Synthesis, Characterization, and the Potential for Closed Loop Recycling of Plant Oil-Based PA X.19 Polyamides

Abstract

We report on plant oil-based linear aliphatic polyamides from 1.19-nonadecanedioic acid and aliphatic diamines of different chain lengths. Their thermal, mechanical, and rheological properties as well as the water uptake and crystalline structures were analyzed. The polyamides were synthesized with high molecular weights of 26 000 to 52 000. All polyamides showed high thermal stability with T 5% of >400 °C as well as high crystallinities of ∼50%. Injection molding of the plant-oil-based polyamides was successfully performed to produce tensile test specimens. Chemical recycling of the polyamides was demonstrated by microwave-assisted hydrolysis, with a recovery of 99% for 1.19-nonadecanedioic acid. Melt polycondensation using the recovered monomer was successfully performed to synthesize recycled polyamide in similar quality, which underlines its potential for closed loop recycling.

Synthesis and Deconstruction of Polyethylene-type Materials

“…200 Although not exactly addressing a polyethylene-like material, it is notable that Greiner and Rist also demonstrated the chemical recycling of a long-chain polyamide, PA-6,19, by hydrolysis. 149 The monomers could be recovered in a quality suitable for repolymerization into a material with mechanical properties akin to the virgin material.…”

Toughening of Bio‐Based PA 6.19 by Copolymerization with PA 6.6 – Synthesis and Production of Melt‐Spun Monofilaments and Knitted Fabrics

“…Synthesis of Dimethyl-1.19-Nonadecanedionate: The synthesis of dimethyl-1.19-nonadecanedionate was performed as previously reported. [16] All steps were performed under inert gas atmosphere. 121 mg (0.40 mmol, 4 mol%) palladium(II)acetylacetonate and 627.0 mg (1.59 mmol, 1.6 mol%) 1,2-Bis(di-tert-butylphosphino-methyl)benzene (dtbpx) were weighed into a 250 mL stainless steel autoclave equipped with a stirring bar.…”

“…Synthesis of 1.19-Nonadecanedioic Acid: The synthesis of 1.19nonadecanedioic acid was performed as previously reported. [16] 24.5 g (68.6 mmol) dimethyl-1.19-nonadecanedionate were transferred into a 1 L round bottom flask equipped with a large stirring bar. A solution of 46.2 g potassium hydroxide in 462 mL methanol was added to the flask and heated to 85 °C while stirring for 12 h to form a white slurry.…”

“…Recently we investigated the mechanical properties of PA X.19 and they showed good melt processability. [ 16 ] However, they exhibited significantly lower tensile strength compared to commercial polyamides such as PA 6. Copolymerization with a tougher material like PA 6.6 could potentially increase the tensile strength and ultimately create a partially bio‐based material with comparable or better properties than commercial PA 6.…”

Biobased Semi-Interpenetrating Polymer Networks of Poly(ε-caprolactone) and Epoxidized Soybean Oil with Nanoscale Morphology, Shape-Memory Effect, and Biocompatibility

“…Plant oils are readily available and cost-effective materials in a large volume. − The chemical structures of all plant oils contain triglycerides of fatty acids of different degrees of unsaturation (i.e., the number of carbon–carbon double bonds). Plant oils can be chemically modified and functionalized into different reactive functional groups, such as hydroxyl, carboxylic acid, epoxy, amines, etc., to increase their utilization in making sustainable products. − Based on the different chemical modifications and functionalizations, plant oils can be used to synthesize many biobased polymers including polyesters, polyurethanes, and polyamides. − …”