copolymerized poly(titaconic acid)and poly(ethylene glycol), to enhance the density of hydrogen bonding and obtain a more ordered structure, to adopt in mucoadhesive applications [43]. Polybutylene itaconate for modification with divinylbenzene (DVB) and glycerol has been successfully copolymerized by [PERSON] et al., to form a 3-D network structure to increase the thermal stability of the copolyester [44]. For biomass material, 2,5-furan dicarboxylic acid (FDCA), was used to synthesize the unsaturated copolyester with fumaric acid, succinic acid, 1,3-propanediol, and 2-hydroxyethyl methacrylate, as a cross-linking agent, to form a cross-linked resin that has a good thermal stability at 231 \({}^{\circ}\)C, and a higher \(T_{\text{g}}\) around 87-104 \({}^{\circ}\)C, due to the effect of the furan ring [45]. As fully bio-based unsaturated polyester has become a more popular research topic, [PERSON] and colleagues considered fully bio-based unsaturated copolyesters consisting of FDCA and itaconic acid, which have a higher temperature of 5% thermal weight loss, tensile strength, and a Young's modulus of 330 \({}^{\circ}\)C, 122.8 MPa, and 3521 MPa, respectively [46]. PBA is a typical polymorph aliphatic polyester. Therefore, the various crystal phases could be transformed in \(\alpha\)-, \(\beta\)-, and an \(\alpha\)-\(\beta\) complex, through an isothermal annealing process [38; 39]. The \(\alpha\)-phase is related to the thermodynamic stability, while the \(\beta\)-phase is a metastable phase and can be transformed into an \(\alpha\)-phase, via annealing treatment. The \(\alpha\)-phase of PBA achieved from the isothermal method, and annealing procedure has a different crystal morphology, size, and biodegradation behavior, due to the effect of the thermal history. Biodegradation ability is strongly related to heat treatment, and it is easy to investigate the structure-property relationship. Additionally, the unsaturated polyester, PBI, is a novel unsaturated polyester that is prepared from 1,4-butanediol (1,4-BDO) and biomass materials itaconic acid (IA), through conventional bulk melting polymerization [47]. IA is a dicarboxylic acid chemical, which is biomass, unsaturated, and sustainable material, and can be fermented with _Aspergillus Terreus_. It has been widely applied in adhesion resin applications [48; 49]. The IA, succinic acid, and 1,4-BDO were copolymerized through solvent-free polycondensation, for bio-based, UV-cured coating application, which indicated that the mechanical property was a function of IA concentration [50]. Novel aliphatic copolyesters like poly(butylene adipate-co-butylene itaconate) (PBABI) [51], which has a relatively high molecular weight but poor mechanical properties, have additionally been studied. The cross-linking agents focus on copolymerization to improve the mechanical and thermal properties of copolyesters. Ethylenediaminetetraacetic acid (EDTA) is a conventional chelating agent that is widely used to remove metal ion, antioxidant, textile, and biomedical applications [52; 53]. Based on the chemical structure, the EDTA has four symmetrical carboxyl groups, which could react with the hydroxy group to form an ester bond. Copolymerizing with EDTA as a cross-linking agent can form network polymers to increase the toughness and elasticity of copolymers [54]. These kinds of network structures play a role in improving the thermal stability and mechanical strength of copolymers [55]. Hence, a small amount of EDTA was applied as a cross-linking agent to form a partial 3-D network structure in this study. Herein, the purpose of this research was to investigate the straightforward preparation of a series of PBABI copolyesters, based on AA, IA, and 1,4-BDO with EDTA, using titanium (IV) butoxide and dibutyltin dilaurate as the catalyst, via melting polymerization through a 2 L steel autoclave reactor. IA was adopted to achieve controllable hardness in the low-melting point PBABI copolyesters, following UV curing, due to the higher partial cross-linking formation, as shown in Scheme 1.