Rearrangement of polymer chains

At 200°F (about 90°C), deck boards would further accelerate the rearrangement of polymer chains in 4 = 64 times faster than that at 60°C (see above), which is in about 9 h. This is a common annealing time period for WPC deck boards. 

Despite the abovementioned quasi-equilibrium character of the cyclic voltam-metric curves, a pronounced hysteresis (i.e., a considerable difference between the anodic and cathodic peak potentials) appears. Slow heterogeneous electron transfer, effects of local rearrangements of polymer chains, slow mutual transformations of various electronic species, a first-order phase transition due to an S-shaped energy diagram (e.g., due to attractive interactions between the electronic and ionic... 

Slow heterogeneous electron transfer, effects of local rearrangements of polymer chains, slow mutual transformations of... 

Experiments pertaining to a new system for the application of bromine to flame retardant polypropylene and foamed polystyrene are described. The FR compound, ammonium bromide, is formed in the amorphous regions of the polymer phase by the interaction of bromine sorbed on the polymer and ammonia, sorbed subsequently. Gaseous nitrogen which is also produced, expands and brings about the rearrangement of the chains to produce a porous structure. The ammonium bromide produced is finely divided and imparts FR properties to the polymer. 

Polymer Adsorption. A review of the theory and measurement of polymer adsorption points out succinctly the distinquishing features of the behavior of macromolecules at solid - liquid interfaces (118). Polymer adsoiption and desorption kinetics are more complex than those of small molecules, mainly because of the lower diffusion rates of polymer chains in solution and the "rearrangement" of adsorbed chains on a solid surface, characterized by slowly formed, multi-point attachments. The latter point is one which is of special interest in protein adsoiption from aqueous solutions. In the case of proteins, initial adsoiption kinetics may be quite rapid. However, the slow rearrangement step may be much more important in terms of the function of the adsorbed layer in natural processes, such as thrombogenesis or biocorrosion / biofouling caused by cell adhesion. 

The absorption of vapor by the surface layer of a polymer film will necessitate some rearrangement of the polymer molecules, and it is reasonable to consider that the more active the segmental motion of polymer chains becomes, the more rapidly the surface layer takes up penetrant to the equilibrium concentration. This implies that the surface concentration gradually approaches an equilibrium value at a finite rate which may depend upon the rate of relaxation motions of the polymer molecules. Crank and Park (1951) expressed this situation by the equation ... 

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