I. Noda1,*, P. R. Green2, M. M. Satkowski1, and L. A. Schechtman3
1 The Procter & Gamble Company, 8611 Beckett Rd., West Chester, OH 45069, USA
2 The Procter & Gamble Company, 11530 Reed Hartman Hwy, Cincinnati OH 45241, USA
3 The Procter & Gamble Company, PO Box 538707, Cincinnati OH 45253-8707, USA
NodaxTM is a family of biodegradable polyhydroxyalkanoate (PHA) copolymers introduced by the Procter & Gamble Company. NodaxTM consists of at least two types of comonomer units: 3-hydroxybutyrate (3HB) and other 3-hydroxyalkanoates (3HAs) with medium chain length (mcl) side groups consisting of at least 3 to about 20 carbon units. The copolymer structure resembles that of linear-low density polyethylene, where 3HB units provide the basic crystalline backbone, while mcl side groups of other 3HA units provide structural irregularity leading to the reduced crystallinity and melt temperature.
Within the Nodax™ family, there are several different grades of polymers available, depending on the average molecular weight, mcl-3HA content, and mcl chain length. The mcl-3HA content regulates the Tm and crystallinity of copolymer, almost independently of the mcl size as long as more than three carbons are present as side group. On the other hand, the side group chain length of mcl-3HA has a profound effect on the flexibility of Nodax™ copolymer. Currently, NodaxTM is produced by the bacterial fermentation of various carbon sources derived from renewable resources. We also prepared a series of representative samples of Nodax™ with different mcl size by chiral chemical synthesis.
The unique molecular structure of Nodax™ provides a set of useful properties not achieved by other more traditional PHA polymers, like PHB homopolymer or PHBV copolymers comprising 3HB and 3-hydroxyvalerate. NodaxTM exhibits high toughness and ductility, as well as convenient thermal property ranges similar to those of polyethylene. Other advantages of Nodax™ include the total biodegradability in not only aerobic but also in anaerobic environments. Nodax™ also shows robust ambient hydrolytic stability, digestibility in hot alkaline solution, superb oxygen and odour barrier performance, excellent surface property for printing and adhesion, and versatile compatibility with many other materials, including other degradable polymers, like poly(lactic acid).
