SYNTHESIS AND-CHARACTERIZATION OF THE SOLUBLE, HIGH MOLECULAR WEIGHT AND LADDERLIKE POLYHYDROSILSESQUIOXANE AND ITS COPOLYMERS

The high molecular ladderlike polyhydrosilsesquioxane (LPHSQ) and its copolymer, ladderlike random copolymethylhydrosilsesquioxane (LR-PMHSQ) and ladderlike block copolymethylsilsesqui-oxane(LB-PMHSQ) have been synthesized by a preaminolysis reaction of the corresponding trichlorosilane with 1 ,4-phenylene diamine(PDA) then by hydrolysis and polycondensation reactions The thermographs of these polymers measured by DSC method indicate that these macromolecular backbones are very rigid as seen from the DSC curves which are almost horizontal from room temperature until 350 ~C without noticeable glass transition. The content of Si—H group in the polymers can be regulated by changing the composition of the two copolymerized monomers. So the ladderlike polymers including its copolymers can be the useful precursors for the functional polymers, especially such as fishbone-like liquid crystalline polymers.     

Synthesis and characterization of a novel soluble reactive ladder‐like polysilsesquioxane with side‐chain 2‐(4‐chloromethyl phenyl) ethyl groups

A new kind of soluble structure‐ordered ladder‐like polysilsesquioxane with reactive side‐chain 2‐(4‐chloromethyl phenyl) ethyl groups ( L ) was first synthesized by stepwise coupling polymerization. The monomer, 2‐(4‐chloromethyl phenyl) ethyltrichlorosilane ( M ), was synthesized successfully by hydrosilylation reaction with dicyclopentadienylplatinum(II) chloride (Cp₂PtCl₂) ­catalyst. Monomer and polymer structures were characterized by FT‐IR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vapor pressure osmometry (VPO) and X‐ray diffraction (XRD). This novel reactive ladder‐like polymer has promise potential applications as initiator for atom transfer radical polymerization, and as precursor for a variety of advanced functional polymers. Copyright © 2001 John Wiley & Sons, Ltd.     

SYNTHESIS AND CHARACTERIZATION OF A SOLUBLE LADDERLIKE POLYSILSESQUIOXANE CONTAINING REACTIVE ESTER GROUPS*

A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for thefirst time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. Themonomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoatewith trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp_2PtCl_2) catalyst. Combination of FTIR,~1H-NMr, ~(13)C-NMR, ~(29)Si-NMR, XRD, DSC, TGA and VPO methods was used to demonstrate that the polymer obtained hasan ordered ladderlike structure. The synthesized Ester-T may have promising applications as a precursor of advanced functional polymers.     

Preparation of Functionalized Polysilsesquioxane and Polysilsesquioxane‐Metal Nanoparticle Composite Spheres

Summary: Network polysilsesquioxane spheres made solely of poly(vinylsilsesquioxane) (PVSQ) and poly(3‐mercaptopropylsilsesquioxane) (PMPSQ) were prepared from heterogeneous mixtures of triethylamine (TEA), water, and either vinyltrimethoxysilane (VTMS), or 3‐mercaptopropyltrimethoxysilane (MPTMS). The microscopic, macroscopic observations, and the relationship between the diameters of spheres and the amount of each ingredient in the reaction system, showed that spheres formed via a mechanism similar to emulsion polymerization and suspension polymerization, depending on the reaction conditions. Diameters of spheres could be controlled from tens of nanometers to a few micrometers by adjusting the amounts of TEA, water, and a surfactant. Heating aqueous solutions of metal ions with these spheres produced polysilsesquioxanes (PSQ)‐metal nanoparticle composite spheres. The spheres prepared in this study were characterized by scanning electron microscopy, transmission electron microscopy, solid state NMR spectroscopy, IR spectroscopy, elemental analysis, and differential thermal analysis. These spheres would be useful in recovering metals from their ionic solutions and probes after chemical modifications.

An image of the spheres of poly(vinylsilsesquioxane)‐gold nanoparticle composite.     

超支化高分子桥联聚倍半硅氧烷复合物的NMR研究

以三羟甲基丙烷(TMP)为内核,二羟甲基丙酸(DMP)为支化单元用准一步法合成了重均分子量为12100的第四代端羟基脂肪族超支化聚酯(HBPE-G4),用3-异氰酸酯基丙基三乙氧基硅烷(TPIC)对它进行了端基改性,并以其为桥联剂,与聚倍半硅氧烷(PMSQ)复合制备出超支化高分子桥联聚倍半硅氧烷复合物．利用固体核磁共振(NMR),傅立叶红外(FI-IR),分子纳米粒度分析等方法表征了改性超支化高分子和复合物的结构和反应程度,并通过测量¹³C T₁,¹H T₂,¹H T_1ρ研究了体系中各组分的运动性能,以及超支化高分子与聚倍半硅氧烷之间的相容性．     

聚有机硅倍半氧烷的合成及其在涂层材料中的应用

聚有机硅倍半氧烷由于具有优异的力学、电学、光学性能,近年来被广泛应用作涂层材料以提高其热稳定性、耐腐蚀性、耐磨性、耐刮伤性、绝缘性等。介绍了聚有机硅倍半氧烷的合成方法及其在涂层材料中的应用。     

巯基功能化聚倍半硅氧烷微球对银离子的吸附性能

以甲基三甲氧基硅烷(MTMS)和巯丙基三甲氧基硅烷(MPTMS)为前驱体、氨水为催化剂,通过共聚合法制备了单分散性良好的巯基功能化聚倍半硅氧烷(PSQ-SH)微球。利用扫描电镜(SEM)和红外光谱(FT-IR)对PSQ-SH微球进行了表征,并系统地研究了其对银离子的吸附性能。结果表明:25℃下、银离子初始浓度为0.025mol/L时,PSQ-SH微球对银离子的最大吸附容量为750.21mg/g。PSQ-SH微球对银离子的吸附符合Langmuir等温吸附模型,吸附动力学更适合准二级动力学吸附模型。热力学参数表明该吸附过程为吸热反应,并且是自发进行的。     

Proton‐conductive polymer nanocomposite membranes prepared from telechelic fluorinated polymers containing perfluorosulfonic acid side chains

New classes of fluorinated polymer–polysilsesquioxane nanocomposites have been designed and synthesized. The synthesis method includes radical polymerization using the functional benzoyl peroxide initiator for the telechelic fluorinated polymers with perfluorosulfonic acids in the side chains and a subsequent in situ sol–gel condensation of the prepared triethoxylsilane‐terminated fluorinated polymers with oxide precursors. The telechelic polymer and nanocomposites have been carefully characterized by ¹H and ¹⁹F NMR, FTIR, TGA, and TEM. The ion‐exchange capacity (IEC), water uptake, the state of the absorbed water, and transport properties of the composite membranes have been extensively studied as a function of the content and structure of the fillers. Unlike the conventional Nafion/silica composites, the proton conductivity of the prepared membranes increases steadily with the addition of small amounts of the polysilsesquioxane fillers. In particular, the sulfopropylated polysilsesquioxane‐based nanocomposites display proton conductivities greater than Nafion. This is attributed to the presence of pendant sulfonic acids in the fillers, which increases IEC and offers continuous proton transport channels between the fillers and the polymer matrix. The methanol permeability of the prepared membranes has also been examined. Lower methanol permeability and higher electrochemical selectivity than those of Nafion have been demonstrated in the polysilsesquioxane‐based nanocomposites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

SYNTHESIS OF HIGH THERMOSTABLE SILICONE GELS CONSTRUCTED WITH LADDERLIKE POLYSILSESQUIOXANES*

Heat-resistant silicone gels were synthesized by replacing the single main chain polymethylhydrosiloxane withreactive ladderlike polyhydrosilsesquioxane copolymers. Because of the interaction between polydimethylsiloxane chainsand the ladderlike polysilsesquioxanes chains, the cyclization of the polydimethylsiloxane chains is hindered. The highthermal stability of the ladderlike polymers can improve the thermal stability of the silicone gels without sacrificing their good comprehensive properties.     

Synthesis,characterization, and thermal properties of ladderlike polyepoxysiloxanes

Starting from trichlorosilanes and using 1,4‐phenylenediamine as a template, we have synthesized some ladderlike poly(glycidyl‐co‐alkyl/aryl)siloxanes (polyepoxysiloxanes or polyepoxies for short). The structures of copolymers were confirmed through IR, ¹H NMR, elemental analyses, and gel permeation chromatography. Curing behaviors of these polyepoxies in the absence and presence of a curing agent have been studied with DSC. It was shown that these epoxies could be cured without any curing agent. Copolymers having aromatic groups showed higher curing reactivity than those having alkyl groups. The experimental results also demonstrate that the curing reaction occurred solely via epoxy functionality, not via the condensation reaction of the hydroxy groups located at the end of polymer main chains. The thermal stability of the cured polymers was examined by thermogravimetric analysis. The results confirm that polyepoxies with aromatic groups had better thermal stability than those with alkyl groups. It was also found that polyepoxies cured with a diamine have a higher thermal stability than those cured in the absence of a curing agent. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2215–2222, 2001