Unsaturated, biobased polyesters and their cross‐linking via radical copolymerization

Abstract

Biobased, unsaturated polyesters derived from isosorbide, maleic anhydride, and succinic acid were synthesized and characterized. The presence of maleic anhydride units in the structure of the polyesters allowed converting them into cured coatings by radical copolymerization with crosslinking agents such as 2‐hydroxyethyl methacrylate, N‐vinyl‐2‐pyrrolidinone, acrylic acid or methacrylamide. The investigated polyesters were obtained via bulk polycondensation, catalyzed by titanium(IV) n‐butoxide. 2D NMR and MALDI‐Tof‐MS spectroscopy proved that this polymerization resulted in isomerization of maleic acid units into fumaric ones and in the formation of slightly branched structures by the reaction of isosorbide (end) groups with main chain unsaturated bonds. Moreover, some double bonds proved to have reacted with the condensation by‐product water. The resulting polyesters displayed the expected correlation between variables such as molecular weight and content of unsaturated bonds and their Tg values. Since the thermal properties of the obtained polyesters were appropriate for coating applications, the polymers were crosslinked with unsaturated monomers by radical copolymerization. The crosslinking process was studied using FTIR spectroscopy and by measurements of the soluble part of the cured coatings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2885–2895, 2010

Going greener: Synthesis of fully biobased unsaturated polyesters for styrene crosslinked resins with enhanced thermomechanical properties

“…The low M n for this sample can result from two factors: 1) The endo isomer of isosorbide is known to suffer steric hindrance, contributing to a lower reactivity; 2) The endo hydroxyl groups have the capacity to establish strong hydrogen bonds during the polycondensation which is translated in an imbalance between the -OH/-COOH ratios [10,39]. It is interesting to note that, despite its low M n , BioUP_6 is the polyester with the highest viscosity.…”

“…Also, the 1 H NMR spectrum of BioUP_6 revelead the presence of some unreacted Iso. The presence of unreacted Iso in the final product can be ascribed to lower reactivity during the polycondensation, caused by the presence of steric hindered endo-hydroxyl groups in its structure [10,12,31]. Figure 4 presents the 1 H NMR spectrum of BioUP_7, with ItaAc.…”

“…However, the increasing environmental concerns, as well as the need to develop sustainable alternatives to fossil based monomers, have led to a remarkable interest in the development of biobased UPRs (BioUPRs). In the market, there are already a considerable number of available renewable monomers for the synthesis of UPs and UPRs [6][7][8] and, in the last years, some authors have focused their work on the development of UPRs partially based on these raw materials [4,[9][10][11]. The work of Gonçalves et al [4] reports the preparation of UPRs for microstereo-thermal-lithography (μSTL), with a biobased content between 24 and 47 wt%.…”

Fabrication and Characterization of Unsaturated Copolyesters Based on Diarylidenecyclohexanone

“…Unsaturated polyesters are among the most common polymers used in conjunction with glass fibre reinforcing [1,2] and widely used as thermosetting resins in various industrial areas [3][4][5]. They are prepared by polycondensation of diacids and diols using titanium or tin alkoxides as catalysis [6].…”

Fabrication and Characterization of New Unsaturated Terpolyesters Based on Diarylidenecyclohexanone

“…Unsaturated polyesters are among the most common polymers used in conjunction with glass fiber reinforcing [4,5] and widely used as thermosetting resins in various industrial areas [6][7][8]. They are prepared by polycondensation of diacids and diols using titanium or tin alkoxides as catalysis [9].…”