The tendency to form heterogenous structure manifested by occurrence of low temperature glass transition, Tg, and high melting temperature, Tm, depends on polymer-polymer miscibility and can be predicted based on the solubility parameters of respective components. Flory-Huggins theory (further modified by Hoy, Hoftyzer and Van Krevelen) describes the thermodynamics of the polymer-solvent or polymer-polymer interactions. Materials/components having close values of solubility parameter are likely to be compatible and should be miscible . The solubility parameter encompasses dispersive (δd), polar (δp), and hydrogen bonding (δh) contributions. When the total solubility parameters (δT) of the components closely match, it suggests a higher probability of miscibility. Prior investigations support the integration of dimerized fatty acid as the soft segment with poly(butylene terephthalate) (PBT), highlighting favorable aspects of miscibility in segmented polymers . Given the close solubility parameters of poly(butylene succinate) (PBS) and PBT, theoretical predictions anticipate good miscibility. The reported total solubility parameters of 20.3 MPa 1/2 for PBS and 20.8 MPa 1/2 for PEG further supports their compatibility , . According to Van Krevelen et al.'s research , a polymer's optimal solubility level is achieved when the differences between the solubility parameters (∆δ) are ≤ 5 MPa 1/2 . In light of the provided data, the solubility parameters differences of the components (PBS, DLS, PEG) are all below 5 MPa 1/2 , suggesting a good miscibility.