Chain polymer, regions

Osmotic pressures of chain polymers in the semi-dilute region (2-20% v) are appreciable and no longer molecular-weight dependent. At 50% v, osmotic pressures of chain polymers are of the order of 100 atm, far greater than any transmembrane pressure used in ultrafiltration T). 

These materials may also be included in guest-host or side-chain polymer systems, similar to those exploited in electro-optic polymer studies. This would improve processability for waveguide devices. The coefficients quoted above show that such a doped polymer could function at reasonable power levels and waveguide dimensions with an active region 1-2 mm long. 

To construct the model, it has been assumed that the amorphous polymer regions posses an approximately paracrystalline order with chain bundles locally parallel. A penetrant molecule may diffuse through the matrix of the polymer by two modes of motion, Fig. 5-2. 

Figure 8.7 Capillary gel electrophoresis profiles of collagen chains and chain polymers in 4% polyacrylamide 75 mm i.d. capillary, 45 cm long (35 cm to the detector). Tris-glycine buffer, pH 8.8, 10 kV. Detection by UV absorbance at 220 nm. (A) Complete sample. (B) a-Region proteins sampled from a preceding slab gel run. (C) As in (A), but /3-region excised from the slab gel. The appearance of the gel separation is shown at top (cathode on the right side of the gel). (From Deyl and MikSik, 1995, with permission.)...

Miller et al. have shown that the variation of/for semirigid-chain polymers does not change the general form of the diagram. However, with increasing of flexibility a narrow heterophase region is shifted toward higher concentrations and considerably broadened. 

Figure 16 shows a schematic diagram of phase transformations for rigid-chain polymers separated from isotropic solutions by introducing a nonsolvent into the system (this is a usual method of obtaining fibres and films) (cf. >). The initial isotropic solution with the polymer concentration V2 and the value of the Huggins-Flory parameter is in the monophase region. The critical concentration of the transition into liquid crystalline state for this system is v. When a nonsolvent is introduced, i.e. when x is increased up to the value >0.5 (x ), two routes of the phase transition... 

Branched-chain polymers exhibit more tangled arrangements they are less likely to form crystalline regions and tend to be weaker, less dense materials. 

For blends of long chain polymers (large N) the critical region is very small and the mean-field theory applies at nearly all temperatures. 

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