Balanced laminates

Figure 4-21 Unbonded View of Simple Quasi-isotropic Laminates Balanced Laminates...

Adhesives. Acryhc emulsion and solution polymers form the basis of a variety of adhesive types. The principal use is in pressure-sensitive adhesives, where a film of a very low T (<—20 " C) acrylic polymer or copolymer is used on the adherent side of tapes, decals, and labels. Acrylics provide a good balance of tack and bond strength with exceptional color stabiUty and resistance to aging (201,202). AcryUcs also find use in numerous types of constmction adhesive formulations and as film-to-film laminating adhesives (qv). 

Automotive and architectural laminates of PVB develop maximum impact strength near 20°C, as shown in Figure 2. This balance is obtained by the plasticizer-to-resin ratio and the molecular weight of the resins. It has been adjusted to this optimum temperature based on environmental conditions and automobile population at various ambient temperatures. The frequency and severity of vehicle occupant injuries vs temperature ranges at the accident location have been studied (5), and the results confirm the selection of the maximum performance temperature and decreasing penetration resistance at temperature extremes. 

The dry-processed, peel-apart system (Fig. 8b) used for negative surprint apphcations (39,44) is analogous to the peel-apart system described for the oveday proofing apphcation (see Fig. 7) except that the photopolymer layer does not contain added colorant. The same steps ate requited to produce the image. The peel-apart system rehes on the adhesion balance that results after each exposure and coversheet removal of the sequentially laminated layer. Each peel step is followed by the apphcation of the appropriate process-colored toners on a tacky adhesive to produce the image from the negative separations. The mechanism of the peel-apart process has been described in a viscoelastic model (45—51) and is shown in Figure 8c. 

First, we need a common, unambiguous manner of writing how a laminate is specified to be laid-up, i.e., stacking-sequence notation. Then, quasi-isotropic, balanced, and hybrid laminates are defined. 

Although the word balanced is ambiguous and not definitive, the common meaning for a balanced laminate is a laminate in which all equal-thickness laminae at angles 0 other than 0° and 90° to the reference axis occur only in 0 pairs. The individual -n O and - 0 layers are not necessarily adjacent to each other. Note also that balanced laminates are required to be symmetric about the laminate middle surface, so there must be two + Q laminae and two - 0 laminae for each 0 pair. The behavioral characteristics of a balanced laminate are that shear-... 

Jonsson, P. Carman, R., and Wulff, F. (1990) Laminated sediments in the Baltic—a tool for evaluating nutrient mass balances. Ambio 19, 152-158. 

For most constructions and applications it is essential to face the reverse of the composite board with a balancing laminate similar in construction and moisture content to the decorative face laminate (failure to do this results invariably in differential movement of the faces and problems with bowing of the board). 

Barrier properties of organic polymers cannot equal metals and glass. Plastics offer so many other advantages that we often try to compromise or laminate to optimize overall balance of properties. It is known that molecular rigidity and crystallinity improve barrier... 

Ti. These can be combined with additional cocatalysts such as Ce, V, or W. With a large excess of ammonia, the selectivity to aniline is 87 to 90 percent at a phenol conversion of 98 percent. The byproducts are dipheny-lamine and carbazole. This technology is used at one plant in Ohio and at another plant in Japan. The economics of this process are favorable if low-cost phenol is available, and high-purity aniline is desired. Capital costs are low because benzene nitration is avoided. A typical process sketch along with a material balance is shown in Fig. 22.32. 

During fabrication using the MWR process, two forces act on the plastic injection (longitudinal) and rotation (hoop). The targeted balanced orientation is a result of those forces. As the product wall cools, additional high-magnitude, cross-laminated orientation is developed frozen in and throughout the wall thickness. Orientation on molecular... 

Equation 15.60 has to be coupled with the R time dependency coming out from a mass balance made up on the tri-laminate, donor, and receiver compartments. This mass balance reads... 

Glucocorticoids also have weak mineralocorti-coid effects as they have some affinity for miner-alocorticoid receptors. The laminitis-producing effects of the glucocorticoids have recently been linked to their ability to stimulate mineralocorti-coid receptors and produce changes in blood flow and electrolyte balance. 

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