含双键聚硅烷的电化学合成

采用电化学合成法,以三氯甲基硅烷和烯丙基氯为单体合成出含有双键的聚硅烷,通过FT-IR,GPC,1H-NMR表征了其结构。研究了单体配比、单体浓度、电极材料、反应电量、换向时间和电解质浓度对含双键聚硅烷电化学合成的影响。结果表明,三氯甲基硅烷与氯丙烯的比率为3/1,电极为镁电极时,重均分子量和双键保留率达到了最高值,分别为3749和12.6%。增加反应电量、缩短换向时间和降低单体浓度都可以提高产物的分子量和产率。     

电化学合成聚硅烷的反应速率

采用电化学法,合成出含双键聚硅烷与不含双键聚硅烷,通过FT-IR,UV,1H NMR表征其结构.分别研究了电化学反应体系和直接化学反应体系中Si-Cl键含量的变化,以及加入引发剂蒽对反应速率的影响.结果表明:含双键聚硅烷的合成反应速率快于不含双键的聚硅烷,相同反应电量下含双键聚硅烷反应体系中的Si-Cl键含量比不含双键聚硅烷少10%～15%;在电化学合成聚硅烷的过程中,单体与镁发生的格氏反应在整个反应中占有相当的比例;引发剂蒽的加入能够有效地提高不含双键聚硅烷的反应速率.本文还对电化学合成聚硅烷的反应机理进行了推测.     

聚烯丙基环戊二烯基硅烷的电化学合成与表征

采用电化学合成法,以三氯甲基硅烷、氯丙烯和环戊二烯为单体合成出聚烯丙基环戊二烯基硅烷.通过红外光谱(FT-IR),紫外光谱(UV),核磁共振(1H-NMR)和热重法(TG)等表征了其结构,测定了产物的双键保留率,并对产物进行交联固化.结果表明,产物的双键保留率为11.2%,烯丙基和环戊二烯基的引入使其最大吸收波长发生了...     

SiC纤维先驱体—聚碳硅烷的催化合成

研究了在硼酸丁酯存在下由低分子聚硅烷（ＬＰＳ）合成聚碳硅烷（ＰＣ）的反应。结果表明，硼酸丁酯具有催化聚合的作用，可在较低温度下合成较高分子量的产物。研究了合成条件对产物特性的影响，并对催化作用原理进行了分析与讨论。     

道康宁公司聚硅烷研究新进展

聚硅烷经高温处理可转化成SiC陶瓷,而SiC陶瓷材料是具有极大应用前景的新材料。因此,研制收率高、性质优良的聚硅烷聚合物成了有机硅工业中的一个热点。道康宁公司在八十年代初开始研制用于制作SiC陶瓷的聚硅烷。最近,该公司在聚硅烷的研制和改性方面取得了几项新成果。 1.含金属陶瓷聚硅烷的研制将聚硅烷和具有空轨道、能形成配位体的金属化合物接触可形成含金属聚硅烷。在一项具体实验中,用7.0克苯基甲基聚硅烷     

单体固化特性对光热敏微胶囊显影密度的影响

利用界面聚合技术制备了以不同单体为囊芯的新型感光材料光热敏微胶囊.借助于傅里叶红外光谱及原子力显微技术对不同单体的双键交联固化及固化产物的表面形貌进行了分析,利用热显影打印技术检测了光热敏微胶囊显影密度随曝光时间的变化.实验结果表明,不同单体的双键交联固化速度主要与单体官能度有关,并且单体固化产物的表面形貌与单体的双键...     

枝状/树枝状聚硅烷的合成研究进展

综述了采用Wurtz偶合法和电化学法合成枝状聚硅烷的研究进展,并对树枝状聚硅烷的合成方法和结构特征进行简要概述,展望了其应用前景。     

聚硅烷导电性能及氧化掺杂

介绍了聚硅烷导电材料的国内外研究进展 ,侧重阐述了聚硅烷的中性半导体行为及其独特的σ电子的离域性 ;并简单介绍了提高聚硅烷导电性能的不同掺杂手段 ,着重叙述了聚硅烷氧化掺杂导电的机理及影响其掺杂功效的几个重要因素 ,同时对该领域今后的发展方向作出展望     

超支化聚硅烷的合成及应用进展

超支化聚硅烷兼具超支化聚合物的高流动性以及有机硅聚合物的高耐热性等优良性能。在介绍超支化聚硅烷特点的基础上,重点综述了超支化聚硅烷的制备方法,包括硅氢加成聚合法、亲核取代法、水解缩合法、伍兹偶联法等,并总结了超支化聚硅烷在各个领域的应用,指出了其今后的研究方向及发展前景。     

聚硅烷改性含硅芳炔树脂的耐热性能研究

含硅芳炔树脂具有优异的耐高温性能,在高温下可形成C/SiC有机无机杂化材料,用聚硅烷对含硅芳炔树脂进行改性以提高其含硅量。采用示差扫描量热(DSC)、红外光谱(FT-IR)分析了改性含硅芳炔树脂的固化行为,采用TGA考察了改性含硅芳炔树脂固化产物及其烧结物的热稳定性能,并用XRD对烧结物进行了分析。研究表明,改性后的含硅芳炔树脂黏度降低、硅含量提高;固化物和烧结物在1200℃下空气中的残留率均提高了40%以上;固化物经1450℃烧结后形成了β-SiC,含聚硅烷30%的改性树脂烧结物中SiC含量达到41%。     

Synthesis and characterization of silver nanoparticle composite with poly(p-Br-phenylsilane)

The one-pot synthesis and characterization of silver nanoparticle-poly(p-Br-phenylsilane) composites have been carried out. The conversion of silver(+1) salt to stable silver(0) nanoparticles is promoted by poly(p-Br-phenylsilane), Br-PPS possessing both possible reactive Si-H bonds in the polymer backbone and C-Br bonds in the substituents. The composites were characterized using XRD, TEM, FE-SEM, and solid-state UV-vis analytical techniques. TEM and FE-SEM data show the formation of the composites where large number of silver nanoparticles (less than 30 nm of size) are well dispersed throughout the Br-PPS matrix. XRD patterns are consistent with that for fcc-typed silver. The elemental analysis for Br atom and the polymer solubility confirm that the cleavage of C-Br bond and the Si-Br dative bonding were not occurred appreciably at ambient temperature. Nonetheless, TGA data suggest that some sort of cross-linking was occurred at high temperature. The size and processability of such nanoparticles depend on the ratio of metal to Br-PPS. In the absence of Br-PPS, most of the silver particles undergo macroscopic aggregation, which indicates that the polysilane is necessary for stabilizing the silver nanoparticles.     

Formation process of mixed silicon and titanium carbide from copyrolysis of polysilane and metallic titanium: Part II

In part I we reported a copyrolysis of polysilane with metallic tungsten [1]. Now copyrolysis of chlorine containing polysilane with metallic titanium addition in the range of 0–10 at % Ti was performed. A significant decrease of the mass loss during the polysilane pyrolysis was observed. Also the specific surface area, gas evolution and occuring phase formation changes. The titanium forms preferently carbides and temporary silicides depending on the applied pyrolysis temperature. The reactions are controlled by transport phenomena of carbon and titanium. In the end of the process silicon carbide (SiC) and titanium carbide (TiC_x) are stable.     

Synthesis and investigation of the properties of a star-shaped polysilane

The intermediate monomer of a star-shaped polymer's cyclosiloxane core, was prepared from CH₃HSiCl₂ and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane(D₄^vi) through the basic method of hydrosilylation reaction. Then, a star-shaped polysilane [poly(core-methylphenyl-diphenyl)silane] was synthesized by the classical Wurtz coupling reaction. Futhermore, UV absorption, fluorescent spectrum, UV-resistant stability and thermal properties of the star-shaped polysilane were investigated. Results reveal that star-shaped polysilane possesses good UV-resistant stability, favourable thermo-oxidative stability and strong fluorescence emitting near 400 nm.     

Weak anchoring of nematic liquid crystals on photo-induced surface relief gratings of organic polysilane

Surface relief gratings on organic polysilane thin films are fabricated by holographic exposure of ultra-violet light, and Au gratings are subsequently prepared on polysilane gratings by vapor deposition of Au. The anchoring energies of 4-pentyl-4′-cyanobiphenyl (5CB) nematic liquid crystal on the fabricated gratings are determined with a saturation voltage method. The anchoring energies of Au gratings are weaker than those of organic polysilane gratings because of suppression of π–π interaction between the liquid crystal and the alignment layer. The polar anchoring energies of Au gratings are also weaker than those reported in literature.     

聚硅烷—高分辨的光致抗蚀剂

概述了光致抗蚀剂在微电子工业中的作用,着重介绍了聚硅烷光致抗蚀剂的特点,以及聚硅烷紫外、深紫外、X射线、电子未等抗蚀剂的发展状况     

Determination of phospholipid regiochemistry by Ag(I) adduction and tandem mass spectrometry

Collision-activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) of Ag-adducted phospholipids were investigated as structural tools. Previously, determination of the acyl chains at the two phospholipid esterification sites has been performed based on the R(1)COO(-)/R(2)COO(-) ratio in negative ion mode CAD tandem mass spectrometry. However, the observed product ion ratio is dependent on the extent of unsaturation of the fatty acyl group at sn-2 as well as on the total chain length. Similarly, in positive ion mode CAD with/without alkaline or alkaline earth metal adduction, the ratio of product ions resulting from either R(1)COOH or R(2)COOH neutral losses is dependent on the nature of the phospholipid polar headgroup. Ag(+) ion chromatography, in which silver ions are part of the stationary phase, can provide information on double bond number/distribution as well as double bond configuration (cis/trans) because of interaction between Ag(+) ions and olefinic π electrons of fatty acids and lipids. We hypothesized that interactions between double bonds and Ag(+) may be utilized to also reveal phospholipid esterification site information in tandem mass spectrometry. CAD and IRMPD of Ag-adducted phospholipids with unsaturated fatty acids (R(x)COOH, x = 1 or 2) provided characteristic product ions, [R(x)COOH + Ag](+), and their neutral losses. The characteristic product ions and their abundances do not depend on the type of polar headgroup or the number of double bonds of unsaturated acyl chains. Tandem mass spectrometry of Cu-adducted phospholipids was also performed for comparison based on the Lewis acid and base properties of Cu(+) and phospholipid double bonds, respectively.     

Formation process of mixed silicon and tungsten carbide from copyrolysis of polysilane and metallic tungsten: Part I

Copyrolysis of polysilane with metallic tungsten addition in the range of 0–12 at % W was performed. A significant decrease of the mass loss during the polysilane pyrolysis was observed. Also the specific surface area, gas evolution and occuring phase formation changed. The tungsten forms silicides and carbides depending on the applied pyrolysis temperature. The reactions are controlled by transport phenomena of carbon and tungsten. In the end of the process the silicon carbide (SiC) and tungsten carbide (WC) are stable. The obtained powders are sintered to porous ceramics with a significant pore gradient and a variation of the hardness in a micrometer range.