B-stage

Bryamycin Bryostatin 1 BSA-SILICA B-stage B-stage resins B. subtilis 66333 BTEPE [37853-59-1]... 

The reinforcing ply acts as the carrier for the plastic resin during intermediate processing steps known as saturation and B-staging. It is this ply that together with the resin makes a laminate a composite material, and the layering of these pHes that makes the final product a laminate. 

Laminates. Laminate manufacture involves the impregnation of a web with a Hquid phenoHc resin in a dip-coating operation. Solvent type, resin concentration, and viscosity determine the degree of fiber penetration. The treated web is dried in an oven and the resin cures, sometimes to the B-stage (semicured). Final resin content is between 30 and 70%. The dry sheet is cut and stacked, ready for lamination. In the curing step, multilayers of laminate are stacked or laid up in a press and cured at 150—175°C for several hours. The resins are generally low molecular weight resoles, which have been neutralized with the salt removed. Common carrier solvents for the varnish include acetone, alcohol, and toluene. Alkylated phenols such as cresols improve flexibiUty and moisture resistance in the fused products. 

Air and oil filters are made by a dry-web process in which the filter paper is dried over heated metal dmms. The paper is saturated with the phenoHc resin solution, either off- or on-line, and dried in an oven advancing the resin to the B-stage (semicured). The sheet, containing 20—30% resin, is roUed and shipped to the filter-unit manufacturer, where the sheet is convoluted and the filter assembled and cured to the C-stage (fully cured). 

The resins used in air and oil filters are moderate-to-low molecular weight, catalyzed by caustic in one step 10—20% alcohol is added soHds content is in the range of 50—60%. These resins are designed to penetrate the sheet thoroughly, yet not to affect the porosity of the paper. In the B-stage, the resin must have sufficient flexibiHty to permit pleating the C-stage should have stiffness and resistance to hot oil. 

Heat-resistant resin compositions based on bismaleknide—epoxy blends are achieved by reaction of a BMI—y -aminophenol [591-27-5] (1 1) adduct with epoxy. This prepolymer is fully cured with an imida2ole catalyst (54). Blends of hydroxy-terminated BMI—aminophenol adducts can easily be B-staged, that is, prepolymerked, and subsequendy ground to provide a powder that can be molded by the appHcation of heat and pressure. 

B-stage Intermediate-stage reaction steps for various thermosetting resins. During this stage, the material swells when in contact with... 

Soluble B-staged material amenable to fabrication good thermal stability. 

Fig. 6-4 Viscosity changes during the processing of TS. The B-stage represents the start of the heating cycle followed by a chemical reaction (cross-linking) and solidification of the plastic.

Fig. 8-67 Automated-integrated RP vacuum lay-up process that use prepreg sheets that are in the B-stage.

Small sections (0.5 cm ) of pericarp tissue from B stage fruit were cut and placed immediately into boiling 95% (v/v) ethanol and refluxed for 15 min. The ethanol was then decanted and the boiled tissue was homogenized in cold water. The sample was... 

Lu, N. Kofke, D. A. Woolf, T. B., Staging is more important than perturbation method for computation of enthalpy and entropy changes in complex systems, J. Phys. Chem. B 2003,107, 5598-5611... 

Figure 8. Schematic representation of a) the stage 2 —> stage 1 transition through superdense stage 2 compound such as LijsCn (or LiojsCf) and, b) stage 1 —> stage 2 transition involving...

The kinetic curve has a sigmoidal shape and can be intuitively divided into four stages (a) induction period, (b) stage of accelerated hydroperoxide formation, (c) stage of retarded ROOH formation, and (d) stage with prevalence of ROOH decomposition after the point... 

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