Double-decker Silsesquioxane Research Articles

Unusual cis and trans architecture of dihydrofunctional double-decker shaped silsesquioxane and synthesis of its ethyl bridged π-conjugated arene derivatives

An original family of well-defined molecular and macromolecular double-decker silsesquioxane derivatives with ethyl bridged π-conjugated arenes is obtained via hydrosilylation reaction.

Synthesis and properties of castor oil based polyurethanes reinforced with double-decker silsesquioxane

Hybrid polyurethanes with double-decker silsesquioxane (DDSQ) in the main chains were synthesized using castor oil and isophorone diisocyanate (IPDI) as feedstock. Double-decker octaphenylsilsesquioxanetetraol (DDSQ) was prepared and characterized by 1H NMR and MALDI-TOF–MS. Meanwhile, FTIR, TGA, DSC, SEM, UV–Vis spectrophotometer, tensile test techniques and static contact angle were also carried out to investigate the structures and properties of the hybrid polyurethanes. The DDSQ-containing hybrid polyurethanes exhibited improved thermal stability in terms of thermogravimetric analysis (TGA). DSC analysis demonstrated that the hybrid polyurethanes with DDSQ displayed enhanced glass transition temperature. According to the results of SEM and UV–Vis spectrophotometer, the aggregates of DDSQ were dispersed homogeneously in the hybrid polyurethanes matrix. With the inclusion of DDSQ, the hydrophobicity of the hybrid material was significantly improved as the results of the static contact angles revealed.

POSS‐based poly(aryl ether sulfone)s random terpolymer linked POSS to the main chain: effect of chemical structure and POSS content on properties

In order to investigate the effect of polyhedral oligomeric silsesquioxane content and the structure‐function related on the dielectric property and hydrophobicity, three kinds of poly(aryl ether sulfone)s (PAESs) random terpolymer with different chemistry structure at variable polyhedral oligomeric silsesquioxane content in the main chain are prepared. The structures of PAESs are characterized by infrared (IR), nuclear magnetic resonance (NMR), and wide‐angle X‐ray diffraction (WXRD) spectra. The results show that the dielectric constant initially increases then decrease to 2.68 at 100%‐double‐decker silsesquioxane (DDSQ)‐PAES(molar content of DDSQ = 100%) at 1 MHz. The contact angle increased to 97.5° at 100%‐DDSQ‐PAES. While the chemical structure of organic chains also plays an important role on thermostability, dielectric, and hydrophobic properties. The results are discussed and interpreted in detail. Copyright © 2016 John Wiley & Sons, Ltd.

Organic–inorganic poly(N‐vinylpyrrolidone) copolymers with double‐decker silsesquioxane in the main chains: Synthesis, glass transition, and self‐assembly behavior

ABSTRACTAn organic–inorganic copolymer with polyhedral oligomeric silsesquioxane (POSS) and xanthate moieties in the main chain was synthesized via the polycondensation between 3,13‐di(2‐bromopropionate)propyl double‐decker silsesquioxane (DDSQ) and 1,4‐di(xanthate potassium)butane. This hybrid copolymer was used as the macromolecular chain transfer agent to obtain the organic–inorganic poly(N‐vinylpyrrolidone) (PVPy) copolymers via a reversible addition fragmentation chain transfer/macromolecular design via the interchange of xanthates (RAFT/MADIX) polymerization approach; the polymerization behavior of N‐vinyl pyrrolidone was investigated by means of gel permeation chromatography. It was found that the polymerization was in a living and controlled manner. Transmission electron microscopy (TEM) showed that the organic–inorganic PVPy copolymers with DDSQ in the main chains were microphase‐separated in bulks. Compared to plain PVPy, the organic–inorganic PVPy copolymers displayed the decreased glass transition temperatures (Tgs); the decreased Tgs are attributable to the effect of the introduced DDSQ cages on the packing of PVPy chains as evidenced by means of Fourier transform infrared spectroscopy (FTIR). In water, the organic–inorganic PVPy copolymers can self‐assemble into the spherical nano‐objects with the size of 20–50 nm in diameter. In the self‐assembled nano‐objects, the aggregates of the hydrophobic DDSQ constituted the cores of the polymeric micelles whereas the PVPy chains between the DDSQ behaved as the coronas of the polymeric micelles. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2949–2961

Organic–inorganic polyimides with double decker silsesquioxane in the main chains

In this contribution, we report the synthesis of organic–inorganic polyimides with double decker silsesquioxane in the main chains with a novel and well-defined POSS diamine.

Soy-castor oil based polyurethanes with octaphenylsilsesquioxanetetraol double-decker silsesquioxane in the main chains

In these DDSQ-containing hybrid polyurethanes, DDSQ cages in the main chain act as the nanosized crosslinkers to participate in the formation of polymer networks.

Synthesis and characterization of functionalized molecular and macromolecular double-decker silsesquioxane systems

Synthesis and characterization of new, molecular and macromolecular DDSQ-based compounds functionalized by substituted styrenes and distyrylarenes (also with heteroatoms) in a stereoselective manner is presented.

A new class of stereoregular vinylene-arylene copolymers with double-decker silsesquioxane in the main chain

A synthesis of a new macromolecular class of vinylene-arylene copolymers with double-decker silsesquioxane in the main chain is presented. Two transition-metal-catalyzed processes, which is silylative-coupling copolycondensation (SCC) and ADMET copolymerization of divinyl-substituted double-decker silsesquioxanes (DDSQ-2SiVi) with selected diolefins, are reported to be highly efficient tools for the formation of stereoregular copolymers containing DDSQ-silylene-vinylene-arylene units. The copolymeric products are studied in terms of their structural, thermal, and mechanical properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1044–1055

Synthesis and characterization of sustainable polyurethane based on epoxy soybean oil and modified by double-decker silsesquioxane

A series of environmentally friendly and sustainable polyurethanes using epoxy soybean oil as feedstock were synthesized with the introduction of double-decker silsesquioxane. Feature is that through the two-step polymerization, double-decker octaphenylsilsesquioxanetetraol was added to partially replace 1,4-butanediol acting as chain extender, and petroleum-based polyol was effectively replaced for polyurethane synthesis. On top of that, POSS tetraol was prepared and characterized by 1H NMR and MALDI-TOF MS. As for the organic–inorganic hybrid nanocomposites, their structures and properties were investigated by FTIR, DSC, TGA, SEM, tensile test techniques, and static contact angle. DSC analysis showed that covalent incorporation of POSS into the PU network would increase the glass transition temperature (T g) of the systems. TG analysis demonstrated that the hybrid nanocomposites were indeed more oxidative thermal stable, compared to virgin polyurethane especially at high temperature. SEM revealed that both nano- and micro-sized POSS aggregates were shown to be dispersed heterogeneously in the polyurethane matrix, despite the expectation to be dispersed or corporate into molecular chains by chemical bonding between OH and NCO. According to the tensile test results, POSS-containing nanocomposites exhibited an increased modulus with an increasing POSS concentration at low POSS content, and with high loading, these values would decline. The results of the static contact angles revealed that the hydrophobicity of the hybrid material was significantly improved with the inclusion of POSS.

Synthesis and characterization of bead-like poly(N-isopropylacrylamide) copolymers with double decker silsesquioxane in the main chains

A bead-like PNIPAAm copolymer with double-decker silsesquioxane (DDSQ) in the main chain was synthesized via a reversible addition–fragmentation chain transfer polymerization (RAFT) approach.

Preparation, characterization, and properties of poly(aryl ether sulfone) systems with double-decker silsesquioxane in the main chains by reactive blending

A series of copoly(aryl ether sulfone)s containing double-decker-shaped silsesquioxane (DDSQ) in the main chain was prepared. Toward this end, a novel diphenol polyhedral oligomeric silsesquioxane macromer was synthesized by hydrosilylation between 3,13-dihydro octaphenyl double-decker silsesquioxane (denoted dihydro DDSQ) and eugenol. The poly(aryl ether sulfone)s were synthesized from diphenol DDSQ, bisphenol A (BPA), and 4-fluorophenyl sulfone using a one-step high-temperature solution method. By adjusting the ratio of diphenol DDSQ to BPA, copolymers with variable DDSQ content in the main chains were obtained. With increased DDSQ content in the main chain, the glass transition temperature decreased based on differential scanning calorimetry, and anti-degradation was enhanced based on thermogravimetric analysis. Moreover, the dielectric constant κ of pure polymer (3.19 at 1 MHz) initially increased to 4.04 (DDSQ molar ratio = 10%), and then decreased to 2.68 at 1 MHz (DDSQ molar ratio = 100%). Crystallization behavior, solubility, and surface hydrophobicity were also investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 780–788

Organic-inorganic copolymers with double-decker silsesquioxane in the main chains by polymerization via click chemistry

A series of novel organic–inorganic copolymers with polyhedral oligomeric silsesquioxane (POSS) in the main chains were synthesized via the copper-catalyzed Huisgen 1,3-dipolar cycloaddition polymerization approach. Toward this end, we synthesized 3,13-azidopropyloctaphenyl double-decked silsesquioxane (DDSQ). This difunctional POSS macromer was used to copolymerize with α,ω-dialkynyl-terminated oligoethylenes with variable number of ethylene units. The organic–inorganic copolymers were obtained with the mass fraction of POSS up to 79%. Gel permeation chromatography showed that the high-molecular-weight copolymers were successfully obtained in all the cases. Differential scanning calorimetry showed that the amplitude of glass transitions for these copolymers was very feeble, suggesting that the segmental motions responsible for the glass transitions was highly restricted with DDSQ cages in the main chains. Thermogravimetric analysis showed that the organic–inorganic hybrid copolymers displayed extremely high thermal stability. Contact angle measurements showed that these organic–inorganic copolymers are highly hydrophobic and possessed very low surface energy. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4221–4232

Organic–inorganic polyurethanes with 3,13-dihydroxypropyloctaphenyl double-decker silsesquioxane chain extender

In this contribution, we reported the synthesis of organic–inorganic polyurethanes with polyhedral oligomeric silsesquioxane (POSS) in the main chains. Toward this end, 3,13-dihydroxypropyloctaphenyl double-decker silsesquioxane (DDSQ) was synthesized; this POSS diol was used as a chain extender to obtain hybrid polyurethanes with DDSQ in the main chains. By controlling the molar ratio of 3,13-dihydroxypropyloctaphenyl DDSQ to 1,4-butanediol (BDO), organic–inorganic polyurethanes were obtained with a content of DDSQ up to 48 wt%. The results of 1H nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC) showed that 3,13-dihydroxypropyloctaphenyl, DDSQ, can be successfully used as a chain extender to afford linear organic–inorganic polyurethanes. Differential scanning calorimetry (DSC) showed that the organic–inorganic polyurethanes displayed enhanced glass transition temperatures (Tg's) compared to control polyurethane; the Tg's increased with increasing content of DDSQ in the main chains. Compared to control polyurethane, the organic–inorganic polyurethanes displayed improved thermal stability in terms of thermogravimetric analysis (TGA). With the inclusion of DDSQ in the main chains, the organic–inorganic polyurethanes displayed enhanced surface hydrophobicity.

A Silica-Supported Double-Decker Silsesquioxane Provides a Second Skin for the Selective Generation of Bipodal Surface Organometallic Complexes

A well-defined silica-based material with a homogeneous nanolayer presenting identical pairs of vicinal silanols has been prepared by reaction of the surface organometallic species[ SiOZr(CH2CMe3)(3)], obtained on a silica dehydroxylated at 900 degrees C, with the double-decker-shaped silsesquioxane (OH)(2)DD(OH)(2). The surface structure has been established using extensive NMR characterization (H-1, C-13, Si-29, HETCOR, double-quantum, triple-quantum). Treatment with Zr(CH2CMe3)(4) leads to the first well-defined single-site bipodal grafted bis-neopentyl zirconium complex.

Organic-inorganic poly(hydroxyether of bisphenol A) copolymers with double-decker silsesquioxane in the main chains

In this communication, we reported the synthesis of organic-inorganic poly(hydroxyether of bisphenol A) (PH) copolymers with polyhedral oligomeric silsesquioxane (POSS) in the main chains via direct polymerization between diepoxy and bisphenol A. Toward this end, a novel diepoxy POSS macromer, i.e., 3,13-diglycidyloxypropyloctaphenyl double-decker silsesquioxane (denoted diglycidyloxypropyl DDSQ) was synthesized via the hydrosilylation between 3,13-dihydrooctaphenyl double-decker silsesquioxane (denoted dihydro DDSQ) and allyl glycidyl ether. Both diglycidyloxypropyl DDSQ and diglycidyl ether of bisphenol A (DGEBA) were used as the diepoxy monomers. By adjusting the ratio of diglycidyloxypropyl DDSQ to DGEBA, the PH copolymers with variable content of POSS in the main chains were obtained. It is found that with the direct polymerization the PH copolymers with POSS in the main chains of polymers can be successfully obtained while the content of diglycidyloxypropyl DDSQ was not very high. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the glass transition temperatures (Tg) of the organic-inorganic PH copolymers were quite dependent on the contents of POSS in the copolymers. Thermogravimetric analysis (TGA) indicates that the stability of the copolymers was significantly improved in terms of the temperatures at the maximum rate of degradation and the yields of degradation residues. Owing to the presence of POSS in the main chains, the surface hydrophobicity of the organic-inorganic copolymers was significantly improved compared to control PH.

Polysiloxanes with Periodically Distributed Isomeric Double-Decker Silsesquioxane in the Main Chain

[(2-Methylpropyl)hydroxysilyl]-bridged double-decker silsesquioxane was synthesized, and its stereoisomers were obtained by fractional precipitation followed by silica gel column chromatography, and their structures were confirmed by 1H and 29Si NMR and single crystal X-RD. The pure cis, trans and mix isomer were polymerized with silane-terminated octamethyltetrasiloxane via cross-dehydrocoupling polycondensation catalyzed by tris(pentafluorophenyl)borane to give completely alternating structure of the double decker silsesquioxane, and linear octamethyltetrasiloxane. All the polymers showed significantly increased glass transition temperature, compared with linear poly(dimethylsiloxane). Excellently transparent organo-soluble polymers gave self-supporting film by simple casting method.