Synthesis of soluble, liquid crystalline aramids via transition metal {pi}-complexation
- Du Pont Central Research & Development, Wilmington, DE (United States)
An organo-soluble, liquid crystalline organometallic polymer, (p-phenylene-terephthalamide)Cr(CO){sub 3}((PPTA)Cr(CO){sub 3}), is prepared by polycondensation of (p-phenylene-diamine)Cr(CO){sub 3} with terephthaloyl chloride. Polarizing optical microscopy of this high molecular weight metallo-aramid shows a nematic liquid crystalline texture in N,N-dimethylacetamide (DMAc), demonstrating that metal {pi}-complexation maintains the lyotropic, rigid-rod character of PPT. APPTA copolymer with 50% of the diamine rings Cr(CO){sub 3} {pi}-complexed is also soluble and lyotropic in DMAc. The organometallic substituent is a site for polymer functionalization: exchange of a carbonyl for a trimethylphosphine ligand, and subsequent polymerization affords the phosphine-functionalized (PPTA)Cr(CO){sub 2}P(CH{sub 3}){sub 3}. Oxidative decomplexation of the Cr(CO){sub 3} group yields the parent PPTA, demonstrating the reversibility of the organometallic modification approach and its utility for polymer processing.
- OSTI ID:
- 141690
- Report Number(s):
- CONF-930304--
- Country of Publication:
- United States
- Language:
- English
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