Amphiphilic Sun-Shaped Polymers by Grafting Macrocyclic Copolyesters with PEO

Abstract

An amphiphilic sun-shaped copolymer was successfully prepared by esterification of carboxylic acid terminated PEO with the pendent hydroxyl groups of high molecular weight (M n = 28 000) cyclic PCL. The cyclic structure of the copolyester originally resulted from the polymerization initiation by a cyclic tin dialkoxide and was ultimately stabilized by the intramolecular cross-linking of a few unsaturated groups.

Synthesis of Amphiphilic Tadpole-Shaped Linear-Cyclic Diblock Copolymers via Ring-Opening Polymerization Directly Initiating from Cyclic Precursors and Their Application as Drug Nanocarriers

“…[1][2][3] It has been well-established that the topological structures and chemical composition of nonlinearshaped block copolymers can exhibit dramatic effects on the solution properties and self-assembling morphologies as compared with their linear counterpart. [4][5][6][7][8][9] It is worthy of noting that the developments of a variety of controlled radical polymerization techniques 10 such as atom transfer radical polymerization (ATRP), [11][12][13] reversible addition-fragmentation chain transfer (RAFT) polymerization, [14][15][16] and nitroxide-mediated polymerization (NMP) 17,18 have facilitated the synthesis of nonlinear-shaped polymers with varying chain architectures such as cyclic, 8,9,[19][20][21][22][23] (miktoarm) star, [24][25][26] star block copolymers, 27,28 comb, [29][30][31][32] sun-shaped, [33][34][35] H-shaped, [36][37][38] and θ-shaped 39,40 polymers. Among these nonlinear chain topologies, tadpole-shaped linearcyclic diblock copolymers [41]…”

A novel strategy towards cyclic aliphatic (co)polyesters

“…The deprotection of the triethylsilanolate groups released hydroxyl groups that were esterified by carboxylic acid end-capped PEO, with formation of an amphiphilic sun-shaped copolymer, i.e., macrocyclic copolyesters grafted with PEO as shown in Figure 3 [32]. The SEC traces could be superposed before and after deprotection, whereas the molar composition (DP !-HO"CL = 17, DP "CL = 178) determined by 1 H NMR analysis remained unchanged after deprotection.…”

“…Functional cyclic copolyesters In order to make a cyclic functional copolyesters available, a comonomer containing a protected hydroxyl group [32], i.e., !-triethylsilyloxy-"-caprolactone (!-Et 3 SiO"CL), has been random copolymerized with "-caprolactone initiated by cyclic DSDOP in toluene, followed by the addition and sequential polymerization of a few units of #$"CL with formation of a cyclic precursor (CP) as shown in Figure 2, poly(!-Et 3 SiO"CL-co-"CL-b-#$"CL) 4 g/mol, M n,SEC = 2.55·10 4 g/mol, M w /M n = 1.45, F !-Et 3 SiO"CL = 8.8%). Then intramolecular photo cross-linking of the unsaturations next to the propagating sites is carried out, with formation of a functionalized macrocyclic random copolyester poly(!-Et 3 SiO"CL-co-"CL) after hydrolysis of tin alkoxides.…”

“…The novel strategy has been successfully tested for the synthesis of cyclic PCL [30] and cyclic functional copolyesters [32]. It relies on the intramolecular photo cross-linking of few acrylic unsaturations in the close vicinity of a cyclic precursor (CP) synthesized by ring-opening polymerization initiated by a cyclic tin alkoxide.…”

Grafting‐from Afforded Cyclic Graft Copolymers from Cyclic Anionic Macroinitiator via Lithiation of Tolyl Groups

“…Deffieux et al reported cyclic graft copolymers by coupling of polystyryllithium with cyclic poly(chloroethyl vinyl ether)s. [12] Jérôme et al synthesized by condensation reaction between hydroxyl-functionalized polyesters and poly(ethylene oxide) (PEO) having a carboxylate end group. [13] Click reactions are also used for grafting-onto approach. [14][15][16][17][18] Compared with the diverse graftingonto approach, the examples of graftingfrom approach which comprises polymerization of monomers from cyclic macroinitiators are relatively limited in spite of advantages in controlling grafting density and capability of terminal functionalization.…”