Enzymatic biodegradation of synthetic atactic poly(R,S-3-hydroxybutyrate) enhanced by an amorphous nonbiodegradable polymer

The phase structure and biodegradability were investigated for blends of ch emosynthetic atactic poly(R,S-3 -hydroxybutyrate), a-P(R,S-3HB), with poly( methyl methacrylate), PMMA. A series of blends with different composition w as prepared from casting the chloroform solution on a Teflon dish. The ther mal analysis indicated that amorphous a-P(R,S-3HB)/PMMA blends possess soph isticated phase behavior and are partially miscible at PMMA contents rangin g from 10 to 50 wt.%. a-P(R,S-3HB) was enriched in the 'air' surface while PMMA was enriched in the 'bottom' surface of the film as suggested by the A TR FTIR spectra of the blend with PMMA content of 40 wt.%. The depolymerase of natural poly((R)-3-hydroxybutyrate) purified from Alcaligenes faecalis T1 did not degrade chemosynthesized a-P(R,S-3HB) at all in the pure state, but it degraded a-P(R,S-3HB) in some a-P(R,S-3HB)I PMMA blends. The results suggested that enzymatic degradation of a-P(R,S-3HB) can be enhanced by bl ending with an amorphous nonbiodegradable polymer. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.