The effect of aging on the mechanical properties was investigated for a series of bacterial copolyester
poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HH)] with 3HH molar fraction ranging from 5 to
18 mol %. The mechanism behind the aging phenomenon was studied by using gel permeation chromatography
(GPC), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and small-angle X-ray
scattering (SAXS) in parallel to the tensile testing. It was found that the high initial crystallinity and the narrower
amorphous region in the P(3HB-co-3HH) films are the key factors that cause the secondary crystallization in the
aging process to embrittle the films of copolymers with 3HH fraction lower than 10 mol %. For the copolymers
with 3HH fractions higher than 10 mol %, because of the intrinsically lower crystallinity and thicker amorphous
region, the secondary crystallization cannot affect the mechanical properties significantly.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.