Simple synthesis of amphiphilic poly(3-hydroxy alkanoate)s with pendant hydroxyl and carboxylic groups via thiol-ene photo click reactions

Biodegradable polymers gained worldwide attention among researchers because of environmental and petroleum reserve limitation issues. In this manner, poly (3-hydroxyalkanoate)s, PHAs, are very useful materials from the point of this view. They can be easily obtained by using several bacteria from renewable substrate such as sugar, plant oils and as well as synthetic chemicals. The improvement of their mechanical properties and enhance hydrophilic character are still main challenge of the polymer scientists. Herein we report the thiol-ene photo click reactions of the unsaturated medium chain length PHAs produced by using Pseudomonas oleovorans from 10-undecenoic acid, octanoic acid and/or soybean oily acids that are coded as poly(3-hydroxy undecenoate) (PHU), poly(3-hydroxy octanoate-co-undecenoate) (PHOU) and poly(3-hydroxy octanoate-co-soybean oil polymer) (PHOSy), respectively, in order to obtain their hydroxyl and carboxyl derivatives. The molecular weights of the modified PHAs obtained in this work were the same as those of the starting PHAs. Structural analysis of the PHA derivatives was performed by using 1H-, 13C, HMBC and HSQC NMR techniques. Melting and glass transitions of the hydroxyl and carboxyl derivatives of the microbial polyesters were found to be relatively higher than that of the starting unsaturated PHAs.