Macromolecular packing direction

Many variations on this theme that allow repetitive, direct injection and chromatographic analysis of untreated sample matrices including tissue homogenates, milk, plasma, and saliva (107-112) have appeared since the original publication. These packings have been described generically as restricted-access media because they are generally characterized by a limited accessibility of macromolecular compounds to the adsorption sites of the porous supports. 

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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