Anthracene−Maleimide-Based Diels−Alder “Click Chemistry” as a Novel Route to Graft Copolymers

Abstract

Using the Diels−Alder (DA) “click chemistry” strategy between anthracene and maleimide functional groups, two series of well-defined polystyrene-g-poly(ethylene glycol) (PS-g-PEG) and polystyrene-g-poly(methyl methacrylate) (PS-g-PMMA) copolymers were successfully prepared. The whole process was divided into two stages: (i) preparation of anthracene and maleimide functional polymers and (ii) the use of Diels−Alder reaction of these groups. First, random copolymers of styrene (S) and chloromethylstyrene (CMS) with various CMS contents were prepared by the nitroxide-mediated radical polymerization (NMP) process. Then, the choromethyl groups were converted to anthryl groups via the etherifaction with 9-anthracenemethanol. The other component of the click reaction, namely protected maleimide functional polymers, were prepared independently by the modification of commercially available poly(ethylene glycol) (PEG) and poly(methyl methacrylate) (PMMA) obtained by atom transfer radical polymerization (ATRP) using the corresponding functional initiator. Then, in the final stage PEG and PMMA prepolymers were deprotected by retro-Diels−Alder in situ reaction by heating at 110 °C in toluene. The recovered maleimide groups and added anthryl functional polystyrene undergo Diels−Alder reaction to form the respective (PS-g-PEG) and (PS-g-PMMA) copolymers. The graft copolymers and the intermediates were characterized in detail by using 1H NMR, GPC, UV, fluorescence, DSC, and AFM measurements.

Polypropylene-based graft copolymers via CuAAC click chemistry

“…On the other hand, the melting points of PCL and PEG segments were slightly shifted to lower temperatures. These change could be due to the segmental mobility, polarity and rigidity of backbone compared with the other segments [64,65]. The surface properties of graft copolymers and initial PP-Cl sample were investigated by water contact angle (WCA) analysis at room temperature ( Figure 8).…”

Intramolecular Cross-linking of Polymers Using Difunctional Acetylenes via Click Chemistry

“…The Diels-Alder cycloaddition reac-tion [24][25][26] and thiol-ene chemistry [27,28] have recently been introduced as alternative click routes for providing new materials. Click reactions have been widely used for the synthesis of polymers with different compositions and topologies, ranging from linear (telechelic [29], macromonomer [30,31], macrophotoinitiator [32,33] and block co-polymer [34][35][36]) to nonlinear macromolecular structures (graft [37][38][39], star [40,41], miktoarm star [42,43], H-type [44], dendrimer [45][46][47], dendronized linear polymers [48,49], macrocyclic polymers [50,51], self-curable polymers [52][53][54], network systems [55,56] and polymeric nanoparticles [14,57]).…”

High-performance triazole-containing brush polymers via azide–alkyne click chemistry: a new functional polymer platform for electrical memory devices

“…8 Extensive effort has been devoted to overcome such drawbacks, resulting in the development of metal-free azide-alkyne click chemistry as well as azide-free click chemistry. [9][10][11][12][13][14][15] Nevertheless, the drawbacks arising from triazole ring formation have not yet been solved.…”