DEGRADABLE HIGH-MOLECULAR-WEIGHT RANDOM COPOLYMERS, BASED ON EPSILON-CAPROLACTONE AND 1,5-DIOXEPAN-2-ONE, WITH NON-CRYSTALLIZABLE UNITS INSERTED IN THE CRYSTALLINE-STRUCTURE
Ac. Albertsson et M. Gruvegard, DEGRADABLE HIGH-MOLECULAR-WEIGHT RANDOM COPOLYMERS, BASED ON EPSILON-CAPROLACTONE AND 1,5-DIOXEPAN-2-ONE, WITH NON-CRYSTALLIZABLE UNITS INSERTED IN THE CRYSTALLINE-STRUCTURE, Polymer, 36(5), 1995, pp. 1009-1016
High-molecular-weight copolymers of epsilon-caprolactone (CL) and 1,5-
dioxepan-2-one (DXO) over the complete range of compositions have been
synthesized and studied. Stannous 2-ethylhexanoate was used as a cata
lyst and the polymerization was carried out in bulk. Reactivity ratios
were r(CL) = 0.6 and r(DXO) = 1.6, which give r(1)r(2) = 1, thus lead
ing to an ideal copolymer. The copolymers exhibited crystallinity as l
ong as the proportion of 1,5-dioxepan-2-one did not exceed 40%. The cr
ystallinity and melting temperature of the copolymers decreased with i
ncreasing content of 1,5-dioxepan-2-one. Analysis of the melting-point
depression data of the copolymers indicates that about 40% of the 1,5
-dioxepan-2-one comonomer units are incorporated into the CL crystals.