Allied Chemical Corporation

Allied Corporation

Edith A Turi

Ray H Baughman

Anthony F Preziosi

Kwok-Chun Yee

Shaul M Aharoni

Theodore Largman

Yash P Khanna

A process for preparing quasi-random copolymers is described which involves heating a mixture of polyamides in the presence of one or more phosphite promotor(s). The process is conducted at temperatures between about 265.degree. C. and 315.degree. C. with the process time generally ranging from about 2 to about 20 minutes. The process is especially useful for preparing copolymers from a mixture of poly(caproamide) and poly(hexamethylene adipamide). The copolymer products prepared in accordance with the process are particularly suitable for the production of plastic films which have improved properties as compared to either of the homopolymers.

Quasi-random copolymers from homopolymers

There are provided composites having near-zero uniaxial thermal expansion coefficients. One or more polyacetylenes having a negative uniaxial thermal expansion coefficient are uniaxially or biaxially oriented within one or more solid matrix materials having a positive thermal expansion coefficient to yield a composite material having a uniaxial thermal expansion coefficient which is nearly zero. The polyacetylenes are obtained by the solid-state polymerization of crystals of monomers containing at least one --C.tbd.C--C.tbd.C-- grouping per molecule. Also provided are processes for producing the above-described composites.

Organic polymers with near-zero uniaxial thermal expansion coefficients

There are provided processes and compositions for obtaining organic polymeric materials having near-zero uniaxial thermal expansion coefficients. According to one embodiment, an organic polymer having a negative uniaxial thermal expansion coefficient is treated by thermal processing under conditions sufficient to cause at least a portion of the polymer chains to become misaligned, thereby decreasing the magnitude of this thermal expansion coefficient to nearly zero. According to a second embodiment, one or more organic polymers having a negative uniaxial thermal expansion coefficient are combined with one or more materials having a positive thermal expansion coefficient to yield a composite material having a uniaxial thermal expansion coefficient which is nearly zero. Useful in the practice of the invention are polyacetylenes having a negative macroscopic thermal expansion coefficient, which are obtained by the solid-state polymerization of crystalline monomers containing two or more conjugated acetylene groups.

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Livingston, NJ, United States of America

Edith A Turi