Organosilicon Polymers Research Articles

Study on organosilicon positive resist. I. Syntheses and characterization of silsesquioxane, siloxane, and silmethylene polymers with phenolic hydroxy groups

AbstractSilsesquioxane, siloxane, and silmethylene polymers with phenolic hydroxy groups were prepared in order to obtain alkali‐soluble organosilicon polymers. These polymers have structures in which the phenol moieties are separated by one carbon from the silicon. The hydroxy groups were protected as methoxy groups in polymerization processes, then were changed into hydroxy groups by a reaction with trimethylsilyl iodide followed by alcoholysis. In the course of discussion on the characteristics of these polymers, silsesquioxane with phenolic hydroxy groups is found to possess excellent properties for matrix resins of alkalidevelopable organosilicon resists, such as O2RIE resistance and heat resistance.

Synthesis of organosilicon polymers—I. Silicone and silicon carbide copolymers: synthesis and physical properties

This work relates to a novel silicone and silicon carbide copolymer prepared by copolymerizing a cyclic or polycyclic non-conjugated diene with polysiloxane or dihydrosilyl hydrocarbon through the so-called hydrosilation. Norbornadiene, 5-vinyl-[2,2, 1]bicyclohept-2 ene and 4-vinylcyclohexene have been copolymerized with 1,1,3,3-tetramethyldisiloxane and 1,4-bis(dimethylsilyl)benzene. The polymers are stable thermally up to 440°.

Effect of silicon-containing additives on the properties of corundum concrete

When developing corundum concretes suitable for lining the combustion chambers having oxidizing atmospheres and the reactors used for production of co=~ercial-grade carbon at high rates, the Ukrainian Scientific-Research Institute of Refractories carried out extensive studies for obtaining shrinkage-free concretes having the required levels of the other properties. In order to ensure volume constancy during service, the quality of the finely dispersed binder constituent is extremely important even when using fused and fired (at high temperatures) refractory oxides having a specific granulometric composition (with a proper ratio of the fractions) as fillers. It must possess high levels of properties including corrosion and erosion resistance. This can be achieved either by increasing the AI203 content of the binder and improving the structure of the products or by introducing the additives facilitating the occurance of various processes such as modification, chemical interaction, and formation of solid solutions that lead to volumetric expansion. Addition of such additives must not cause deterioration of the quality of the products. This paper deals with a study of the effect of different silicon-containing additives on the properties of corundum concretes. In order to carry out this study, we compacted a series of cylindrical specimens measuring 36 mm in diameter and 50 mm in height at a compaction pressure of I00 N/mm 2 using the corundum concretes based on an electromelted corundum filler having a grain size of 5 mm and the finely dispersed binder constituent obtained from a high-alumina cement and the GK grade alumina. Table 1 shows the chemical composition of the silicon-containing additives used in this study. The SiO 2 additive was introduced into the finely dispersed constituent part in the form of finely milled sand (its quantity amounted to 3, 5, and 8%* in the Nos. i-3 systems, respectivelz), quartzite (Nos. 4-6), and quartz sand (Nos. 7-9) and, also, into the coarse-grained filler (3 and 5%) as the minus 0.5-mm fraction of sand having natural granularity (Nos. i0 and ii) and the 3-1 mm fraction of quartzite that contains equal quantities of the 3-2 and 2-1 mm fractions (Nos. 12 and 13). A binder containing an organosilicon polymer (silicone) was introduced into the Nos. 14-16 systems; in these systems, its quantity amounted to i, 3.5, and 7%, respectively. Table 2 shows the properties of the unfired specimens of the corundum concrete. We note that mullite formation (that leads to volumetric expansion) occurs against the background of the phase transformations of the main mineralogical components of the corundum concrete and the water-setting binder and, also, the interaction between this binder and the corundum-containing component of the finely dispersed binder. The conducted studies established that when the finely milled silicon-containing additives are introduced into the finely dispersed binder constituent of the corundum concrete in the form of quartz sand, quartzite, and quartz glass, the shrinkage occuring during the sintering process in the 1400-1750~ range is not compensated. A shrinkage free corundum concrete is obtained only in the presence of 8% quartzite and in the presence of 3 and 8% quartz glass and at a temperature of 1400~ Subsequent increase of the firing temperature of the corundum concrete up to 1580 and 1750~ activates the sintering process independent of the type and the quantity of the introduced finely milled silicon-containing additive. Figure i shows the temperature dependence of the main parameters of the corundum concretes containing SiO 2.

Characterization of pyrolysed silacyclobutasilazane

Silacyclobutasilazane (SCBZ) is a candidate organosilicon polymer suited to many hightemperature applications. Pyrolysis of SCBZ occurs over two distinct temperature ranges 400–800 and 1400–1800 °C. X-ray diffraction analysis showed that amorphous SCBZ transforms to crystalline SiC above 1400 °C. Thin foils of the pyrolysed (1800 °C) SCBZ were prepared and examined using the analytical electron microscope. The material was found to contain ∼ 200 nmβ-SiC particles scattered through a matrix consisting of ∼ 50 nm radiating clusters of pyrolytic graphite crystals and a highly carbonaceous amorphous background. It is suggested that during 1400–1800 °C pyrolysis two major reactions occurred. Initially, SCBZ through nitrogen loss, decomposed to crystalline SiC and amorphous carbon. Subsequent graphitization then produced the radiating crystal clusters.

A novel electron beam resist system acid catalized conversion of poly(di-t-butoxysiloxane) into glass.

A glass precursor polymer is designed on the basis of an idea of conversion of organosilicone polymer to an inorganic substance by lithographic procedure. Poly(di-t-butoxysiloxane) with photoacid generator is exposed followed by baking to give SiO2. The mechanism of the conversion is confirmed from the IR spectra. The sensitivity changes by deprotection ratio of t-butyl groups in the polymer chain, structurally improved polymer gives high sensitivity of 1.65μC/cm2. The glass precursor resist resolves 0.2μ m L/S patterns. O2-RIE durability of the resist film after exposure and PEB is, extremly high, over 62 times compared with bottom resist.

The influence of polarization on hole transport in plasma-polymerized organosilicon films

The influence of polarization procedure on charge carrier transport in plasma polymerized organosilicon films was investigated. Mobility of holes was determined using the time-of-flight method. It was found that frozen-in polarization of the plasma polymerized hexamethyldisilazane films increases the value of drift mobility. This process is fully reversible and after depolarization the value of drift mobility returns to the one before polarization. >

Structure and properties of ceramic fibers prepared from organosilicon polymers

This paper is a review of structure and properties of ceramic fibers derived from organosilicon polymers, with emphasis on the author's research. Ceramic fibers are prepared from organosilicon polymers by melt-spinning, cross-linking, and pyrolysis. Desirable polymeric precursors display the following properties: high char yield of desired composition, thermal stability at melt-spinning temperature, stable rheology, high purity and freedom from particulate impurities, and ability to undergo rapid cure (cross-linking). Ceramic fibers in the Si-C-O or Si-C-N-O systems display a rich nanostructure consisting of some or all of the following metastable phases: (1) an amorphous, continuous siliconoxycarbide or siliconoxycarbonitride phase; (2) dispersed carbon nanocrystallites; (3) dispersed β-SiC or Si3N4 nanocrystallites; and (4) closed, globular nanopores. The crystalline phases increase in volume fraction and crystallite size as stoichiometry approaches the crystalline composition and as pyrolysis temperature increases. The Si-C-N-O fibers are amorphous. Pore size increases and total pore volume decreases with increasing pyrolysis temperature. Considerable variation in ceramic fiber composition can be achieved by varying cure conditions and pyrolysis atmosphere. Polycrystalline SiC fibers can be produced by pyrolysis above 1600°C. Fiber diameters range from 7 to 20 µm. Elastic moduli vary from 140 to >420 GPa (20 to >60 Msi) and are controlled by composition, nanostructure, and fiber density. Fiber densities range from ∼2.2 to >3.1 g/cm3. Tensile strengths range up to ∼5 GPa (700 ksi) and are Griffith flaw-controlled.

Synthesis and Characterization of β’‐SiAlON Ceramics from Organosilicon Polymers

A polycarbosilane has been modified with aluminum alkoxide to obtain a new preceramic compound. The pyrolysis in NH3 flow of this polyaluminocarbosilane leads to the formation of an amorphous Si‐Al‐O‐N phase. The nitridation process has been followed by IR and 29Si MAS‐NMR spectroscopies. A fine‐grained β‐SiAION ceramic is obtained by firing the amorphous phase at 1500°C. The crystallization process has been studied by XRD, 29Si MAS‐NMR, and TEM techniques.

Electronic structures of simplified polymeric organosilicon systems containing .pi.-conjugated moieties

Electronic structures of simplified polymeric organosilicon systems containing .pi.-conjugated moieties

Polymeric organosilicon systems. 10. Synthesis and conducting properties of poly[2,5-(disilanylene)thienylenes

Preparation des polymeres [SiR(Me)−SiR(Me)−(C 4 H 2 S)] n (R=Me, Ph, p-tolyl) par couplage catalyse par PdCl 2 des 2,5-bis(chlorosilyl) thiophenes correspondants. Les polymeres obtenus sont photodegradables, ont une conductivite de 1-10 S/cm a l'etat dope par SbF 5 . Leur structure electronique est calculee

Preceramic organoboron–silicon polymers

AbstractSeveral boron‐containing organosilicon polymers were synthesized from a sodium‐coupling reaction of silicon and boron halides with and without alkyl halide in hydrocarbon solvents. The B–Si preceramic polymers were characterized using techniques such as IR, UV, and NMR spectrometry, gel permeation chromatography, elemental analysis, molecular weight measurement, and thermal analyses (TGA, DSC, DTA, and TMA). The chemical structures of the preceramic polymers were postulated based on the analytical results. Black ceramic materials were obtained from the precursor polymers upon thermal degradation at temperatures above 1000°C in an inert atmosphere. The precursor polymers had a ceramic yield of up to 70%. Thermogravimetric analysis of the ceramic material in air at a flow rate of 100 mL/min showed it was stable up to 1000°C with little weight gain or loss. Several methods were used to characterize the ceramic materials: XRD, solid NMR, high‐temperature DTA, elemental analysis, and acid digestion. The analyses indicated that the ceramic materials comprised a mixture of silicon carbide (SiC), silicon borides (SiB4, SiB6), and amorphous Si–B–C ceramics, with small amounts of silica and free silicon.

Selective synthetic routes to electroconductive organosilicon polymers containing thiophene units

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelective synthetic routes to electroconductive organosilicon polymers containing thiophene unitsPhilippe Chicart, R. J. P. Corriu, Joel J. E. Moreau, Francis Garnier, and Abderahim YassarCite this: Chem. Mater. 1991, 3, 1, 8–10Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 January 1991https://doi.org/10.1021/cm00013a004RIGHTS & PERMISSIONSArticle Views218Altmetric-Citations69LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (413 KB) Get e-Alerts Get e-Alerts

Synthesis and Useful Reactions of Organosilicon Polymeric Precursors for Ceramics

Inorganic and organometallic polymers are macromolecular systems in which the polymer backbone contains elements other than the carbon, oxygen and nitrogen usually found in organic polymers [1]. To take as an example silicon-containing polymers, in the silicones the polymer backbone is composed of the Si-O repeat unit; in polysilazanes, of the Si-N unit; in polysilmethylenes, of the Si-C unit. In the polysilanes there are only silicon atoms in the polymer backbone. Many of the other metalloids and metals among the elements in the Periodic Table have been or, in principle, can be incorporated into polymeric systems, so it is clear that the field of inorganic and organometallic polymers is a very large one. Inorganic and organometallic polymers have been of interest to chemists for a long time. It was the commercial development of the silicones in the 1940's that gave this field of research its modem impetus [2]. Once it was appreciated how useful these versatile organosilicon polymers could be, chemists became interested in the possibility of developing other organometallic (and also inorganic) polymers, ones that might complement or even surpass the silicones as far as useful applications were concerned. Research on inorganic and organometallic polymers became very active in the 1950's and 1960's. Work in this area became an international effort, prompted by the need for new materials that would meet the exacting demands of the jet age that had effectively commenced around the end of World War II. Even greater demands, in terms of materials that would still be useful under extreme conditions, came with the space age.

Laser evaporation of some solid organosilicon polymers

AbstractContinuous wave (cw) CO2 laser irradiation of some organosilicon polymers composed of ‐Me2Si‐, ‐Me2SiMe2SiCH2‐, RMeSi‐ and RMeSiMe2SiCH2CH2‐ units (where R = methyl, adamantyl, phenyl and hydrogen) leads to the evaporation of the polymer and is dominated by the formation of a solid deposit that has a continuous structure. It is assumed that chemical changes occur prior to the transfer of ejected material to the gas phase and that these consist mainly of the formation of high molecular biradicals or 1,2‐disilacyclobutane monomer that both re‐polymerize spontaneously upon their deposition onto a nearby cold surface. The mechanism of these specific decompositions of the polymers is assessed on the basis of the IR spectra of the deposits and, for the minor gaseous products, identification by GC MS techniques.

A novel synthesis of organosilicon polymers with reactive vinyl groups

A novel synthesis of organosilicon polymers with reactive vinyl groups

Organosilicon polymers: synthesis of poly[(silanylene)diethynylene]s with conducting properties

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganosilicon polymers: synthesis of poly[(silanylene)diethynylene]s with conducting propertiesRobert J. P. Corriu, Christian Guerin, Bernard Henner, Alain Jean, Francis Garnier, Abderahim Yassar, and Thomas KuhlmannCite this: Chem. Mater. 1990, 2, 4, 351–352Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://doi.org/10.1021/cm00010a008RIGHTS & PERMISSIONSArticle Views287Altmetric-Citations79LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (294 KB) Get e-Alerts Get e-Alerts

Dielectric and high Tc superconductor applications of sol-gel and modified sol-gel processing to microelectronics technology

Microelectronic applications for sol-gel processed dielectric materials (e.g. dopant sources, resist patterning, substrates, planarization layers) are briefly reviewed. The preparation and properties of dielectric thin films of a ladder siloxane, useful for some of these applications, are described. The properties of an as-spun film of this material are intermediate between those of an organic (e.g. a resist) and an inorganic (e.g. an oxide). These organosilicon polymers can also be used as precursors for the preparation of inorganic oxides; silica, phosphosilicate, borosilicate and borophosphosilicate thin films have been prepared. The amount of boron and phosphorus incorporated appears to be limited by the organosilicon functionality. Conversion to the inorganic oxide can be accomplished by either pyrolysis or plasma oxidation. Also discussed is the processing and properties of an aqueous based sol-gel process for the preparation of superconducting YBa 2Cu 3O 7− y , a material which could have application as a thick film chip-carrier metal interconnect. Materials prepared using this process demonstrate an excellent resistivity versus temperature superconducting transition behavior but have low critical current densities.

E-beam and duv exposure of RIE PCM two-layer systems

Abstract This paper focuses on the two-layer RIE PCM system [1] using both DUV and E-Beam exposures. An organosilicon polymer (SNR M2 from TOYO SODA) serves as top image resist and is spin coated over a thick crosslinked novolak layer (HPR 204). This system allows a very high aspect ratio image to be attained which is an essential characteritic for obtaining high resolution.

ＰＣＳ系ＳｉＣ繊維強化アルミニウム複合線材の高温強度

Preform wires, which are organosilicone polymer (polycarbosilane) derived SiC fiber reinforced Al composite are expected to be a useful semi-finished material for fabricating FRM. High temperature strength and thermal stability of those preform wires were investigated. The tensile strength of wires at 723K was about 85% of the strength at room temperature. The degradation in the strength was not due to degradation in the fiber strength, and was due to degradation in the transmission ability of stress from the matrix to the fibers. Those preform wires can be used as semi-finished materials without the degradation of strength during fabricating FRM at elevated temperature.

ＰＣＳ系ＳｉＣ繊維強化アルミニウム複合線材の熱的安定性

Preform wires, which were organosilicone polymer (polycarbosilane) derived SiC fiber reinforced Al composite were high specific strength and high specific modulus. The thermal stability of those preform wires were investigated. Before and after exposure test at elevated temperature, the tensile strength of wires and extracted fibers were measured at room temperature. There was no degradation in the strength at 623K until 3600ks. In higher temperature, the strength of wires began to decrease gradually after about 108ks at 723K and after about 36ks at 773K. The limit of thermal stability was estimated to be about 700K for the preform wires.