Crystalline bridges

From the foregoing it is clear that indentation anisotropy is a consequence of high molecular orientation within highly oriented fibrils and microfibrils coupled with a preferential local elastic recovery of these rigid structures. We wish to show next that the influence of crystal thickness on AMH is negligible. The latter quantity is independent on 1 and is only correlated to the number of tie molecules and inter-crystalline bridges of the oriented molecular network. 

In POM a careful examination of WAXS and SAXS measurements on a wide range of drawn samples, showed that the average crystal length, even for the highest modulus material was only comparable with the long period Again it must be concluded that the crystalline bridge model is not applicable. 

A cohesion (by cohesion forces in trot supersaturated solutiotrs or by crystalline bridges in supersaturated solutiotrs)... 

The equation = 3.67 G x is only valid when all MSMPR assumptions are fulfilled (besides other no attrition and no agglomeration). However, in the case a < 0.1 the mean crystal size L q and especially the maximum ciystal size with max 2 Z50 is controlled by attrition, see Fig. 8.5-1 below. On the other hand, agglomeration can be the dominant process parameter for a > 10. Nanocrystals can only be produced if the relative supersaturation is high with the result of high rates of activated nucleation and by the avoidance of agglomeration. Aggregates which are formed under low or zero supersaturation do not possess crystalline bridges and can be redispersed. 

The selection of equipment depends on the material and its properties 16], including particle shape, size, size distribution, and compaction force needed. For compaction the general rule is that the larger particles should be accompanied by fines to fill in the larger pores or open space. The van der Waals attraction forces are often not sufficient to produce flake with adequate strength. Sometimes binders are added, or creation of crystalline bridges is used. 

The temperature of the product wAien placed in storage is another important factor having an effect on caldng tendency [97,98,99,100]. Higher temperatures increase the chemical reactivity, such as the reevaporation of water, w ich results in recrystallization and formation of solid crystalline bridges. Addition-... 

Deformation Mechanism. The deformation mechanism has been studied in more detail for the case of semicrystalline polymers, polyethylene, in particular (1,2). There exist a number of models explaining the evolution of polymer structure at high draws. The models can be subdivided into two categories (2), namely, the microfiber plus the tie molecule model, as proposed by Peterlin and co-workers and the extended chain model, which is similar to Ward s crystalline bridge model. 

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