Sylgard

By far the best efforts to measure product compns were made by Orncllas co-workers (Refs 3, 4 6) who made accurate calorimetry and compn measurements on highly confined and unconfined expl samples. The expls he studied were PETN, HMX, NM, TNT, Bis(2,2-dinitro-2-fluoroethyl)formal (FEFO), l,2-Bis(difluoro-amino) propane (1,2 DP), Benzotrifuroxan (BTF), LX-11-0 (80.1/19.9 HMX/Viton), XTX-8003 (80/20 PETN/Sylgard 182), and three Hydrazine Nitrate (HN) mixts. Of course, most of these measured compns are not CJ products, but reequilibrated mixts of CJ products at some frozen equilibrium temp Tfr < TCJ... 

A stable setup for oocyte recording is essential for the proper acquisition of electrical currents. The oocyte bath is placed under a microscope on a vibration isolation table (e.g., Micro-g, Technical Manufacturing Corporation, Peabody, MA) to dampen mechanical vibrations that can lead to a less stable voltage clamp and therefore electrical noise. The bath chamber is a hollowed groove in a small block of Lucite, partially filled with a sihcone elastomer (e.g., Sylgard, Dow Corning) to provide a smooth bed surface on which the oocyte can be deposited prior to impalement with the recording electrodes. 

MDX-4-4210 was blended with 10 Sylgard 527, by weight, to decrease viscosity for casting purposes. 

In this paper detailed methods for the determination of placement and assay of silicon hydride (Si-H), silicon hydroxide (Si-OH) and silicon phenyl (Si-0) functional groups in molecular weight components of silicones of the Sylgard (Dow-Corning Co.) type will be described. The methods are illustrated with the analysis of Sylgard addition prepolymers and of model polydimethylsiloxanes (PDMS). 

This is indeed observed with model PDMSs having hydride groups in terminal positions. If Si-H positions are random in Sylgard 182B and there are several Si-Hs per molecule, most of them must be in internal positions on the chains. 

Higher resolution measurements of the Si-H stretching band in model compounds revealed a significant difference in the frequency of this band between terminal and internally placed hydride groups (Figure 3). For terminal hydrides the frequency was about 2127 cm l, while for internal ones it was about 2167 cm l (Table I). The frequency for the two Sylgards was about 2163 cm l, nearly that for internal placements, and in line with a random distribution. 

Quantitation of phenyl content in Sylgards was performed by comparison of areas of UV absorbance at 215 nm with a calibration curve generated with PS463, a phenyl terminated PDMS. In performing the integration for phenyl content the absorbance due to the THF peroxide band was omitted but other bands, due to lower molecular weight impurities which contain phenyls, were included to permit comparisons with bulk analytical methods, such as NMR. 

Interference by functional groups other than Si-H, which are present in many Sylgard prepolymers, has not been investigated. It is expected that aromatic groups such as biphenyl and naphthyl will give absorbances similar to phenyl. The absorbance of Si-H containing PDMSs at 215 nm was negligible. 

Isolate or cultivate cells according to the protocols given before. Pull pipettes of 2-3 resistance, fire-polish in a microforge or treat with sylgard. Prepare the following solutions. 

XTX-8003 (eXTrudable explosive). Los Alamos National Scientific Laboratory (LASL) designation for an extrudable expl contg PETN (80 wt% 69.9 vol %) coated with a low-temp vulcanizing silicone resin, Sylgard 182 (20 wt % 30.1 vol %) atomic compn Ci. 8<>H3.64N , 0103 3 jSi0.27 white putty curable to rubbery solid d, TMD 1.556g/cc, nominal 1.50-1.53g/cc mp 129-135°. XTX-8003 is used in special applications that require expls with small detonation failure diameters... 

Properties Properties of Plastic Bonded HMX PBXN-101 Sylgard-HMX Polyester-HMX PBXC-113 Plasticized Polyester-HMX... 

Holovka, Effects of HE-Binder Interactions on the Viscoelastic Properties of PETN/ and RDX/-Sylgard-182 Formulations , CompatPlastOther-MaterExplosProplnts, Pyrot Symp 1976, III-C CA 87, 87228 (1977) 41) W. Falterman ... 

Solvent BDNPA BDNPF Cab-O Sil DOP Estane 5702-F1 Exon 461 Kel-F Polystyrene Sylgard 182 TEF Viton A... 

Efimenko K, Wallace WE, Genzer J (2002) Surface modification of Sylgard-184 poly(dimethyl siloxane) networks by ultraviolet and ultraviolct/ozone treatment. J Colloid Interface Sci 254 306-315... 

Continuous studies were performed in specially prepared microreactors molded from PDMS, designated PDMS (Sylgard 184 silicone elastomer Dow Corning) poured onto silicon wafer molds. The microreactor molds were prepared using 4-in. silicon wafers of Type P, crystal orientation of , resistivity of 1 to 2 Q, and thickness of 457-575 pm from Silicon Quest (Santa Clara, C A). After preparation, mixtures of urease enzyme and PDMS (designated PDMS-E) were poured onto the microreactor mold and allowed to cure at ambient conditions. 

FIGURE 2.12 Fabrication procedure of a PDMS chip (a) silicon master wafer with positive surface relief, (b) pre-mixed solution of Sylgard 184 and its curing agent poured over the master, (c) cured PDMS slab peeled from the master wafer, (d) PDMS slab punched with reservoir holes, and (e) ready-to-use device sealed with another slab of PDMS [159]. Reprinted with permission from the American Chemical Society. 

It was found that Sylgard 184 provided a higher tensile strength and elongation than RTV 615, and so the former was selected for fabrication of the microvalve control layer [449]. Moreover, the control channel must be filled with water before use, in order to prevent bubble formation in the fluidic channel due to the gas permeability of PDMS [449]. 

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