多面体低聚八氨基苯基硅倍半氧烷合成方法改进及其表征

以八硝基苯基硅倍半氧烷(ONPS)为原料, 5% Pd/C 和FeCl₃ 为催化剂, 水合肼为还原剂, 在四氢呋喃溶液中反应 1 h 合成了八氨基苯基硅倍半氧烷(OAPS). 相比文献中已有的其它合成方法, 该方法合成过程简单且稳定, 催化效率高、产率高、周期短. 通过FTIR, ¹H NMR, GPC 对产物进行了表征, 证明了硝基已完全转化. 通过催化剂的控制, 分离出ONPS 向OAPS 转化过程中的一种含有羟胺和二羟胺基团的中间体. 分析了OAPS 合成机理, 提出了ONPS 和水合肼的反应历程. 认为ONPS 中的硝基先经过2 电子转移转化为二羟胺化合物, 然后经过脱水加氢生成羟胺化合物, 最后再经过脱水加氢生成OAPS; 在有ONPS 存在的情况下, 水合肼主要转化为氮气和氢气, 待ONPS 完全转化为OAPS 后, 水合肼转化为氮气和氨气.     

Polyhedral oligomeric silsesquioxane as flame retardant for thermoplastic polyurethane

In this work, the reaction to fire of thermoplastic polyurethane (TPU) containing polyhedral oligomeric silsesquioxanes (or POSSs) was investigated by mass loss calorimetry. This composite exhibits a large reduction of peak of heat release rate (PHRR) compared to virgin TPU. The protection occurs via an intumescent mechanism. Mechanism of protection is examined in chemical and physical ways. Solid state NMR of carbon and silicon on heat-treated materials reveals that there is no significant chemical interaction between TPU and POSS. Nevertheless the intumescent char is characterized as ceramified char made of silicon network in a polyaromatic structure. The expansion occurs because of the partial volatilization of the organic part of POSS and because of the evolving degrading products of TPU. The formation of this intumescent structure makes an efficient insulating material at the surface of the substrate limiting heat and mass transfer and then decreasing heat release rate.     

Polyhedral oligomeric silsesquioxane (POSS) reinforced-unsaturated polyester hybrid nanocomposites: Thermal,thermomechanical and morphological properties

Unsaturated polyester (UP)-POSS hybrid nanocomposites have been developed successfully through the reaction between maleimide groups Octa (maleimido phenyl) silsesquioxane (OMPS) and olefinic reactive sites (maleimide and styrenic units) present in the unsaturated polyester resin system through free radical polymerization using benzoyl peroxide (BP) as the initiator. The hybrid molecular structure of nanocomposites resulted was evaluated by FT-IR spectroscopy. The data obtained from XRD, SEM and TEM analysis ascertain the presence of homogeneous morphology and nanoscale dispersion of OMPS into the polyester hybrid nanocomposites. Data resulted from thermal (DSC and TGA) and thermo-mechanical (DMA) studies indicated that the incorporation of octamaleimide functionalized POSS into unsaturated polyester systems appreciably improved the thermal properties of the hybrid nanocomposites according to their percentage concentration.     

多面体低聚八硝基苯基硅倍半氧烷纯度分析

使用高效液相色谱-电喷雾四级杆飞行时间质谱(HPLC-ESI-Q-TOF MS)联用技术对八硝基苯基硅倍半氧烷(ONPS)纯度进行分析, 从而判定ONPS产物峰及杂质峰的位置, 根据ONPS峰和杂质峰的面积比计算ONPS的纯度. 通过改变HPLC的洗脱梯度和测试时间, 将ONPS产物中的杂质峰完全分开, 测得硝基苯基硅倍半氧烷(NPS)质量分数为97.55%, 其中ONPS的纯度约为92.42%, 产物中含有九硝基八苯基硅倍半氧烷(9-NPS)约5.13%, 其它杂质含量约为2.45%. 通过对ONPS高效液相色谱图峰形和同分异构体极性情况分析, 进一步证明ONPS分子中硝基取代发生于对位和间位. 使用超高效液相色谱(UPLC)对ONPS进行分析, 以更高的分离效率验证了HPLC的结果. 该方法可作为ONPS纯度的分析方法.     

Preparation and properties of polyhedral oligomeric silsesquioxane polymers

Polyhedral oligomeric silsesquioxane (POSS) polymers were synthesized by the dehydrogenative condensation of (HSiO_3/2)₈ with water in the presence of diethylhydroxylamine followed by trimethylsilylation. Coating films were prepared by spin‐coating of the coating solution prepared by the dehydrogenative condensation of POSS. The hardness of the coating films was evaluated using a pencil‐hardness test and was found to increase up to 8H with increases in the curing temperature. Free‐standing film and silica gel powder were prepared by aging the coating solution at room temperature. The silica gel powder was subjected to heat treatment under air atmosphere to show a specific surface area of 440 m² g⁻¹ at 100 °C, which showed a maximum at 400 °C as 550 m² g⁻¹. Copyright © 2011 John Wiley & Sons, Ltd.     

Rheological behavior of polypropylene/octavinyl polyhedral oligomeric silsesquioxane composites

The reactive blending composites of isotactic polypropylene (PP)/octavinyl polyhedral oligomeric silsesquioxane (POSS) were prepared in the presence of dicumyl peroxide. Comparison of the rheological behavior of physical and reactive blending composites was made by oscillatory rheological measurements. It was found that the viscosity of physical blending composites drops at lower POSS content (0.5–1 wt %) and thereafter increases with increasing POSS content; that of reactive blending composites increases with increasing POSS content and displays a solid‐like rheological behavior at low frequency region when POSS content is higher than 1 wt %. The deviation of reactive blending composites from the scaling log G′–log G″ of linear polymer in Han plot, upturning at high viscosity in Cole–Cole plot, and from van Gurp–Palmen plot are related to the gelation behavior reactively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 526–533, 2008     

Synthesis of peptide dendrimers with polyhedral oligomeric silsesquioxane cores via click chemistry

Inorganic polyhedral oligomeric silsesquioxane (POSS) was used as the core for the synthesis of poly(Llysine) peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.     

Synthesis and characterization of poly（methyl methacrylate-co-polyhedral oligomeric silsesquioxane） hybrid nanocomposites

A novel poly(methyl methacrylate-co-polyhedral oligomeric silsesquioxane) hybrid nanocomposite was synthesized by free radical polymerization and characterized by ~1H NMR,~(29)Si NMR,and TGA technologies.Compared with PMMA homopolymer, the nanocomposite has better thermal stability.     

A novel poly-benzoxazinyl functionalized polyhedral oligomeric silsesquioxane and its nanocomposite with polybenzoxazine

The novel poly-benzoxazinyl functionalized polyhedral oligomeric silsesquioxane macromonomer (BZ-POSS), containing 7.6 benzoxazine groups per molecule on average was synthesized from octaaminophenylsilsesquioxane, p-cresol and paraformaldehyde. BZ-POSS was well miscible with bisphenol A-based benzoxazine (BBZ) melt. By ring-opening copolymerization of BBZ and BZ-POSS under condition similar to that used for polymerizing neat BBZ, the transparent and uniform BBZ/BZ-POSS organic-inorganic hybrid nanocomposites were prepared. The nano-scale dispersion of POSS cores in the nanocomposite was verified by powder X-ray diffraction and transmission electron microscopy studies. Dynamic mechanical analyses and thermal gravimetric analysis indicated that thermal stabilities, cross-link densities and the flame retardance of the nanocomposites were increased in comparison with neat PBBZ resin, although only small amounts of inorganic POSS cores were incorporated into the systems. Structural analyses of BZ-POSS and BBZ/BZ-POSS nanocomposites are discussed herein.     

Bridged polyhedral oligomeric silsesquioxane (POSS): A potential member of silsequioxanes

Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si₈O₁₂ cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ’corner-capping’ reaction.X-ray diffraction demonstrates that those two POSS have the similar T₈ structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.     

Liquid crystal alignment behaviours on poly(methyl methacrylate) having polyhedral oligomeric silsesquioxane groups

A series of poly(methyl methacrylate) derivatives containing polyhedral oligomeric silsesquioxane (POSS) groups (MCP#) were synthesised via free radical polymerisation (FRP) using methacryl isobutyl POSS (MA-POSS) and methyl methacrylate as monomers to investigate liquid crystal (LC) alignment property of these polymer films. The LC cells made from the films of the polymers having 100 mol% of MA-POSS units (MCP100) showed vertical LC alignment having a pretilt angle of about 90°. The vertical LC alignment behaviour on the MCP100 film was ascribed to the very hydrophobic MCP100 surface having the surface energy value smaller than about 23 mJ/m² generated by the nonpolar bulky POSS group. Good electro-optical characteristics, such as voltage holding ratio (VHR) and residual DC voltage (R-DC), were observed for the LC cells fabricated using MCP100 as a LC alignment layer.     

Synthesis of new polyhedral oligomeric silsesquioxane derivatives as some possible antimicrobial agents

1,3-Dipolar cycloaddition reactions were studied to synthesize Polyhedral oligomeric silsesquioxane (POSS)-based norbornyl imide derivatives containing izoxazoline groups in good yields. And also 1,3-dipolar cycloaddition reactions of azomethine ylides with POSS-based norbornene dipolarophiles for a synthesis of the novel POSS-based norbornane-fused spiro-1,3-indandionolylpyrrolidines are reported. All newly synthesized POSS compounds were structurally characterized by FTIR, ¹H, ¹³C NMR, HRMS and GC/MS analyses.     

Inorganic–organic nanocomposites of polybenzoxazine with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane

Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was used to prepare the polybenzoxazine (PBA‐a) nanocomposites containing polyhedral oligomeric silsesquioxane (POSS). The crosslinking reactions involved with the formation of the organic–inorganic networks can be divided into the two types: (1) the ring‐opening polymerization of benzoxazine and (2) the subsequent reaction between the in situ formed phenolic hydroxyls of PBA‐a and the epoxide groups of OpePOSS. The morphology of the nanocomposites was investigated by means of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Differential scanning calorimetry and dynamic mechanical analysis showed that the nanocomposites displayed higher glass‐transition temperatures than the control PBA‐a. In the glassy state, the nanocomposites containing less than 30 wt % POSS displayed an enhanced storage modulus, whereas the storage moduli of the nanocomposites containing more than 30 wt % POSS were lower than that of the control PBA‐a. The dynamic mechanical analysis results showed that all the nanocomposites exhibited enhanced storage moduli in the rubbery states, which was ascribed to the two major factors, that is, the nanoreinforcement effect of POSS cages and the additional crosslinking degree resulting from the intercomponent reactions between PBA‐a and OpePOSS. Thermogravimetric analysis indicated that the nanocomposites displayed improved thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1168–1181, 2006     

Modification of polyhedral oligomeric silsesquioxane derivatives with heck reaction as possible new bio-hybrid materials

Abstract

The regioselective synthesis of Polyhedral oligomeric silsesquioxane (POSS)-based norbornyl imide derivatives through palladium catalyzed Heck coupling reaction was reported on an effective synthetic method to organic–inorganic bio-hybrids serving as advanced materials. The reaction of POSS-based imide derivatives with various aryl iodides catalyzed by palladium acetate in the presence of triethyl amine, as the base, in DMF afforded the products in moderate yields. All new POSS derivatives were structurally characterized by FTIR, ¹H, ¹³C NMR, HRMS and GC/MS analyses.     

Regioselective formation of β‐(E)‐ and α‐alkenylsilane moiety attached to silsesquioxane core via Pt‐ and Ru‐based hydrosilylation

The first attempts to use ethynylsiloxysilsesquioxanes as reagents for hydrosilylation in the presence of Pt‐ and Ru‐based catalysts are reported. The results obtained strongly depend on the catalytic system used. The catalysts are proved to promote regioselective introduction of β‐(E)‐ and α‐fragments of the alkenylsilane group to the silsesquioxane core. The favourable features of these catalytic systems are their high selectivity and the requirement for relatively mild conditions. This methodology was also successfully applied to dihydro‐substituted organosilicon compounds to obtain a new class of silsesquioxane‐based compounds.     

Modified bentonite by polyhedral oligomeric silsesquioxane and quaternary ammonium salt and adsorption characteristics for dye

To remove methylene blue dye from water by adsorption, bentonites were modified by polyhedral oligomeric silsesquioxane (POSS) and three kind of quaternary ammonium surfactants (dodecyl trimethyl ammonium bromide, tetrabutyl ammonium bromide, cetyl trimethylammonium bromide) in aqueous solution. Systematic adsorption experiments were carried out, the adsorption mechanism was studied, and the factors governing the adsorption of methylene blue on modified bentonite were discussed. The adsorption capacity of methylene blue on all three modified bentonites in 1000 mg·L⁻¹ solutions quickly reached equilibrium within 2000 s, and the removal rate was basically 100%; however, the removal rate in raw bentonite samples was only 60%. The pseudo second-order kinetic model can provide satisfactory kinetic data fitting. The obtained adsorption isotherms fit well with the Dubinin-Radushkevich isotherm model. The thermodynamic results showed that the adsorption process was a spontaneous endothermic physical adsorption process. With increasing pH and KCl concentration, the removal of methylene blue increased significantly. The results of this study confirmed that the modified bentonite is a candidate material as a cationic dye adsorbent.     

Polymers and cyclic compounds based on a side‐opening type cage silsesquioxane

Polymers having polyhedral oligomeric silsesquioxane (POSS) in the main chains are an important class of organic–inorganic hybrid materials. Despite the increasing attention to the POSS polymers, variation of the monomers is still limited. Herein, we have proposed side‐opening POSS (SO‐POSS) monomers. Platinum‐catalyzed hydrosilylation polymerization proceeded to produce polysiloxanes having SO‐POSS in the main chains. The obtained polysiloxanes showed good solubility, high thermal stability, high transparency, and tunable reflective index. In addition, cyclic compounds were obtained during the investigation of the polymerization, and were synthesized with high selectivity under the slightly diluted conditions. The obtained cyclic compounds showed high thermal stability due to the silsesquioxane backbone, and the high dispersibility as a filler in poly(methyl methacrylate) was demonstrated. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2243–2250     

Solventless silicone hybrids based on polyhedral oligomeric silsesquioxane and hyperbranched polysiloxane for vacuum pressure impregnation process

A novel kind of solventless silicone hybrids (SSiH) containing branched poly(methylphenylvinylsiloxane) (PMPVSi), end‐capped hydrogen‐functionalized hyperbranched polysiloxane (EHFHPSi), and octavinyl‐polyhedral oligomeric silsesquioxane (OVPOS) was developed through a hydrosilylation reaction. Each of the three basic components was synthesized by harmless and recyclable methods. The new hybrids are considerably suitable for vacuum pressure impregnation process, and can serve as an excellent class C insulating material. The effect of differing stoichiometries of OVPOS and EHFHPSi on the performance of cured hybrids is discussed. Results show that SSiH hybrids possess excellent dielectric and thermal properties as well as low viscosity. The reduction in the dielectric constant and the improvement of thermal property of SSiH hybrids can be explained by the unique structure and morphology of hybrids resulting from the presence of OVPOS and EHFHPSi. The novel silicone hybrids exhibit great potential to be used for many cutting‐edge industries, especially the microelectronic and insulation fields. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,morphology, and viscoelastic properties of cyanate ester/polyhedral oligomeric silsesquioxane nanocomposites

Cyanate ester (PT‐15, Lonza Corp) composites containing the inorganic–organic hybrid polyhedral oligomeric silsesquioxane (POSS) octaaminophenyl(T₈)POSS [ 1 ; (C₆H₄NH₂)₈(SiO_1.5)₈] were synthesized. These PT‐15/POSS‐ 1 composites (99/1, 97/3, and 95/5 w/w) were characterized by X‐ray diffraction (XRD), transmission election microscopy (TEM), dynamic mechanical thermal analysis, solvent extraction, and Fourier transform infrared. The glass‐transition temperatures (T_g's) of the composite with 1 wt % 1 increased sharply versus the neat PT‐15, but 3 and 5 wt % 1 in these cyanate ester composites depressed T_g. All the PT‐15/POSS composites exhibited higher storage modulus (E′) values (temperature > T_g) than the parent resin, but these values decreased from 1 to 5 wt % POSS. The loss factor peak intensities decreased and their widths broadened upon the incorporation of POSS. XRD, TEM, and IR data were all consistent with the molecular dispersion of 1 due to the chemical bonding of the octaamino POSS‐ 1 macromer into the continuous cyanate ester network phase. The amino groups of 1 reacted with cyanate ester functions at lower temperatures than those at which cyanate ester curing by cyclotrimerization occurred. In contrast to 1 , 3‐cyanopropylheptacyclopentyl(T₈)POSS [ 2 ; (C₅H₉)₇(SiO_1.5)₈CH₂CH₂CH₂CN] had low solubility in PT‐15 and did not react with the resin below or at the cure temperature. Thus, phase‐separated aggregates of 2 were found in samples containing 1–10 wt % 2 . Nevertheless, the T_g and E′ values (temperature > 285 °C) of these composites increased regularly with an increase in 2 . © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3887–3898, 2005