Thermoresponsive poly(γ‐propyl‐<scp>l</scp>‐glutamate)‐graft‐(oligo ethylene glycol)s: Synthesis, characterization, and properties

J. Polym. Sci. Part A: Polym. Chem.

Yuan

et al. 2015

Self Cite

A series of side-chain-functionalized a-helical polypeptides, i.e., poly (c-4-(3-chloropropoxycarbonyl)benzyl-L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of c-4-(3-chloropropoxycarbonyl)benzyl-L -glutamic acid-based N-carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via coppermediated [213] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt a-helical conformations both in solution and the solid state. Polymers bearing OEG (m 5 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I 2 counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures (T pt s) were dependent on the mainchain length and polymeric concentration.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and thermoresponsive properties of Helical Polypeptides Derivatized from Poly(γ−4‐(3‐chloropropoxycarbonyl)benzyl‐_L‐glutamate)

Deng

J. Polym. Sci. Part A: Polym. Chem.

Yuan

et al. 2015

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“…[20][21][22] While water-soluble thermoresponsive polypeptides with LCSTs have been developed by incorporation of oligo-ethylene-glycols in the side chains via directly ring-opening polymerization (ROP) of peglated amino acids-based N -carboxyanhyrides (NCAs) [23][24][25] or post-polymerization through click chemistry. [26][27][28] The molecular design of water-soluble thermoresponsive polypeptides with a UCST still remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Water‐Soluble Thermoresponsive α‐Helical Polypeptide with an Upper Critical Solution Temperature: Synthesis, Characterization, and Thermoresponsive Phase Transition Behaviors

Deng

Macromol. Rapid Commun.

et al. 2015

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Water‐soluble polypeptides bearing 1‐alkylimidazolium (methyl or n‐butyl) and various counter‐anions (i.e., Cl−, I− or BF4−) are prepared by ring‐opening polymerization of γ‐4‐chloromethylbenzyl‐l‐glutamate‐based N‐carboxyanhydride (3), post‐polymerization of poly(γ‐4‐chloromethylbenzyl‐l‐glutamate) (4), and ion‐exchange reaction. Circular dichroism (CD) analysis reveals that the resulting polypeptides adopt an α‐helical conformation in water with a fractional helicity in the range of 30%–56% at 20 °C and exhibit good conformational stability against temperature variations. The polypeptides exhibit lower critical solution temperature (LCST)‐type or upper critical solution temperature (UCST)‐type transitions in organic solvents or in water. The UCST‐type transition temperature (Tpt) in water is independent on the molecular weight, yet it decreases upon addition of NaCl and increases upon addition of NaI or NaBF4, suggesting a mainly electrostatic interaction mechanism.

“…Numerous methods were successively developed for preparing TVPs to endow polymer solutions with thermothickening ability, besides graft modification in organic solvent, free radical copolymerization in bulk monomers, or different media such as aqueous solution, dodecane dispersion, micellar solution were also developed. In addition, the living radical polymerization was also employed to synthesize TVPs.…”

Section: Introductionmentioning

confidence: 99%

Thermoviscosifying polymers based on polyether prepared from inverse emulsion polymerization

J of Applied Polymer Sci

Sun

Han

et al. 2018

Thermoviscosifying polymers are attractive for enhancing oil recovery owing to their exceptional thickening power as temperature increases. However, the polymers reported to date show inadequacies including obligatory high polymer concentration to get the thermothickening ability because of their low molecular weight (MW), and inconvenient post-treatment due to the high viscosity after manufacturing. To overcome these drawbacks, inverse emulsion polymerization was used here for preparing polyether-based thermoviscosifying polymers (TVP-Ps) by grafting acrylic monomers onto triblock copolymers PEO-PPO-PEO. It was found the MW of final products could reach 8 million Daltons, making them thermoviscosifying at 0.2 wt %. The viscosity of polymerized inverse emulsions was as low as 175 mPaÁs, leading to direct dispersing. The TVP-Ps containing Pluronic F127, F108, F68 all exhibited significant thermothickening behaviors in both aqueous solutions and brines, and the critical thermoassociative temperature could be tuned by changing the nature or amount of Pluronics. After aging at 45 8C for 60 days with equal initial viscosity, TVP-Ps shows 21% higher viscosity retention than the reference polymer without Pluronic, PAMA, and preliminary core flooding test demonstrated TVP-Ps can get 2.1% higher incremental oil recovery than PAMA. This work paves a new avenue for scaled-up preparation and potential use of TVP-Ps. potential use of TVP-Ps.