Polyamide copolymers having 2,5-furan dicarboxamide units

1. A polyamide copolymer comprising at least one alkylene 2,5-furan dicarboxamide unit and at least one alkylene terephthalamide unit, wherein the polyamide copolymer has 35 weight % to 95 weight % alkylene terephthalamide units, with the proviso that the copolymer does not comprise —(CH 2 ) 10 — alkylene units,

wherein the polyamide copolymer has a difference between melting temperature (T m ) and crystallization temperature T c of at most 50° C.;

wherein the crystallization temperature (T c ) is taken as the maximum of the crystallization exotherm of a differential scanning calorimetry (DSC) thermogram obtained by cooling the polyamide copolymer from 300° C. to 25° C. at 20° C. per minute; and

wherein the melting temperature (T m ) is taken as the maximum of the melting endotherm of a differential scanning calorimetry (DSC) thermogram obtained by subsequently heating the polyamide copolymer from 25° C. to the molten state at 20° C. per minute.

2. The polyamide copolymer of claim 1 wherein the at least one alkylene 2,5-furan dicarboxamide unit is of the formula:

wherein k=6-9 or 11-30.

3. The polyamide copolymer of claim 1 wherein the at least one alkylene terephthalamide unit is of the formula:

wherein m=6-9 or 11-30.

4. The polyamide copolymer claim 1 , wherein the copolymer further comprises at least one alkylene adipamide unit.

5. The polyamide copolymer of claim 4 wherein the at least one alkylene adipamide unit is of the formula:

wherein n=6-9 or 11-30.

6. The polyamide copolymer of claim 1 wherein the difference between melting temperature (T m ) and crystallization temperature (T c ) is at most 40° C.

7. The polyamide copolymer of claim 1 wherein the difference between melting temperature (T m ) and crystallization temperature (T c ) is at most 30° C.

8. The polyamide copolymer of claim 1 , wherein all the amide units in the copolymer include the same diamine fragment.

9. A method of fabricating an article comprising:

providing a polyamide copolymer according to claim 1 ; and

melt processing the polyamide copolymer under conditions effective to form the article.

10. The method of claim 9 wherein conditions effective comprise one or more of injection molding, compression molding, transfer molding, and extrusion.

11. A method of preparing a polyamide copolymer, the method comprising:

providing a copolyamide prepolymer comprising alkylene 2,5-furan dicarboxamide repeat units and alkylene terephthalamide repeat units, with the proviso that the copolyamide prepolymer does not comprise —(CH 2 ) 10 — alkylene units; and

heating the copolyamide prepolymer under conditions effective to form the polyamide copolymer, wherein the polyamide copolymer has 35 weight % to 95 weight % alkylene terephthalamide units,

wherein the polyamide copolymer has a difference between melting temperature T m and crystallization temperature T c of at most 50° C.

wherein the crystallization temperature (T c ) is taken as the maximum of the crystallization exotherm of a differential scanning calorimetry (DSC) thermogram obtained by cooling the polyamide copolymer from 300° C. to 25° C. at 20° C. per minute; and

wherein the melting temperature (T m ) is taken as the maximum of the melting endotherm of a differential scanning calorimetry (DSC) thermogram obtained by subsequently heating the polyamide copolymer from 25° C. to the molten state at 20° C. per minute.

12. The method of claim 11 wherein the copolyamide prepolymer further comprises alkylene adipamide repeat units.

13. A method of preparing a polyamide copolymer, the method comprising:

providing a copolyamide prepolymer comprising alkylene 2,5-furan dicarboxamide repeat units and alkylene adipamide repeat units; and

heating the copolyamide prepolymer under conditions effective to form the polyamide copolymer, wherein the polyamide copolymer has 35 weight % to 95 weight % alkylene adipamide units,

wherein the polyamide copolymer has a difference between melting temperature T m and crystallization temperature (T c ) of at most 50° C.;

wherein the crystallization temperature (T c ) is taken as the maximum of the crystallization exotherm of a differential scanning calorimetry (DSC) thermogram obtained by cooling the polyamide copolymer from 300° C. to 25° C. at 20° C. per minute; and

wherein the melting temperature (T m ) is taken as the maximum of the melting endotherm of a differential scanning calorimetry (DSC) thermogram obtained by subsequently heating the polyamide copolymer from 25° C. to the molten state at 20° C. per minute.

14. The method of claim 13 wherein the copolyamide prepolymer further comprises alkylene terephthalamide repeat units.