A second type of aliphatic polyester are polyhyroxyalkanoates which are comprised of repeat units of the following structure: wherein m is an integer of 0 to 10, and R10 is selected from the group consisting of hydrogen; C1-C12 alkyl; C1-C12 alkyl substituted with one to four substituents independently selected from the group consisting of halo, C6-C10 aryl, and C1-C4 alkoxy; C5-C10 cycloalkyl; an