B(C6F5)3在有机化学及高分子化学中的应用研究进展

B(C6F5)3与传统的Lewis酸相比,具有化学性质稳定、酸性强、使用方便等优点,被称为非传统的Lewis酸。B(C6F5)3的应用领域已经从最初的烯烃聚合共催化剂向有机化学及高分子化学的其它各个领域发展。B(C6F5)3催化的反应与传统Lewis酸催化的反应在反应机理及反应结果上均有很大的不同。本文主要综述B(C6F5)3近年来在有机化学及高分子化学中的应用研究成果。     

Silica－supported Polysiloxane with Selenacrown Ether Moieties and Its Platinum Complex

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MODIFICATION OF EPOXY RESIN WITH POLYSILOXANE BEARING PENDANT QUATERNARY AMMONIUM GROUPS

Polysiloxane bearing pendant quaternary ammonium groups (PSI) was used to modify the surface properties ofepoxy resins. In the cured resin, PSI formed the dispersed phase. Remarkable enrichment and gradient distribution ofpolysiloxane on the surface region of the epoxy resins were demonstrated by XPS analysis. The composition and propertiesof the surface of PSI-modified epoxy resin, which is in contact with the mold, are dependent on the material of the mold.Through the incorporation of PSI, epoxy resins with low surface energy and low friction coefficient were obtained.Polysiloxane with lower ionic group content shows a higher degree of enrichment on the resin surface and leads to a highercontact angle against water, while the polysiloxane having optimum compatibility with the epoxy resin shows a greater effectin reducing the static friction coefficient of the resin against glass.     

有机硅微乳液的研究进展

近年来大量研究表明,有机硅微乳液与有机硅乳液相比,具有许多优异的性能,如优异的热稳定性、渗透性等。本文主要阐述了有机硅微乳液的形成原理、制备方法及制备过程中的影响因素。在有机硅微乳液的形成原理里,详细介绍了增溶理论和界面张力理论;在有机硅微乳液的制备中,着重讨论了表面活性剂、助表面活性剂、催化剂等对有机硅微乳液形成的影响。     

NOVEL SULPHONATED POLYSILOXANE POLYUREA-URETHANE IONOMERS

A series of novel polysiloxane polyurea-urethane blockcopolymers based on methy-lene bis (p-phenylisocyanate (MDI), sodium-s-1, 2-dihydroxy propyl sulphonate (SDPS) andaminopropyl-terminated polydimethylsiloxane (ATPS) was synthesized with varying lengthof soft segments and neutralizing cation. The effect of the chemical composition and thecation on the morphology and mechanical properties of the samples were studied.It was found that the SDPS chain extender based samples have definite chemical struc-ture (-MDI-SDPS-MDI-ATPS-). As the length of the soft segment increases, an improve-ment of phase separation was observed. In addition, when SO_3Na was translated into SO_3Hor the sulphonic acid groups were neutralized with different charge cations (Na~+, Zn~(2+) andAl~(3+)), the morphology and mechanical properties changed greatly.     

Interactions of some polar compounds with methylsilicone liquid phases in gas chromatography

Summary The changes in the heat of solution of polar compounds and xylene isomers in methylsilicone fluid OV-101 deposited on Chromosorb W AW DMCS were studied. It was shown that the heat of solution increases with an increase of the percentage loading of the OV-101 up to 10%. Solution and adsorption thermodynamic characteristics of the studied system are briefly discussed.     

偶氮苯侧链共聚硅氧烷的合成及液晶行为的研究

以苯酚、十一烯酸、正溴己烷、对硝基苯酚和二氯亚砜为主要原料 ,通过取代、还原、重氮化和偶合等反应 ,合成了一种新的液晶单体 4 己氧基 4′ 十一烯 [1 0 ] 酰氧基偶氮苯 ,并与聚 (甲基氢硅氧烷 )通过硅氢加成生成一种新的高分子液晶 .通过1 H NMR和IR对单体和聚合物的结构进行了表征 ,并证实了聚合物的硅氢化程度近于完全 .通过DSC和热台偏光显微镜 (POM)对单体和聚合物的液晶行为进行了研究 ,证明了都具有液晶性     

Azo compounds for free radical crosslinking of polysiloxane stationary phases

There has been much effort spent in recent years developing the technology for free radical crosslinking of polysiloxane polymers to prepare capillary columns coated with thermally stable and nonextractable stationary phases. Organic peroxides have been used extensively as the free radical initiators for the in situ polymerization of the stationary phases. However, these peroxides adversely affect the phase polarity and column activity. Seven azo compounds were studied for crosslinking efficiency. Azo compounds can be used as free radical initiators to prepare nonextractable stationary phases without the adverse effects caused by peroxides.     

Mössbauer and NMR characterization of tin octoate: Neat and residues in RTV foams

We have investigated hydrolysis and oxidation effects on tin octoate and on tin-octoate residues in RTV polysiloxane foams by means of Nuclear Magnetic Resonance (NMR) and Mössbauer spectroscopy (MS). ¹¹⁹Sn NMR showed the presence of various tin species whereas ¹¹⁹Sn MS detected the presence of two oxidation states: Sn(II) and Sn(IV). The relative abundance of Sn(IV) increased as both the tin octoate and the foam aged. Foams were also solvent extracted and no selective extraction of one tin oxidation state was observed; both oxidation states were detected. ¹³C NMR indicated that octanoic acid is present in the tin octoate and in the foams as a residue. MS data showed that aging treatments of the foams and of the neat catalyst have a great effect on the tin oxidation state. The two spectroscopic methods complement each other in following the effects of hydrolysis and oxidation.     

A polymeric liquid crystal capillary column for GC-MS analysis of PCDD and PCDF

A newly developed side chain liquid crystal polysiloxane has been investigated as a stationary phase for the isomer-specific analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans substituted at positions 2, 3, 7, and 8. The retention times from the chromatograms of a standard solution containing all PCDD and PCDF isomers were compared with those from solutions containing only those tetra- to octa-chlorinated compounds substituted at positions 2, 3, 7, and 8. In general, PCDDs substituted at positions 2, 3, 7, and 8 eluted later than most other isomers of the same congener group. The separations obtained on this stationary phase were compared with those obtained elsewhere using a commercially available product.