Phase separation collection mechanisms

To describe the deformation behaviour of semi-crystalline polymers Strobl et al. (Hong, 2004, 2006) separated different mechanisms of stress transfer with respect to amorphous and crystalline units. They distinguished between four phases onset of local block sliding (1), collective motion slightly below the yield pwint (2), disassociation of crystalline blocks and transformation into fibrils (3) and the start of disentangling (4). 

Although thermoplastics and thermoplastic composites are potentially easy and economical to recycle, in practice there are some impediments to the implementation of widespread recycling. The main one is that the used materials must be collected, separated and cleaned economically. This is feasible in some instances but often it is not. In general, polymers are immiscible with one another, and, if melt processed as a mixture, the result is phase separation to give domains of one polymer in the other. This morphology leads to rather poor mechanical properties. Therefore, there are efforts to find better separation techniques in order to avoid the problem or to use compatibilisers [152] that lower the interfacial tension, improve the adhesion of the two phases, and encourage smaller domains of the disperse phase. 

Water collection from fog is a system to extract a discrete phase from a continuous phase. There is another case where the extraction of a discrete phase from a continuous phase has practical application value, which is oil/water separation. The separation device mentioned above was founded on a mesh surface, and the lowest-sized oil droplets that could be collected strongly depended on the size of the mesh in use. Li et al. prepared a separation device that could separate oil droplets much smaller in size than those separated by the mesh separator. The idea is similar to the fog collection mechanism, i.e., the oil droplets are captured and transported by the spine arrays. PDMS arrays on a planar substrate were prepared via puncturing mold replication. As shown in Figure 16.9B, since the oil droplets are carried by the water flow and subjected to the tilted PDMS cone arrays, they collide on the cones, accumulate, and are transported to the cone base via the Laplace pressure difference. Using the separation apparatus shown in Figure 16.9B, the oil droplets can be continuously separated until clean water is obtained. 

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