Polymer networks experimental details

These experimental results give only a first insight into the fascinating properties of these very new l.c. elastomers. Further detailed studies have to come to a more profound understanding of the interactions of polymer networks and l.c. order of the mesogenic side chains. The exceptional photoelastic and thermoelastic properties promise to open up a new scientific and technological field of interest. 

The approach presented here was first developed for the dielectric relaxation of regular mesh-like polymer networks built from macromolecules with longitudinal dipole moments [30], and was later applied to disordered polymer networks [31,32]. Its key assiunption, namely the absence of any correlations in the orientations of the dipole moments of the different GGS bonds is obviously rather simphfied. However, it leads, as shown above, to simple analytical expressions for the dielectric susceptibility, a very important dynamical quantity in experimental studies of polymers we can now analyze it in great detail for particular GGS systems of interest. Another advantage of this model arises from the fact that one has a straightforward correspondence between the mechanical and the dielectric relaxation forms. From the expressions for the storage and loss modulus, Eqs. 20 and 21, and from those for the dielectric susceptibility Ae, Eqs. 41 and Eq. 42, one sees readily that [31]... 

In the following we focus our attention to the most complete study of birefringence so far [74] instead of completely reviewing all research on polymer dispersions in liquid crystals. We show how one can, with a rather simple experimental method combined with the phenomenological description of liquid crystalline ordering, point out important details about the polymer network structure on both the micro and macro levels. 

Table 1. Experimental Details for the Preparation of Polymer Networks 5a-e.

Thus it is clear that the understanding of physical models for reactive processed polymers is less mature than that for network polymer models. However, it is also very clear that useful models that characterize both network and reactively processed polymers require concurrent chemical and physical models. The experimental techniques and models for network and reactive polymers will now be examined in detail in the remaining chapters. 

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