UV-induced crosslinking of the biopolyester poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate)

Films of the biopolyester poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate) PHB-HV, a microbe-derived poly(hydroxyalkanoate), were crosslinked with 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone BA under UV irradiation. The degree of network formation reached 90% within irradiation times lower than 1 min. The 3 wt% concentration of BA in PHB-HV was found to be the optimum with respect to the rate of crosslinking relative to the rate of chain scission, which were derived from Charlesby-Pinner analyses. The PHB-HV/BA system could successfully be used for the generation of one-and two-step photolithographic imprints with reasonable resolution in the 50 mu m range and, hence, proved to be an efficient system for finishing with biopolyesters.