Focusing on an eco-friendly approach, biodegradable poly[(butylene succinate)-co-(dilinoleic succinate)] (PBS-DLS) copolymers with 70:30 (wt%) ratio of hard to soft segments were successfully synthesized via various processes and catalytic systems. In this approach, biobased succinate was polymerized with renewable 1,4-butanediol and dimer linoleic diol to obtain 'green' copolyesters as sustainable alternatives to petroleum-based materials. In the first procedure, a two-step synthesis in diphenyl ether was performed using Candida antarctica lipase B (CAL-B) as a biocatalyst. A second material was produced via two-step melt polycondensation in the presence of heterogeneous titanium dioxide/silicone dioxide (C-94) catalyst. The obtained PBS-DLS copolyesters were further characterized in regard to their number-average molecular weight (M n ), chemical structure, thermal transition temperatures and crystallization behavior. Here, digital holographic microscopy was used to study the crystallization behavior of synthesized segmented copolyesters for the first time. Using this technique, it was possible to reveal the twisting of crystalline regions in formed spherulites and observe the differences in crystallization behavior of copolyesters depending on the type of catalyst used in their synthesis. Structural characterization indicated random and blocky structure of copolymers depending on the type of catalyst. M n was noticeably higher in the case of PBS-DLS 70:30 copolymer catalyzed using C-94 than PBS-DLS 70:30 synthesized with the use of CAL-B. However, the degree of crystallinity was lower for polymer catalyzed with the heterogeneous catalyst. Furthermore, differential scanning calorimetric thermal analysis revealed that synthesized copolyesters exhibit low glass transition temperature as well as high melting point which are typical for thermoplastic elastomers.

To systematically investigate the synthesis of poly(butylene succinate)-co-(dilinoleic succinate) (PBS-DLS) copolymers and to enrich the library of polyesters synthesized via a sustainable route, we conducted a two-step polycondensation using fully biobased monomers such as diethyl succinate (DS), 1,4-butanediol (1,4-BD) and dilinoleic diol (DLD) in diphenyl ether, using Candida Antarctica lipase B (CAL-B) as biocatalyst. A series of PBS-DLS copolyesters with a 90-10, 70-30 and 50-50 wt% of hard (PBS) to soft (DLS) segments ratio were compared to their counterparts, which were synthesized using heterogenous titanium dioxide/silicon dioxide (TiO2/SiO2) catalyst. Chemical structure and molecular characteristics of resulting copolymers were assessed using nuclear magnetic spectroscopy (1H- and 13C-NMR) and gel permeation chromatography (GPC), whereas thermal and thermomechanical properties as well as crystallization behavior were investigated by differential scanning microscopy (DSC), dynamic mechanical thermal analysis (DMTA), digital holographic microscopy (DHM) and X-ray diffraction (XRD). The obtained results showed that, depending on the type of catalyst, we can control parameters related to blockiness and crystallinity of copolymers. Materials synthesized using CAL-B catalysts possess more blocky segmental distribution and higher crystallinity in contrast to materials synthesized using heterogenous catalysts, as revealed by DSC, XRD and DHM measurements.

Enzymatically-catalyzed polycondensation as more environmentally friendly method for creating sustainable alternatives to traditional aromatic–aliphatic polyesters is a valuable step towards resource-efficiency optimization.

An environmentally friendly method of creating sustainable alternatives to traditional aromatic-aliphatic polyesters is discussed as a valuable step towards resource-efficiency optimization. A group of furan-based copolymers was synthesised via temperature-varied two-step polycondensation reaction in diphenyl ether using Candida antarctica lipase B (CAL-B) as biocatalyst where dimethyl 2,5-furandicarboxylate (DMFDCA), a,w-aliphatic linear diols (a,w-ALD), and dimerized fatty acid diol (DLD) were used as the starting materials. Nuclear magnetic spectroscopy (1H and 13C NMR), Fourier transform spectroscopy (FTIR) and gel permeation chromatography (GPC) were used to analyze the resulting copolymers. Additionally, crystallization behavior and thermal properties were studied using X-ray diffraction (XRD), digital holographic microscopy (DHM), and differential scanning microscopy (DSC). The results showed that the diol chain length of a,w-ALD used in the synthesis had a significant effect on the material thermal properties and crystalline structure thus being an important guideline in design of entirely bio-based copolymers prepared by biocatalytic process.

Considering the rising demand to diminish energy consumption and CO2 emissions, the biobased segmented block copolymer, poly(butylene succinate-co-dilinoleic succinate) (PBS-DLS) with 70:30 (wt %) ratio of hard to soft segments was obtain using Candida antarctica lipase B (CAL-B) as a biocatalyst. Throughout two-step synthesis in diphenyl ether, biobased diethyl succinate was polymerized with renewable 1,4–butanediol and dimer linoleic diol to obtain “green” copolyester as a sustainable alternative to petroleum-based materials. Proton nuclear magnetic resonance (1H NMR) analysis confirmed that, using enzyme as a catalyst, we were able to produce multiblock copolymer and gel permeation chromatography (GPC) measurements revealed number-averaged molecular mass to be 25,000 g/mol. Additionally, differential scanning calorimetry (DSC) analysis revealed low-temperature glass transition (Tg) of soft segments and high melting point (Tm) of hard segments which indicate on two-phase morphology. Furthermore, cytotoxicity test using L929 murine fibroblasts was conducted on extracts of obtained PBS-DLS copolymer, indicating excellent biocompatibility in vitro.