Thermoresponsive Molecular Brushes with a Rigid-Chain Aromatic Polyester Backbone and Poly-2-alkyl-2-oxazoline Side Chains

A new polycondensation aromatic rigid-chain polyester macroinitiator was synthesized and used to graft linear poly-2-ethyl-2-oxazoline as well as poly-2-isopropyl-2-oxazoline by cationic polymerization. The prepared copolymers and the macroinitiator were characterized by NMR, GPC, AFM, turbidimetry, static, and dynamic light scattering. The molar masses of the polyester main chain and the grafted copolymers with poly-2-ethyl-2-oxazoline and poly-2-isopropyl-2-oxazoline side chains were 26,500, 208,000, and 67,900, respectively. The molar masses of the side chains of poly-2-ethyl-2-oxazoline and poly-2-isopropyl-2-oxazoline and their grafting densities were 7400 and 3400 and 0.53 and 0.27, respectively. In chloroform, the copolymers conformation can be considered as a cylinder wormlike chain, the diameter of which depends on the side chain length. In water at low temperatures, the macromolecules of the poly-2-ethyl-2-oxazoline copolymer assume a wormlike conformation because their backbones are well shielded by side chains, whereas the copolymer with short side chains and low grafting density strongly aggregates, which was visualized by AFM. The phase separation temperatures of the copolymers were lower than those of linear analogs of the side chains and decreased with the concentration for both samples. The LCST were estimated to be around 45 °C for the poly-2-ethyl-2-oxazoline graft copolymer, and below 20 °C for the poly-2-isopropyl-2-oxazoline graft copolymer.

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Study on Preparation and Dispersion Effect of Polycarboxylate Superplasticizer with Broken Dentiform Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.984 ◽

2011 ◽

Vol 250-253 ◽

pp. 984-989 ◽

Cited By ~ 3

Author(s):

Zhi Yong Liu ◽

Chong Cui ◽

Li Li

Keyword(s):

Carboxylic Acid ◽

Chemical Structure ◽

Side Chain ◽

Side Chains ◽

Test Results ◽

Dispersion Effect ◽

Anionic Polymer ◽

Short Side ◽

Carboxylic Acid Groups ◽

Radical Polymerisation

Based on the analysis of the chemical structure of polycarboxylate-type SPs grafted PEO side chains, as well as sulfonic and carboxylic acid groups, a kind of polycarboxylate-based SPs grafted varied PEO side chains were synthesized by using radical polymerisation techniques.The relative dispersing effectiveness of the SPs was evaluated in cement paste and concrete by measuring paste flow and concrete slumps. The test results indicat that the copolymers with shorter PEO side chains (with 9 and 14 EO units) give lower initial dispersing power but higher time retention,with the prolonging of PEO side chains the higher initial dispersing effect and the lower time retention can be received. The excellent dispersing property and time retention of synthesized SPs for cementious systems can be achieved by grafted long side chain(with 45 EO units) integrated with short side chain(9 or 14 EO) at the backbone of anionic polymer.

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Side-chain crystallization behavior of graft copolymers consisting of amorphous main chain and crystalline side chains: Poly(methyl methacrylate)-graft-poly(ethylene glycol) and poly(methyl acrylate)-graft-poly(ethylene glycol)

Journal of Polymer Science Part B Polymer Physics ◽

10.1002/polb.20311 ◽

2004 ◽

Vol 43 (1) ◽

pp. 79-86 ◽

Cited By ~ 18

Author(s):

Katsuhiro Inomata ◽

Eiji Nakanishi ◽

Yasuo Sakane ◽

Masao Koike ◽

Takuhei Nose

Keyword(s):

Ethylene Glycol ◽

Methyl Methacrylate ◽

Methyl Acrylate ◽

Crystallization Behavior ◽

Main Chain ◽

Graft Copolymers ◽

Side Chain ◽

Side Chains ◽

Poly Ethylene Glycol ◽

Poly Ethylene

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Effective dispersants for concentrated, nonaqueous suspensions

Journal of Materials Research ◽

10.1557/jmr.1992.2884 ◽

1992 ◽

Vol 7 (10) ◽

pp. 2884-2893 ◽

Cited By ~ 15

Author(s):

I. Sushumna ◽

R.K. Gupta ◽

E. Ruckenstein

Keyword(s):

Main Chain ◽

Side Chain ◽

Solid Loading ◽

Head Group ◽

Side Chains ◽

Concentrated Suspensions ◽

Fatty Esters ◽

Solids Loading ◽

High Solids Loading ◽

Order Of Magnitude

With the aim of identifying effective dispersants that would yield stable, high solids loading (≥60 vol.%) suspensions of oxides, carbides, or nitrides in nonaqueous carriers such as paraffinic oils, a number of dispersants were evaluated, using in most cases A16SG grade alumina from Alcoa as the filler. Among those evaluated were some common dispersants, such as menhaden fish oil and oleic acid, and commercial dispersants not commonly used in ceramic processing, such as polymeric fatty esters and petroleum sulfonates. More importantly, a few dispersants were synthesized and evaluated. The latter dispersants contained straight or cyclic (benzenic) side chains located far from the head group on 18 carbon main-chain fatty acid molecules. Among these, the dispersants with a 5–10 carbon side chain or with a benzenic side chain yielded very fluid suspensions (≥60 vol.%) compared to those with long polymeric or oligomeric side chains, or with no side chains, or the commercial dispersants; in some cases, for the same solid loading, the suspension viscosities were an order of magnitude lower with the synthesized side chain dispersants. These results indicate that molecules with an optimum side chain length located sufficiently far from the head group and an optimum backbone (main chain) constitute the most effective dispersants for concentrated suspensions. By combining the advantages provided by wider particle size distributions and by these effective dispersants, suspensions highly concentrated (up to 74 vol.%), and yet processable and “flowing” paste-like have been prepared.

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

Polymers ◽

10.3390/polym12112643 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2643 ◽

Cited By ~ 1

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.

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DMFC Performance of Polymer Electrolyte Membranes Prepared from a Graft-Copolymer Consisting of a Polysulfone Main Chain and Styrene Sulfonic Acid Side Chains

Energies ◽

10.3390/en9080658 ◽

2016 ◽

Vol 9 (8) ◽

pp. 658 ◽

Cited By ~ 2

Author(s):

Nobutaka Endo ◽

Yoshiaki Ogawa ◽

Kohei Ukai ◽

Yuriko Kakihana ◽

Mitsuru Higa

Keyword(s):

Polymer Electrolyte ◽

Graft Copolymer ◽

Sulfonic Acid ◽

Main Chain ◽

Polymer Electrolyte Membranes ◽

Side Chains ◽

Electrolyte Membranes ◽

Styrene Sulfonic Acid

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New Photoreactive Polymers Containing Short Side Chains as Orientation Layer Materials: Effect of Side Chain Lengths on the Alignment of Liquid-Crystals

Molecular Crystals and Liquid Crystals Science and Technology Section A Molecular Crystals and Liquid Crystals ◽

10.1080/10587250108029981 ◽

2001 ◽

Vol 368 (1) ◽

pp. 503-508 ◽

Cited By ~ 2

Author(s):

M. Ree ◽

S. W. Lee ◽

J.-H. Kim

Keyword(s):

Liquid Crystals ◽

Side Chain ◽

Side Chains ◽

Short Side ◽

Chain Lengths

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Synthesis and Characterization of Thermoplastic Graft Copolymer Elastomers with a Polyether Main Chain and Uniform Urethane-Based Side Chains

Macromolecules ◽

10.1021/ma00111a005 ◽

1995 ◽

Vol 28 (7) ◽

pp. 2133-2139 ◽

Cited By ~ 7

Author(s):

Claus D. Eisenbach ◽

T. Heinemann

Keyword(s):

Graft Copolymer ◽

Main Chain ◽

Synthesis And Characterization ◽

Side Chains

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Effect of perfluorosulfonic acid side chains on oxygen permeation in hydrated ionomers of PEMFCs: Molecular dynamics simulation approach

10.21203/rs.3.rs-127966/v1 ◽

2020 ◽

Author(s):

Sung Hyun Kwon ◽

Haisu Kang ◽

Young-Jun Sohn ◽

Jinhee Lee ◽

Sunbo Shim ◽

...

Keyword(s):

Molecular Dynamics ◽

Water Content ◽

Polymer Electrolyte Membrane ◽

Md Simulations ◽

Dynamics Simulation ◽

Side Chain ◽

Side Chains ◽

Perfluorosulfonic Acid ◽

Short Side ◽

Water Contents

Abstract We prepared two types of perfluorosulfonic acid (PFSA) ionomers with Aquivion (short side chain) and Nafion (long side chain) on a Pt surface and varied their water contents (2.92 ≤ λ ≤ 13.83) to calculate the solubility and permeability of O2 in hydrated PFSA ionomers on a Pt surface using full atomistic molecular dynamics (MD) simulations. The solubility and permeability of O2 molecules in hydrated Nafion ionomers were greater than those of O2 molecules in hydrated Aquivion ionomers at the same water content, indicating that the permeation of O2 molecules in the ionomers is affected not only by the diffusion coefficient of O2 but also by the solubility of O2. Notably, O2 molecules are more densely distributed in regions where water and hydronium ions have a lower density in hydrated Pt/PFSA ionomers. Radial distribution function (RDF) analysis was performed to investigate where O2 molecules preferentially dissolve in PFSA ionomers on a Pt surface. The results showed that O2 molecules preferentially dissolved between hydrophilic and hydrophobic regions in a hydrated ionomer. The RDF analysis was performed to provide details of the O2 location in hydrated PFSA ionomers on a Pt surface to evaluate the influence of O2 solubility in ionomers with side chains of different lengths. The coordination number of C(center)–O(O2) and O(side chain)–O(O2) pairs in hydrated Nafion ionomers was higher than that of the same pairs in hydrated Aquivion ionomers with the same water content. Our investigation provides detailed information about the properties of O2 molecules in different PFSA ionomers on a Pt surface and with various water contents, potentially enabling the design of better-performing PFSA ionomers for use in polymer electrolyte membrane fuel cells.

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Hierarchical superstructures of norbornene-based polymers depending on dendronized side-chains

Polymer Chemistry ◽

10.1039/c6py01286h ◽

2016 ◽

Vol 7 (33) ◽

pp. 5304-5311 ◽

Cited By ~ 16

Author(s):

Dae-Yoon Kim ◽

Dong-Gue Kang ◽

Suyong Shin ◽

Tae-Lim Choi ◽

Kwang-Un Jeong

Keyword(s):

Self Assembly ◽

Ring Opening ◽

Main Chain ◽

The Self ◽

Side Chain ◽

Side Chains ◽

Ring Opening Metathesis Polymerization ◽

Metathesis Polymerization ◽

Main Chain Polymers

For understanding the self-assembly behaviours of norbornene-based main-chain polymers depending on side-chain pendants, a series of polynorbornenes containing the programmed dendrons is newly designed and successfully synthesized via ring opening metathesis polymerization.

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