scholarly journals Study on the Synthesis and Thermal Stability of Silicone Resin Containing Trifluorovinyl Ether Groups

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2284
Author(s):  
Rui Huang ◽  
Jinshui Yao ◽  
Qiuhong Mu ◽  
Dan Peng ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ir Spectra ◽  
Silicone Resin ◽  
Methyl Silicone ◽  
Test Results ◽  
Oh Groups ◽  
Air Atmosphere ◽  
Thermal Degradation Behavior ◽  
Ft Ir ◽  
Trifluorovinyl Ether

Silicone resin is a high-temperature resistant material with excellent performance. The improvement of its thermal stability has always been the pursuit of researchers. In this paper, a sequence of silicone resins containing trifluorovinyl ether groups were prepared by the co-hydrolysis-polycondensation of methyl alkoxysilane monomers and {4-[trifluorovinyl(oxygen)]phenyl}methyldiethoxysilane. The structures of the silicone resins were characterized by FT-IR and 1H NMR. The curing process of them was studied by DSC and FT-IR spectra, and results showed that the curing of the resins included the condensation of the Si-OH groups and the [2 + 2] cyclodimerization reaction of the TFVE groups, which converted to perfluorocyclobutane structure after curing. The thermal stability and thermal degradation behavior of them was studied by TGA and FT-IR spectra. Compared with the pure methyl silicone resin, silicone resins containing TFVE groups showed better thermal stability under both N2 and air atmosphere. Their hydrophobic properties were characterized by contact angle test. Results showed that PFCB structure also improved the hydrophobicity of the silicone resin.

Preparation and Properties of Silicon-Containing Arylacetylene Resins with Octa(maleimidophenyl)silsesquioxane

2012 ◽  
Vol 557-559 ◽  
pp. 1152-1156
Author(s):  
Yan Zhou ◽  
Fu Wei Huang ◽  
Fa Rong Huang ◽  
Lei Du
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Thermal Polymerization ◽  
Curing Process ◽  
Thermal Stabilities ◽  
Curing Reaction ◽  
Air Atmosphere ◽  
Ft Ir ◽  
Dsc Analyses

Modified silicon-containing arylacetylene resins (DMSEPE-OMPS) were prepared from poly(dimethylsilyleneethynylenephenyleneethynylene) (DMSEPE) and Octa(maleimidophenyl)- silsesquioxane (OMPS). The curing reaction of DMSEPE-OMPS resin was studied by FT-IR and DSC techniques. Thermal stability and dielectric properties of cured DMSEPE-OMPS resins were determined. FT-IR and DSC analyses indicate that thermal polymerization of DMSEPE-OMPS resin occurs in the curing process. Thermal stabilities of cured DMSEPE-OMPS resins under N2 and air atmosphere decrease gradually with the increment of OMPS components. The incorporation of OMPS can obviously reduce dielectric constant of DMSEPE-OMPS resins.

scholarly journals Study on the synthesis and thermal stability of silicone resins reinforced by Si–O–Ph cross-linking

RSC Advances ◽  
2021 ◽  
Vol 11 (49) ◽  
pp. 30971-30979
Author(s):  
Huadong Zhang ◽  
Zhongyi Yan ◽  
Zhizhou Yang ◽  
Jinshui Yao ◽  
Qiuhong Mu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Catalytic Hydrogenation ◽  
Phenolic Hydroxyl ◽  
Cross Linking ◽  
Silicone Resin ◽  
Oh Groups ◽  
Thermal Stability Of

A novel silicone resin (SR-OH) containing phenolic hydroxyl (Ph–OH) groups was designed and synthesized via co-hydrolysis/condensation and catalytic hydrogenation.

Synthesis and Imidization of Polyamic Acid

2011 ◽  
Vol 301-303 ◽  
pp. 9-15 ◽  
Author(s):  
Jian Li Cheng ◽  
Cun Zhou ◽  
Guo Zheng ◽  
Yu Sun
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Ir Spectra ◽  
Organic Solvents ◽  
Glass Plate ◽  
Aromatic Diamine ◽  
Scanning Calorimetry ◽  
Heat Curing ◽  
Polar Organic Solvents ◽  
Ft Ir

Polyamic acids (PAA) were synthesized by solution polycondensation of aromatic diamine with dianhydride and PAA were readily soluble in polar organic solvents (N-methylpyrrolidinone, N, N-dimethylacetamide and DMF). It was found that the most appropriated reaction conditions of synthesis of PAA solution were the ratio of dianhydride with diamine being 1.02:1and 3h reaction time at ambient temperature in both N-methylpyrrolidinone and N, N-dimethylacetamide polar organic solvents. PAA thin films were prepared by PAA solution spread on the glass plate and PI thin films were obtained by the casted thin films which underwent a special high-temperature (300°C, 2h) heat curing. The structures of PAA and PI films were characterized by FT-IR spectra and degree of imidization of PAA solution was indicated from IR spectra. The thermal stability was studied by thermogravimetric analysis (TGA) and the thermal behaviors were investigated by differential scanning calorimetry (DSC) in this paper. It was shown that PAA solution were imidization at 200°C mostly and PI had higher thermal stability.

Fabrication of the SiOC/HfO2 Ceramic Composites by the Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 912-915
Author(s):  
Dai Shou ◽  
Ding Shan Ruan ◽  
Feng Hou
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Ir Spectra ◽  
Ceramic Composite ◽  
Raw Materials ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ft Ir

In this paper, Hf element was introduced into the Si-O-C network by the sol-gel method using the dimethyldiethoxysiloxane (DMDES, (CH3)2Si(OC2H5)2) and hafnium tetra(n-butoxide) (HfOR, Hf(OC4H9)4) as raw materials. The SiOC/HfO2 ceramic composite was obtained by pyrolyzing Si-Hf-O-C gel at 1000 °C in argon. FT-IR spectra revealed the presence of Si-O-Hf peaks at 932 cm-1. The weight loss of the as-prepared SiOC/HfO2 was about 0.2 wt.% under argon atmorsphere up to 1550 °C, which was much lower than the hafnia-free SiOC composites and exhibited a remarkable improved thermal stability.

Thermal and Oxidative Stability Thermosets Derived from Hybrids of Cyclosilazanes and Silicon-Containing Polyarylacetylene

2014 ◽  
Vol 1004-1005 ◽  
pp. 286-292
Author(s):  
Qian Hu ◽  
Hui Min Qi ◽  
Fan Wang ◽  
Ya Ping Zhu
Keyword(s):  
Thermal Stability ◽  
Hybrid Materials ◽  
Polymer Networks ◽  
High Thermal Stability ◽  
Thermooxidative Stability ◽  
H Nmr ◽  
Air Atmosphere ◽  
Thermal And Oxidative Stability ◽  
Ft Ir ◽  
Stable Hybrid

Oxidative stable hybrid thermosets derived from silicon-containing polyarylacetylene (PSA-V) and branched methylvinylcyclosilazane (b-MVSZ) have been prepared, and b-MVSZ was synthesized by coammonolysis reaction of methylvinyldichlorosilane and vinyltrichlorosilane, which was characterized by using GC-MS, FT-IR,1H NMR and GPC. The cure behaviors of PSA-V/b-MVSZ hybrids were investigated by DSC and the thermal and oxidative stabilities of the cured PSA-V/b-MVSZ hybrids were determined by TGA under nitrogen and air atmosphere. The results indicated that the PSA-V/b-MVSZ hybrids could be thermally cross-linked through the vinyl/ethynyl groups to form polymer networks. The cured PSA-V/b-MVSZ hybrids possessed high thermal stability, and with increasing the content of b-MVSZ, the thermooxidative stability of the hybrid materials was enhanced.

Preparation, Characterization and Antifoaming Property of Fluorosilicone Oils with Fluoroalkyloxypropyl Group Substitution

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Li Zhan-xiong
Keyword(s):  
Thermal Stability ◽  
Silicone Oil ◽  
Methyl Silicone ◽  
Analysis Technique ◽  
Lower Viscosity ◽  
Silicone Oils ◽  
Ft Ir ◽  
Thermal Stability Of ◽  
Elemental Analysis Technique ◽  
Better Than

AbstractThe current work has focused on the preparation and property of a novel fluorosilicone oil with polyfluoroalkyloxypropyl group substitution. Using fluoroalcohols as materials, three kinds of fluorosilicone oil, named [3-(2,2,2- trifluoroethyl-oxy)propyl]methylsilicone oil, [3-(2,2,3,3-tetrafluoropropyl-oxy)propyl] methylsilicone oil and [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oil, were prepared via condensation, hydrosilylation, cyclization and ringopening polymerization. All the fluoroalkyl derivatives were characterized by NMR, FT-IR, MS and elemental analysis technique. The thermal stability of these fluoroalkyoxypropylmethylsilicone oils was identified to be excellent by thermogravimetric analysis. [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oils with different viscosity were prepared by varying the amount of endblock reagent in the polymerization, and the antifoam property of these fluorosilicone oils was investigated. The result showed that the antifoam property of octafluorosilicone oil with higher viscosity was better than that with lower viscosity.

Light- or Dark-Colored, L-DOPA-Based Melanins

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Margaret M. Whalen
Keyword(s):  
Human Physiology ◽  
Ir Spectra ◽  
Immune Cells ◽  
Chemical Properties ◽  
Chemical Signature ◽  
Ft Ir

<p>This report is a continuation of previous research on the H<sub>2</sub>O<sub>2</sub>-mediated synthesis of melanin-like pigments. We synthesized and characterized L-DOPA-based pigments using air- or H<sub>2</sub>O<sub>2</sub>-mediated<sub> </sub>oxidation. We compared their physic-chemical properties and evaluated their capacity to affect the interleukin release from immune cells. The use of higher concentrations of H<sub>2</sub>O<sub>2</sub> resulted in melanin-like materials with a distinct chemical signature in their FT-IR spectra and a lighter color. All pigments enhanced the interleukin release from immune cells. The possibility that lighter-colored melanins can be generated is discussed in the context of the importance of melanin-based pigmentation in human physiology.</p>

scholarly journals Spectroscopy as a useful tool for the identification of changes with time in post-mortem vitreous humor for forensic toxicology purposes

2021 ◽  
Author(s):  
Anna Wójtowicz ◽  
Agata Mitura ◽  
Renata Wietecha-Posłuszny ◽  
Rafał Kurczab ◽  
Marcin Zawadzki
Keyword(s):  
Ir Spectra ◽  
Forensic Toxicology ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Vitreous Humor ◽  
Attenuated Total Reflection ◽  
Glass Slides ◽  
Added Benefit ◽  
Ft Ir ◽  
Non Destructive

AbstractVitreous humor (VH) is an alternative biological matrix with a great advantage of longer availability for analysis due to the lack of many enzymes. The use of VH in forensic toxicology may have an added benefit, however, this application requires rapid, simple, non-destructive, and relatively portable analytical analysis methods. These requirements may be met by Fourier transform infrared spectroscopy technique (FT-IR) equipped with attenuated total reflection accessory (ATR). FT-IR spectra of vitreous humor samples, deposited on glass slides, were collected and subsequent chemometric data analysis by means of Hierarchical Cluster Analysis and Principal Component Analysis was conducted. Differences between animal and human VH samples and human VH samples stored for diverse periods of time were detected. A kinetic study of changes in the VH composition up to 2 weeks showed the distinction of FT-IR spectra collected on the 1st and 14th day of storage. In addition, data obtained for the most recent human vitreous humor samples—collected 3 and 2 years before the study, presented successful discrimination of all time points studied. The method introduced was unable to detect mephedrone addition to VH in the concentration of 10 µg/cm3. Graphic abstract

Luminescent Properties of Zn2SiO4:Eu3+,Dy3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.

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