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Environmentally degradable, high-performance thermoplastics from phenolic phytomonomers

Nature Materials volume 5, pages 966970 (2006) | Download Citation

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Abstract

Aliphatic polyesters, such as poly(lactic acid), which degrade by hydrolysis, from naturally occurring molecules form the main components of biodegradable plastics1. However, these polyesters have become substitutes for only a small percentage of the currently used plastic materials because of their poor thermal and mechanical properties. Polymers that degrade into natural molecules and have a performance closer to that of engineering plastics would be highly desirable. Although the use of a high-strength filler such as a bacterial cellulose2 or modified lignin3 greatly increases the plastic properties, it is the matrix polymer that determines the intrinsic properties of the composite. The introduction of an aromatic component into the thermoplastic polymer backbone is an efficient method to intrinsically improve the material performance3,4. Here, we report the preparation of environmentally degradable, liquid crystalline, wholly aromatic polyesters. The polyesters were derived from polymerizable plant-derived chemicals—in other words, ‘phytomonomers’ that are widely present as lignin biosynthetic precursors5. The mechanical performance of these materials surpasses that of current biodegradable plastics, with a mechanical strength, σ, of 63 MPa, a Young’s modulus, E, of 16 GPa, and a maximum softening temperature of 169 C. On light irradiation, their mechanical properties improved further and the rate of hydrolysis accelerated.

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Acknowledgements

This research was supported mainly by a Grant-in-Aid for NEDO (03A44014c) and Handai FRC. T.K. thanks K. Hirata, Y. Nagase, T. Bamba and M. Kaneko (Osaka University) for helpful discussions about bioproduction of phytomonomers and in-soil degradation, Wako Chemical Co. for help with high-performance liquid chromatography measurements and K. Hasegawa and J. Kadota (Osaka Municipal Technical Research Institute) for their help in material processing.

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Author notes

    • Tatsuo Kaneko

    Present address: School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi 923-1292, Japan

Affiliations

  1. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita 565-0871, Japan

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Contributions

T.K.: project planning; experimental work; data analysis; paper preparation. T.T.: experimental work; data analysis. D.S.: experimental work; data analysis. M.A.: project planning.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Tatsuo Kaneko or Mitsuru Akashi.

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DOI

https://doi.org/10.1038/nmat1778

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