Nylon Hybrids from Plants or PET

Nylon hybrids are polyamides that possess additional functional groups within the main-chain. These additional functional groups can be used to tune the polymeric thermal properties and degradation behavior. Described here are polyesteramides that derive from (1) brassylic acid, an increasingly-available C13 diacid from Brassica carinata, a seed oil crop studied for aviation biofuel production, or (2) post-consumer polyethylene terephthalate (PET). Aminolysis of dimethylbrassylate or PET with ethanolamine yields bis-hydroxyethylbrassylamide (HEBA) or bis-hydroxyethylterephthalamide (HETA), respectively. These diols can be copolymerized with a variety of diacids to yield aliphatic or semi-aromatic polyesteramides having thermal properties with either high glass transition temperatures (e.g., T_g = 125 °C) or high melting temperatures (e.g., T_m = 138 °C), which render them potential replacements for high T_g or high T_m commodity plastics, such as polystyrene (PS) or high density polyethylene (HDPE). These polyesteramides undergo ester hydrolysis under environmentally relevant conditions, yielding oligomers that are water soluble and thus can proceed to biodegradation to carbon dioxide. For example the all aliphatic polyesteramide built from HEBA and adipic acid loses 37% of its number average molecular weight (M_n) over the course of one year in seawater. Moreover, it was discovered that HEBA or HETA are capable of homopolymerization—whereby amide functional groups are converted to ester functional groups with loss of ethanolamine. The formed polymers are also polyesteramides with 50% amide and 50% ester functionality; their aminolysis with ethanolamine yields the original monomers HEBA or HETA—demonstrating their potential for chemical recycling.