Poly(diethylsiloxane-co-diphenylsiloxane) and poly(diethylsiloxane-co-3,3,3-trifluoropropylmethylsiloxane): synthesis, characterization and low-temperature properties

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

doi:10.1016/0032-3861(94)90673-4

Cited by 28 publications

(22 citation statements)

References 24 publications

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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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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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“…Low‐ and high‐molecular‐weight poly(dimethylsiloxane‐ co ‐diphenylsiloxanes) have also been reported, in which the T g is expected to significantly increase because the intermolecular force of the phenyl group is larger than those of the ethyl and methyl groups . Similarly, poly(diethylsiloxane‐ co ‐diphenylsiloxane) and poly(diethylsiloxane‐ co ‐3,3,3‐trifluoropropylmethylsiloxane), as well as poly(diethylsiloxane‐ co ‐ethylphenylsiloxane) and poly(diethylsiloxane‐ co ‐methylphenylsiloxane), have been reported. In addition to the aforementioned copolymers that bear two units, copolymers with three and four units have also been prepared .…”

Section: Introductionmentioning

confidence: 99%

“…Silicone rubbers have been widely used in recent years because of their excellent chemical properties, such as resistance to ozone and weathering, electrical insulating property, and excellent low‐temperature resistance . For example, high‐molecular‐weight poly(diethylsiloxane) (PDES) possesses a low glass transition temperature ( T g ) of −137°C, which is the lowest for any known polymer . However, a rigid crystal forms at temperatures below −73°C, and a conformational disorder in crystals at high temperatures limits the utilization of PDES .…”

Section: Introductionmentioning

confidence: 99%

“…Various structural modifications have been studied to obviate the crystallization of PDES or PDMS. Copolymers of dimethylsiloxane and 3,3,3‐trifluoropropylmethylsiloxane are used as materials for processes at low temperatures . The fluorinated group as a copolymerization‐modified chain undermines the crystallization of the dimethylsiloxane segment.…”

Section: Introductionmentioning

confidence: 99%

“…The fluorinated group as a copolymerization‐modified chain undermines the crystallization of the dimethylsiloxane segment. Consequently, crystallization‐free copolymers with T g as low as −115°C are obtained . Low‐ and high‐molecular‐weight poly(dimethylsiloxane‐ co ‐diphenylsiloxanes) have also been reported, in which the T g is expected to significantly increase because the intermolecular force of the phenyl group is larger than those of the ethyl and methyl groups .…”

Section: Introductionmentioning

confidence: 99%

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Preparation and kinetic analysis of room‐temperature vulcanized methylethylsilicone rubbers

Zhang

Zhai

et al. 2015

J of Applied Polymer Sci

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Random copolymer poly(dimethylsiloxane-co-diethylsiloxane) is synthesized through anionic ring-opening polymerization. Two-component room-temperature vulcanization (RTV-2) silicone rubbers with excellent low-temperature resistance are prepared using the poly(dimethylsiloxane-co-diethylsiloxane) and hydrosilicone. The mechanical properties of RTV-2 rubbers with different formulas are investigated, and the optimized formula is obtained. Moreover, the curing kinetic analysis of RTV-2 silicone rubber with optimized formula is conducted using in situ Fourier transform infrared spectroscopy. The obtained kinetic equations are used to forecast the tack-free time at different temperatures. The results converge with the actually measured tack-free time.

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Curing characteristics, morphology, thermal stability, mechanical properties, and irradiation resistance of methylethylsilicone/methylphenylsilicone rubber blends

Tan

et al. 2014

J of Applied Polymer Sci

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Methylethylsilicone rubber (MESR)/methylphenylsilicone rubber (MPSR) blends were cured with 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane. The curing characteristics, morphology, thermal behaviors, mechanical properties at different temperatures, radiation resistance, and thermal aging resistance of the MESR/MPSR blends were investigated. The results show that a high MPSR content could decrease the optimum curing time and improve the scorch safety. Dynamic mechanical analysis revealed that the glass-transition temperature of the blends increased slightly with the addition of MPSR. Scanning electron microscopy showed that MESR and MPSR had good compatibility in the blends. Thermogravimetric analysis indicated that the thermal stability of the blends increased with increasing quantity of MPSR. The blends had excellent mechanical properties at low temperatures. However, these properties were significantly reduced when the temperature was increased. Moreover, changes in the mechanical properties decreased with increasing MPSR content at high temperatures, especially at temperatures higher than 100 C. In addition, the radiation resistance and thermal aging resistance of the blends increased with increasing MPSR content.

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Poly(diethylsiloxane-co-diphenylsiloxane) and poly(diethylsiloxane-co-3,3,3-trifluoropropylmethylsiloxane): synthesis, characterization and low-temperature properties

Cited by 28 publications

References 24 publications

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

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

Preparation and kinetic analysis of room‐temperature vulcanized methylethylsilicone rubbers

Curing characteristics, morphology, thermal stability, mechanical properties, and irradiation resistance of methylethylsilicone/methylphenylsilicone rubber blends

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