Epoxy density

Fig. 4. Operational stability of penicillin G amidase immobilized on epoxy carrier. Batch cycles were run in a 1.5-1 laboratory reactor at 10% penicillin G, 6 kU L 36 °C. pH was maintained at 8.0 by the addition of 2 N NH3. Initial splitting time was 65 min. The initial activity (relative base consumption per min at the beginning of each batch conversion) is plotted against the cycle number. PGA was immobilized on polymethacrylate with an epoxy density >2000 pmol g" (squares) or of 600 pmol g" (triangles)...

What weight of carbon fibres (density = 1800 kg/m ) must be added to 1 kg of epoxy (density = 1250 kg/m ) to produce a composite with a density of 1600 kg/m. ... 

Syntactic Cellular Polymers. Syntactic cellular polymer is produced by dispersing rigid, foamed, microscopic particles in a fluid polymer and then stabilizing the system. The particles are generally spheres or microhalloons of phenoHc resin, urea—formaldehyde resin, glass, or siUca, ranging 30—120 lm dia. Commercial microhalloons have densities of approximately 144 kg/m (9 lbs/fT). The fluid polymers used are the usual coating resins, eg, epoxy resin, polyesters, and urea—formaldehyde resin. 

ARALL laminates, a family of hybrid composites consisting of aramid fibers bonded with epoxy between 0.3 mm thick aircraft ahoy sheets, were introduced in the 1980s (53). The laminates have lower density than even the new Al—Li ahoys and are greatly superior to monolithic aluminum sheet in resisting the growth of fatigue cracks. ARALL laminates have been specified for aircraft stmcture which is subjected to cycHc tension loads (see Laminates). 

The positive plates are siatered silver on a silver grid and the negative plates are fabricated from a mixture of cadmium oxide powder, silver powder, and a binder pressed onto a silver grid. The main separator is four or five layers of cellophane with one or two layers of woven nylon on the positive plate. The electrolyte is aqeous KOH, 50 wt %. In the aerospace appHcations, the plastic cases were encapsulated in epoxy resins. Most usehil cell sizes have ranged from 3 to 15 A-h, but small (0.1 A-h) and large (300 A-h) sizes have been evaluated. Energy densities of sealed batteries are 26-31 W-h/kg. 

Eig. 10. The variation of the density of carbon-fiber reinforced epoxy resin with the fiber volume fraction, based on the rule of mixtures. 

In planning cathodic protection, the specific resistivity of the water, the size of the surfaces to be protected and the required protection current densities have to be determined. The protection current density depends on the type and quality of the coating. Thermosetting resins (e.g., tar-epoxy resin coatings) are particularly effective and are mostly used today on coastal structures. They are chemically... 

In the ease where the turbine and supports have a minimal eross seetion, then the ability to inerease the stiffness of these pedestals is minimized. Consequently, the objeetive is to eoneentrate on inereasing the mass of the pedestals. This inerease is aeeomplished by filling the eavities with a speeial mortar prepared with epoxy and steel shot. The density of this speeial mortar ean be in exeess of 300 pounds per eubie foot. To injeet this speeial mortar, a pipe has been installed in the aeeess hole that was drilled in the side of the pedestal near the top. These same teehniques ean be employed to stabilize the foundations under mueh smaller equipment. 

Fig. 5. Examples of ihe correlation between measured adhesive strength and (l+cos6). (a) Plot of data from Raraty and Tabor [171J for adhesion of ice to various solids, (b) Plot of data of Barbaris [172] for adhesion of a mixture of epoxy and polyamide resin to low density poly(ethylene) treated in various ways. Both figures from ref. [31], by permission.

During the temperature ramp period, pressure is applied. How much pressure is applied depends on the adhesive and the type of assembly. Honeycomb assemblies are limited by the compression strength of the honeycomb core, so cure pressure is typically limited to 50 psi for aluminum core of standard density. Metal to metal assemblies can withstand higher pressures and usually have fewer bondline voids when cured at higher pressures. Metal-to-metal assemblies bonded with standard modified epoxies are cured at 90 psi. 

Example 3.1 The density of a composite made from unidirectional glass fibres in an epoxy matrix is 1950 kg/m. If the densities of the glass and epoxy... 

A hybrid composite material is made up of 20% HS carbon fibres by weight and 30% E-glass fibres by weight in an epoxy matrix. If the density of the epoxy is 1300 kg/m and the data in Fig. 3.2 may be used for the fibres, calculate the density of the composite. 

---