Synthesis and application of polyamide 510 from bio-based monomers

Abstract

This dissertation deals with synthesis and properties of poly(pentamethylene sebacamide) (PA510) prepared by condensation polymerization of bio-based monomers, cadaverine and sebacic acid. PA510 produced from bio-based monomers (bio-PA510) is an alternative polymeric material for plastic industry to deal with oil depletion crisis. Furthermore, the production of polyamides having odd-numbered carbon repeating units economically extends the use of polyamide materials in various applications. Firstly, we optimized the reaction condition for melt polymerization of PA510 by using commercially available reagent grade monomers produced from petrochemical feedstock, and then by using the same reaction condition, we polymerized the bio-based monomers, cadaverine and sebacic acid that were prepared by biological way, fermentation and whole cell bioconversion from lysine. Polymerization results suggest that the cadaverine obtained by biological process can be used as a monomer for the production of PA510 when it is purified properly (~99%). The synthesized bio-PA510 has excellent thermal properties equivalent to the commercialized nylons. However, the PA510 produced by melt polymerization in large scale showed a yellow color. Secondly, to solve the problems of the melt polymerization for bio-PA510 in large scale, we carried out the solid-state polymerization (SSP) to prepare bio-PA510. For easy handling, the prepolymer of bio-PA510 was prepared as particles without flash process. So it is easier to treat than a powder form produced by flash process. By controlling the reaction time, temperature, particle size and type of by-product removal, we successfully produced bio-PA510 by SSP under 200℃ without a color problem and the physical properties of polymers are equivalent to those obtained by melt polymerization. Lastly, we investigated the material properties and processability of bio-PA510 to find out the effect of odd number carbon repeating units in the main chain. Fabrication of molded parts and analysis of mechanical properties suggest that bio-PA510 has a suitable processability and mechanical properties in automotive, electric and electronics parts applications regardless of its thickness. Interestingly, bio-PA510 shows not only lower water absorption property but also higher oxygen barrier property than other even numbered polyamides such as PA66, PA610 and PA612, that are very important properties for food packaging film application. This interesting characteristics of PA510 is attributed to its chemical structure consisting of the amide group and the odd numbered 5 methylene repeating unit together with the even numbered 10 methylene repeating unit which is exactly double of 5 methylene repeating unit. PA510 has different crystal structure and smaller diffraction spacing from its corresponding even number nylons due to its molecular orientation and hydrogen bonding pattern.