Epoxy substrates

The MABR-promoted rearrangement, when applied to optically active epoxy substrates, has been shown to proceed with rigorous transfer of the epoxide chirality. Accordingly, used in combination with the Sharpless asymmetric epoxidation of allylic alcohols,5 this rearrangement represents a new approach to the synthesis of various... 

As the epoxy/substrate bond is mechanical, not chemical, it is absolutely necessary that the surface be clean, dry, oil-free, and have a recommended surface profile. Surface preparation is one of the most important factors in performance of any coating. It includes ... 

Various substrate surface treatments suggested for use with a common epoxy-substrate joint and service environment combinations are discussed in this chapter. Surface preparation processes for a range of specific substrates and detailed process specifications are provided in App. F. The reader is also directed to several excellent texts that provide prebond surface treatment recipes and discuss the basics of surface preparation, the importance of contamination or weak boundary layers, and specific processes for adhesive systems other than epoxy.1,2,3... 

Fig. 7 Development of fatigue cracks in an epoxy/glass contact under gross slip condition (1Hz, displacement amplitude 60 xm) (from [97]). White arrows indicate the occurrence of crack initiation and propagation at the edge of the contact under the action of tensile stresses. The lateral contact stiffness, K, is essentially a measurement of the elastic response of the epoxy substrate within the contact zone. Brittle crack propagation is associated to a drop in stiffness due to the additional accommodation of the imposed displacement provided by crack opening mechanisms...

Such approaches have been applied to the contact cracking problems under sliding conditions in order to assess the values of the stress intensity factors K and Ku under cyclic tangential loading. As an example, Fig. 18 shows the numerical simulations corresponding to a cracked epoxy substrate. 

Epoxy resins based on glycidylation of bisphenols, cresol and phenol novolacs, polycarboxylic acids, polyols, amines, and aminophenols have been long known. Epoxidized linear and cyclic olefins have also been used as specialty epoxy resins. More recently, glycidylated heterocycles have been introduced, initially as specialty resins promising improved resistance to weathering. One heterocycle in particular, the hydantoin ring, has become of particular interest as an epoxy substrate (J ). 

The requirements for advanced military MLBs are shown in Table I. One of the major problems of using leadless ceramic chip carriers in advanced avionics (VHSIC and VLSI) applications is the mismatch between the CTE of alumina chip carriers (6.4 ppm/°C) or silicon (3 ppm/°C) and conventional glass/epoxy substrates (12 to 17 ppm/°C). This mismatch results in work-hardening and cracking of solder joints which attach the devices to the substrate. 

On the other hand, in the case of anion type little substituent effect on inhibiting the photofading of on epoxy substrate was observed, as shown in Fig. 10. These results are consistent with the above prediction from evaluation k and k in solution. An amount of 10-15% of nickel complexes is necessary at least to get good lightfastness of the optical disc using a cyanine dye, from analogy of Figures 9 and 10. 

External corrosion of the cars is primarily because of atmospheric exposure. While corrosion damage is still a concern, car appearance takes precedence therefore, the car manufacturers/lessees often choose to apply an exterior paint system to address the aesthetic issues. The paint systems are typically direct-to-metal (DTM) epoxy or epoxy with a urethane coat. This epoxy substrate adds protection against ultraviolet radiation. 

Sprinkle the mineral grains over the epoxy film, making sure by stereomicroscope or hand-lens examination that only the bottom side of the particles is in contact with the epoxy substrate. Particles ranging from approximately 74 to 149 pm are recommended for this type of preparation. 

Scanning Electron Microscopy. The epoxy substrates were analyzed in a Gemini 1530 PEG SEM (Zeiss, Gemany) at 3-5 kV, at room temperature, gold-coated as described above. 

The cable test piece consists of ten untwisted strands of btu e copper wire moimted on a glass fiber-filled epoxy substrate with holes to allow flux residues to pass from the underside of the board to contaminate the cables on the topside during wave soldering. A DC power supply poleuizes the test pieces anodically with respect to the copper conductor track on the laminate. 

B.iii. Palladium(0)-Catalyzed Reaction of Various Epoxy Substrates... 

Table 10.4 Improvements in lap shear strength on epoxy substrates with ROMP-based adhesion promoters.

TABLE 61.10 Properties of Thin Glass/Epoxy Substrate... 

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