New Thermo‐Sensitive Graft Copolymers Based on a Poly(<i>N</i>‐isopropylacrylamide) Backbone and Functional Polyoxazoline Grafts with Random and Diblock Structure

Rueda, Juan Carlos; Zschoche, Stefan; Komber, Hartmut; Krahl, Franziska; Arndt, Karl‐Friedrich; Voit, Brigitte

doi:10.1002/macp.200900437

Cited by 32 publications

(30 citation statements)

References 25 publications

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“…Voit et al prepared thermo-sensitive graft copolymers based on poly(N-isopropyl-acrylamide)-co-poly(chloromethyl styrene) as the backbone, onto which MeOx and EtOx were grafted as chains of random or block copoly(2-oxazoline)s [103]. The CROP of 2-oxazolines was initiated by the benzyl chloride groups of the backbone copolymer.…”

Section: Grafting From Heteropolymer Side-chainsmentioning

confidence: 99%

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

2013

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Abstract:The polymer class of poly(2-oxazoline)s currently is under intensive investigation due to the versatile properties that can be tailor-made by the variation and manipulation of the functional groups they bear. In particular their utilization in the biomedic(in)al field is the subject of numerous studies. Given the mechanism of the cationic ring-opening polymerization, a plethora of synthetic strategies exists for the preparation of poly(2-oxazoline)s with dedicated functionality patterns, comprising among others the functionalization by telechelic end-groups, the incorporation of substituted monomers into (co)poly(2-oxazoline)s, and polymeranalogous reactions. This review summarizes the current state-of-the-art of poly(2-oxazoline) preparation and showcases prominent examples of poly(2-oxazoline)-based materials, which are retraced to the desktop-planned synthetic strategy and the variability of their properties for dedicated applications.

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Section: Grafting From Heteropolymer Side-chainsmentioning

confidence: 99%

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

2013

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“…Moreover, the ester can be hydrolyzed to the corresponding carboxylic acid providing a versatile handle for conjugation as well as a means to introduce pH responsiveness. Although the potential of side-chain methyl ester-containing PAOx copolymers is well established, there is remarkably little known about their thermal features and thermoresponsive behavior [33,[43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Thermal Properties of Methyl Ester-Containing Poly(2-oxazoline)s

et al. 2015

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This paper describes the synthesis and thermal properties in solution and bulk of poly(2-alkyl-oxazoline)s (PAOx) containing a methyl ester side chain.Homopolymers of 2-methoxycarbonylethyl-2-oxazoline (MestOx) and 2-methoxycarbonylpropyl-2-oxazoline (C3MestOx), as well as copolymers with 2-ethyl-2-oxazoline (EtOx) and 2-n-propyl-2-oxazoline (nPropOx), with systematic variations in composition were prepared. The investigation of the solution properties of these polymers revealed that the cloud point temperatures (T CP s) could be tuned in between 24˝C and 108˝C by variation of the PAOx composition. To the best of our knowledge, the T CP s of PMestOx and PC3MestOx are reported for the first time and they closely resemble the T CP s of PEtOx and PnPropOx, respectively, indicating similar hydrophilicity of the methyl ester and alkyl side chains. Furthermore, the thermal transitions and thermal stability of these polymers were investigated by DSC and TGA measurements, respectively, revealing amorphous polymers with glass transition temperatures between´1˝C and 54˝C that are thermally stable up to >300˝C.

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“…Already small amounts of carboxylic groups stabilize the micelle formation in a broad temperature range. 26 Furthermore, it is believed that the architecture of the polymer is important for its function as polymeric carrier. 27 In this contribution, the synthesis of a new linear poly(2-oxazoline), namely poly(2-cyclopropyl-2-oxazoline) (pCPropOx), and of the comb polymer, poly[(oligo-2-cyclopropyl-2-oxazoline)methacrylate] (p[(OCPropOx)MA]), containing OCPropOx side-chains and a MA backbone, are described ( Figure 1).…”

Section: ' Introductionmentioning

confidence: 99%

Poly(2-cyclopropyl-2-oxazoline): From Rate Acceleration by Cyclopropyl to Thermoresponsive Properties

et al. 2011

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There is a high potential for thermoresponsive polymers to be used in various applications, such as drug delivery systems 1À5 and separation processes, 6,7 and, therefore, these materials received significant attention over the last few years. Polymers that exhibit "lower critical solution temperature" (LCST) behavior are soluble in water below their LCST 3,7,8 due to effective hydration of the polymer based on hydrogen bonds between the polymer and the solvent. With increasing temperature, the hydrogen bonds are weakened resulting in dehydration when the LCST is reached. This entropically driven phase transition, i.e., release of water molecules, leads to a collapse of the hydrophobic polymer chains and the formation of aggregates. Therefore, the LCST can be tuned, e.g., by variation of the polymer side chains or by copolymerization with other monomers, as fully explored for the most widely studied thermo-responsive polymer, poly(N-isopropylacrylamide) [PNIPAM]. 3,6,9,10 Poly(2-oxazoline)s with methyl, ethyl, isopropyl, or n-propyl side chains are water-soluble and, except for the most hydrophilic poly(2-methyl-2-oxazoline) (pMeOx), show LCST behavior in water. 11,12 The cloud points (CP) of these poly(2-oxazoline)s increase with increasing hydrophilicity and depend on the degree of polymerization (DP) and concentration. 13À15 The CP can easily be tuned by copolymerization of various 2-oxazoline monomers, as well as by controlling the length and end groups. 16À19 Poly(2-ethyl-2-oxazoline) (pEtOx) is known to only reveal a CP when the DP is above 100, since smaller polymer chains are soluble up to 100°C. 15 Poly(2-isopropyl-2-oxazoline) (piPropOx) is an interesting thermoresponsive polymer, since its CP is close to body-temperature, making it suitable for biomedical applications. 20 However, due to its semicrystallinity the thermo-responsiveness becomes irreversible after annealing above the LCST. 21À23 Poly(2-n-propyl-2-oxazoline) (pnPropOx) is amorphous but has a lower LCST of ∼24°C. 15 In addition, the rather low T g of ∼40°C, which decreases in the presence of water, makes it difficult to handle and to store the polymer at ambient temperature. Therefore, an alternative thermo-responsive poly(2-oxazoline) with a reversible critical temperature close to body temperature is desired.Besides linear poly(2-oxazoline)s, we recently also reported comb polymers containing oligo(2-ethyl-2-oxazoline) (OEtOx) sidechains and a methacrylate (MA) backbone as thermo-responsive ABSTRACT: The synthesis and microwave-assisted living cationic ring-opening polymerization of 2-cyclopropyl-2-oxazoline is reported revealing the fastest polymerization for an aliphatic substituted 2-oxazoline to date, which is ascribed to the electron withdrawing effect of the cyclopropyl group. The poly(2-cyclopropyl-2-oxazoline) (pCPropOx) represents an alternative thermo-responsive poly(2-oxazoline) with a reversible critical temperature close to body temperature. The cloud point (CP) of the obtained pCPropOx in aqueous solution was evaluated i...

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New Thermo‐Sensitive Graft Copolymers Based on a Poly(N‐isopropylacrylamide) Backbone and Functional Polyoxazoline Grafts with Random and Diblock Structure

Cited by 32 publications

References 25 publications

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

Thermal Properties of Methyl Ester-Containing Poly(2-oxazoline)s

Poly(2-cyclopropyl-2-oxazoline): From Rate Acceleration by Cyclopropyl to Thermoresponsive Properties

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