Liquid crystallinity, IR analysis, and mechanical properties of thermotropic polyamides having alkylene spacers

✍ Scribed by Hui Teng; Jin-Cherl Song; Kohsaku Okuyama; Kaname Katsuraya; Takashi Kato; Toshiyuki Uryu

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 756 KB
• Volume: 34
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19961130)34:16<3407::aid-pola18>3.0.co;2-k

✦ Synopsis

Thermotropic polyamides with high molecular weights were synthesized by melt polycondensation of 3,3'-disubstituted-4,4'-biphenylenediacetamides with a,o-diphenoxyalkane-4,4'dicarboxylic acids. Methyl, methoxy, and chloro groups were used as 3,3'-substituents. IR measurements revealed that there are hydrogen-bonded carbonyls and free carbonyls the intensities of which depended on the polymer structure and the temperature. The thermotropic liquid crystallinity of the polyamides is assumed to occur by a decrease in intermolecular hydrogen bondings between carbonyls and amide NH's which was caused both with 3,3'-substitutions of the biphenylene moiety and with introduction of long alkylene spacers in the polymer backbone. In addition, mechanical properties of the thermotropic polyamides were measured on the molded dumbbell-type specimen. The 3,3'-dichloro polyamides showed medium tensile strengths and moduli in the range of 500-890 kgf/cm2 and 19.0 X lo3 to 27.0 X lo3 kgf/cm2, respectively.