Theta Solvents

Elias, Hans‐Georg

doi:10.1002/0471532053.bra054

Cited by 9 publications

(9 citation statements)

References 443 publications

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“…Such phenomena were reported previously for PMMA in good solvent conditions 14, 15. In our case, the transition point is very close to the theta condition16, 17 and the macromolecular chain exhibits the same flexibility below and above the transition point.…”

Section: Resultssupporting

confidence: 89%

Synthesis, characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

Morariu¹,

Bercea²

2004

Polymer International

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Copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with methyl methacrylate and styrene were synthesized in benzene at 85 °C in the presence of 2,2′‐azobisisobutyronitrile as initiator. The structure of the resulting copolymers was investigated and a polymerization mechanism was proposed. The intrinsic viscosity of the copolymers in dilute solutions of carbon tetrachloride was determined as a function of temperature and conformational transitions were investigated. Copyright © 2004 Society of Chemical Industry

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Section: Resultssupporting

confidence: 89%

Synthesis, characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

Morariu¹,

Bercea²

2004

Polymer International

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“…An important parameter used to describe the thermal behavior of non-structured, amorphous polymer networks is the glass transition temperature (T g ). The glass transition in the DSC curves (2nd heating curves to eliminate influences of thermal history; see Supporting Information ) indicates the temperature range where segmental motions in polymers start [ 80 , 81 ]. In networks, this relates to the behavior of the segments between network knots.…”

Section: Resultsmentioning

confidence: 99%

In Situ Preparation of Crosslinked Polymer Electrolytes for Lithium Ion Batteries: A Comparison of Monomer Systems

et al. 2020

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Solid polymer electrolytes for bipolar lithium ion batteries requiring electrochemical stability of 4.5 V vs. Li/Li+ are presented. Thus, imidazolium-containing poly(ionic liquid) (PIL) networks were prepared by crosslinking UV-photopolymerization in an in situ approach (i.e., to allow preparation directly on the electrodes used). The crosslinks in the network improve the mechanical stability of the samples, as indicated by the free-standing nature of the materials and temperature-dependent rheology measurements. The averaged mesh size calculated from rheologoical measurements varied between 1.66 nm with 10 mol% crosslinker and 4.35 nm without crosslinker. The chemical structure of the ionic liquid (IL) monomers in the network was varied to achieve the highest possible ionic conductivity. The systematic variation in three series with a number of new IL monomers offers a direct comparison of samples obtained under comparable conditions. The ionic conductivity of generation II and III PIL networks was improved by three orders of magnitude, to the range of 7.1 × 10−6 S·cm−1 at 20 °C and 2.3 × 10−4 S·cm−1 at 80 °C, compared to known poly(vinylimidazolium·TFSI) materials (generation I). The transition from linear homopolymers to networks reduces the ionic conductivity by about one order of magnitude, but allows free-standing films instead of sticky materials. The PIL networks have a much higher voltage stability than PEO with the same amount and type of conducting salt, lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). GII-PIL networks are electrochemically stable up to a potential of 4.7 V vs. Li/Li+, which is crucial for a potential application as a solid electrolyte. Cycling (cyclovoltammetry and lithium plating-stripping) experiments revealed that it is possible to conduct lithium ions through the GII-polymer networks at low currents. We concluded that the synthesized PIL networks represent suitable candidates for solid-state electrolytes in lithium ion batteries or solid-state batteries.

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“…Up to the boiling point of the solvent, T b , the information refers to 1 bar. For the endothermal theta temperature of the system the Polymer Handbook8 states values from 307.1 to 308.1 K.…”

Section: Evaluation Of Experimental Datamentioning

confidence: 99%

Chain Connectivity and Conformational Variability of Polymers: Clues to an Adequate Thermodynamic Description of their Solutions, 3

Stryuk

Wolf

2003

Macro Chemistry & Physics

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A simple expression for the composition dependence of the Flory‐Huggins interaction parameter of polymer/solvent systems reported earlier is used to model the demixing of polymer solutions into two liquid phases. To this end, the system specific parameters ζ and ν of that approach are calculated as a function of temperature using the thermodynamic expressions resulting for the critical conditions on one side and from experimentally determined critical data for polymers of different molar mass on the other side. By means of data reported for the system cyclohexane/polystyrene it is demonstrated that binodal and spinodal lines are very accurately modeled at low temperatures (UCSTs) and at high temperatures (LCSTs). The parameters obtained from the demixing behavior match well with that calculated from the composition dependence of the vapor pressure at temperatures where the components are completely miscible. Information on the phase separation of the system trans‐decalin/polystyrene for different molecular weights and at different elevated pressures is used to show that the approach is also apt to model pressure influences. The thus obtained ζ(T;p) and ν(T;p) enable the prediction of the (endothermal) theta temperature of the system as a function of pressure in quantitative agreement with the data directly obtained from light scattering measurements with dilute solutions.

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Theta Solvents

Cited by 9 publications

References 443 publications

Synthesis, characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

Synthesis, characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

In Situ Preparation of Crosslinked Polymer Electrolytes for Lithium Ion Batteries: A Comparison of Monomer Systems

Chain Connectivity and Conformational Variability of Polymers: Clues to an Adequate Thermodynamic Description of their Solutions, 3

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