PA X,20 from renewable resources via metathesis and catalytic amidation

Polyamides (PA) are engineering plastics with various commercial applications due to their outstanding properties such as high durability, high hardness and rigidity [1]. Methods for the production of polyamides by polycondensation of aliphatic diamines and dicarboxylic acids or the polyaddition of lactams are often described in the literature. These articles are mostly dedicated to standard polyamides based on depleting fossil resources. However, bio-based polyamides are not yet well developed. The unique example of industrially produced 100% bio-based polyamide is the AB-type polyamide-11 [2]. Synthesis of 100% bio-based AABB type polyamides are not expected because of the non-availability of bio-based diamines. Meanwhile, research on routes to obtain diacids from glucose (adipic acid) or vegetable oils (azelaic acid, sebacic acid) for the production of partially biobased polyamides-6,6, -6,9, and -6,10 are under investigation [3].
Among various polycondensation methods, acyclic diene metathesis (ADMET) polycondensation is useful in the synthesis of a veriety of polymer architecures that would otherwise be difficult to obtain [4]. The main goal of this study is to describe the synthesis of unsaturated polyamides that can be obtained from plant oil derivatives via two different approaches. First, long chain aliphatic α,ω dienes with two symmetrically spaced amide segments were polymerized via ADMET polymerization. Secondly, E-dimethyl-eicos-10-enedioate, a bio-based unsaturated monomer that was obtained via metathesis and other reactions from castor oil, was polymerized with different aliphatic diamines using strong organic bases, such as TBD, as catalysts. Both reaction pathways led to PA X,20 and the two different routes were investigated, optimized and comapred to one another. Moreover, the properties of the resulting polyamides were investigated revealing that these long-chain polyamides are well applicable as engeneering plastics and that their properties depended on the structure of the applied monomers, as expected. Last, but not least our investigations led to new synthetic approaches that allow for the synthesis of ABA type polyamide block-copolymer with interesting application possibilities.

References:
1. M. I. Kohan (editor), Nylon plastics handbook. New York: Hanser, 1995.
2. M. A. R. Meier, J. O. Metzger, U. S. Schubert, Chem. Soc. Rev. 2007, 36, 1788.
3. M. Crank, M. Patel, F. Marscheider-Weidemann, J. Schleich, B. Hüsing, G. Angerer, Techno-Economic Feasibility of Large-Scale Production of Bio-Based Polymers in Europe, O. Wolf, Technical Report EUR 22103 EN, European Communities 2005.
4. T. W. Baughman, K. B. Wagener, Adv. Polym. Sci. 2005, 176, 1.