| abstract |
A polymer composition comprises an aliphatic polyester and at least one compound of the general formula (I): R1a (A) R2b, where A is a polyfunctional hydrocarbon group; R1 is an electron-donating group such as hydroxy, amino, thiol or a derivative thereof; R2 is an electron-withdrawing group such as carboxylic acid, carboxylic amide and quaternary onium; and a and b are at least 1. Preferably the compound is an α-amino carboxylic acid especially with at least one group R¿1? additional to the carboxylic and α-amino group, or is a phosphatidyl choline. Preferably the polyester is capable of over 30 % crystallinity in the absence of plasticiser and is an (R)-stereospecific polyhydroxyalkanoate product of microbiological fermentation, containing less than 2000 ppm w/w of nitrogen as N. |