Electronic applications of polymers

Now is numerically equal to the molar refraction R which is an additive property. It has been shown that R is a property which can be calculated by adding the refractions of various electron groups. Six values for such partial molar refractions are given in Table 6.3. 

The calculated value for polypropylene (2.27) is also within the range of observed values (2.15-2.30) but the calculated value for PTFE (1.7) is less than the observed values of about 2.0. 

The dipole moment of a molecule is another additive property since it arises from the difference in electronegativity of two atoms connected by a double bond. It should therefore be possible to associate a dipole moment with every linkage. Eucken and Meyer have suggested the following moments for various linkages (in units of 10 e.s.cm) 

In each case the left-hand atom of the pair as written is the least electronegative. Since dipole moments have direction as well as magnitude it is necessary to add the moments of each bond vertically. For this reason the individual dipole moments cancel each other out in carbon tetrachloride but only partially in chloroform. In other molecules, such as that of water, it is necessary to know the bond angle to calculate the dipole moment. Alternatively since the dipole moment of the molecule is measurable the method may be used to compute the bond angle. 

Computation of the dipole moment and hence the dielectric constant in polymers becomes complex but consideration of the bond dispositions allows useful qualitative prediction to be made. 

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Report 22 Electronics Applications of Polymers, M.T.Goosey, Plessey Research (Caswell) Ltd. 

Report 93 Advances in Thermoforming, J.L. Throne, Sherwood Technologies Inc. Report 120 Electronics Applications of Polymers II, M.T. Goosey, Shipley Ronal. 

Electronics Applications of Polymers II, M.T. Goosey, Shipley Ronal. 

Plastics have played critical roles in every aspect of the ongoing revolution in electronics [38-41]. They are now found in everything from computer housings and floppy discs to encapsulants and connectors. The wide range of electrical and electronic applications of polymers includes wire and cable coverings, housing adhesives, printed circuit boards and insulators (Table 7.1). 

To well understand the characteristics of polymers for electronic applications, the general synthetic methods are described in Chapter 2, and the relationships between structure and property are then presented in Chapter 3. The necessity to introduce a second phase into polymers is also carefully discussed on the basis of solving the remaining challenges of bare polymers in Chapter 4. The representative electronic applications of polymers are highlighted in the following chapters. 

Electronic applications of polymers are well established, but a variety of new uses, based on polymer electronic properties, are now emerging and give promise of future technological advantages. Three opportunities are suggested for this area ... 

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