Subject segmental mobility

Sternstein and Ongchin (28) considered that if cavitation occurs in crazes the criterion for crazing initiation should include the dilative stress component. They proposed the criterion to fit the experimental data for surface craze initiation in PMMA when the polymer is subjected to biaxial tension. The segmental mobility of the polymer will increase due to dilative stresses, thus provoking cavitation and the orientation of molecular segments along the maximum stress direction. 

Chlorinated polyvinyl chloride has the higher glass transition temperature because the added chlorines restrict chain segment mobility when subjected to thermal energy. 

The general area of adhesion and adhesion science has been one of the most important application areas identified thus far in a variety of applications for the subject imide-siloxane copolymers [74-82]. Many references in the patent literature [83-90] have been found that relate to the utilization of the copolymers in various important applications such as die attach adhesives, encapsulants, interphase agents, etc. It would appear that the combination of very good thermal stability, coupled with the adhesive bonding capabilities provided by the siloxane mobile segment, has attracted a great deal of attention and will be the... 

Fig. 6. Schematic drawing of the ion-hopping mechanism. Inner circles represent multi-plets containing several ion pairs, indicated by smaller black and white circles. The shaded area represents restricted mobility regions. The thicker curved lines are jwlymer chain segments, which are subjected to move from one multiplet to the other.

A model of filled polymers was proposed [12], consisting of two layers surrounding the filler particle. The first layer is near the phase border where all the macromolecules are subjected to the action of the field of surface forces. This layer includes both the adsorption part where macromolecular segments are in direct contact with the surface and more remote segments that are not bound directly. Filled melt may also be represented by the same model. However, the layers differ in ratio of the melt components due to selective interaction with the surface. Also, all the factors determining properties of the surface layers in filled polymers are operative namely, the molecular conformations in the surface layer, packing densities, molecular mobility, and so on are different from those in the bulk of a melt [6]. 

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