Aramid block copolymers
AssigneeE. I. Du Pont de Nemours and Company
InventorRobert S. Irwin
Life of this patent
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Abstract
Aramid block copolymers which contains blocks whose polymer chains are flexible, and blocks whose polymer chains are flexible in solution and in undrawn polymer, but relatively rigid in drawn polymer, are disclosed. The aramids are tough materials with high modulus and tensile strength. Also disclosed is a process for making such block copolymers. The copolymers are useful as fibers and films, for example in ropes and composites.
Claims31
An aramid block copolymer, comprising, two or more first aramid blocks, said first aramid being flexible in solution and in the undrawn solid polymer but is rigid after drawing of the solid polymer, and two or more second aramid blocks, said second aramid being flexible in solution and in the drawn and undrawn solid state, provided the number of repeat units in each of said first aramid blocks and said second aramid blocks is at least 3.
A process for making an aramid block copolymer, comprising, in solution;
- reacting a first aromatic diacid with a first aromatic diamine in such proportions that an oligomer containing at least 3 repeat units is produced, and the ends of said oligomer are derived from either said first aromatic diacid or said first aromatic diamine;
- adding a second aromatic diacid and a second aromatic diamine in such amounts, and proportions to each other that an approximately equal number of second blocks as the oligomer molecules are formed, and said second blocks contain 3 or more repeat units;
- to form an aramid block copolymer of first blocks composed of said first aromatic diamine and said first aromatic diacid, and of said second blocks composed of said second aromatic diamine and said second aromatic diacid;
- and
- provided that one of said first block or said second block is flexible in solution and in a solid undrawn state, and is rigid in a solid drawn state, and that one of said first block or said second block is flexible in solution and in the solid drawn and undrawn states, and further provided that no aramid blocks are produced that are rigid in the undrawn solid state or in solution.
Dependencies are inferred from the claim text.