Table 3.

Effect of different segments and chain extender on the properties of PU [56].

Segment	Effect
PEG	Increases solubility and hydrolytic degradation
PTCM	Contributes to maintain mechanical properties for long periods
PCL	Improves hydrolytic degradation
GAE	Reduces enzymatic biodegradation rate
PCN	Provides high tensile strength, yields relatively low pro-inflammatory degradation products
HEMA	Confers cross-linking functionality to the polymer
DTH	Contributes to peptide degradation by products
ISO	Enhances biological activity

PTCM: polytrimethylene carbonate, GAE: glycerol α-monoallyl ether, PCN: polyhexamethylene carbonate diol, HEMA: hydroyethyl methacrylate, DTH: desamino tyrosine tyrosyl hexyl ester, ISO: 1,4:3,6-dianhydro-D-sorbitol.