Poly(diethylsiloxane-co-ethylphenylsiloxane) and poly(diethylsiloxane-co-methylphenylsiloxane): synthesis and characterization

Brewer, J. R.; Tsuchihara, Kenji; Morita, Reinaldo Yoshio; Jones, John R.; Bloxsidge, James P.; Fujishige, Shoei

doi:10.1016/0032-3861(94)90674-2

Cited by 18 publications

(18 citation statements)

References 13 publications

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“…In fact, the nature of the primary transitions of siloxane oligomers, silanols,68 and cyclosiloxanes68 have been exhaustively investigated by several groups 69–76. It has often been reported that siloxane polymers may have a solid–liquid crystalline transition.…”

Section: Resultsmentioning

confidence: 99%

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Prado

Torriani

Yoshida

2010

J. Polym. Sci. A Polym. Chem.

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Self-supported translucent films constituted of poly(n-octylsilsesquioxane) or poly(n-dodecylsilsesquioxane) were obtained from the hydrolysis and condensation of n-octyltriethoxysilane (OTES) or n-dodecyltriethoxysilane (DTES), respectively. Dense films were obtained in the absence of organic solvents, with dibutyltin diacetate as catalyst. These films exhibited good optical transparency and thermal stability. The incorporation of oligomeric dimethylsiloxane units (D Me,Me ) in these materials, derived from silanol-terminated poly(dimethylsiloxane) (PDMS) or 1,1,3,3-tetramethyl-1,3-diethoxydisiloxane (TMDES), was carried out during the hydrolysis and condensation of OTES and DTES and was confirmed by solid-state 29 Si NMR. Poly(n-octylsilsesquioxane) showed a glass-transition temperature at À65 C, due to the increase in the free volume, promoted by the bulky n-octyl groups. The differential scanning calorimetric (DSC) curves of the polymer derived from DTES were characterized by first-order transitions at temperatures ranging from À15.8 to À0.7 C. Further studies of these networks by low-temperature XRD evidenced narrowing of the diffraction halos suggesting a partial order-disorder transition for these materials at lower temperatures. Good thermal stability up to 350 C and the solvent-free production process make these polymers potential candidates for the development of self-supported hydrophobic protective coatings.

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Section: Resultsmentioning

confidence: 99%

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Prado

Torriani

Yoshida

2010

J. Polym. Sci. A Polym. Chem.

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“…Poly(diethylsiloxane) stands out among all other poly(diorganosiloxane)s in that it has, so far, the lowest glass‐transition temperature ( T g ): −138 °C,2, 3 although its low‐temperature use as an elastomer is limited by its crystallization at temperatures near −73 °C and a mesomorphic phase transition at approximately 20 °C 4–7. Previous studies on poly(diethylsiloxane) copolymers mainly focused on copolymers bearing two kinds of units, including the introduction of diphenylsiloxane (Ph 2 SiO), 3,3,3‐trifluoropropylmethylsiloxane, ethylphenylsiloxane, or methylphenylsiloxane (MePhSiO)8, 9 into the poly(diethylsiloxane) backbone to disrupt the crystallization. However, there have been few reports on copolymers with three or four kinds of R 1 R 2 SiO basic units.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of poly(diethylsiloxane) and its copolymers with different diorganosiloxane units

Liu

Yang

Zhang

et al. 2003

J. Polym. Sci. A Polym. Chem.

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Poly(diethylsiloxane) and its copolymers with various kinds of R 1 R 2 SiO (R 1 ϭ R 2 ϭ methyl or phenyl, or R 1 ϭ methyl and R 2 ϭ phenyl) units have been prepared by the equilibrium polymerization of cyclosiloxanes. All the polymers have been characterized by 1 H and 29 Si NMR, gel permeation chromatography, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) measurements. The results indicate that a random distribution of different units has been obtained in the structures of copolymers containing 50 mol % diethylsiloxane units content. DSC and DMA show that the presence of 2.5 mol % diphenylsiloxane units or 5.0 mol % methylphenylsiloxane units in the copolymer can disrupt the crystallinity and lead to noncrystalline copolymers with low glass-transition temperatures (ranging from Ϫ133 to Ϫ137°C according to DSC).

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“…The multiple signals of Si-CH 3 in PDMS-co-PMPS and PDMS-co-PDPS indicated various chemical environments due to the effect of Si-C 6 H 5 ( Figure A3), but it was impossible to assign each split peak to the corresponding methyl. Fortunately, 29 Si NMR spectroscopy is well established as an effective method to determine the microstructures of polysiloxanes [28][29][30][31][32][33]. As shown in Figure 1a, the 29 Si NMR spectrum of PDMS displayed only one peak at 21.91 ppm, which corresponded to the Me 2 SiO unit (denoted by D), indicating that the sample was a homopolymer.…”

Section: Structural Characterization and Sequence Analysismentioning

confidence: 99%

Molecular Insights into Sequence Distributions and Conformation-Dependent Properties of High-Phenyl Polysiloxanes

Zhu

Cheng

et al. 2019

Polymers

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The excellent performance and wide applications of phenyl polysiloxanes are largely due to their phenyl units and monomer sequences. However, the relationship between molecular structure and material properties has not been explicitly elucidated. In this work, the sequence distribution and microstructure of random copolymers were quantitatively investigated by means of a molecular dynamics (MD) simulation combined with experimental verification. The results of 29Si NMR showed that the large number of phenyl units not only shortened the length of the dimethyl units, but also significantly increased the proportion of consecutive phenyl units. The simulation results indicated the attraction between adjacent phenyl groups that were effectively strengthened intra- and inter- molecular interactions, which determined the equilibrium population of conformations and the dynamics of conformational transitions. Furthermore, the evolution of bond angle distribution, torsion distribution, and mean-squared displacements (MSD) shed light on the conformational characteristics that induce the unique thermodynamics properties and photophysical behavior of high-phenyl polysiloxanes. Differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), spectrofluorimetry, and laser scanning confocal microscopy (LSCM) were performed to verify the conclusions drawn from the simulation. Overall, the complementary use of MD simulations and experiments provided a deep molecular insight into structure–property relationships, which will provide theoretical guidance for the rational design and preparation of high-performance siloxanes.

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Poly(diethylsiloxane-co-ethylphenylsiloxane) and poly(diethylsiloxane-co-methylphenylsiloxane): synthesis and characterization

Cited by 18 publications

References 13 publications

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Synthesis and characterization of poly(diethylsiloxane) and its copolymers with different diorganosiloxane units

Molecular Insights into Sequence Distributions and Conformation-Dependent Properties of High-Phenyl Polysiloxanes

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