In‐chain functionalized poly(ε‐caprolactone): A valuable precursor towards the synthesis of 3‐miktoarm star containing hyperbranched polyethylene

Abstract

Well-defined 3-miktoarm star copolymer 3μ-HBPE(PCL) 2 (HBPE: hyperbranched polyethylene, PCL: poly[ε-caprolactone]) was synthesized by combining chain walking polymerization (CWP), ring-opening polymerization (ROP), and "click" chemistry. The synthetic methodology includes the following steps: (a) synthesis of in-chain ethynyl-functionalized PCL, (PCL) 2-C ≡ CH by ROP of ε-caprolactone (CL) with ethylene-functionalized solketal (3-[prop-2-yn-1-yloxy] propane-1,2-diol) as difunctional initiator and phosphazene superbase t-BuP 2 as catalyst; (b) synthesis of azido-functionalized hyperbranched PE (HBPE-N 3) by CWP of ethylene with α-diimine-Pd (II) catalyst, followed by quenching with excess 4-vinylbenzyl chloride and transformation of chloro to azide group with sodium azide; and (c) "clicking" HBPE-N 3 and (PCL) 2-C ≡ CH using copper(I)-catalyzed azide-alkyne cycloaddition. 1 H NMR spectroscopy, gel permeation chromatography, Fouriertransform infrared spectroscopy, and differential scanning calorimetry were used to determine the molecular characteristics and thermal properties of the polymers. Self-assembly behavior of 3μ-HBPE (PCL) 2 in petroleum ether, a selective solvent for HBPE, was investigated by dynamic light scattering, atomic force microscopy, and transmission electron microscopy. The in-chain alkyne-functionalized poly(ε-caprolactone) is a valuable precursor for PCLbased complex macromolecular architectures.

3,4-Ethylenedioxythiophene (EDOT) End-Group Functionalized Poly-ε-caprolactone (PCL): Self-Assembly in Organic Solvents and Its Coincidentally Observed Peculiar Behavior in Thin Film and Protonated Media

“…This comparison supports the conclusion that not only the processing conditions but most importantly, the structural peculiarities (position of the functional group—the end group—vs. “in chain” group [ 26 ]—and the type of the group) are also decisive aspects of the supramolecular organization of the functionalized oligo-/poly(ε-caprolactone) in thin films.…”

“…Being widely commercially available, PCL has a high capacity to be miscibly blended, and this has resulted in interesting compatibilization studies [ 22 , 23 , 24 ]. Whether in blends or copolymers of various architectures [ 25 , 26 , 27 ], PCL is easily shaped and manufactured in the form of hydrogels [ 22 , 23 ], nanoparticles [ 24 ], nanofibers [ 27 , 28 ], and, more importantly, due to its crystallizable nature, into a well-defined and geometrically shaped 2D lamellar single-crystal structure that has various and interesting applications [ 25 , 29 ].…”

“…Moreover, functional groups have often been added to PCL to transform it into a reactive intermediate in order to subsequently use them in coupling reactions. These reactions led to various macromolecular structures [ 26 , 30 ], macroinitiators [ 31 , 32 ], and, very importantly, well-defined macromonomers [ 33 , 34 , 35 ]. Macromonomers are, in fact, oligomer or polymer chains that are functionalized with polymerizable end-groups.…”

Tailor-Made Functional Polyolefins of Complex Architectures: Recent Advances, Applications, and Prospects

“…165,166 Hadjichristidis et al designed and synthesized well-defined AB 2 type 3-miktoarm star copolymers of ethylene and ε- shown in Figure 20. 167 The star copolymers of poly[εcaprolactone] (PCL) are widely used in biomedical applications, 168−170 drug delivery systems, 171 nanoelectronics, 172,173 and polymers modification 174,175 thanks to their ability to form self-assemblies and micelles in selective solvents. 176 Moreover, both the alkyne-containing PCL and azide-functionalized HBPE are valuable precursors for synthesizing complex tailor-made PCL and HBPE-based architectures, respectively.…”

“…Hadjichristidis et al designed and synthesized well-defined AB 2 type 3-miktoarm star copolymers of ethylene and ε-caprolactone [3 μ-HBPE (PCL) 2 ] using successive CWP, ROMP, and azide–alkyne cycloaddition click chemistry, as shown in Figure . The star copolymers of poly­[ε-caprolactone] (PCL) are widely used in biomedical applications, − drug delivery systems, nanoelectronics, , and polymers modification , thanks to their ability to form self-assemblies and micelles in selective solvents .…”