This study examined poly(glycerol-1,8-octanediol-sebacate)(PGOS) copolymers with low-level substitution of O (1,8-octanediol) for G(glycerol) units (G/O ratios 0.5:0.5, 0.66:0.33, 0.75:0.25, 0.8:0.2, and0.91:0.09) prepared in bulk by immobilizedCandida antarcticaLipase B(N435) catalysis. The central question explored was the extent thatexchanging less than half of poly(glycerol sebacate) (PGS) glycerol unitswith 1,8-octanediol can be used as a strategy tofine-tune biomaterialproperties. Synthesized copolymers having G/O ratios of 0.66:0.33, 0.75:0.25,0.8:0.2, and 0.91:0.09 have similar molecular weights, whereMwvaried from52,800 to 63,800 g/mol,Mnvaried from 5100 to 6450 g/mol, and??M(molecular mass dispersity,Mw/Mn) values were also similar (8.4-11.4). All ofthe copolymers were branched, and dendritic glycerol units reached 11% forPGOS-0.91:0.09:1.0. Analysis of DSC second heating scans revealed thatcopolymers with higher 1,8-octanediol contents have relatively higherTmand Delta Hfvalues. Over the copolymer compositional rangestudied herein,Tmand Delta Hfvalues varied from 5.3 to 21.1 degrees C and 8.0 to 23.1 J/g, respectively. Stress-strain curves of PGOScopolymers cured at 140 degrees C for 48 h exhibited either a unimodal, bimodal, or trimodal response to tensile loading. Varying G/Ofrom 10:1 to 2:1 resulted in significant increases in the peak stress (0.26-4.01 MPa), preyield modulus (0.65-62.59 MPa), failure tostrain (64-110%), and failure toughness (0.1-0.56 MPa). This demonstrates that altering the G/O ratio over a narrowcompositional range provides biomaterials with widely different yet tunable mechanical properties. Further investigation of PGOS-0.75:0.25:1.0films revealed that varying the cure conditions from 120 to 160 degrees C for periods of 24-72 h provides access tobiomaterials with a failure strain range from 15 to 224% and Young's modulus from 1.17 to 10.85 MPa. Hence, using the dualvariables of compositional variation and changes in cure conditions provides an exciting platform for PGS analogues to optimizematerial-tissue interactions. Increased contents of 1,8-octanediol slowedin vitrodegradation. Slowed degradation of PGOS relativeto PGS will be valuable for use in slower healing wounds
