Molecular print boards

Huskeens J, Deij MA, Reinhoudt DN (2002) Attachment of molecules at a molecular print-board by multiple host-guest interactions. Angew Chem Int Ed 41 4467-4471... 

Matsuwaki [5] prepared polyimide films, (V), having molecular orientation in the machine direction that were used in high-density mounting of flexible printed circuit boards. 

Halogen-free, flame-resistant, electronic printed circuit boards are made of EP with phosphorus compounds and heterocyclic nitrogen compotmds in the macro-molecular framework. (A. Franck [17]). 

Properties Liq. fumes in air m.w. 99.18 dens. 0.867 (0 C) b.p. 132-134 C flash pt. 48.2 F Precaution Very dangerous fire hazard Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of NOx Uses Intermediate for pharmaceuticals catalyst surface treatment agent for copper in printed circuit boards stabilizer for polyvinyl alcohol spinning sol ns. template for molecular sieves... 

The ° T1, in the Th decay series, and 7 " Bi in the decay series are used as indicators of the amount of their parents in the materials. Other members of each chain will also be present. Apart from these primordial nuclides (those surviving from the formation of the solar system), traces of anthropogenic (human-made) species are seen, such as Co in steels and Cs in molecular sieves. There are obvious reasons for some of these radioactive contents aluminium always has traces of uranium and thorium within it, and it is not unreasonable to expect in molecular sieves. However, relatively large amounts (compared to other materials in the list) of uranium and thorium daughter nuclides in epoxies and printed circuit boards are unexpected. Clearly, for some materials, there is ample scope for reducing the activity the detector sees by selecting a material with a lower activity. In a similar table to that above, Dassie (in a private communication) reported 4.3 Bq of Cs kg of Csl and 33 Bq of kg of Nal, considerably more than in Table 13.6 this latter would be a problem were it to be used for low level Compton suppression systems. 

One of the largest areas of use of nitrile rubber modified epoxy systems is in the printed circuit board area. A number of systems have been described that are composed of carboxyl-containing nitrile rubber such as Hycar 1072 mixed with epoxy resin. " The low molecular weight functionally terminated nitrile rubbers have also found significant application in this area. Other workers have found useful a system that combines a high molecular weight nitrile rubber with the liquid functionally terminated materials. Finally, other references describe the use of non carboxylated nitrile rubbers in circuit board applications. 2 ... 

The main engineering applications of phenolic resins are laminates, foundry and friction materials. In the electrical laminating field, phenolic resins are used to impregnate kraft paper for the production of insulation boards, printed circuits and transformer bushings. The resin used in this case is usually based on cresol or a substituted phenol and used in a water/alcohol solution. The properties obtained would be a function of the reinforcement and the characteristics of resin used, eg high or low molecular weight. 

Polyimide films are used in a variety of interconnect and packaging applications including passivation layers and stress buffers on integrated circuits and interlayer dielectrics in high density thin film interconnects on multi-chip modules and in flexible printed circuit boards. Performance differences between poly-imides are often discussed solely in terms of differences in chemistry, wiAout reference to the anisotropic nature of these films. Many of the polyimide properties important to the microelectronics industry are influenced not only by the polymer chemistry but also by the orientation and structure. Properties such as the linear coefficient of thermal expansion (CTE), dielectric constant, modulus, strength, elongation, stress and thermal conductivity are affected by molecular orientation. To a lesser extent, these properties as well as properties such as density and volumetric CTE are also influenced by crystdlinity (molecular ordering). 

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