 has three fluoride substituents and wherein m is between 6 and 100.

3. The copoly(imide oxetane) of claim 2 containing 0.002 to 15 mass percent of G.

4. The copoly(imide oxetane) of claim 3 which is a block co-polymer.

5. The copoly(imide oxetane) of claim 3 which is a random co-polymer.

6. A coating having an outer surface and a bonding surface comprising the copoly(imide oxetane) of claim 1, said coating having an anisotropic distribution of fluorine atoms over its thickness with a higher concentration at the outer surface.

7. The coating of claim 6 having a water contact angle of at least 90° at the outer surface.

8. A method for coating a substrate with the copoly(imide oxetane) of claim 1, the method comprising applying on the substrate a solution containing a copoly(amic acid oxetane) having the structure represented by:
-(G-A)-(D-A)- wherein: G is represented by the formula
—NH—R.sup.1—C(O)—O-J-C(O)—R.sup.1—HN— wherein: J is [CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O].sub.m or [(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.p—(R.sup.6—O).sub.q—(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.r] wherein R.sup.6 is substituted or unsubstituted aliphatic or aromatic moiety of 2 to 16 carbons; R.sup.1 is aliphatic or aromatic hydrocarbon moiety of 1 to 10 carbon atoms; R.sup.2 is —H, —F, or alkyl of 1 to 6 carbon atoms; R.sup.3 is —F, —R.sup.4H.sub.(n-a)F.sub.a, —R.sup.5—O—R.sup.4H.sub.(n-a)F.sub.a, and —O—R.sup.4H.sub.(n-a)F.sub.a, wherein R.sup.4 is an alkyl or ether moiety of 1 to 30 carbons, R.sup.5 is an alkyl moiety of 1 to 30 carbons, a is an integer of 3 to n, and n is twice the number of carbon atoms in the alkyl moiety plus 1; and m is between about 4 and 500, p is between about 4 and 150, q is between about 1 and 150, and r is an integer; A is represented by the formula ##STR00003## wherein: L is a hydrocarbyl-containing moiety of 2 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, silyl, sulfur, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; D is represented by the formula
—NH—Z—NH— wherein: Z is a hydrocarbyl-containing moiety of 1 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, sulfur, silyl, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; in a volatile solvent to form a copoly(amic acid oxetane) coating, and subjecting the copoly(amic acid oxetane) coating to drying and imidization conditions to form the anisotropic copoly(imide oxetane) coating.

9. A polymer composite comprising a copolymer containing the copoly(imide oxetane) of claim 1 and a particulate filler, wherein the polymer composite has a water contact angle of at least 100°.

10. An article of manufacture comprising a polymeric matrix and the copoly(imide oxetane) of claim 1, said article having an outer surface, and said article of manufacture having a higher concentration of fluorine atoms at the outer surface than that of the polymeric matrix without the copoly(imide oxetane).

11. The article of manufacture of claim 10 which is a cast article of manufacture.

12. The article of manufacture of claim 10 which is a molded article of manufacture.

13. A method for making the article of manufacture of claim 10 comprising W forming the polymeric matrix containing comprising a copoly(amic acid oxetane) having the structure represented by:
-(G-A)-(D-A)- wherein: G is represented by the formula
—NH—R.sup.1—C(O)—O-J-C(O)—R.sup.1—HN— wherein: J is [CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O].sub.m or [(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.p—(R.sup.6—O).sub.q—(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.r] wherein R.sup.6 is substituted or unsubstituted aliphatic or aromatic moiety of 2 to 16 carbons; R.sup.1 is aliphatic or aromatic hydrocarbon moiety of 1 to 10 carbon atoms; R.sup.2 is —H, —F, or alkyl of 1 to 6 carbon atoms; R.sup.3 is —F, —R.sup.4H.sub.(n-a)F.sub.a, —R.sup.5—O—R.sup.4H.sub.(n-a)F.sub.a, and —O—R.sup.4H.sub.(n-a)F.sub.a, wherein R.sup.4 is an alkyl or ether moiety of 1 to 30 carbons, R.sup.5 is an alkyl moiety of 1 to 30 carbons, a is an integer of 3 to n, and n is twice the number of carbon atoms in the alkyl moiety plus 1; and m is between about 4 and 500, p is between about 4 and 150, q is between about 1 and 150, and r is an integer; A is represented by the formula ##STR00004## wherein: L is a hydrocarbyl-containing moiety of 2 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, silyl, sulfur, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; D is represented by the formula
—NH—Z—NH— wherein: Z is a hydrocarbyl-containing moiety of 1 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, sulfur, silyl, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; into a first article having an outer surface and (2) subjecting the first article to imidization conditions to form the article of manufacture comprising the copoly(imide oxetane).

14. The method of claim 13 wherein the article of manufacture is a cast article of manufacture.

15. The method of claim 13 wherein the article of manufacture is a molded article.

16. The method of claim 15 wherein the molded article is produced from dry polymeric matrix particles comprising the copoly(amic acid oxetane) and formed into the shape of the article under pressure and imidization conditions.

17. A method for making the article of manufacture of claim 10 comprising (1) forming a polymeric matrix comprising a copoly(amic acid oxetane) into a first article having an outer surface, (2) contacting the outer surface with at least one of (i) at least one diamine oligomer represented by the formula:
(E).sup.yR.sup.1—C(O)—O-J-C(O)—R.sup.1(E).sub.y wherein: J is [CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O].sub.m or [(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.p—(R.sup.6—O).sub.q—(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.r] wherein R.sup.6 is substituted or unsubstituted aliphatic or aromatic moiety of 2 to 16 carbons; E is —NH.sub.2; y is 1 or 2; R.sup.1 is aliphatic or aromatic hydrocarbon moiety of 1 to 10 carbon atoms; R.sup.2 is —H, —F, or alkyl of 1 to 6 carbon atoms; R.sup.3 is —F, —R.sup.4H.sub.(n-a)F.sub.a, —R.sup.5—O—R.sup.4H.sub.(n-a)F.sub.a, and —O—R.sup.4H.sub.(n-a)F.sub.a, wherein R.sup.4 is an alkyl or ether moiety of 1 to 30 carbons and the omega carbon of R.sup.4 has three fluoride substituents, R.sup.5 is an alkyl moiety of 1 to 30 carbons, a is an integer of 3 to n, and n is twice the number of carbon atoms in the alkyl moiety plus 1; and m is between about 6 and 100, p is between about 4 and 150, q is between about 1 and 150, and r is an integer, and (ii) at least one copoly(amic acid oxetane) having the structure represented by:
-(G-A)-(D-A)- wherein: G is represented by the formula
—NH—R.sup.1—C(O)—O-J-C(O)—R.sup.1—HN— wherein: J is [CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O].sub.m or [(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.p—(R.sup.6—O).sub.q—(CH.sub.2—CR.sup.2R.sup.3—CH.sub.2—O).sub.r] wherein R.sup.6 is substituted or unsubstituted aliphatic or aromatic moiety of 2 to 16 carbons; R.sup.1 is aliphatic or aromatic hydrocarbon moiety of 1 to 10 carbon atoms; R.sup.2 is —H, —F, or alkyl of 1 to 6 carbon atoms; R.sup.3 is —F, —R.sup.4H.sub.(n-a)F.sub.a, —R.sup.5—O—R.sup.4H.sub.(n-a)F.sub.a, and —O—R.sup.4H.sub.(n-a)F.sub.a, wherein R.sup.4 is an alkyl or ether moiety of 1 to 30 carbons, R.sup.5 is an alkyl moiety of 1 to 30 carbons, a is an integer of 3 to n, and n is twice the number of carbon atoms in the alkyl moiety plus 1; and m is between about 4 and 500, p is between about 4 and 150, q is between about 1 and 150, and r is an integer; A is represented by the formula ##STR00005## wherein: L is a hydrocarbyl-containing moiety of 2 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, silyl, sulfur, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido; D is represented by the formula
—NH—Z—NH— wherein: Z is a hydrocarbyl-containing moiety of 1 to 100 carbon atoms optionally containing divalent radicals selected from the group consisting of oxygen, sulfur, silyl, carbonyl, sulfonyl, phosphonyl, perfluoro, tertiary amino, and imido, to produce a second article, and (3) subjecting the second article to imidization conditions to form the article of manufacture comprising the poly(imide oxetane).

Description

EXAMPLES

(1) The following examples are to further illustrate the invention and are not in limitation thereof. All parts and percentages are by mass unless otherwise stated or clear from their context.

Example 1: Synthesis of Dinitro-Terminated Oxetane Oligomer

(2) This example uses a hydroxyl-terminated oxetane available as POLYFOX™ PF-6320, 3-(2,2,2-trifluoroethoxymethyl)-3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-oxetane oligomer having an approximate molecular weight of 3400 g/mole. To a glass flask blanketed with nitrogen which contains about 150 milliliters of toluene are charged 60.32 grams of the oligomer. Triethyl amine (14.52 grams) is added and the solution is stirred for about 10 minutes and heated to about 50° C. A previously prepared solution of 10.4 grams of p-nitrobenzoyl chloride dissolved in 150 milliliters of toluene is added to the oligomer-containing solution drop wise over a period of about 30 minutes. The solution is then stirred under reflux for about 16 hours, then cooled to room temperature. The solution is then filtered, washed twice (250 milliliters) with an aqueous solution of 5 mass percent sodium bicarbonate and then once with 250 milliliters of deionized, distilled water. Thereafter the solution is dried over magnesium sulfate. The liquor is then rotary evaporated to yield a viscous, honey-colored oil. The oil is vacuumed dried. The dried sample contains the dinitro-terminated oxetane oligomer.

Example 2: Synthesis of Diamine-Terminated Oxetane Oligomer

(3) A 100 milliliter, mechanically stirred, glass reaction vessel is charged with 8.8 grams of the dinitro-terminated oxetane oligomer of Example 1, 0.445 grams of palladium on carbon hydrogenation catalyst available from Aldrich Chemical Co. having a metal loading of 5 mass percent, and 40 milliliters of anhydrous ethanol. The resulting solution is degassed and subsequently backfilled with hydrogen to 200 kPa gauge. The solution is maintained under agitation for 16 hours. After removing hydrogen, the solution is filtered through diatomaceous earth (CELITE™ available from Celite Corporation, Goleta, Calif., United States) followed by rotary evaporation and vacuum drying. The dried sample contains the diamine of the oxetane oligomer.

Example 3: Synthesis of Copoly(Imide Oxetane)

(4) A series of copoly(imide oxetane)s are prepared using the following general procedure: 1. The diamine-terminated oxetane oligomer is dissolved in N,N-dimethylacetamide to provide an oligomer solution. 2. The other diamine, 4,4′-oxydianiline, is added to a stirred, glass reaction flask and dissolved in N,N-dimethylacetamide. 3. An amount of the oligomer solution is added to the flask to provide a sought mass ratio of the oxetane oligomer to the diamine. 4. The solution in the flask is stirred for about 10 minutes and then dianhydride, 3,3′,4,4′-bisphenyltetracarboxylic dianhydride, is added to the flask. The amount of dianhydride added provides a molar ratio of dianydride to total diamine of about 1.0:0.95. Sufficient N,N-dimethylacetamide is added to provide a 20 mass percent solids solution. 5. The solution is stirred at ambient temperature (about 22° C.) for about 16 hours under an inert gas atmosphere.

(5) The solution contains copoly(amic acid oxetane). Table I summarizes the polymers made.

Example 4: Imidization to Copoly(Imide Oxetane)

(6) Imidization of the polymer material is done using the following general procedure. Samples of each solution made in Example 3 are centrifuged to remove gas bubbles. A film is cast from each sample using a doctor blade to an approximate thickness of about 500 to 750 microns on glass and each film is placed in a forced air drying chamber at room temperature for about 24 to 48 hours to remove solvent and provide a tack-free surface. Some of the films are then thermally imidized under nitrogen using a cure cycle with stages at 150° C., 175° C., 200° C. and 250° C. with a minimum hold of 40 minutes at each stage.

(7) Some of the copoly(amic acid oxetane) solutions are chemically imidized by reaction with acetic anhydride and pyridine. In this procedure, 33.02 grams of a 10 mass percent solids copoly(amic acid oxetane) and N,N-dimethylacetamide solution are poured into a 100 milliliter 3-necked round bottomed flask. Then 3.9 milliliters of pyridine and 3.3 milliliters of acetic anhydride are added to the flask and the reaction mixture is mechanically stirred overnight under an inert atmosphere. After about 16 hours the reaction mixture is poured into a blender containing water resulting in precipitation of the chemically imidized copoly(imide oxetane) product. The copoly(imide oxetane) is filtered, stirred in hot water for several hours, filtered again and allowed to dry.

Example 5: Evaluation of Copoly(Imide Oxetane)

(8) The cast and imidized coatings are evaluated for various characteristics and performance properties.

(9) Modulus of the coatings is determined using a Sintech 2W test frame with a crosshead speed of 5.08 millimeters per minute and analyzed using Testworks 8.0 software (both available from MTS Systems Corporation, Eden Prairie, Minn., United States). See Table I.

(10) A ThermoFisher ESCA lab 250 X-ray photoelectron spectrometer (available from Thermofisher Scientific, Waltham, Mass., United States) is used for XPS analysis.

(11) A FTA 1000B contact angle goniometer available from First Ten Angstroms, Inc., Portsmouth, Va., United States is used to measure the water contact angle with an 8 microliter drop being used. See Table I.

(12) Dust adhesion is evaluated by adhering a 6 millimeter diameter sample of the cast film on the end of a sonication device. The surface is coated with an approximate monolayer of particles having a particle diameter of less than about 30 microns. The sonication device uses a series of sonication steps of increasing magnitude.

(13) With respect to dust adhesion, the copoly(imide oxetane)-containing films exhibit improved surface clearance and potentially lower adhesion values than the homopolymer.

(14) The XPS surface analysis indicates that the fluorine population of the exterior (air-facing) surface of the coating films reaches a plateau at a low fluorine-containing oxetane moiety content in the copoly(imide oxetane) material. The data are presented in Table I. For sake of comparison, the fluorine atomic concentration of the oxetane oligomer is about 29 atomic percent. The interior surface (glass-facing surface) has a fluorine population higher than that of the bulk, but less than that of the exterior surface (air-facing surface) which is also reported in Table I. The XPS analysis thus confirms an unexpected migration of the fluorine-containing oxetane moieties in the copoly(imide oxetane) to the surface, and further indicates that only a very small amount of the oxetane oligomer is required to provide sought low surface energies. Although the presence of the oxetane oligomer does not unduly adversely affect the mechanical properties of the copoly(imide oxetane) at somewhat higher levels, the ability to achieve the low surface energies with very small amounts of the oxetane oligomer would not detract from the desirable bulk properties of the copoly(imide oxetane) material.

(15) TABLE-US-00001 TABLE I Diamine Exterior Glass oxetane Surface Surface oligomer, mass Break Stress, Elongation at Water Contact Fluorine, Fluorine, % Modulus, MPa MPa Break, % Angle, ° Atomic % Atomic % 0 3590 141 10.1 81 5 2 0.01 3560 142 8.3 93 0.1 3570 142 9.2 95 14 5 0.2 3510 139 11.5 95 14 0.4 3450 138 7.5 94 20 0.5 3350 142 5.5 94 16 9 0.8 3460 138 11.2 94 17 1.0 3440 141 8.7 98 19 8 2.0 3380 138 8.7 94 17 5.0 3140 126 9.7 95 18 4