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 which are crystalline and blocks that are noncrystalline after drawing and where 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.
Claims26
An aramid block copolymer, comprising, two or more first aramid blocks, said first aramid blocks being crystalline after drawing of the solid polymer, and two or more second aramid blocks, said second aramid blocks being noncrystalline after drawing of the solid polymer, said first and second aramid blocks being flexible in solution and in the undrawn solid polymer and rigid in the drawn solid state, and provided the average 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 an average of 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 crystalline in the drawn solid state, and that one of said first or second block is noncrystalline in the solid state, and further provided that said first and said second blocks are flexible in solution and the undrawn solid state and rigid in the drawn solid state.
Dependencies are inferred from the claim text.