Metal-Free Click Modification of Triple Bond-Containing Polyester with Azide-Functionalized Vegetable Oil: Plasticization and Tunable Solvent Adsorption.

Pressure from environmental nongovernmental organizations and the public has accelerated research on the development of innovative and renewable polymers and additives. Recently, biobased "green" plasticizers that can be covalently attached to replace toxic and migratory phthalate-based plasticizers have gained a lot of attention from researchers. In this work, we prepared an azide-functionalized soybean oil derivative (AzSBO) and investigated whether it can be used as a plasticizer. We covalently attached AzSBO to an electron-deficient triple-bond-containing polyester via a metal-free azide-alkyne click reaction. The thermal, mechanical, and solvent absorption behaviors of different amounts of azidated oil-containing polyesters were determined. Moreover, the plasticization efficiency of AzSBO was compared with the commercial plasticizers bis(2-ethylhexyl) phthalate and epoxidized soybean oil. At relatively lower AzSBO ratios, the degree of cross-linking was higher and thus the plasticization was less pronounced but the solvent resistance was significantly improved. As the ratio of AzSBO was increased, the glass transition temperature of the pristine polymer decreased up to 31 °C from 57 °C. Furthermore, the incorporation of AzSBO also improved the thermal properties and 20% AzSBO addition led to a 60 °C increase in the maximum weight loss temperature.

Synthesis of Poly(vitamin C) through ADMET.

l-Ascorbic acid, commonly known as vitamin C and one of the most important biological compounds, is converted to a α,ω-diene monomer and subsequently polymerized for the first time by acyclic diene metathesis. Various experimental conditions such as polymerization medium, catalyst type, temperature, and monomer/catalyst ratio are studied. The moderate molecular weight polymers are achieved when the polymerizations are conducted under bulk conditions employing the Grubbs first generation (G1) or Hoveyda-Grubbs second generation catalyst (HG-2). In the solution case, on the other hand, low molecular weight polymers are obtained regardless of the catalyst type. Moreover, when the catalyst performances are compared, it is found that G1 produces the higher molecular weight as well as higher yield polymers with respect to the HG-2.

Triple click reaction strategy for macromolecular diversity.

This Feature Article focuses on the rapidly emerging concept of the "triple click reactions" towards the design and synthesis of macromolecules with well-defined topology and chemical composition, and also precise molecular weight and narrow molecular weight distribution. The term "triple click reaction" used in this feature article is based on the utilization of three chemically and mechanistically different click reactions for polymer-polymer conjugation and post-modification of the polymers. Three sequential click reactions of which two are identical should not be considered to be triple click reactions. The triple click reaction strategy for polymer conjugation and post-modification of polymers is classified in this article based on the resultant architectures: linear and non-linear structures.

Synthesis of terpolymers by click reactions.

Well-defined polymeric structures were easily generated through living polymerization systems, in particular, living radical polymerizations. The polymeric precursors with orthogonal functionalities were subsequently clicked together with single or double (combinatorial) click reactions, such as the copper-catalyzed azide-alkyne cycloadditions (CuAAC) and Diels-Alder reactions, to create a wide variety of linear and nonlinear terpolymers.