Solution behavior of thermoresponsive random and gradient copolymers of 2-n-propyl-2-oxazoline

Oleszko-Torbus, Natalia; Utrata-Wesołek, Alicja; Wałach, Wojciech; Dworak, Andrzej

doi:10.1016/j.eurpolymj.2016.11.008

Cited by 24 publications

(27 citation statements)

References 46 publications

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“…Additionally, it should be emphasized that the observed hysteresis is "reversed": the transition during heating occurs at a lower temperature than the transition during cooling of the system. Such behavior was already observed for some poly(2-oxazoline)s [40,41] and was explained by the organization of the polymer chains into specific structures. Most likely, at certain concentrations, agglomerates of micelle-like structures are formed, but they are not stable during cooling; thus, their disintegration occurred at higher temperatures than their formation during heating [40].…”

Section: Iprox/mox Copolymers In Aqueous Solutionsupporting

confidence: 58%

“…Such behavior was already observed for some poly(2-oxazoline)s [40,41] and was explained by the organization of the polymer chains into specific structures. Most likely, at certain concentrations, agglomerates of micelle-like structures are formed, but they are not stable during cooling; thus, their disintegration occurred at higher temperatures than their formation during heating [40]. homopolymers with different chain ends [22][23][24][25], gradient iPrOx copolymers with n-propyl-2oxazoline at an amount of nPrOx equal to or less than 15 mol% [26], and for block iPrOx copolymers with MOx with a degree of polymerization of 50 for each block [27].…”

Section: Iprox/mox Copolymers In Aqueous Solutionsupporting

confidence: 58%

“…The degree of polymerization (DP) of copolymers was calculated on the basis of monomer feed and nuclear magnetic resonance (NMR) data. The reactivity ratios calculated basing on the monomer consumption rate [40] clearly indicated the gradient structure of iPrOx/MOx copolymers. The symbols, amounts of comonomers, molar masses and dispersity of the obtained copolymers are provided in Table 1.…”

Section: Methodsmentioning

confidence: 89%

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Selective Partial Hydrolysis of 2-isopropyl-2-oxazoline Copolymers towards Decreasing the Ability to Crystallize

et al. 2020

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Poly(2-isopropyl-2-oxazoline) (PiPrOx) is readily prone to crystallization both in solid and from solutions. This feature is detrimental for certain applications. Here, we examine whether the presence of unsubstituted ethyleneimine (EI) units, a gradient distributed within a polymer chain composed of 2-isopropyl-2-oxazoline (iPrOx) and 2-methyl-2-oxazoline (MOx) units, decreases the ability to crystallize the copolymer and affects thermal properties compared to the homopolymer of iPrOx. We assumed that the separation of stiff iPrOx units by the more flexible EI will affect the spatial arrangements of the ordered chains, slightly plasticize and, as a result, decrease their ability to crystallize. The selective hydrolysis of gradient iPrOx and 2-methyl-2-oxazoline (MOx) copolymers, carried out under mild conditions, led to iPrOx/MOx/EI copolymers. To the best of our knowledge, the selective hydrolysis of these copolymers has never been carried out before. Their thermal properties and crystallization abilities, both in a solid state and from an aqueous solution, were analyzed. Based on the analysis of polymer charge and cytotoxicity studies, the potential use of the copolymers obtained was indicated in some biological systems.

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Section: Iprox/mox Copolymers In Aqueous Solutionsupporting

confidence: 58%

Section: Iprox/mox Copolymers In Aqueous Solutionsupporting

confidence: 58%

Section: Methodsmentioning

confidence: 89%

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Selective Partial Hydrolysis of 2-isopropyl-2-oxazoline Copolymers towards Decreasing the Ability to Crystallize

et al. 2020

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“…Copolymerisation of iPrOx with nPrOx led to copolymers of gradient distribution of comonomers. The precise kinetics of this reaction have been shown elsewhere [50]. The symbols and characterisation data of the obtained (co)polymers are summarised in Table 1.…”

Section: Synthesis and Characterisation Of (Co)poly(2-oxazoline)smentioning

confidence: 99%

Processing of (Co)Poly(2-oxazoline)s by Electrospinning and Extrusion from Melt and the Postprocessing Properties of the (Co)Polymers

et al. 2020

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Poly(2-oxazoline) (POx) matrices in the form of non-woven fibrous mats and three-dimensional moulds were obtained by electrospinning and fused deposition modelling (FDM), respectively. To obtain these materials, poly(2-isopropyl-2-oxazoline) (PiPrOx) and gradient copolymers of 2-isopropyl- with 2-n-propyl-2-oxazoline (P(iPrOx-nPrOx)), with relatively low molar masses and low dispersity values, were processed. The conditions for the electrospinning of POx were optimised for both water and the organic solvent. Also, the FDM conditions for the fabrication of POx multi-layer moulds of cylindrical or cubical shape were optimised. The properties of the POx after electrospinning and extrusion from melt were determined. The molar mass of all (co)poly(2-oxazoline)s did not change after electrospinning. Also, FDM did not influence the molar masses of the (co)polymers; however, the long processing of the material caused degradation and an increase in molar mass dispersity. The thermal properties changed significantly after processing of POx what was monitored by increase in enthalpy of exo- and endothermic peaks in differential scanning calorimetry (DSC) curve. The influence of the processing conditions on the structure and properties of the final material were evaluated having in a mind their potential application as scaffolds.

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“…This characteristic makes such gradient copolymers a great potential in biomimetic applications. [21][22][23][24][25][26][27][28][29] Various studies are done on the effect of additives on the solubility behavior of thermoresponsive polymers [30][31][32][33][34][35][36][37][38][39] including POEOMAs, [40][41][42][43][44] but so far there is no comprehensive study to compare the effect of different additives on the phase transition of thermoresponsive copolymers with different structure.…”

Section: Introductionmentioning

confidence: 99%

Solubility behaviour of random and gradient copolymers of di- and oligo(ethylene oxide) methacrylate in water: effect of various additives

2020

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Poly[oligo(ethylene oxide)] based gradient and random copolymers with different compositions are synthesized via Cu-based atom transfer radical polymerization. The solubility behavior of these copolymers in pure water and in the presence of different salts, surfactants and ethanol is investigated. According to dynamic light scattering results, the lower critical solution temperature (LCST) depends on the structure of the copolymer and changes slightly in the presence of additives. Good cosolvents like ethanol can increase the LCST through dissolving the collapsed copolymer chains to some extent. The same effect is observed for surfactants that make the copolymer solution more stable by preventing aggregation.Above a certain concentration of surfactant, depending on the copolymer structure, the solution is stable at all temperatures (no LCST). The effect of salts on the solubility of the copolymers follows the Hofmeister series and it is related linearly to the salt concentration. Based on their affinity to the copolymer, the salts can increase or decrease the LCST. There is a considerable difference in phase transition changes for gradient or random copolymers after salt addition. While both copolymers show a two-step phase transition in the presence of different salts, the changes in the hydrodynamic radius and normalized scattering intensity are rather broad for random compared to gradient copolymers. Contrary to what was expected, varying the cations has no distinguishable effect on the LCST for both copolymers. All chlorides decrease the LCST. This decrease is almost the same for gradient copolymers and fluctuates for random copolymers.

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Solution behavior of thermoresponsive random and gradient copolymers of 2-n-propyl-2-oxazoline

Cited by 24 publications

References 46 publications

Selective Partial Hydrolysis of 2-isopropyl-2-oxazoline Copolymers towards Decreasing the Ability to Crystallize

Selective Partial Hydrolysis of 2-isopropyl-2-oxazoline Copolymers towards Decreasing the Ability to Crystallize

Processing of (Co)Poly(2-oxazoline)s by Electrospinning and Extrusion from Melt and the Postprocessing Properties of the (Co)Polymers

Solubility behaviour of random and gradient copolymers of di- and oligo(ethylene oxide) methacrylate in water: effect of various additives

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