scholarly journals Synthesis, Structure, Hydrodynamics and Thermoresponsiveness of Graft Copolymer with Aromatic Polyester Backbone at Poly(2-isopropyl-2-oxazoline) Side Chains

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2643 ◽  
Author(s):  
Elena Tarabukina ◽  
Emil Fatullaev ◽  
Anna Krasova ◽  
Mikhail Kurlykin ◽  
Andrey Tenkovtsev ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Graft Copolymer ◽  
Graft Copolymers ◽  
Linear Chain ◽  
Terminal Group ◽  
Solution Temperature ◽  
Side Chains ◽  
Critical Solution Temperature ◽  
Copolymer Solution ◽  
Aromatic Polyester

New thermoresponsive graft copolymers with an aromatic polyester backbone and poly(2-isopropyl-2-oxazoline) (PiPrOx) side chains are synthesized and characterized by NMR and GPC. The grafting density of side chains is 0.49. The molar masses of the graft-copolymer, its backbone, side chains, and the modeling poly-2-isopropyl-2-oxaziline are 74,000, 19,000, 4300, and 16,600 g·mol−1, respectively. Their conformational properties in nitropropane as well as thermoresponsiveness in aqueous solutions are studied and compared with that of free side chains, i.e., linear PiPrOx with a hydrophobic terminal group. In nitropropane, the graft-copolymer adopts conformation of a 13-arm star with a core of a collapsed main chain and a PiPrOx corona. Similarly, a linear PiPrOx chain protects its bulky terminal group by wrapping around it in a selective solvent. In aqueous solutions at low temperatures, graft copolymers form aggregates due to interaction of hydrophobic backbones, which contrasts to molecular solutions of the model linear PiPrOx. The lower critical solution temperature (LCST) for the graft copolymer is around 20 °C. The phase separation temperatures of the copolymer solution were lower than that of the linear chain counterpart, decreasing with concentration for both polymers.

scholarly journals Oxazoline-Methacrylate Graft-Copolymers with Upper Critical Solution Temperature Behaviour in Yubase Oil

2021 ◽  
Author(s):  
Matilde Concilio ◽  
Nga Nguyen ◽  
C. Remzi Becer
Keyword(s):  
Aqueous Solutions ◽  
Graft Copolymers ◽  
Solution Temperature ◽  
Temperature Behaviour ◽  
Critical Solution Temperature ◽  
Soluble Polymers ◽  
Upper Critical Solution Temperature ◽  
Fundamental Understanding

Thermoresponsive behavior of polymers in aqueous solutions has been widely studied and utilized in various applications. However, the fundamental understanding on the use of oil soluble polymers in non-aqueous solutions...

Synthesis and characterization of amphiphilic graft copolymers with hydrophobic poly(α-methylstyrene) backbone and hydrophilic poly(n-vinylpyrrolidone) side chains

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Fatima Zohra Sebba ◽  
Seghier Ould Kada ◽  
Mohamed Benaicha ◽  
Nerjesse Nemiche
Keyword(s):  
Graft Copolymer ◽  
Graft Copolymers ◽  
Radical Copolymerization ◽  
Side Chains ◽  
Free Radical Copolymerization ◽  
Good Efficiency ◽  
Molecular Weights ◽  
Grafting Reaction ◽  
Viscosity Variation ◽  
End Capping

AbstractIn this study, 2-oxopropylmethacrylate-terminated poly(N-vinyl-2- pyrrolidone) is produced by cationic polymerization using HClO4 as an initiator. Termination (end capping) step is accomplished using 2- hydroxypropylmethacrylate (2HPMA) and the polymer product has different chain lengths of molecular weight averages ranging from 672 to 3049 g/mol. The study also synthesised amphipathic graft copolymers having hydrophobic poly(α- methylstyrene) as a backbone chain and hydrophilic poly(N-vinyl-2-pyrrolidone) (PVP) as side chains of various lengths. The copolymer synthesis was accomplished by free radical copolymerization of ω-oxopropylmethacrylate PVP in the presence of α-methyl styrene initiated with benzoyl peroxide. Measurements of the dynamic viscosity of the polymer solution (20% weight of macromonomers in ethanol) show that the viscosity is proportional to the average molecular weights M̅n . However, a reverse behaviour of the viscosity variation with regard to M̅n is observed for graft copolymer samples. The viscosity variation with respect to the graft copolymer mass must be due to steric effects, which are strongly pronounced in grafted copolymer chains. Appearance of the number of side chains attached to poly(α-methylstyrene) backbone reveals that the grafting reaction has occurred with good efficiency.

scholarly journals Effects of the Hydrophilic–Lipophilic Balance of Alternating Peptides on Self-Assembly and Thermo-Responsive Behaviors

2019 ◽  
Vol 20 (18) ◽  
pp. 4604 ◽  
Author(s):  
Ihsan ◽  
Nargis ◽  
Koyama
Keyword(s):  
Aqueous Solutions ◽  
Self Assembly ◽  
Polymer Chains ◽  
Systematic Evaluation ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Hydrophilic Lipophilic Balance ◽  
Upper Critical Solution Temperature ◽  
Cloud Points ◽  
Micellization Behavior

A series of N-substituted poly(Gly–alter–Val) peptides were successfully synthesized for the systematic evaluation of the micellization behavior of alternating peptides. Three-component polymerization employing an aldehyde, a primary ammonium chloride, and potassium isocyanoacetate afforded four alternating peptides in excellent yields. We investigated the dependence of the hydrophilic–lipophilic balance of alternating peptides on the micellization behavior. All the aqueous solutions of alternating peptides exhibited upper critical solution temperature (UCST) behaviors, strongly indicating that the alternating binary pattern would mainly contribute to the UCST behaviors. The cloud points of alternating peptides shifted to higher temperatures as the side chains became more hydrophilic, which is opposite to the trend of typical surfactants. Such unusual micellization behaviors appeared to be dependent on the quasi-stable structure of single polymer chains formed in water.

Spinning of Fibers from Graft Copolymers of Polyacrylonitrile and Poly(Methyl Acrylate)

1976 ◽  
Vol 46 (2) ◽  
pp. 77-81 ◽  
Author(s):  
Samy Abdel Monem El-Garf
Keyword(s):  
Graft Copolymer ◽  
Methyl Acrylate ◽  
Graft Copolymers ◽  
Coagulation Bath ◽  
Side Chains ◽  
Initial Value

Fibers were spun from graft copolymers of polyacrylonitrile and poly(methyl acrylate). Increasing poly(methyl acrylate) side chains from 5 to 8% decreased the viscosity of the spinning solution in dimethylformamide. The spinning solutions were unstable. When the graft copolymer contained 5% side chains, the viscosity of these solutions returned to almost its initial value by heating. Fibers were obtained from graft copolymers containing from 5–13% poly(methyl acrylate) side chains. These were formed at the temperature of the coagulation bath (50°C), while at temperatures less than 50°C the fibers were not obtained. Weak fibers were produced from a graft copolymer containing 13% side chains at the temperatures of the coagulation bath (20 and 50°C). No fibers were obtained from graft copolymer containing 25% side chains. The method of dissolution of the graft copolymers does affect the drawing of fibers produced from them. It was observed that the heating of the spinning solution decreases the amount of drawing of the produced fibers. The presence of the flexible side chains of poly(methyl acrylate) in the graft copolymer improves the maximum possible degree of drawing of the fibers relative to that of fibers from the initial linear copolymer and homopolyacrylonitrile.

scholarly journals Influence of Cross-Linking Degree on Hydrodynamic Behavior and Stimulus-Sensitivity of Derivatives of Branched Polyethyleneimine

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1085
Author(s):  
Alina Amirova ◽  
Tatyana Kirila ◽  
Mikhail Kurlykin ◽  
Andrey Tenkovtsev ◽  
Alexander Filippov
Keyword(s):  
Aqueous Solutions ◽  
Mole Fraction ◽  
Solution Temperature ◽  
Linear Polymers ◽  
Intermolecular Hydrogen Bonds ◽  
Critical Solution Temperature ◽  
Cross Linker ◽  
The Cross ◽  
Derivatives Of ◽  
Constant Characteristics

Cross-linked derivatives of acylated branched polyethyleneimine containing 2-isopropyl-2-oxazoline units were investigated in chloroform and aqueous solutions using methods of molecular hydrodynamics, static and dynamic light scattering, and turbidity. The studied samples differed by the cross-linker content. The solubility of the polyethyleneimines studied worsened with the increasing mole fraction of the cross-linker. Cross-linked polyethyleneimines were characterized by small dimensions in comparison with linear analogs; the increase in the cross-linker content leads to a growth of intramolecular density. At low temperatures, the aqueous solutions of investigated samples were molecularly dispersed, and the large aggregates were formed due to the dehydration of oxazoline units and the formation of intermolecular hydrogen bonds. For the cross-linked polyethyleneimines, the phase separation temperatures were lower than that for linear and star-shaped poly-2-isopropyl-2-oxazolines. The low critical solution temperature of the solutions of studied polymers decreased with the increasing cross-linker mole fraction. The time of establishment of the constant characteristics of the studied solutions after the jump-like change in temperature reaches 3000 s, which is at least two times longer than for linear polymers.

Construction of semi-fluorinated amphiphilic graft copolymer bearing a poly(2-methyl-1,4-bistrifluorovinyloxybenzene) backbone and poly(ethylene glycol) side chains via the grafting-onto strategy

RSC Advances ◽  
2015 ◽  
Vol 5 (50) ◽  
pp. 39668-39676 ◽  
Author(s):  
Guolin Lu ◽  
Hao Liu ◽  
Haifeng Gao ◽  
Chun Feng ◽  
Yongjun Li ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Graft Copolymer ◽  
Graft Copolymers ◽  
Side Chains ◽  
Poly Ethylene Glycol ◽  
Amphiphilic Graft Copolymer ◽  
Amphiphilic Graft Copolymers ◽  
Poly Ethylene ◽  
Williamson Reaction ◽  
Grafting Onto

Amphiphilic graft copolymers bearing a hydrophobic PMBTFVB backbone and hydrophilic PEG side chains were synthesized by Williamson reaction through the grafting-onto strategy.

Triply-Responsive Poly(N,N-Dimethylaminoethyl Mathacrylate) with an Azobenzene Moiety

2010 ◽  
Vol 663-665 ◽  
pp. 1049-1052
Author(s):  
Xin De Tang ◽  
Xin Wang ◽  
Yuan Yuan Dou
Keyword(s):  
Uv Light ◽  
Aqueous Media ◽  
Gel Permeation Chromatography ◽  
Terminal Group ◽  
Light Irradiation ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Molecular Weights ◽  
Azobenzene Moiety ◽  
Azobenzene Group

A serious of triply-responsive poly(N,N-dimethylaminoethyl methacrylate) (PMAEMA) containing an azobenzene group as the terminal group were synthesized by atom transfer radical polymerization (ATRP). The ATRP process of DMAEMA was initiated by an azobenzene derivative substituted with a 2-bromoisobutyryl group (Azo-Br) using CuCl/Me6TREN as catalyst and the mixture of DMA and H2O (v/v = 3:1) as solvent. The molecular weights and their distributions of the resulting homopolymers (Azo-PDMAEMA) were characterized by gel permeation chromatography (GPC). The polymers are soluble in aqueous media and exhibit a lower critical solution temperature (LCST) that alternated reversibly in response to pH and photoisomerization of the terminal azobenzene moiety. It was found that the LCST increased as pH decreased in the range of testing. Under UV light irradiation, the trans-to-cis photoisomerization of the azobenzene moiety resulted in a higher LCST, while it recovered under visible light irradiation.

Cloud Point Curves of Aqueous Solutions of Poly(N-ethylmethacrylamide)

1993 ◽  
Vol 58 (10) ◽  
pp. 2370-2382 ◽  
Author(s):  
Miloslav Bohdanecký ◽  
Jiří Horský ◽  
Vladimír Petrus ◽  
Libuše Mrkvičková ◽  
Karel Ulbrich
Keyword(s):  
Molecular Weight ◽  
Aqueous Solutions ◽  
Cloud Point ◽  
Threshold Concentration ◽  
Solution Temperature ◽  
Threshold Temperature ◽  
Critical Solution Temperature ◽  
Dilute Solution Properties ◽  
Experimental Errors ◽  
The Difference

Aqueous solutions of poly(N-ethylmethacrylamide) have a lower critical solution temperature (LCST). Cloud point curves of five polydisperse samples (Mw . 10-6 = 0.06 to 2.04) in aqueous solutions at concentrations from 0.002 to 0.1 g/ml were obtained. The threshold concentration was found to be almost independent of the molecular weight. The threshold temperature decreases moderately with increasing M and the limiting value for infinite M obtained by the Shultz-Flory method is ΘLPE = 340.5 K. This value is lower by 2.5 K than the temperature ΘLη at which the intrinsic viscosity is proportional to the square root of the molecular weight. The difference cannot be assigned to experimental errors. The entropy-of-dilution parameter is negative (ψ = -2) and much higher than the value obtained from dilute solution properties. The differences in Θ and ψ values are discussed in terms of theory of polymer solutions where a higher-order interaction parameter is included.

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