Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions

Brunchi, Cristina‐Eliza; Morariu, Simona; Cazacu, Maria; Bercea, Maria

doi:10.1021/ie1015238

Cited by 10 publications

(16 citation statements)

References 37 publications

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“…Figure also illustrates very clearly the limitation of the Huggins equation in the data evaluation, especially in the region of very low concentrations, where the reduced viscosity deviates upward from linearity. Such positive deviations from linear behavior in the dependence of η sp / c versus c in the region of very low concentrations have been reported previously for many polymer solutions, ,,, making the extrapolation of the experimental data to zero concentration more difficult.…”

Section: Resultsmentioning

confidence: 54%

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The Behavior of Poly(dimethylsiloxane-co-diphenylsiloxane)s in Good and Theta Solvents

Morariu¹,

Brunchi²,

Cazacu³

et al. 2011

J. Chem. Eng. Data

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In this work, we investigated the behavior of poly(dimethylsiloxane-co-diphenylsiloxane)s under good and theta solvent conditions by using turbidimetry and viscosimetry. The evolution of the optical properties as a function of the solvent quality allowed the composition of the methylbenzene/methanol mixtures at the theta point to be determined. The intrinsic viscosity was determined in good (methylbenzene) and theta (methylbenzene/methanol) solvents at T = 298 K using different approaches. The unperturbed dimension parameters were calculated and are discussed as a function of copolymer composition. The introduction of the diphenylsiloxane units into a poly(dimethylsiloxane) chain results in an increase in the unperturbed dimensions as a consequence of the decrease in chain flexibility.

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Section: Resultsmentioning

confidence: 54%

“…The compositions of the resulting copolymers (Table ) were estimated on the basis of the corresponding 1 H NMR spectra recorded on a BRUKER Avance DRX 400 spectrometer using CDCl 3 as the solvent. The peaks corresponding to the protons in the methyl (0.15 ppm) and phenyl [(7.0 to 7.6) ppm] groups, respectively, were taken into account for this …”

Section: Methodsmentioning

confidence: 99%

The Behavior of Poly(dimethylsiloxane-co-diphenylsiloxane)s in Good and Theta Solvents

Morariu¹,

Brunchi²,

Cazacu³

et al. 2011

J. Chem. Eng. Data

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“…Thus, ultra-high molecular weight polydimethylsiloxane (UHMW-PDMS) with M w of order 1400 kDa and polydispersity index, PDI = 1.2 was obtained [ 41 ]. This procedure was also implemented for the synthesis of the dimethyldiphenylsiloxane copolymers ( Figure 1 d) and other polysiloxanes functionalized with basic groups [ 16 , 42 , 43 ]. Significant research efforts have focused on using synthetic ion exchangers as catalysts in the equilibrium reactions involving siloxane bonds, including kinetic and optimization studies.…”

Section: Context and Early Romanian Achievements In The Field Of Siliconesmentioning

confidence: 99%

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Cazacu¹,

Racleş²,

Zaltariov³

et al. 2021

Polymers

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Polydimethylsiloxane (PDMS), in spite of its well-defined helical structure, is an amorphous fluid even at extremely high molecular weights. The cause of this behavior is the high flexibility of the siloxane backbone and the lack of intermolecular interactions attributed to the presence of methyl groups. These make PDMS incompatible with almost any organic or inorganic component leading to phase separation in siloxane-siloxane copolymers containing blocks with polar organic groups and in siloxane-organic copolymers, where dimethylsiloxane segments co-exist with organic ones. Self-assembly at the micro- or nanometric scale is common in certain mixed structures, including micelles, vesicles, et cetera, manifesting reversibly in response to an external stimulus. Polymers with a very high degree of ordering in the form of high-quality crystals were obtained when siloxane/silane segments co-exist with coordinated metal blocks in the polymer chain. While in the case of coordination of secondary building units (SBUs) with siloxane ligands 1D chains are formed; when coordination is achieved in the presence of a mixture of ligands, siloxane and organic, 2D structures are formed in most cases. The Romanian research group’s results regarding these aspects are reviewed: from the synthesis of classic, amorphous silicone products, to their adaptation for use in emerging fields and to new self-assembled or highly ordered structures with properties that create perspectives for the use of silicones in hitherto unexpected areas.

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“…In dilute solutions, the solvent quality determines the hydrodynamic dimensions of macromolecular chains and thus it has a high influence on different parameters such as: intrinsic viscosity , preferential and total adsorption coefficients , optical properties , Flory‐Huggins interaction parameter .…”

Section: Introductionmentioning

confidence: 99%

Temperature influence on the behavior of polysulfone‐b‐poly(alkylene oxide)‐b‐poly(dimethylsiloxane) triblock copolymers in a selective solvent

Bercea¹,

Airinei²,

Hamciuc³

2016

Polymer Engineering & Sci

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Triblock copolymers containing polysulfone, poly(alkylene oxide), and poly(dimethylsiloxane) segments were obtained by addition of preformed a,x-bis(hydrogensilyl) poly(dimethylsiloxane) oligomers to alyl end-capped poly(alkylene oxide)-bpolysulfone. Viscometric and UV absorption measurements were carried out in dilute 1,2-dichlorethane solutions, in the temperature range of 20-758C. The specific interactions exhibited by the block copolymers in a selective solvent are influenced by the copolymer composition and temperature. The results point to a conformational transition phenomenon, located around 558C, which is attributed to the transition from a segregated to a pseudo-Gaussian conformation through a compressed-segregated conformation. POLYM. ENG. SCI.,

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Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions

Cited by 10 publications

References 37 publications

The Behavior of Poly(dimethylsiloxane-co-diphenylsiloxane)s in Good and Theta Solvents

The Behavior of Poly(dimethylsiloxane-co-diphenylsiloxane)s in Good and Theta Solvents

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Temperature influence on the behavior of polysulfone‐b‐poly(alkylene oxide)‐b‐poly(dimethylsiloxane) triblock copolymers in a selective solvent

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