Liquid crystalline thermosets from ester, ester-imide, and ester-amide oligomers

• US 20020132933A1
• Filed: 01/05/2001
• Published: 09/19/2002
• Est. Priority Date: 09/13/2000
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: Erik S. Weiser, St. Clair, Terry L., Theodorous J. Dingemans
• Inventors: Weiser, Erik S., St. Clair, Terry L., Dingemans, Theodorous J.
• Granted Patent: US 6,939,940 B2
• Time in Patent Office: Days
• US Class Current: 525/437
• CPC Class Codes: C08G 63/60 derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
• CPC Class Codes: C08G 63/6854 derived from polycarboxylic acids and polyhydroxy compounds
• CPC Class Codes: C08G 69/44 Polyester-amides
• CPC Class Codes: C08G 73/16 Polyester-imides
• CPC Class Codes: C09K 19/3804 with mesogenic groups in the main chain
• CPC Class Codes: C09K 19/3823 containing heterocycles having at least one nitrogen as ring hetero atom

Abstract

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.

Claims

1. An oligomer mixture with self-reactive end-caps comprising:

the general structure

wherein Z is a liquid crystal backbone of the oligomer mixture selected from the group consisting of an ester, an ester-imide and an ester-amide,

wherein E and E′

are selected from the group consisting of

wherein R′

is selected from the group consisting of hydrogen, alkyl groups containing six or less carbon atoms, aryl groups containing less than ten carbon atoms, lower alkoxy groups containing six or less carbons, lower aryloxy groups containing ten or less carbon atoms, fluorine, chlorine, bromine, and iodine.

3. An oligomer mixture with self-reactive end-caps as claimed in claim 1, wherein E and E′

are identical.

4. An oligomer mixture with self-reactive end-caps as claimed in claim 1, wherein the molecular weight range of the oligomers is between approximately 1000 and approximately 15,000 grams per mole.

5. An oligomer mixture with self-reactive end-caps as claimed in claim 1, wherein the melt viscosities of the oligomer mixture is between approximately 1 and approximately 250 poise at approximately 200°

C. to approximately 350°

C.

6. A polymer product comprising an oligomer mixture with self-reactive end-caps according to claim 1 wherein said product is prepared by a process selected from the group consisting of melt processing, molding, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injecting (RFI), powder molding, injection molding, blow molding, thermo-forming, plasma spraying, and pultrusion molding.

7. The polymer product of claim 1 wherein said product is a form selected from the group consisting of a fibre, filament, coating, film, lining, tube, pipe, sheath, sheet, and panel.

2. An oligomer mixture with self-reactive end-caps comprising:

the general structure

wherein Z is a liquid crystal backbone of the oligomer mixture having at least one structural repeat unit selected from the group consisting of

wherein R is selected from the group consisting of

wherein n is a number less than 500,

wherein m is a number less than 500,

wherein Ar is selected from the group consisting of

wherein X is selected from the group consisting of

wherein n is a number less than 500,

wherein E and E′

are selected from the group consisting of

wherein R′

can be selected from the group consisting of hydrogen, alkyl groups containing six or less carbon atoms, aryl groups containing less than ten carbon atoms, lower alkoxy groups containing six or less carbons, lower aryloxy groups containing ten or less carbon atoms, fluorine, chlorine, bromine, and iodine.

8. An oligomer mixture as in claim 2 wherein

E and E′

are

Z is

wherein Ar is

9. An oligomer mixture as in claim 2 wherein

E and E′

are

Z is

wherein Ar₁ and Ar₂ are

10. An oligomer mixture as in claim 2 wherein

E and E′

are

and Z is selected from the group consisting of

where Ar₁ and Ar₃ are

and Ar₂ is