| abstract |
Liquid phase processable crystalline diacetylene polymers are obtained by the solid state reaction of monomers having the formula R1-C 3BOND C-C 3BOND C-R2 where R1 and R2 are independently selected from the group consisting of (a) CH3(CH2)m- (b) HO(CH2)n- and (c) R3NHOCO(CH2)p- where "m" is an integer of from 0 to 15, "n" is an integer of from 1 to 15, "p" is an integer of from 1 to 15, and R3 is a member selected from the group consisting of (i) C6H5(CH2)r- (ii) CH3(CH2)r- and (iii) C10H7(CH2)r- where "r" is an integer of from 0 to 11; with the proviso that where R1 and R2 are the same and are either (b) or (c), neither "n" nor "p" equals 1; and with the further proviso that where R1 and R2 are different and are either (b) or (c), the sum of "n" plus "p" is greater than 2. Polymerization proceeds by 1,4-addition reaction at each diacetylene group to produce a crystalline diacetylene polymer having the structure <IMAGE> or the alternate head-to-head structure: <IMAGE> where R1 and R2 are as defined above. The structure of such polymers is characterized by Raman intense nu C=C and nu C 3BOND C vibrations at, respectively 1450 to 1540 cm-1 and 2060 to 2140 cm-1, which replace the Raman intense nu C 3BOND C vibration at approximately 2260 cm-1 in the monomer. The polymers are further characterized by intense optical dichroism, which is indicative of a high degree of chain alignment, and by high thermal dimensional stability. They are useful as photoconductive materials, pigments, high strength materials, and optical polarizers. |