Bio-based Aliphatic polyester, consisting of different length of CH₂ group and ester bonds within the main-chain or side-chain, has been attracted more and more attention in recent years due to its lower melting temperature, reusable, flexibility, thermoplastic, easy processability, and biodegradability. Nevertheless, weaker thermal and mechanical characteristics have been limited in many ways to their suitability for commercial applications. Unsaturated aliphatic polyester has been amended to practice the partial cross-linking via UV curing processing to adjust their physical property or through the cross-linking process with covalent bonds to produce thermoset-like copolyesters, or by combining it with epoxy material. The purpose of this operation is to achieve tremendous physical-chemical properties that provide unique characteristics of copolyesters, such as stronger hardness, higher rigidity, better tensile strength, chemical resistance, and thermal stability. Besides, eco-friendly TPEE foam has been paid attention to by researchers. Microcellular TPEE foams, prepared by scCO₂, have outstanding superior compression attributes and low-temperature flexibility. Nonetheless, TPEE foam has frail foamability and acute contraction issues, and its cellular morphology faces severe challenges. The acute contraction issue of TPEE foam is complex and affected by poor melt strength, which causes the collapse or aggregation of bubbles during bubble growth and cell nucleation. Therefore, the crucial design of TPEE is considered an effective and acceptable pathway to improve the foam's dimensional stability and relieve foam shrinkage.