High-performance bio-based materials are indispensable for establishment of green-sustainable societies. Most of bioplastics, however, have lower thermal and mechanical performances than the conventional materials. A series of aliphatic polyesters, such as polyhydroxyalkanoates and poly(lactic acid) became popular in industry but had low mechanical performances. In order to improve the mechanical properties, we have tried to use rigid aromatic biomonomers. Here we report aramid-type fibers derived from functional amino acid, 4-aminocinnamic acid (4ACA), which was bioavailable by a microorganismal engineering. The photodimer of 4ACA was prepared via [2+2] cycloaddition, which is a kind of biological dianilines. The dianilines were indispensable for preparation of aramid but generally were very difficult to produce by a direct method of fermentation. Besides we synthesized acetylated 4ACA photodimer as a bio-derived diacid, and then the bio-diacid was polycondensed with the dianilines to produce rigid polyamides composed of phenylamide and cyclobutane in their backbone. Cyclobutanes sandwiched by two phenylene rings can behave as a V-type molecular spring. The molecular spring imparted ultra-high strength to the corresponding aramid fibers stronger than heavy materials such as glasses and as strong as high-tensile steels [2]. Moreover structural optimization using diacid comonomers created high-performance fibers as tough as spider silks.

Ultra-tough bio-aramide fibers derived from functional amino acids

254th National Meeting (2017)

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