Effect of enzymatic versus titanium dioxide/silicon dioxide catalyst on crystal structure of ‘green’ poly[(butylene succinate)‐co‐(dilinoleic succinate)] copolymers

Abstract

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.

“Green” Poly(Butylene Succinate-co-Dilinoleic Succinate) Copolymers Synthesized Using Candida antarctica Lipase B (CAL-B) as Biocatalyst

“…1 H NMR analysis confirmed the expected chemical structure of PBS-DLS 70:30 copolyester. Furthermore, based on the 1 H NMR spectra, the sample composition was assessed following method presented in [12] and showed in Table 1. Mn-number average molecular mass, Mw-weight average molecular mass, Đ-dispersity index, a value calculated from 1 H NMR b values determined from GPC.…”

Enzymatic Synthesis of Poly(alkylene succinate)s: Influence of Reaction Conditions

“…The lipase-catalyzed polycondensation reactions under solvent-less conditions have been carried out also for synthesis of polyesters from adipic acid and sebacic acid with different diols [12,[40][41][42][43] yielding different molar masses from 10 3 -to 10 4 g/mol. Aliphatic building blocks with unsaturated units can also be converted without crosslinking [25,[44][45][46][47][48]. Aliphatic-aromatic polyesters were prepared enzymatically as well [49].…”

Molecular Decoration of Ceramic Supports for Highly Effective Enzyme Immobilization—Material Approach

“…Apart from varied enzyme immobilization methods, numerous support materials with specific chemical and nanostructural properties have been studied. For instance, the immobilization of lipase CALB on silica aerogel [13], titanium and silicon dioxide [14], carbon nitride [15], and magnetic magnetite (iron oxide) nanoparticles [16] were reported. The feature of the supporting material (e.g., surface property, size, and morphology) have a substantial influence on the performance of the immobilized enzymes and amid various supporting materials, nanostructured ones have received growing interest since (i) providing a higher specific surface area for enzyme anchoring, and (ii) a high physical curvature allowing for a greater degree of freedom for the enzyme active sites location, thus minimizing lateral interactions between enzymes and self-digestion.…”