Claims
- 1. A polymer film comprising an ordered rod-like extended chain aromatic heterocyclic polymer selected from the group consisting of poly(p-phenylenebenzo bisthiazole) and poly(p-phenylenebenzo bisoxazole) having a binder selected from the group consisting of glass, ceramic, polysulfone, epoxy and polyimide interpenetrated in the microinfrastructure, and wherein the polymer is infiltrated with the binder to form a microcomposite of the polymer and binder.
- 2. The film of claim 1, wherein said binder is a thermoset acetylene-terminated polyimide.
- 3. A polymer film comprising an ordered rod-like extended chain aromatic heterocyclic polymer selected from the group consisting of poly(p-phenylenebenzo bisthiazole) and poly(p-phenylenebenzo bisoxazole having a binder precursor selected from the group consisting of glass, ceramic, polysulfone, epoxy and polyimide interpenetrated in the microinfrastructure, and wherein the polymer is infiltrated with the binder precursor to form a microcomposite of the polymer and binder.
- 4. The film of claim 3, wherein said binder is a thermosetting acetylene-terminated polyisoimide.
- 5. A polymer film comprising an ordered rod-like extended chain aromatic heterocyclic polymer selected from the group consisting of poly(para-phenylenebenzo bisthiazole) and poly(para-phenylenebenzo bisoxazole), and a glass binder infiltrated within the polymer to form a microcomposite of the polymer and the binder.
- 6. A polymer film comprising an ordered rod-like extended chain aromatic heterocyclic polymer selected from the group consisting of poly(para-phenylenebenzo bisthiazole) and poly(para-phenylenebenzo bisoxazole), and a glass binder precursor infiltrated within the polymer to form a microcomposite of the polymer and the binder.
- 7. A polymer film comprising an ordered rod-like extended chain aromatic heterocyclic polymer having a binder selected from the group consisting of glass, ceramic, polysulfone, epoxy and polyimide interpenetrated in the microinfrastructure prepared by treating by shear a dope containing an ordered polymer to produce a microscale structure orientation therein, solidifying said microscale structure by coagulation in an aqueous medium, penetrating a binder precursor into the microstructure of said solidified polymer, and converting said precursor to said binder.
REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of application Ser. No. 780,648 filed Sept. 26, 1985 now abandoned.
Ordered polymers are polymers having an "ordered" orientation in space i.e., linear, circular, star shaped, or the like, imposed thereon by the nature of the monomer units making up the polymer. Most ordered polymers possess a linear "order" due to the linear nature of the monomeric repeating units which comprise the polymeric chain. Linear ordered polymers are also known as "rod-like" polymers.
For example, U.S. Pat. No. 4,423,202 to Choe, discloses a process for the production of paraordered, aromatic heterocyclic polymers having an average molecular weight in the range of from about 10,000 to 30,000.
U.S. Pat. No. 4,377,546 to Helminiak, discloses a process for the preparation of composite films prepared from para-ordered, rod-like, aromatic, heterocyclic polymers embedded in an amorphous heterocyclic system.
U.S. Pat. Nos. 4,323,493, and 4,321,357 to Keske et al., disclose melt prepared, ordered, linear, crystalline injection moldable polymers containing aliphatic, cycloaliphatic and araliphatic moieties.
U.S. Pat. No. 4,229,566 to Evers et al., describes para-ordered aromatic heterocyclic polymers characterized by the presence of diphenoxybenzene "swivel" sections in the polymer chain.
U.S. Pat. No. 4,207,407 to Helminiak et al., discloses composite films prepared from a paraordered, rod-like aromatic heterocyclic polymer admixed with a flexible, coil-like amorphous heterocyclic polymer.
U.S. Pat. No. 4,108,835 to Arnold et al., describes para-ordered aromatic heterocyclic polymers containing pendant phenyl groups along the polymer chain backbone.
U.S. Pat. No. 4,051,108 to Helminiak et al., discloses a process for the preparation of films and coatings from para-ordered aromatic heterocyclic polymers.
Ordered polymer solutions in polyphosphoric acids (including PBT compositions) useful as a dope in the production of polymeric fibers and films are described in U.S. Pat. Nos. 4,533,692, 4,533,693 and 4,533,724 (to Wolfe et al.).
The disclosures of each of the above described patents are incorporated herein by reference.
Molecular orientation can be achieved during rotating die extrusion of thermoplastic polymers but the degree thereof is very low since random coil thermoplastic melts are not oriented to any great extent by shear, unless the melts are anisotropic. Minimal biaxial orientation of thermoplastics is obtained by blowing tubular films of the melt. Even then, the preferential molecular orientation in blown thermoplastic films is in the machine direction.
On the other hand, anisotropic dopes of ordered, rigid-rod polymers contain isolated bundles of oriented molecules suspended in solvent. Counter-rotating tubular extrusion of these polymers orients there crystallites in the direction of shear and stretching of biaxially-oriented tubular films of anisotropic dope by blowing further increaes the degree of orientation in such materials. This is described in copending application Ser. No. 06/780,648, which is now abandoned, hereby incorporated by reference.
The present invention is directed to the production of films having heretofore unavailable strength characteristics. The starting materials useful herein include those lyotropic or thermotropic polymeric materials in which strain produces a material orientation in the microscale structure. The present invention is particularly applicable to dopes and like materials made from ordered polymers, or other rigid rod-like molecules. More specifically, the polymers are ordered rod-like extended chain aromatic heterocyclic polymers. The open microstructure of the polymers is infiltrated by a binder material so as to form an interpenetrated polymer.
The method of the present invention comprises first producing a certain microscale structural orientation within a polymer dope by imposing a strain thereon, precipitating the ordered structure, infiltrating the binder precursor into the solid ordered structure and then converting the precursor into the binder.
The present invention is especially useful in biaxially oriented films, coatings and like materials formed from ordered polymers. A preferred ordered polymer for use in the present invention is poly (para - phenylenebenzo bisthiazole), referred to herein as PBT, a compound having the structure: ##STR1##
Biaxially oriented polymeric films of PBT are especially preferred embodiments of the present invention. These films posses unique properties including:
(a) high tensile strength (most preferably, greater than 100,000 psi ultimate tensile stress in one direction and not less than 40,000 psi ultimate tensile stress in any direction);
(b) high modulus (most preferably, greater than 5.times.10.sup.6 psi tensile modulus in one direction and not less than 8.times.10.sup.5 psi tensile modulus in any direction);
(c) controllable coefficient of thermal expansion (CTE) either negative, positive or zero in any particular direction in the plane of the film;
(d) low dielectric constant (most preferably, less than 3.0);
p (e) low outgassing (most preferably, less than 0.1% weight loss in a vaccum at 125.degree. C. for 24 hours);
(f) low moisture pickup (most preferably, less than 0.5% weight gain in water at 100.degree. C. for 24 hours).
A second preferred ordered polymer is poly (para-phenylenebenzo bisoxazole.
The preferred films and methods of the present invention are described in greater detail in the accompanying darwings and in the detailed description of the invention which follow.
US Referenced Citations (3)
| Number |
Name |
Date |
Kind |
|
4578432 |
Tsai et al. |
Mar 1986 |
|
|
4631318 |
Hwang et al. |
Dec 1986 |
|
|
4695610 |
Egli et al. |
Sep 1987 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
| Parent |
780648 |
Sep 1985 |
|
Patent Grant
4845150
