silica XRD POSS.pdf

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1. Polyhedral oligomeric silsesquioxane/silica/polydimethylsiloxane rubber composites with enhanced mechanical andthermal properties

By Zhang, Dian; Huang, Guangsu; Shi, Yunhui; Zhang, Guangya; Liu, YufengFrom Journal of Applied Polymer Science (2015), 132(26), 42173/1-42173/8. Language: English, Database: CAPLUS,DOI:10.1002/app.42173

Composites of polydimethylsiloxane (PDMS) rubber modified by three kinds of polyhedral oligomeric silsesquioxanes(POSSs) as well as fumed silica were prepd. through soln. blending and then open two-roll mill blending with curingagent. Subsequently, the influences of POSS on mech. and thermal properties of the resulting composites wereinvestigated in detail. The addn. of POSS significantly enhanced the tensile strength and elongation at break of thecomposite but lowered the tensile modulus, which could be ascribed to the interruption of silica-silica and silica-PDMSinteractions. Octamethylsilsesquioxane (OMS)/silica/PDMS and octaphenylsilsesquioxane (OPS)/silica/PDMScomposites did not show desirable mech. and thermal properties. Nevertheless, heptaphenylvinylsilsesquioxane(VPS)/silica/PDMS composite with 5 wt % VPS exhibited enhanced glass transition temp. (Tg), mech. properties, andthermal stability. Further studies revealed that more VPS unfavorably affected properties of the composite. Scanningelectron microscope and X-ray diffraction demonstrated that owing to the grafting reaction, 5 wt % VPS in the rubbermatrix could form microcrystal domains the most effectively. Thus, the improved mech. properties and thermal stabilityjust resulted from the formation of microcrystal domains and the increase in stiffness of PDMS chains because of thegraft of VPS onto PDMS. 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42173.~0 Citings

2. Synthesis of Hybrid Nanocomposites Based on Polyhedral Oligomeric Silsesquioxane Using Atom Transfer RadicalPolymerization

By Ma, Xiang-Mei; Liu, Xue-Ying; Wang, Bin; Ma, Jia-Ju; Zhang, Ming-Xu; He, JieFrom Phosphorus, Sulfur and Silicon and the Related Elements (2015), 190(2), 200-207. Language: English,Database: CAPLUS, DOI:10.1080/10426507.2014.914934

A new org./inorg. hybrid polymer POSS/PMMA was prepd. by atom transfer radical polymn. (ATRP), in which Octa(-chloropropyl) polyhedral oligomeric silsesquioxane (POSSCl) was used as a crosslink agent to incorporate poly(Memethacrylate) (MMA). The structure and compn. of the composite was characterized using various techniques, includingFourier transform IR spectroscopy (FTIR), 1H NMR, X-ray diffraction (XRD) as well as gel permeation chromatog. (GPC).All the results indicated that POSS mol. was successfully incorporated into the PMMA matrix. The thermal stabilityproperty of the composite was investigated by thermal gravimetric anal. (TGA). The results showed that the compositedisplayed good thermal stability and higher temps. at max. wt. loss rate (Tmax) than that of the pure PMMA homopolymer,which may be attributed to the incorporation of rigid silica cube.~0 Citings

3. Polyimide membranes modified by polyhedral oligomeric silsesquioxaneBy Fan, Haibo; Yang, RongjieFrom Gaodeng Xuexiao Huaxue Xuebao (2014), 35(1), 180-185. Language: Chinese, Database: CAPLUS,DOI:10.7503/cjcu20130812

Four kinds of polyimide (PI)/Si membranes were prepd. using PI with octaphenylsilsesquioxane (OPS), octa(aminophenyl) silsesquioxane (OAPS), polyphenylsilsesquioxane (PPSQ) of ladder structure, and nano-silica (SiO2),resp. Their morphologies were studied by scan electron miscroscope (SEM) and the mech. properties were measuredby tensile testing and the thermal properties were studied by differential scanning calorimetry (DSC), thermogravimetricanal. (TGA) and limited oxygen index (LOI). The SEM and XRD results of the PI/Si composites proved that there weregood compatibility between PI and OAPS because the aminophenyl groups in OAPS could participate in the polymn.process of PI. The mech. properties of PI/OAPS membrane were nearly the same with that of PI. And the addn. of OPSor PPSQ decreased the PI mech. properties sharply. DSC anal. implied that the additives could increase the glass-transition temp. (Tg) a little and the Tg of PI/OAPS was the highest because the Si-O caged structures existed in the PImain chain. The addn. of OAPS, PPSQ or SiO2 would improve the thermal stability a little according to the TGA results.One interesting result is that the LOI of PI/Si membranes significantly increased compared with pure PI membrane. TheLOI for PI/OPS membrane was 57%, while that for PI was 46.5% only. The improvement was caused by the formation ofa well covered silicate char structures after burning. And the LOI of the membranes of PI with polyhedral oligomericsilsesquioxanes are higher than PL/SiO2.~0 Citings

SciFinderPOSS XRD Silica

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4. Electrical properties of epoxy/POSS composites with homogeneous nanostructureBy Huang, Xingyi; Li, Yong; Liu, Fei; Jiang, Pingkai; Iizuka, Tomonori; Tatsumi, Kohei; Tanaka, ToshikatsuFrom IEEE Transactions on Dielectrics and Electrical Insulation (2014), 21(4), 1516-1528. Language: English,Database: CAPLUS, DOI:10.1109/TDEI.2014.004314

The knowledge of the structure-property relationship at nanoscale level is important to develop advanced dielec. polymercomposites. Herein dielec. epoxy/polyhedral oligomeric silsesquioxanes (POSS) composites with homogeneousnanostructure were prepd. Unlike the conventional inorg. nanoparticles (e.g., silica) used for polymer nanocompositeprepn., the POSS mols. used in this work have three advantages: a comparable size with the segments of polymerchains, being capable of reacting with the base polymer, good soly. in many solvents. These three advantages make thePOSS be dispersed in polymers at a mol. level and thus their nano-effect could be fully utilized. Microstructure anal. bytransmission electron microscopy, at. force microscopy and X-ray diffraction confirmed the mol.-level dispersion of POSSin the epoxy composites. On this base, the partial discharge erosion resistance, frequency/temp. dependence of dielec.response, space charge distribution and breakdown strength of the epoxy/POSS composites were investigated.Moreover, the correlation between the nanostructure and properties of epoxy/POSS composites was documented.~2 Citings

5. Compatibility and thermostability between polyarylacetylene composites and polyhedral oligomeric silsesquioxanesBy Fan, Hai-bo; Liu, Yan-lin; Yang, Rong-jie; Li, Xiang-meiFrom Cailiao Gongcheng (2014), (3), 1-6. Language: Chinese, Database: CAPLUS, DOI:10.3969/j.issn.1001-4381.2014.03.001

Polyhedral oligomeric silsesquioxanes (POSS) including octaphenylsilsesquioxane (OPS), octa (aminophenyl)silsesquioxane (OAPS) and octa (propargylaminophenyl) silsesquioxane (OPAPS) were used to prep. composite resinswith pre-polyarylacetylene (PAA). The compatibility and thermal properties of the PAA/POSS composites were studiedthrough SEM, XRD, FT-IR, DSC and TGA. The morphologies of PAA/POSS composites and XRD results proved thatthere was good compatibility between PAA and OPAPS because the terminal alkynyl groups in OPAPS could react withPAA, while the compatibility between PAA and OPS was the worst due to the OPS could deposit in the bottom of thecomposites. The FT-IR anal. indicated the formation of a conjugated diene and arom. ring groups in the thermal curingprocesses of the resins. DSC anal. implied that the addn. of inorg. silica-like core to prePAA decreased the exothermicheat. And incorporation of OPAPS could enhance the curing temp. a little. TGA anal. indicated that addn. of OAPS orOPAPS would not reduce the excellent thermal stability so much and somewhat enhance the thermal-oxidative stability.~0 Citings

6. Study on structure of G-POSS modified mesoporous silicaBy Liu, Peng; Jiao, Jian; Cai, YuFrom Zhanjie (2013), 34(6), 30-33. Language: Chinese, Database: CAPLUS

Using the reaction of synthesized aminopropyl mesoporous silica (NH2-MPS) with glycidyl ether polyhedral oligomericsilsesquioxanes (G-POSS), the MPS was partially closed with G-POSS with larger size to prep. and modify the MPSnano particles with uniform size and controllable size and form the structure of POSS-MPS. The performance andstructure were characterized and detd. by FT-IR, X-ray diffraction, nitrogen adsorption-desorption and transmissionelectron microscopy (TEM), and the optimal synthesis process of POSS-MPS was detd.~0 Citings

7. Preparation and characterization of POSS-SiO2/cyanate ester composites with high performanceBy Zhang, Mengmeng; Yan, Hongxia; Liu, Chao; Zhang, JunpingFrom Polymer Composites (2014), Ahead of Print. Language: English, Database: CAPLUS, DOI:10.1002/pc.23091


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In this article, a hybrid filler based on polyhedral oligomeric silsesquioxane and silica, coded as POSS-SiO2, has beensuccessfully synthesized. The structure of POSS-SiO2 was studied by Fourier-transform IR spectra, X-ray diffraction,and SEM. Then the POSS-SiO2 was compounded with dicyclopentadiene bisphenol dicyanate ester (DCPDCE) resin toprep. composites. The effects of POSS-SiO2 on the curing reaction, mech., thermal, dielec. and tribol. properties ofDCPDCE resin were investigated systematically. Results of differential scanning calorimetry show that the addn. ofPOSS-SiO2 can facilitate the curing reaction of DCPDCE and decrease the curing temp. of DCPDCE. Compared withpure DCPDCE resin, the impact and flexural strengths of the composites materials are improved markedly with up to 72and 52% increasing magnitude, resp. Meanwhile, the POSS-SiO2/DCPDCE systems exhibit lower dielec. const. andloss than pure DCPDCE resin over the testing frequency from 10 to 60 MHz. In addn., the thermal stability and tribol.properties of POSS-SiO2/DCPDCE composites are also superior to that of pure DCPDCE resin. POLYM. COMPOS.,2014. 2014 Society of Plastics Engineers.~0 Citings

8. Synthesis of fully capped mesoporous silica and its hybrids with extremely low dielectric constant and lossBy Shan, Wei; Chen, Lei; Chu, Yang; Zhao, Feipeng; Liang, Guozheng; Gu, Aijuan; Yuan, LiFrom Microporous and Mesoporous Materials (2013), 176, 199-208. Language: English, Database: CAPLUS,DOI:10.1016/j.micromeso.2013.04.014

A novel fully capped mesoporous silica (FCMPS) was synthesized by producing a layer of linked polyhedral oligomericsilsesquioxanes (LPOSS) on the surface of a typical mesoporous silica (SBA-15). The structure of FCMPS wascharacterized using Fourier Transform IR (FTIR), NMR (29Si NMR), X-ray Diffraction (XRD), Scanning ElectronMicroscope (SEM), High Resoln. Transmission Electron Microscope (HRTEM), Nitrogen adsorption-desorption andthermogravimetric (TG) analyses. Compared with SBA-15, FCMPS has not only high surface area, pore vol. and size,but also remarkably improved thermal stability, the initial degrdn. temp. (Tdi) of FCMPS increases about 194 C. Inaddn., FCMPS overcomes the drawback of SBA-15, exhibiting much lower and stable dielec. const. and loss. Based onthe synthesis of FCMPS, the FCMPS/bismaleimide resin (BD) hybrids with different contents of FCMPS were prepd., andtheir dielec. properties were investigated. Results show that FCMPS/BD hybrids have much lower and stable dielec.const. and loss than SBA-15/BD hybrids owing to the special structure of FCMPS. With the addn. of 1 wt.% FCMPS intoBD resin, the dielec. const. of the resultant hybrid is as low as about 2.50 over the whole frequency from 10 to 106 Hz;moreover, the dielec. loss of the hybrid is almost independent on the frequency, and the dielec. loss at higherfrequencies (>103 Hz) is even lower than that of BD resin. These attractive features make FCMPS have obviousadvantage in developing materials with low dielec. const. and loss.~1 Citing

9. Crosslinked POSS network from an unusual hydrosilylation: low-T stabilization of -cristobalite phase in its amorphousregions

By Kolel-Veetil, Manoj K.; Keller, Teddy M.From Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2012), 53(2), 185-186.Language: English, Database: CAPLUS

The present study produced three significant results. Firstly, the preferential hydrosilylation at the terminal alkene groupsof an acetylene-contg., alkene-terminated silane linker by a siloxane-functionalized POSS cluster was obsd., contrary tothe conventionally accepted reactivity order. Secondly, the sym. crosslinked POSS network that was producedcontained thermally and thermo-oxidatively stable POSS units, due to the high degree of sym. functionalization resultingin the enhancement of the thermal integrity of the fluorite silica phase of the silica cores possibly due to the shielding ofthe silica core by the functionalities and a cancellation of thermal stresses on the silica core. Thirdly, the sym.crosslinked structure also contained tailored amorphous regions encompassing pairs of silicon atoms situated at optimaldistance for the formation of the y-cristobalite silica phase at approx. 500 oC below its known temp. range of formation.In light of a previous example 15 of such low temp. cristobalite formation from the amorphous contents in natural silicarocks, viz. silica gel and chalcedony, our study in part provides a direct evidence for a similar necessity of suchamorphous regions in a synthetic silica network to enable the lowering of the formation kinetics of particular metastablesilica phases.~0 Citings

10. Crosslinked POSS network from an unusual hydrosilylation: Low-T stabilization of -cristobalite phase in itsamorphous regions


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By Kolel-Veetil, Manoj K.; Keller, Teddy M.From Abstracts of Papers, 244th ACS National Meeting & Exposition, Philadelphia, PA, United States, August 19-23,2012 (2012), POLY-253. Language: English, Database: CAPLUS

A crosslinked network contg. polyhedral oligomeric silsesquioxane (POSS) cores was constructed by the unusualhydrosilylation of the terminal alkene groups of an internal acetylene-contg. silane linker by a POSS monomer. Productsfrom the thermal treatments of this network in either argon or air at 250, 550 and 1000C, resp., were characterized byFT-IR, Solid-state 13C and 29Si CPMAS NMR, XRD and XPS analyses. The highly sym.-functionalized POSS silicaclusters, in the fluorite silica phase, in the network were found to remain unchanged on thermal treatment possibly due tothe shielding of the silica core by the functionalities and a cancellation of thermal stresses on the silica core. Stabilizationof the metastable -cristobalite phase, which is typically formed upon cooling by a - to -transition of the -cristobalitephase formed above 1400C, was obsd. in the amorphous regions in the network sample treated only to 1000C in air.~0 Citings

11. Study on morphology and mechanical properties of PMMA-based nanocomposites containing POSS molecules orfunctionalized SiO2 particles

By Zhang, Chunling; Bai, Xuetao; Lian, Xiaoli; Dou, Yanli; Liu, HongFrom High Performance Polymers (2011), 23(6), 468-476. Language: English, Database: CAPLUS,DOI:10.1177/0954008311417023

Nanocomposites of octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) and functionalized SiO2 were investigatedin order to det. the effect of particles on the morphol. and mech. properties of PMMA. The outcome of the studysuggested that functionalized SiO2 and octavinylPOSS mol. had different morphol. As proved by X-ray diffraction andtransmission electron microscopy anal., the crystal structure of OVPOSS mol. was significantly different from amorphousaggregates of functionalized SiO2. With the addnl. particles in the nanocomposites, the sizes of octavinylPOSS andfunctionalized SiO2 began to reduce. This illustrated that the sepn. of aggregates led to the formation of irregular POSSmols. and amorphous SiO2 particles varied. Differential scanning calorimetry anal. indicated that PMMA-POSSnanocomposites had a homogeneous system. However, there was a significant phase sepn. at 3 wt.% SiO2. PMMA-SiO2 nanocomposites displayed lower reinforcing effects than expected, based on the mech. properties ofnanocomposites contg. OVPOSS mols.~3 Citings

12. Low-k Periodic Mesoporous Organosilica with Air Walls: POSS-PMOBy Seino, Makoto; Wang, Wendong; Lofgreen, Jennifer E.; Puzzo, Daniel P.; Manabe, Takao; Ozin, Geoffrey A.From Journal of the American Chemical Society (2011), 133(45), 18082-18085. Language: English, Database:CAPLUS, DOI:10.1021/ja2080136

Periodic mesoporous organosilica (PMO) with polyhedraloligomeric silsesquioxane (POSS) air pockets integrated intothe pore walls was prepd. by a template-directed, evapn.-induced self-assembly spin-coating procedure to create ahybrid POSS-PMO thin film. A 10-fold increase in the porosityof the POSS-PMO film compared to a ref. POSS film isachieved by incorporating 1.5 nm pores. The increasedporosity results in a decrease in the dielec. const., k, whichgoes from 2.03 in a ref. POSS film to 1.73 in the POSS-PMOfilm.

~25 Citings

13. Hydrogen Bond Assisted Assembly of Well-Ordered Polyhedral Oligomeric Silsesquioxane-Block CopolymerComposites

By Daga, Vikram K.; Anderson, Eric R.; Gido, Samuel P.; Watkins, James J.From Macromolecules (Washington, DC, United States) (2011), 44(17), 6793-6799. Language: English, Database:CAPLUS, DOI:10.1021/ma200926n


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Well-ordered block copolymer nanocomposites with d-spacingsas small as 15 nm and additive loadings greater than 70 mass% were formed upon blending functionalized polyhedraloligomeric silsesquioxanes (POSS) additives into disorderedblock copolymers contg. poly(ethylene oxide) (PEO) as one ofthe blocks. The POSS additives were functionalized withmaleamic acid or aminophenyl groups as ligands to enableselective hydrogen bonding with the PEO chains. Theselective interaction of the additives with the PEO chainscaused microphase sepn. of the block copolymer leading toformation of well-ordered morphologies as evidenced by small-angle X-ray scattering. Further addn. of the additive inducedtransitions between cylindrical and spherical morphologies.While both ligands induced order, the maleamic acid ligandenabled higher levels of incorporation of POSS cages into thePEO phases of the composite. Differential scanningcalorimetry and wide-angle X-ray diffraction were performed toconfirm compatibility and good mixing of the additives withinthe PEO phase. The maleamic ligands can be cross-linked bya thermal treatment. The crosslinking was used to stabilize thestructure of the composites prior to calcination at high temps.,which resulted in the formation of mesoporous silica.Transmission electron microscopy showed that the cylindricaland spherical morphologies of the parent composites weremaintained in the mesoporous silica.

~21 Citings

14. The effect of hybrid nanoparticle additives on epoxy-nanocomposite behavior and morphologyBy Jahren, Susannah; Maennle, Ferdinand; Graff, Joachim Moe; Olafsen, KjellFrom Journal of Applied Polymer Science (2011), 120(6), 3212-3216. Language: English, Database: CAPLUS,DOI:10.1002/app.33259

Amine modified polyhedral oligomeric silsesquioxane (POSS-NH2) was used to modify sodium montmorillonite (MMT)nanoclays for improved dispersion in epoxy resin. The dispersion of the clay particles was inspected using SEM, energydispersive spectroscopy (EDS) and X-Ray diffraction and the thermal properties compared using differential scanningcalorimetry (DSC) and thermogravimetric anal. The introduction of the amine-POSS was found to have a pos. effect onthe dispersion of the MMT clays and prevented agglomeration. The absence of clay agglomerates lead to an increase inglass transition temp. (Tg) from 44C in the samples with the untreated clay up to 54C in the samples with 10% addnl.POSS-NH2. The addn. of POSS-NH2 initial increase of the wt. loss (Td5%) but slowed down the rate of degrdn. due tothe formation of an inert silica layer and eventually leading to an increased char yield. 2011 Wiley Periodicals, Inc. JAppl Polym Sci, 2011.~3 Citings

15. Ultrasonochemical-assisted fabrication and evaporation- induced self-assembly (EISA) of POSS-SiO2@Ag core/ABAtriblock copolymer nanocomposite film

By Veerapandian, Murugan; Yun, KyusikFrom Polymer Composites (2010), 31(9), 1620-1627. Language: English, Database: CAPLUS, DOI:10.1002/pc.20951


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Poly(ethylene glycol)-octafunctionalized polyhedral oligomeric silsesquioxane (POSS) (Mn = 5576.6 g/mol) alloying agentstabilized amphiphilic silica@silver metalloid nanocomposite blended with a triblock copolymer poly(p-dioxanone-co-caprolactone)-block-poly(ethylene oxide)-block-poly(p-dioxanone-co-caprolactone) (POSS-SiO2@Ag/PPDO-co-PCL-b-PEG-b-PPDO-co-PCL) has been synthesized in both water and in org. medium utilizing ultrasonochem. reaction. ThePOSS stabilized pre-made metalloid was successfully dispersed in amphiphilic PPDO-co-PCL-b-PEG-b-PPDO-co-PCL(ABA) triblock copolymer matrix of mol. wt. 45.9 104 g/mol. The mechanism of synthesis of high concn. of SiO2@Agnanocomposite from TEOS/AgNO3 (in the presence of NH4OH as catalyst/NaBH4 as reductant) nonmetal/metalprecursors and the successful EISA of POSS-SiO2@Ag/ABA nanocomposite into films has been discussed. Thesuccessful synthesis of metalloid nanocomposite was morphol. accessed by field emission-SEM, transmission electronmicroscopy and at. force microscopy. Surface plasmon resonance was ensured from UV-visible spectral anal. Identityand the crystallinity of as prepd. nanocomposite were studied by X-ray diffractometer. Structural and luminescenceproperties of the nanocomposite were examd. by Fourier transform IR spectroscopy and photoluminescence.Thermogravimetric anal. was carried out to study the thermal stability of the resulting hybrid nanocomposite. Theresultant inorg.-org. nanocomposite can be easily suspended in water and would be useful in variety of applications.POLYM. COMPOS., 31:1620-1627, 2010. 2009 Society of Plastics Engineers.~6 Citings

16. Octa(aminophenyl)silsesquioxane fabrication on chlorofunctionalized mesoporous SBA-15 for CO2 adsorptionBy Bhagiyalakshmi, Margandan; Anuradha, Ramani; Park, Sang Do; Jang, Hyun TaeFrom Microporous and Mesoporous Materials (2010), 131(1-3), 265-273. Language: English, Database: CAPLUS,DOI:10.1016/j.micromeso.2010.01.001

Chlorofunctionalized mesoporous SBA-15 was synthesized by a direct method, through 1-step condensation of Nasilicate soln. obtained from rice husk ash (RHA) and chloropropyltrimethoxysilane in presence of Pluronic 123 (surfacedirecting agent). Octa(3-aminophenyl)octasilsesquioxane (OAPS) was grafted on chlorofunctionalized mesoporous SiO2SBA-15 and characterized by XRD, FTIR, BET and 29Si MAS NMR. CO2 adsorption/desorption profiles of OAPS graftedchlorofunctionalized SBA-15 (Cl-SBA-15/ OAPS) at 25, 50 and 75 were obtained by TGA under atm. pressure. A max.of 8 wt. % CO2 adsorption capacity (80 mg/g of adsorbent) was achieved over Cl-SBA-15/50% OAPS and also theabsorbent was recyclable, selective and thermally stable. Neat OAPS adsorbs almost no CO2 due to internally H-bonded amine. Cl-SBA-15/OAPS withstands high temp. (180) significantly higher than the sorbent polyethyleneimine(PEI), which decomps. beyond 115. Therefore, the use of rice husk ash (RHA) as SiO2 source and high thermal stabilityof Cl-SBA-15/OAPS are advantageous for CO2 adsorption. Thus, grafting of octa(3-aminophenyl)silsesquioxanes onmesoporous SBA-15 broadens the applications of polyhedral oligomeric silsesquioxanes (POSS) compds. and verified tobe a new candidate for CO2 capture.~15 Citings

17. Bifunctionalized Hybrid Silica Spheres by Hydrolytic Cocondensation of 3-Aminopropyltriethoxysilane andVinyltriethoxysilane

By Nair, Bindu Prasannakumaran; Pavithran, ChorappanFrom Langmuir (2010), 26(2), 730-735. Language: English, Database: CAPLUS, DOI:10.1021/la902432r

Facile, surfactant free synthetic strategy for bifunctionalized hybrid silica spheres (HS) with structural ordering ispresented. HS was prepd. by casting and drying of stable siloxane soln. from hydrolytic co-condensation of 3-aminopropyltriethoxysilane (AS) and vinyltriethoxysilane (VS) with AS:VS mole ratio of 1:3 in ethanol/water mixt.Spheres of size in the range of 250 nm to 2.5 m were produced by adjusting the concn. of reacted siloxane soln. usingethanol. Characterization by FTIR, XRD, TGA, and DSC revealed that the HS was formed from copptn. of fullycondensed polyhedral oligomeric silsesquioxane (POSS) bilayer and incompletely condensed siloxanes (SIL) producedduring drying. Formation of POSS bilayer was confirmed by intercalating and stabilizing POSS within a smectite clay andcharacterizing the modified clay. XRD, FTIR, SEM, and HRTEM of HS heated to 170 C revealed transformation fromdisordered into ordered lamellar structure of POSS bilayer assembly and siloxane network due to rearrangement anddensification of low melting SIL.~20 Citings

18. Preparation and characterization of cellulose hybrids grafted with the polyhedral oligomeric silsesquioxanes (POSS)By Xie, Kongliang; Zhang, Yanli; Yu, YanhongFrom Carbohydrate Polymers (2009), 77(4), 858-862. Language: English, Database: CAPLUS,DOI:10.1016/j.carbpol.2009.03.010


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The cellulose hybrids with polyhedral oligomeric silsesquioxane (POSS) are synthesized by crosslinking graft reaction.Dimethylol dihydroxy ethylene urea (DDEU) as crosslinking agent is used in the graft reaction. The chem. and surfacemorphol. structures of the am-POSS grafted cellulose hybrids are characterized with micro-FT-IR spectra, silicon elementanal., X-ray diffraction, SEM, AFM, and DSC. The results show that the am-POSS grafted cellulose hybrids form newmacromol. structures contg. POSS nano-silica particles. POSS particles are evenly dispersed at the nanometer scale inthe cellulose host matrix, bonding to the cellulose through covalent bonds. The thermal properties of the am-POSSgrafted cellulose hybrids are improved.~28 Citings

19. Self-assembled fernlike microstructures of polyhedral oligomeric silsesquioxane/gold nanoparticle hybridsBy Lu, Chu-Hua; Kuo, Shiao-Wei; Huang, Chih-Feng; Chang, Feng-ChihFrom Journal of Physical Chemistry C (2009), 113(9), 3517-3524. Language: English, Database: CAPLUS,DOI:10.1021/jp808635j

A thiol-functionalized polyhedral oligomeric silsesquioxane was used as a protective group for the prepn. of protectedgold nanoparticles. The org./inorg. hybrid nanoparticles exhibited a platelike morphol. arising from steric hindrancebetween the iso-Bu groups of the silsesquioxane. An XRD study of the org. crystal revealed the relatively large interstice(1.64 nm lattice parameter a > 1.3 nm diam.) on the basal plane of the unit cell, which resulted in a platelike morphol.having lateral dimensions on the order of a few micrometers and thicknesses of a few hundred nanometers. In addn. tobehaving as a stabilizer for the prepn. of Au nanoparticles, an excess of silsesquioxane colloid led to the formation of acryst. template that incorporated the hybrid nanoparticles on its surface which provided a unique fernlike microstructure.After removal of the template (through sublimation and decompn. to a silica char) at 350 in air for 1 h, nanosized Auislands having diams. of 50-100 nm and thicknesses of 2-20 nm were sintered onto the substrate. As a result, thesilsesquioxane is an excellent protective group for the prepn. of Au nanoparticles of high stability.~21 Citings

20. Preparation of ordered mesoporous silica from polyhedral oligomeric silsesquioxaneBy Zhao, Chun-Bao; Yang, Xu-Jie; Wang, Xin; Lu, Lu-DeFrom Wuji Huaxue Xuebao (2007), 23(3), 545-549. Language: Chinese, Database: CAPLUS

Octa(tetramethylammonium)-polyhedral oligomeric silsesquioxane(TMA-POSS) with cage-like structure was synthesized,the structure was characterized by NMR, FTIR and Elemental analyses. The mesoporous silica was prepd. under alk.condition using TMA-POSS as the silicon source and hexadecyltrimethylammonium bromide (CTAB) as the template, thestructures of these products were characterized by XRD, TEM and nitrogen adsorption and desorption methods. Theresults indicate that the synthesized silica exhibites a well-ordered hexagonal pore structure with larger sp. surface area.With increasing of CTAB molar ratio, the spacing of the crystal plane d100 is increased. The effects of the pH values onthe mesoporous structure in the reaction system with different molar ratio of nPOSS/nCTAB were investigated. Thesynthesis mechanism of mesoporous silica was also discussed.~0 Citings

21. Alkoxysilyl derivatives of polyhedral oligosilsesquioxanes containing amino and hydroxyl groups and sol-gel hybridmaterials on their basis

By Tereshchenko, T. A.; Shevchuk, A. V.; Shevchenko, V. V.; Snegir, S. V.; Pokrovskii, V. A.From Vysokomolekulyarnye Soedineniya, Seriya A i Seriya B (2006), 48(12), 2111-2121. Language: Russian,Database: CAPLUS

A mixt. of polyhedral oligosilsesquioxanes (OS) with narrow mol.-wt. distributions described by the empirical formula[(HOCH2CH(OH)CH2)2N(CH2)3SiO1.5]n were prepd. by the hydrolytic condensation of the reaction product of glycidol and3-aminopropyltriethoxysilane. OS were reacted with 3-isocyanatopropyltriethoxysilane to give urethane-contg. alkoxysilylderivs. with various substitution degrees. Modified SO-based organo-inorg. hybrids were prepd. by the sol-gel method.The structure and properties of the products were studied by matrix laser desorption/ionization mass spectrometry, GPC,X-ray diffraction, DSC, and thermogravimetry. Properties of the hybrids can be controlled by varying the ratio of hydroxyland alkoxysilyl groups in OS derivs. and by the incorporation of low-mol.-wt. sol-gel precursors.~1 Citing


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Copyright 2015 U.S. National Library of Medicine.

22. Bifunctionalized hybrid silica spheres by hydrolytic cocondensation of 3-aminopropyltriethoxysilane andvinyltriethoxysilane

By Nair Bindu Prasannakumaran; Pavithran ChorappanFrom Langmuir : the ACS journal of surfaces and colloids (2010), 26(2), 730-5, Language: English, Database:MEDLINE

Facile, surfactant free synthetic strategy for bifunctionalized hybrid silica spheres (HS) with structural ordering ispresented. HS was prepared by casting and drying of stable siloxane solution from hydrolytic co-condensation of 3-aminopropyltriethoxysilane (AS) and vinyltriethoxysilane (VS) with AS:VS mole ratio of 1:3 in ethanol/water mixture.Spheres of size in the range of 250 nm to 2.5 microm were produced by adjusting the concentration of reacted siloxanesolution using ethanol. Characterization by FTIR, XRD, TGA, and DSC revealed that the HS was formed fromcoprecipitation of fully condensed polyhedral oligomeric silsesquioxane (POSS) bilayer and incompletely condensedsiloxanes (SIL) produced during drying. Formation of POSS bilayer was confirmed by intercalating and stabilizingPOSS within a smectite clay and characterizing the modified clay. XRD, FTIR, SEM, and HRTEM of HS heated to 170degrees C revealed transformation from disordered into ordered lamellar structure of POSS bilayer assembly andsiloxane network due to rearrangement and densification of low melting SIL.

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