Enzymatic synthesis and preliminary evaluation as coating of sorbitol-based, hydroxy-functional polyesters with controlled molecular weights

Abstract

(2015). Enzymatic synthesis and preliminary evaluation as coating of sorbitol-based, hydroxy-functional polyesters with controlled molecular weights. European Polymer Journal, 67, 459-475. DOI: 10.1016/j.eurpolymj.2014 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. By using a combination of bio-based monomers (sorbitol, 1,10-decanediol and a range of dicarboxylic acids), a series of novel sorbitol-based polyesters was prepared by solvent-free enzymatic polycondensation using an immobilized form of Candida antarctica lipase B (Novozyme 435). The aim was to prepare linear polyesters with pendant, curable hydroxyl groups along the polymer backbone. To achieve this, the polyester molecular weight was controlled by tuning the reaction time, enzyme loading and reaction stoichiometry. Extensive molecular and thermal characterization was performed, showing that the obtained polyesters were semi-crystalline materials with a low T g . The presence of sorbitol in the polyesters was confirmed through a qualitative investigation using MALDI-ToF-MS. The quantification of the sorbitol content in the polymers was achieved by inverse-gated decoupling 13 C NMR spectroscopy, while 31 P NMR provided information regarding the selectivity of CALB for the primary vs. the secondary hydroxyl groups. Moreover, 31 P NMR and potentiometric titration were utilized for the quantitative determination of the amount of carboxylic groups and hydroxyl functional groups present in the polyesters. The obtained hydroxyl-functional polyesters had suitable properties to be applied as solvent-borne coatings in terms of their molecular weight, functionality and thermal characteristics. Cross-linked coatings were prepared using different conventional curing agents, including two renewable diisocyanates (ethyl ester L-lysine diisocyanate and dimer fatty acid-based diisocyanate). The resulting poly(ester urethane) coatings were tested in terms of solvent resistance, hardness and resistance against rapid deformation, showing the beneficial effect of the implemented sorbitol on network formation.

Environmentally benign synthesis of saturated and unsaturated aliphatic polyesters via enzymatic polymerization of biobased monomers derived from renewable resources

“…24, 25 Kobayashi et al enzymatically synthesized biodegradable epoxide-containing polyesters from vegetal oils. 26 Moreover, many other biobased polyesters are produced by the lipase-catalyzed polycondensation, e.g., sorbitol-based polyesters, 27,28 glucose-based polyesters 29 and furan-based polyesters. 30,31 Itaconate-based aliphatic polyesters are interesting biobased functional polymers containing carbon-carbon double bonds appending to the polymer main chain.…”

Synthesis, structure and properties of poly(ether-urethane)s synthesized using a tri-functional oxypropylated glycerol as a polyol

“…L. Gustini et al obtained hydroxy-functional polyesters based on sorbitol in a controlled way by enzymatic polycondensation, and obtained products can be used in the synthesis of polyurethane coatings. Obtained from mentioned functional polyesters coatings exhibit good solvent resistance and mechanical properties [28]. A. Anand et al [29] obtained polyol by the reaction of sorbitol, 1,2,3,6-tetrahydrophthalic anhydride, adipic acid, and diethylene glycol and zinc acetate as a catalyst.…”

Green process for green materials: viable low-temperature lipase-catalysed synthesis of renewable telechelics in supercritical CO 2

“…This is a consequence of the calibration performed with poly(styrene) (PSt) standards, which will always have hydrodynamic volume different from the analysed polyesters. Similar differences have been encountered by other groups, when using GPC with PSt standards for polyester analysis (9,11,65). Nevertheless, the dispersity values are mostly around 2, which is a value typically expected for linear polycondensations at high conversions and already found by other groups when synthesising low molecular weight telechelics (9,15,65,66).…”

“…It is well known that at higher temperatures (>85°C) side reactions involving acrylate, methacrylate and oxetanes moieties do occur (27,67). In addition, it is known that the selectivity of CaLB towards primary alcohol is significantly reduced at above 100°C; thus leading to branching when monomers or end-capper with secondary -OH groups are exploited (65). Therefore, lower temperature approaches are highly desirable when using CaLB.…”