Synthesis of α-Carboxyl, ω-Amino Heterodifunctional Polystyrene and Its Intramolecular Cyclization

Kubo, Masataka; Hayashi, Takeshi; Kobayashi, Hidenori; Tsuboi, Kae; Itoh, Takahito

doi:10.1021/ma961850v

Cited by 96 publications

(103 citation statements)

References 11 publications

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“…The hydrodynamic volume ratio of 2 against 1 was estimated by comparing their apparent peak molecular weights by SEC, and the value (0.81) was in good agreement with the previous cases of the cyclic and linear polymers. [32][33][34][35] This accords with the effective cyclization by the present metathesis condensation process.…”

supporting

confidence: 85%

Metathesis Polymer Cyclization with Telechelic Poly(THF) Having Allyl Groups

Tezuka

Komiya

2002

Macromolecules

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supporting

confidence: 85%

Metathesis Polymer Cyclization with Telechelic Poly(THF) Having Allyl Groups

Tezuka

Komiya

2002

Macromolecules

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“…The ring closure was achieved at low iMC by means of 2-chloro-N-methyl pyridinium iodide. [84][85][86][87] Scheme 18 presents a simplified illustration of the reaction sequence leading from an anionic polymerization of styrene to a polymeric lactam. A somewhat different reaction pathway was selected for the preparation of cyclic poly(methyl methacrylate).…”

Section: -1351-70mentioning

confidence: 99%

Cyclic polymers: Synthetic strategies and physical properties

Kricheldorf

2009

J. Polym. Sci. A Polym. Chem.

401

442

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Syntheses of cyclic polymers including cyclic homopolymers, cyclic block copolymers, sun-shaped polymers, and tadpole polymers are discussed on the basis of a differentiation between synthetic methods and synthetic strategies (e.g., polycondensation, ring-ring equilibration, or ring-expansion polymerization). Furthermore, all synthetic methods are classified as kinetically or thermodynamically controlled reactions. Characteristic properties of cyclic polymers such as smaller hydrodynamic volume, lower melt viscosities, and higher thermostabilities are compared to the properties of their linear counterparts. Furthermore, the nanophase separation of cyclic diblock copolymers is discussed.

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“…47,48 The third synthetic strategy is based on the coupling reaction between functionalized cyclic and linear polymer precursors. 45,49 Various intra-or intermolecular ring closure/coupling approaches such as electrostatic self-assembly and covalent fixation (ESA-CF), 50,51 amidation/esterification, 47,52,53 etherification reaction (hydroxyl 33 or thiol functionalities 54 ), and high-efficiency and quantitative click reactions 41,42,55 have been utilized. The latter has indeed rendered the facile synthesis of macrocyclic polymers and linear-cyclic diblocks.…”

Section: ' Introductionmentioning

confidence: 99%

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

2011

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We report on the facile synthesis of well-defined amphiphilic and thermoresponsive tadpole-shaped linear-cyclic diblock copolymers via ring-opening polymerization (ROP) directly initiating from cyclic precursors, their self-assembling behavior in aqueous solution, and the application of micellar assemblies as controlled release drug nanocarriers. Starting from a trifunctional core molecule containing alkynyl, hydroxyl, and bromine moieties, alkynyl-(OH)-Br, macrocyclic poly(N-isopropylacrylamide) (c-PNIPAM) bearing a single hydroxyl functionality was prepared by atom transfer radical polymerization (ATRP), the subsequent end group transformation into azide functionality, and finally the intramacromolecular ring closure reaction via click chemistry. The target amphiphilic tadpoleshaped linear-cyclic diblock copolymer, (c-PNIPAM)-b-PCL, was then synthesized via the ROP of ε-caprolactone (CL) by directly initiating from the cyclic precursor. In aqueous solution at 20°C, (c-PNIPAM)-b-PCL self-assembles into spherical micelles consisting of hydrophobic PCL cores and well-solvated coronas of cyclic PNIPAM segments. For comparison, linear diblock copolymer with comparable molecular weight and composition, (l-PNIPAM)-b-PCL, was also synthesized. It was found that the thermoresponsive coronas of micelles self-assembled from (c-PNIPAM)-b-PCL exhibit thermoinduced collapse and aggregation at a lower critical thermal phase transition temperature (T c ) compared with those of (l-PNIPAM)-b-PCL. Temperature-dependent drug release profiles from the two types of micelles of (c-PNIPAM)-b-PCL and (l-PNIPAM)-b-PCL loaded with doxorubicin (Dox) were measured, and the underlying mechanism for the observed difference in releasing properties was proposed. Moreover, MTT assays revealed that micelles of (c-PNIPAM)-b-PCL are almost noncytotoxic up to a concentration of 1.0 g/L, whereas at the same polymer concentration, micelles loaded with Dox lead to ∼60% cell death. Overall, chain topologies of thermoresponsive block copolymers, that is, (c-PNIPAM)-b-PCL versus (l-PNIPAM)-b-PCL, play considerable effects on the self-assembling and thermal phase transition properties and their functions as controlled release drug nanocarriers. ' INTRODUCTIONIn the past decades, enduring attention has been paid to explore the intrinsic correlation between the chain topology of block copolymers and their physical properties, self-assembling behavior in selective solvents or in bulk states, and the associated functional applications. 1-3 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), 11-13 reversible addition-fragmentation chain transfer (RAFT) polymerization, [14][...

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Synthesis of α-Carboxyl, ω-Amino Heterodifunctional Polystyrene and Its Intramolecular Cyclization

Cited by 96 publications

References 11 publications

Metathesis Polymer Cyclization with Telechelic Poly(THF) Having Allyl Groups

Metathesis Polymer Cyclization with Telechelic Poly(THF) Having Allyl Groups

Cyclic polymers: Synthetic strategies and physical properties

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

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