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Junying Zhang - One of the best experts on this subject based on the ideXlab platform.
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a newly designed dual functional epoxy monomer for preparation of fishbone shaped heterochain polymer with a high damping property at low temperature
Macromolecular Materials and Engineering, 2017Co-Authors: Jue Cheng, Junying ZhangAbstract:A novel high purity dual-functional epoxy monomer, diglycidyl ether of 4,4′-diallyl-bisphenol-A, is deliberately designed for the construction of a fishbone-shaped heterochain polymer by polymerizing it with the methyl phenyl Polysiloxane. Their curing reactions with Jeffamine D230 are investigated. The cured fishbone-shaped heterochain polymer presents a wide transition range spanning over 120 °C with a peak half-width of 62 °C. In contrast to the traditional epoxy/Polysiloxane materials, the cured fishbone-shaped heterochain polymer takes full advantage of the cooperative effect of epoxy and Polysiloxane exhibiting excellent damping properties (tan δ > 0.3) at temperatures near the T g of the Polysiloxane. This outstanding low-temperature damping performance can be ascribed to the fishbone-shaped structure of the heterochain polymer. These results provide new approach to explore high damping materials used at extremely low temperature (−125 °C).
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direct synthesis and characterization of crosslinked Polysiloxanes via anionic ring opening copolymerization with octaisobutyl polyhedral oligomeric silsesquioxane and octamethylcyclotetrasiloxane
Journal of Applied Polymer Science, 2006Co-Authors: Hongying Li, Junying Zhang, Riwei Xu, Dingsheng YuAbstract:The crosslinked Polysiloxanes were directly synthesized by anionic ring-opening copolymerization of octaisobutyl-polyhedral oligomeric silsesquioxane (POSS) as a multifunctional monomer with octamethylcyclotetrasiloxane (D4) under base catalysts such as potassium hydroxide (KOH) or tetramethylammonium hydroxide (Me4 NOH) siloxanolate. The mechanism of anionic ring-opening copolymerization of octaisobutyl-POSS and D4 was discussed and the influences of the polar additive N,N-dimethylacetamide on gelation time at different temperatures were investigated. The results of gel content and swelling ratio, GPC, solid-state 29Si and 13C NMR, FTIR, XRD show that octaisobutyl-POSS is reacted and most of the product is crosslinked. The DSC and TG results indicate that the crosslinked Polysiloxanes exhibit distinct glass transition temperatures (Tg) and excellent thermal stability. Compared to that under KOH siloxanolate, the crosslinked Polysiloxane synthesized with Me4NOH siloxanolate has better preferable thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3848–3856, 2006
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a novel and facile method for direct synthesis of cross linked Polysiloxanes by anionic ring opening copolymerization with ph12 poss d4 ph8d4
Polymer, 2005Co-Authors: Hongying Li, Dingsheng Yu, Junying ZhangAbstract:Abstract The cross-linked Polysiloxanes were directly synthesized by anionic ring-opening copolymerization of Ph 12 -POSS as multifunctional monomer with D 4 and Ph 8 D 4 under KOH or Me 4 NOH siloxanolate. And the influences of the polar additive DMAc on gelation time were investigated. The results of gel content and swelling ratio, GPC, solid-state 29 Si and 13 C NMR, FT-IR, WAXD showed that Ph 12 -POSS was reacted and most of the product was cross-linked. The DSC and TG results indicated that the cross-linked Polysiloxanes exhibited distinct glass transition temperatures ( T g ) and excellent thermal stability. Compared to that with KOH siloxanolate, the cross-linked Polysiloxane synthesized with Me 4 NOH siloxanolate has more preferable thermal stability.
Bret J Chisholm - One of the best experts on this subject based on the ideXlab platform.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of Polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for Polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique Polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of Polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for Polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique Polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
Partha Majumdar - One of the best experts on this subject based on the ideXlab platform.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of Polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for Polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique Polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of Polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for Polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique Polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
Chul B Park - One of the best experts on this subject based on the ideXlab platform.
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processing of porous silicon carbide ceramics from carbon filled Polysiloxane by extrusion and carbothermal reduction
Journal of the American Ceramic Society, 2008Co-Authors: Chunmin Wang, Chul B ParkAbstract:Porous silicon carbide (SiC) ceramics with porosities ranging from 60% to 83% were fabricated from extruded blends of carbon-filled Polysiloxane using expandable microspheres as sacrificial templates. The fabrication process involved the following steps: (i) extrusion and in situ foaming of a mixture of Polysiloxane, carbon black (used as a carbon source), Al2O3–Y2O3 (used as a sintering additive), expandable microspheres (used as sacrificial templates), and SiC (an optional inert filler); (ii) cross linking the Polysiloxane in the extruded blends; (iii) transforming the Polysiloxane by pyrolysis into silicon oxycarbide; and (iv) fabricating porous SiC ceramics by carbothermal reduction and subsequent sintering.
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fabrication of open cell microcellular silicon carbide ceramics by carbothermal reduction
Journal of the American Ceramic Society, 2005Co-Authors: Youngwook Kim, Shinhan Kim, Inhyuck Song, Haidoo Kim, Chul B ParkAbstract:A novel processing route for developing open-cell, microcellular SiC ceramics has been developed. The strategy adopted for making microcellular SiC ceramics involved the following: (i) fabricating a formed body from a mixture of Polysiloxane, phenol resin (used as a carbon source), polymer microbeads (used as sacrificial templates), and Al2O3–Y2O3 (an optional sintering additive); (ii) cross-linking the Polysiloxane in the formed body; (iii) transforming the Polysiloxane and phenol resin by pyrolysis into silicon oxycarbide and C, respectively; and (iv) synthesizing SiC by carbothermal reduction. By controlling the microbead and additive contents, it was possible to adjust the porosity so that it ranged from 60% to 95%.
Shengyu Feng - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of luminescent silicone elastomer by thiol ene click chemistry
Journal of Materials Chemistry C, 2014Co-Authors: Haifeng Lu, Xianming Wang, Liang Ning, Shengyu FengAbstract:Novel transparent and luminescent silicone elastomers were prepared by thiol–ene chemistry. They show very intense photoluminescence under ultraviolet light and have very high coloric purity. The luminescence was obtained by complexing lanthanide ions into an N-acetyl–L–cysteine functionalized Polysiloxane. The functionalized Polysiloxane was prepared by an easy thiol–ene reaction and the Polysiloxane was cured by thiol–ene reaction to get a crosslinking network. Their structures and properties were characterized thoroughly. The experimental results indicate complexing lanthanide ions reduced the contact angles.
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the synthesis morphology and liquid crystalline property of Polysiloxane modified perylene derivative
Dyes and Pigments, 2012Co-Authors: Yan Liang, Hua Wang, Dengxu Wang, Hailong Liu, Shengyu FengAbstract:Abstract A novel Polysiloxane-modified perylene derivative was designed and synthesized through the amidation reaction between aminopropyl-terminal Polysiloxane and perylene tetracarboxylic diester monoimides with n -dodecyl as the alkyl chain connected to the perylene core. The synthesized compound was subjected to IR and 1 H NMR. The liquid-crystalline property of the modified perylene derivative at room temperature (ranged from 27.1 °C to 61.3 °C) was characterized via differential scanning calorimetry, polarization optical microscope, X-ray powder diffraction, and small-angle X-ray scattering. The morphology of the compound was evaluated via scanning electron microscopy and atomic force microscopy in tapping mode. The static contact angle of the perylene derivative with distilled water as the test liquid was improved after modification by Polysiloxane. All the measurements revealed that the Polysiloxane-modified perylene derivative exhibited good thermal stability, excellent optical property, good hydrophobic property, and low temperature liquid-crystalline property. These properties may be attributed to the presence of flexible Si–O–Si chain and ordered π – π* stacking between adjacent perylene cores.
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molecular design and photophysical properties of acylamido side functionalized Polysiloxanes with lanthanide ions as luminescent centers
Journal of Photochemistry and Photobiology A-chemistry, 2010Co-Authors: Xiaochen Wang, Hua Wang, Shengyu FengAbstract:Abstract Two series of acylamido side functionalized Polysiloxanes were designed and synthesized from the modifications of amino silane with different acylating agents. They were complexed with lanthanide ions (Tb 3+ , Eu 3+ , Dy 3+ and Sm 3+ ) to obtain functionalized Polysiloxane–lanthanide ions composite materials and exhibit the molecular assembly behaviors. The structures of products were characterized by Fourier transform infrared (FT-IR), 1 H-NMR spectra and diffuse reflectance ultraviolet–visible spectra (DRUVS). Thermal stability was investigated by thermogravimetric analysis (TGA). Narrow-width red and green emissions of the functionalized Polysiloxane–lanthanide ions complexes were recorded under the exposure to ultraviolet light. The results show that four kinds of lanthanide ions were all cooperated successfully with the functionalized Polysiloxanes and an intra-molecular energy transfer process took place in these systems. Further investigations into the luminescence properties of the functionalized Polysiloxane–lanthanide ions composite materials show that the triplet state energy of the benzoylamido side functionalized Polysiloxane is more suitable for the emissive energy level of lanthanide ions than that of acetamido side functionalized Polysiloxane. According to the rules between photophysical properties and diverse chromophoric conjugate groups, we could design and control the properties of the Polysiloxane–lanthanide ion assembly complexes.
