Synthesis of surface-functionalized polyamides

Abstract

The present invention relates to a process for producing a surface-functionalized molding (oF) having a functionalized surface (fO). In this process a surface (O) of a molding (F) is brought into contact with a dienophile-containing solution (dL). The surface (O) comprises a polyamide (P) which comprises furan units. These furan units are able to react with the at least one dienophile present in the dienophile-containing solution (dL) to give the surface-functionalized molding (oF) having the functionalized surface (fO).

Claims

1. A process for producing a surface-functionalized molding (oF) having a functionalized surface (fO), comprising the steps of i) providing a molding (F) having a surface (0) which comprises a polyamide (P), the polyamide (P) comprising diene units of the general formula (I) ##STR00004## in which R.sup.1 and R.sup.2 independently of one another are selected from C.sub.1-C.sub.10 alkanediyl, ii) contacting the surface (O) of the molding (F) provided in step i) with a dienophile-containing solution (dL) which comprises at least one dienophile, the at least one dienophile comprising at least one dienophile unit which is reactive toward the diene units (I) present in the polyamide (P), to give the surface-functionalized molding (oF) having the functionalized surface (fO).

2. The process according to claim 1, wherein in step ii) the at least one dienophile unit present in the at least one dienophile reacts with the diene units (I) present in polyamide (P) in a [4+2] cycloaddition to give the surface-functionalized molding (oF).

3. The process according to claim 1, wherein the dienophile-containing solution (dL) comprises at least one solvent (LM).

4. The process according to claim 3, wherein the at least one solvent (LM) is selected from the group consisting of acetone, acetonitrile, N-methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, hexane, toluene, diethyl ether, tetrahydrofuran, methylene chloride, chloroform, 1,2-dichlorobenzene, water, methanol, ethanol, and isopropanol.

5. The process according to claim 3, wherein the dienophile-containing solution (dL) comprises in the range from 0 to 99.5 wt % of the at least one solvent (LM) and in the range from 0.5 to 100 wt % of the at least one dienophile, based in each case on the total weight of the dienophile-containing solution (dL).

6. The process according to claim 1, wherein the at least one dienophile unit present in the at least one dienophile is selected from the group consisting of CC double bonds, CO double bonds, and CS double bonds.

7. The process according to claim 1, wherein the at least one dienophile present in the dienophile-containing solution (dL) comprises at least one structural unit selected from the group consisting of maleimides, benzophenone, acrylates, methacrylates, acrylonitriles, maleic acid, maleic anhydride, and maleic esters.

8. The process according to claim 1, wherein the at least one dienophile present in the dienophile-containing solution (dL) comprises exactly one dienophile unit.

9. The process according to claim 1, wherein step ii) is carried out at a temperature in the range from 15 to 150 C.

10. The process according to claim 1, wherein the at least one dienophile present in the dienophile-containing solution (dL) comprises at least one further functional unit.

11. The process according to claim 10, wherein the at least one further functional unit is selected from the group consisting of anhydrides, imides, esters, carboxylic acids, amines, alcohols, thiols, and isocyanates.

12. The process according to claim 10, wherein the following step is carried out subsequent to step ii): iii) contacting the functionalized surface (fO) of the surface-functionalized molding (oF) obtained in step ii) with at least one functionalizing agent (FM) which comprises at least one reactive unit which is reactive toward the at least one further functional unit present in the at least one dienophile.

13. The process according to claim 12, wherein the at least one reactive unit present in the at least one functionalizing agent (FM) is selected from the group consisting of amines, alcohols, thiols, isocyanates, carboxylic acids, and anhydrides.

14. A surface-functionalized molding (oF) obtainable by the process according to claim 1.

Description

EXAMPLES

(1) For the measurement of the contact angle, the powders obtained were applied to a flat glass surface and the contact angle of water drops on the powders was determined using a Krss DA 100. For this purpose, using double-sided adhesive tape, a powder layer was produced on a glass slide. For the determination of the contact angle, drops of deionized water of about 2 l in size were placed onto the powder layer and subjected to measurement at 23 C.

Comparative Example 1

(2) Pellets of PA6/F6 (80/20) (W/W), copolymer of caprolactam (80 wt %) with 2,5-bis(aminomethyl)furan and adipic acid (together 20 wt %), were ground under liquid nitrogen in a Retsch ZM 200 cryomill and then sieved to give a powder having a particle size of <500 m. The powder was dried in a vacuum oven at 80 C. The contact angle was 112.9.

Example 2

(3) 5 g of the powder from comparative example 1 were suspended for 24 hours in a 0.1-molar solution of 1,1-(methylenedi-4,1-phenylene)bismaleimide solution in toluene (dienophile-containing solution (dL)) and stirred therein. Subsequently the powder was filtered, washed five times with toluene, and filtered. The powder was subsequently dried in a vacuum oven at 80 C. for 24 hours. The contact angle was 103.8.

Example 3

(4) 10 g of the powder from comparative example 1 were suspended for 24 hours in a 1-molar solution of maleic anhydride solution in toluene (dienophile-containing solution (dL)) and stirred therein. Subsequently the powder was filtered, washed five times with toluene, and filtered. The powder was subsequently dried in a vacuum oven at 80 C. for 24 hours.

Example 4

(5) 5 g of the powder obtained in example 3 were suspended in a 1-molar solution of 1-octadecylamine in toluene (solution of the functionalizing agent (FM)) and then stirred for 24 hours. The powder obtained was filtered, washed five times with toluene, and filtered again. The powder obtained was then dried under reduced pressure at 80 C. for 24 hours. The contact angle was 123.6.

Example 5

(6) 5 g of the powder obtained in example 3 were suspended in water for 24 hours and stirred therein. Subsequently the powder was filtered and then dried in a vacuum oven at 80 C. for 48 hours. The contact angle was 71.2.

(7) From the comparison of the contact angles for the various powders obtained in the examples it is clearly apparent that the surface of PA6/F6 can be modified hydrophobically or hydrophilically by the reaction with a dienophile. When the PA6/F6 powder is treated with maleic anhydride and the product obtained is subsequently reacted with 1-aminooctadecane (example 4), the contact angle is increased significantly, indicating that the surface becomes more hydrophobic. In contrast, on reaction of the polyamide powder with maleic anhydride and subsequently water, the contact angle is significantly lowered, pointing to a greater hydrophilicity on the part of the polyamide.